From: unknown Date: Wed, 12 Feb 2014 23:13:24 +0000 (-0800) Subject: Finish rework of bt_deletekey, w/bug fixes X-Git-Url: https://pd.if.org/git/?p=btree;a=commitdiff_plain;h=a04729a555271c5cf5eef4f0c4c49430634f9f38 Finish rework of bt_deletekey, w/bug fixes --- diff --git a/threads2h.c b/threads2h.c index f1f774d..bb8c236 100644 --- a/threads2h.c +++ b/threads2h.c @@ -1,5 +1,6 @@ // btree version threads2h pthread rw lock version -// 30 JAN 2014 +// with reworked bt_deletekey code +// 12 FEB 2014 // author: karl malbrain, malbrain@cal.berkeley.edu @@ -49,6 +50,7 @@ REDISTRIBUTION OF THIS SOFTWARE. #include #include +#include typedef unsigned long long uid; @@ -169,14 +171,19 @@ typedef struct { // It is immediately followed // by the BtSlot array of keys. -typedef struct Page { +typedef struct BtPage_ { uint cnt; // count of keys in page uint act; // count of active keys uint min; // next key offset - unsigned char bits; // page size in bits - unsigned char lvl:7; // level of page + unsigned char bits:7; // page size in bits + unsigned char free:1; // page is on free list + unsigned char lvl:4; // level of page + unsigned char kill:1; // page is being killed unsigned char dirty:1; // page has deleted keys + unsigned char posted:1; // page fence is posted + unsigned char goright:1; // page is being killed, continue to right unsigned char right[BtId]; // page number to right + unsigned char fence[256]; // page fence key } *BtPage; // The memory mapping pool table buffer manager entry @@ -194,10 +201,19 @@ typedef struct { #endif } BtPool; +// The loadpage interface object + +typedef struct { + uid page_no; // current page number + BtPage page; // current page pointer + BtPool *pool; // current page pool + BtLatchSet *latch; // current page latch set +} BtPageSet; + // structure for latch manager on ALLOC_page typedef struct { - struct Page alloc[2]; // next & free page_nos in right ptr + struct BtPage_ alloc[2]; // next & free page_nos in right ptr BtSpinLatch lock[1]; // allocation area lite latch ushort latchdeployed; // highest number of latch entries deployed ushort nlatchpage; // number of latch pages at BT_latch @@ -215,7 +231,6 @@ typedef struct { uint seg_bits; // seg size in pages in bits uint mode; // read-write mode #ifdef unix - char *pooladvise; // bit maps for pool page advisements int idx; #else HANDLE idx; @@ -240,13 +255,8 @@ typedef struct { BtPage cursor; // cached frame for start/next (never mapped) BtPage frame; // spare frame for the page split (never mapped) BtPage zero; // page frame for zeroes at end of file - BtPage page; // current page - uid page_no; // current page number uid cursor_page; // current cursor page number - BtLatchSet *set; // current page latch set - BtPool *pool; // current page pool unsigned char *mem; // frame, cursor, page memory buffer - int parent; // last loadpage was from a parent level int found; // last delete or insert was found int err; // last error } BtDb; @@ -271,9 +281,7 @@ extern uint bt_startkey (BtDb *bt, unsigned char *key, uint len); extern uint bt_nextkey (BtDb *bt, uint slot); // internal functions -BTERR bt_splitpage (BtDb *bt, BtPage page, BtPool *pool, BtLatchSet *set, uid page_no); -uint bt_cleanpage(BtDb *bt, BtPage page, uint amt, uint slot); -BTERR bt_mergeleft (BtDb *bt, BtPage page, BtPool *pool, BtLatchSet *set, uid page_no, uint lvl); +BTERR bt_removepage (BtDb *bt, BtPageSet *set, uint lvl, unsigned char *pagefence); // manager functions extern BtMgr *bt_mgr (char *name, uint mode, uint bits, uint poolsize, uint segsize, uint hashsize); @@ -319,8 +327,8 @@ extern uint bt_tod (BtDb *bt, uint slot); // one with two keys. // Deleted keys are marked with a dead bit until -// page cleanup The fence key for a node is always -// present, even after deletion and cleanup. +// page cleanup The fence key for a node is +// present in a special array. // Groups of pages called segments from the btree are optionally // cached with a memory mapped pool. A hash table is used to keep @@ -335,12 +343,13 @@ extern uint bt_tod (BtDb *bt, uint slot); // Page 0 is dedicated to lock for new page extensions, // and chains empty pages together for reuse. -// The ParentModification lock on a node is obtained to prevent resplitting -// or deleting a node before its fence is posted into its upper level. +// The ParentModification lock on a node is obtained to serialize posting +// or changing the fence key for a node. // Empty pages are chained together through the ALLOC page and reused. -// Access macros to address slot and key values from the page +// Access macros to address slot and key values from the page. +// Page slots use 1 based indexing. #define slotptr(page, slot) (((BtSlot *)(page+1)) + (slot-1)) #define keyptr(page, slot) ((BtKey)((unsigned char*)(page) + slotptr(page, slot)->off)) @@ -556,19 +565,12 @@ void bt_releaseread(BtLatch *latch) #endif } -void bt_initlockset (BtLatchSet *set, int reuse) +void bt_initlockset (BtLatchSet *set) { #ifdef unix pthread_rwlockattr_t rwattr[1]; - if( reuse ) { - pthread_rwlock_destroy (set->readwr->lock); - pthread_rwlock_destroy (set->access->lock); - pthread_rwlock_destroy (set->parent->lock); - } - pthread_rwlockattr_init (rwattr); - pthread_rwlockattr_setkind_np (rwattr, PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP); pthread_rwlockattr_setpshared (rwattr, PTHREAD_PROCESS_SHARED); pthread_rwlock_init (set->readwr->lock, rwattr); @@ -682,7 +684,7 @@ BtLatchSet *set; #else _InterlockedIncrement16 (&set->pin); #endif - bt_initlockset (set, 0); + bt_initlockset (set); bt_latchlink (bt, hashidx, victim, page_no); bt_spinreleasewrite (bt->mgr->latchmgr->table[hashidx].latch); return set; @@ -747,7 +749,6 @@ BtLatchSet *set; #else _InterlockedIncrement16 (&set->pin); #endif - bt_initlockset (set, 1); bt_latchlink (bt, hashidx, victim, page_no); bt_spinreleasewrite (bt->mgr->latchmgr->table[hashidx].latch); bt_spinreleasewrite (set->busy); @@ -790,7 +791,6 @@ uint slot; free (mgr->pool); free (mgr->hash); free (mgr->latch); - free (mgr->pooladvise); free (mgr); #else FlushFileBuffers(mgr->idx); @@ -829,7 +829,6 @@ BtLatchMgr *latchmgr; off64_t size; uint amt[1]; BtMgr* mgr; -BtKey key; int flag; #ifndef unix @@ -923,7 +922,6 @@ SYSTEM_INFO sysinfo[1]; mgr->pool = calloc (poolmax, sizeof(BtPool)); mgr->hash = calloc (hashsize, sizeof(ushort)); mgr->latch = calloc (hashsize, sizeof(BtSpinLatch)); - mgr->pooladvise = calloc (poolmax, (mgr->poolmask + 8) / 8); #else mgr->pool = GlobalAlloc (GMEM_FIXED|GMEM_ZEROINIT, poolmax * sizeof(BtPool)); mgr->hash = GlobalAlloc (GMEM_FIXED|GMEM_ZEROINIT, hashsize * sizeof(ushort)); @@ -970,13 +968,12 @@ SYSTEM_INFO sysinfo[1]; latchmgr->alloc->bits = mgr->page_bits; for( lvl=MIN_lvl; lvl--; ) { - slotptr(latchmgr->alloc, 1)->off = mgr->page_size - 3; + slotptr(latchmgr->alloc, 1)->off = offsetof(struct BtPage_, fence); bt_putid(slotptr(latchmgr->alloc, 1)->id, lvl ? MIN_lvl - lvl + 1 : 0); // next(lower) page number - key = keyptr(latchmgr->alloc, 1); - key->len = 2; // create stopper key - key->key[0] = 0xff; - key->key[1] = 0xff; - latchmgr->alloc->min = mgr->page_size - 3; + latchmgr->alloc->fence[0] = 2; + latchmgr->alloc->fence[1] = 0xff; + latchmgr->alloc->fence[2] = 0xff; + latchmgr->alloc->min = mgr->page_size; latchmgr->alloc->lvl = lvl; latchmgr->alloc->cnt = 1; latchmgr->alloc->act = 1; @@ -1169,12 +1166,9 @@ int flag; #ifdef unix flag = PROT_READ | ( bt->mgr->mode == BT_ro ? 0 : PROT_WRITE ); - pool->map = mmap (0, (bt->mgr->poolmask+1) << bt->mgr->page_bits, flag, MAP_SHARED, bt->mgr->idx, off); + pool->map = mmap (0, (bt->mgr->poolmask+1) << bt->mgr->page_bits, flag, MAP_SHARED | MAP_POPULATE, bt->mgr->idx, off); if( pool->map == MAP_FAILED ) return bt->err = BTERR_map; - - // clear out madvise issued bits - memset (bt->mgr->pooladvise + pool->slot * ((bt->mgr->poolmask + 8) / 8), 0, (bt->mgr->poolmask + 8)/8); #else flag = ( bt->mgr->mode == BT_ro ? PAGE_READONLY : PAGE_READWRITE ); pool->hmap = CreateFileMapping(bt->mgr->idx, NULL, flag, (DWORD)(limit >> 32), (DWORD)limit, NULL); @@ -1197,17 +1191,6 @@ uint subpage = (uint)(page_no & bt->mgr->poolmask); // page within mapping BtPage page; page = (BtPage)(pool->map + (subpage << bt->mgr->page_bits)); -#ifdef unix - { - uint idx = subpage / 8; - uint bit = subpage % 8; - - if( ~((bt->mgr->pooladvise + pool->slot * ((bt->mgr->poolmask + 8)/8))[idx] >> bit) & 1 ) { - madvise (page, bt->mgr->page_size, MADV_WILLNEED); - (bt->mgr->pooladvise + pool->slot * ((bt->mgr->poolmask + 8)/8))[idx] |= 1 << bit; - } - } -#endif return page; } @@ -1415,10 +1398,8 @@ void bt_unlockpage(BtLock mode, BtLatchSet *set) uid bt_newpage(BtDb *bt, BtPage page) { -BtLatchSet *set; -BtPool *pool; +BtPageSet set[1]; uid new_page; -BtPage pmap; int reuse; // lock allocation page @@ -1429,12 +1410,13 @@ int reuse; // else allocate empty page if( new_page = bt_getid(bt->mgr->latchmgr->alloc[1].right) ) { - if( pool = bt_pinpool (bt, new_page) ) - pmap = bt_page (bt, pool, new_page); + if( set->pool = bt_pinpool (bt, new_page) ) + set->page = bt_page (bt, set->pool, new_page); else return 0; - bt_putid(bt->mgr->latchmgr->alloc[1].right, bt_getid(pmap->right)); - bt_unpinpool (pool); + + bt_putid(bt->mgr->latchmgr->alloc[1].right, bt_getid(set->page->right)); + bt_unpinpool (set->pool); reuse = 1; } else { new_page = bt_getid(bt->mgr->latchmgr->alloc->right); @@ -1450,7 +1432,6 @@ int reuse; if ( !reuse && bt->mgr->poolmask > 0 && (new_page & bt->mgr->poolmask) == 0 ) { // use zero buffer to write zeros - memset(bt->zero, 0, bt->mgr->page_size); if ( pwrite(bt->mgr->idx,bt->zero, bt->mgr->page_size, (new_page | bt->mgr->poolmask) << bt->mgr->page_bits) < bt->mgr->page_size ) return bt->err = BTERR_wrt, 0; } @@ -1458,13 +1439,13 @@ int reuse; // bring new page into pool and copy page. // this will extend the file into the new pages. - if( pool = bt_pinpool (bt, new_page) ) - pmap = bt_page (bt, pool, new_page); + if( set->pool = bt_pinpool (bt, new_page) ) + set->page = bt_page (bt, set->pool, new_page); else return 0; - memcpy(pmap, page, bt->mgr->page_size); - bt_unpinpool (pool); + memcpy(set->page, page, bt->mgr->page_size); + bt_unpinpool (set->pool); #endif // unlock allocation latch and return new page no @@ -1474,142 +1455,160 @@ int reuse; // find slot in page for given key at a given level -int bt_findslot (BtDb *bt, unsigned char *key, uint len) +int bt_findslot (BtPageSet *set, unsigned char *key, uint len) { -uint diff, higher = bt->page->cnt, low = 1, slot; -uint good = 0; +uint diff, higher = set->page->cnt, low = 1, slot; - // if no right link // make stopper key an infinite fence value - // by setting the good flag - if( bt_getid (bt->page->right) ) + if( bt_getid (set->page->right) ) higher++; - else - good++; - // low is the next candidate. + // low is the lowest candidate. // loop ends when they meet - // if good, higher is already + // higher is already // tested as .ge. the given key. while( diff = higher - low ) { slot = low + ( diff >> 1 ); - if( keycmp (keyptr(bt->page, slot), key, len) < 0 ) + if( keycmp (keyptr(set->page, slot), key, len) < 0 ) low = slot + 1; else - higher = slot, good++; + higher = slot; } + if( higher <= set->page->cnt ) + return higher; + + // if leaf page, compare against fence value + // return zero if key is on right link page + // or return slot beyond last key + + if( set->page->lvl || keycmp ((BtKey)set->page->fence, key, len) < 0 ) + return 0; - return good ? higher : 0; + return higher; } // find and load page at given level for given key // leave page rd or wr locked as requested -int bt_loadpage (BtDb *bt, unsigned char *key, uint len, uint lvl, uint lock) +int bt_loadpage (BtDb *bt, BtPageSet *set, unsigned char *key, uint len, uint lvl, uint lock) { uid page_no = ROOT_page, prevpage = 0; -BtLatchSet *set, *prevset; uint drill = 0xff, slot; +BtLatchSet *prevlatch; uint mode, prevmode; BtPool *prevpool; -int parent = 1; // start at root of btree and drill down - bt->set = NULL; - do { // determine lock mode of drill level mode = (lock == BtLockWrite) && (drill == lvl) ? BtLockWrite : BtLockRead; - bt->set = bt_pinlatch (bt, page_no); - bt->page_no = page_no; + set->latch = bt_pinlatch (bt, page_no); + set->page_no = page_no; // pin page contents - if( bt->pool = bt_pinpool (bt, page_no) ) - bt->page = bt_page (bt, bt->pool, page_no); + if( set->pool = bt_pinpool (bt, page_no) ) + set->page = bt_page (bt, set->pool, page_no); else return 0; // obtain access lock using lock chaining with Access mode if( page_no > ROOT_page ) - bt_lockpage(BtLockAccess, bt->set); + bt_lockpage(BtLockAccess, set->latch); // release & unpin parent page if( prevpage ) { - bt_unlockpage(prevmode, prevset); - bt_unpinlatch (prevset); + bt_unlockpage(prevmode, prevlatch); + bt_unpinlatch (prevlatch); bt_unpinpool (prevpool); prevpage = 0; } // obtain read lock using lock chaining - bt_lockpage(mode, bt->set); + bt_lockpage(mode, set->latch); if( page_no > ROOT_page ) - bt_unlockpage(BtLockAccess, bt->set); + bt_unlockpage(BtLockAccess, set->latch); // re-read and re-lock root after determining actual level of root - if( bt->page->lvl != drill) { - if ( bt->page_no != ROOT_page ) + if( set->page->lvl != drill) { + if ( set->page_no != ROOT_page ) return bt->err = BTERR_struct, 0; - drill = bt->page->lvl; + drill = set->page->lvl; if( lock == BtLockWrite && drill == lvl ) { - bt_unlockpage(mode, bt->set); - bt_unpinlatch (bt->set); - bt_unpinpool (bt->pool); + bt_unlockpage(mode, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); continue; } } + prevpage = set->page_no; + prevlatch = set->latch; + prevpool = set->pool; + prevmode = mode; + + // if page is being deleted and we should continue right + + if( set->page->kill && set->page->goright ) { + page_no = bt_getid (set->page->right); + continue; + } + + // otherwise, wait for deleted node to clear + + if( set->page->kill ) { + bt_unlockpage(mode, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); + page_no = ROOT_page; + prevpage = 0; + drill = 0xff; +#ifdef unix + sched_yield(); +#else + SwitchToThread(); +#endif + continue; + } + // find key on page at this level // and descend to requested level - if( slot = bt_findslot (bt, key, len) ) { + if( slot = bt_findslot (set, key, len) ) { if( drill == lvl ) - return bt->parent = parent, slot; + return slot; + + if( slot > set->page->cnt ) + return bt->err = BTERR_struct; - while( slotptr(bt->page, slot)->dead ) - if( slot++ < bt->page->cnt ) + while( slotptr(set->page, slot)->dead ) + if( slot++ < set->page->cnt ) continue; - else { - page_no = bt_getid(bt->page->right); - parent = 0; - goto slideright; - } + else + return bt->err = BTERR_struct, 0; - page_no = bt_getid(slotptr(bt->page, slot)->id); - parent = 1; + page_no = bt_getid(slotptr(set->page, slot)->id); drill--; + continue; } // or slide right into next page - else { - page_no = bt_getid(bt->page->right); - parent = 0; - } - - // continue down / right using overlapping locks - // to protect pages being split. - -slideright: - prevpage = bt->page_no; - prevpool = bt->pool; - prevset = bt->set; - prevmode = mode; + page_no = bt_getid(set->page->right); } while( page_no ); @@ -1619,189 +1618,287 @@ slideright: return 0; // return error } -// remove empty page from the B-tree -// by pulling our right node left over ourselves +// drill down fixing fence values for left sibling tree -// call with bt->page, etc, set to page's locked parent -// returns with page locked. +// call with set write locked +// return with set unlocked & unpinned. -BTERR bt_mergeright (BtDb *bt, BtPage page, BtPool *pool, BtLatchSet *set, uid page_no, uint lvl, uint slot) +BTERR bt_fixfences (BtDb *bt, BtPageSet *set, unsigned char *newfence) { -BtLatchSet *rset, *pset, *rpset; -BtPool *rpool, *ppool, *rppool; -BtPage rpage, ppage, rppage; -uid right, parent, rparent; -BtKey ptr; -uint idx; +unsigned char oldfence[256]; +BtPageSet next[1]; +int chk; + + memcpy (oldfence, set->page->fence, 256); + + while( !set->page->kill && set->page->lvl ) { + next->page_no = bt_getid(slotptr(set->page, set->page->cnt)->id); + next->latch = bt_pinlatch (bt, next->page_no); + bt_lockpage (BtLockParent, next->latch); + bt_lockpage (BtLockAccess, next->latch); + bt_lockpage (BtLockWrite, next->latch); + bt_unlockpage (BtLockAccess, next->latch); + + if( next->pool = bt_pinpool (bt, next->page_no) ) + next->page = bt_page (bt, next->pool, next->page_no); + else + return bt->err; - // cache node's parent page + chk = keycmp ((BtKey)next->page->fence, oldfence + 1, *oldfence); - parent = bt->page_no; - ppage = bt->page; - ppool = bt->pool; - pset = bt->set; + if( chk < 0 ) { + next->page_no = bt_getid (next->page->right); + bt_unlockpage (BtLockWrite, next->latch); + bt_unlockpage (BtLockParent, next->latch); + bt_unpinlatch (next->latch); + bt_unpinpool (next->pool); + continue; + } - // lock and map our right page - // it cannot be NULL because of the stopper - // in the last right page + if( chk > 0 ) + return bt->err = BTERR_struct; - bt_lockpage (BtLockWrite, set); + if( bt_fixfences (bt, next, newfence) ) + return bt->err; - // if we aren't dead yet + break; + } - if( page->act ) - goto rmergexit; + memcpy (set->page->fence, newfence, 256); - if( right = bt_getid (page->right) ) - if( rpool = bt_pinpool (bt, right) ) - rpage = bt_page (bt, rpool, right); - else - return bt->err; - else - return bt->err = BTERR_struct; + bt_unlockpage (BtLockWrite, set->latch); + bt_unlockpage (BtLockParent, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); + return 0; +} - rset = bt_pinlatch (bt, right); +// return page to free list +// page must be delete & write locked - // find our right neighbor +void bt_freepage (BtDb *bt, BtPageSet *set) +{ + // lock allocation page - if( ppage->act > 1 ) { - for( idx = slot; idx++ < ppage->cnt; ) - if( !slotptr(ppage, idx)->dead ) - break; + bt_spinwritelock (bt->mgr->latchmgr->lock); - if( idx > ppage->cnt ) - return bt->err = BTERR_struct; + // store chain in second right + bt_putid(set->page->right, bt_getid(bt->mgr->latchmgr->alloc[1].right)); + bt_putid(bt->mgr->latchmgr->alloc[1].right, set->page_no); + set->page->free = 1; - // redirect right neighbor in parent to left node + // unlock released page - bt_putid(slotptr(ppage,idx)->id, page_no); - } + bt_unlockpage (BtLockDelete, set->latch); + bt_unlockpage (BtLockWrite, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); - // if parent has only our deleted page, e.g. no right neighbor - // prepare to merge parent itself + // unlock allocation page - if( ppage->act == 1 ) { - if( rparent = bt_getid (ppage->right) ) - if( rppool = bt_pinpool (bt, rparent) ) - rppage = bt_page (bt, rppool, rparent); - else - return bt->err; + bt_spinreleasewrite (bt->mgr->latchmgr->lock); +} + +// remove the root level by promoting its only child +// call with parent and child pages + +BTERR bt_removeroot (BtDb *bt, BtPageSet *root, BtPageSet *child) +{ +uid next = 0; + + do { + if( next ) { + child->latch = bt_pinlatch (bt, next); + bt_lockpage (BtLockDelete, child->latch); + bt_lockpage (BtLockWrite, child->latch); + + if( child->pool = bt_pinpool (bt, next) ) + child->page = bt_page (bt, child->pool, next); else - return bt->err = BTERR_struct; + return bt->err; + + child->page_no = next; + } + + memcpy (root->page, child->page, bt->mgr->page_size); + next = bt_getid (slotptr(child->page, child->page->cnt)->id); + bt_freepage (bt, child); + } while( root->page->lvl > 1 && root->page->cnt == 1 ); + + bt_unlockpage (BtLockWrite, root->latch); + bt_unpinlatch (root->latch); + bt_unpinpool (root->pool); + return 0; +} + +// pull right page over ourselves in simple merge + +BTERR bt_mergeright (BtDb *bt, BtPageSet *set, BtPageSet *parent, BtPageSet *right, uint slot, uint idx) +{ + // install ourselves as child page + // and delete ourselves from parent - rpset = bt_pinlatch (bt, rparent); - bt_lockpage (BtLockWrite, rpset); + bt_putid (slotptr(parent->page, idx)->id, set->page_no); + slotptr(parent->page, slot)->dead = 1; + parent->page->act--; - // find our right neighbor on right parent page + // collapse any empty slots - for( idx = 0; idx++ < rppage->cnt; ) - if( !slotptr(rppage, idx)->dead ) { - bt_putid (slotptr(rppage, idx)->id, page_no); + while( idx = parent->page->cnt - 1 ) + if( slotptr(parent->page, idx)->dead ) { + *slotptr(parent->page, idx) = *slotptr(parent->page, idx + 1); + memset (slotptr(parent->page, parent->page->cnt--), 0, sizeof(BtSlot)); + } else break; - } - if( idx > rppage->cnt ) - return bt->err = BTERR_struct; - } + memcpy (set->page, right->page, bt->mgr->page_size); + bt_unlockpage (BtLockParent, right->latch); - // now that there are no more pointers to our right node - // we can wait for delete lock on it + bt_freepage (bt, right); - bt_lockpage(BtLockDelete, rset); - bt_lockpage(BtLockWrite, rset); + // do we need to remove a btree level? + // (leave the first page of leaves alone) - // pull contents of right page into our empty page + if( parent->page_no == ROOT_page && parent->page->cnt == 1 ) + if( set->page->lvl ) + return bt_removeroot (bt, parent, set); - memcpy (page, rpage, bt->mgr->page_size); + bt_unlockpage (BtLockWrite, parent->latch); + bt_unlockpage (BtLockDelete, set->latch); + bt_unlockpage (BtLockWrite, set->latch); + bt_unpinlatch (parent->latch); + bt_unpinpool (parent->pool); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); + return 0; +} - // ready to release right parent lock - // now that we have a new page in place +// remove both child and parent from the btree +// from the fence position in the parent +// call with both pages locked for writing - if( ppage->act == 1 ) { - bt_unlockpage (BtLockWrite, rpset); - bt_unpinlatch (rpset); - bt_unpinpool (rppool); - } +BTERR bt_removeparent (BtDb *bt, BtPageSet *child, BtPageSet *parent, BtPageSet *right, BtPageSet *rparent, uint lvl) +{ +unsigned char pagefence[256]; +uint idx; - // add killed right block to free chain - // lock latch mgr + // pull right sibling over ourselves and unlock - bt_spinwritelock(bt->mgr->latchmgr->lock); + memcpy (child->page, right->page, bt->mgr->page_size); - // store free chain in allocation page second right + bt_unlockpage (BtLockWrite, child->latch); + bt_unpinlatch (child->latch); + bt_unpinpool (child->pool); - bt_putid(rpage->right, bt_getid(bt->mgr->latchmgr->alloc[1].right)); - bt_putid(bt->mgr->latchmgr->alloc[1].right, right); + // install ourselves into right link of old right page - // unlock latch mgr and right page + bt_putid (right->page->right, child->page_no); + right->page->goright = 1; // tell bt_loadpage to go right to us + right->page->kill = 1; - bt_unlockpage(BtLockDelete, rset); - bt_unlockpage(BtLockWrite, rset); - bt_unpinlatch (rset); - bt_unpinpool (rpool); + bt_unlockpage (BtLockWrite, right->latch); - bt_spinreleasewrite(bt->mgr->latchmgr->lock); + // remove our slot from our parent + // signal to move right - // delete our obsolete fence key from our parent + parent->page->goright = 1; // tell bt_loadpage to go right to rparent + parent->page->kill = 1; + parent->page->act--; - slotptr(ppage, slot)->dead = 1; - ppage->dirty = 1; + // redirect right page pointer in right parent to us - // if our parent now empty - // remove it from the tree + for( idx = 0; idx++ < rparent->page->cnt; ) + if( !slotptr(rparent->page, idx)->dead ) + break; - if( ppage->act-- == 1 ) - if( bt_mergeleft (bt, ppage, ppool, pset, parent, lvl+1) ) - return bt->err; + if( bt_getid (slotptr(rparent->page, idx)->id) != right->page_no ) + return bt->err = BTERR_struct; -rmergexit: - bt_unlockpage (BtLockWrite, pset); - bt_unpinlatch (pset); - bt_unpinpool (ppool); + bt_putid (slotptr(rparent->page, idx)->id, child->page_no); + bt_unlockpage (BtLockWrite, rparent->latch); + bt_unpinlatch (rparent->latch); + bt_unpinpool (rparent->pool); - bt->found = 1; - return bt->err = 0; -} + // free the right page + + bt_lockpage (BtLockDelete, right->latch); + bt_lockpage (BtLockWrite, right->latch); + bt_freepage (bt, right); -// remove empty page from the B-tree -// try merging left first. If no left -// sibling, then merge right. + // save parent page fence value -// call with page loaded and locked, -// return with page locked. + memcpy (pagefence, parent->page->fence, 256); + bt_unlockpage (BtLockWrite, parent->latch); + + return bt_removepage (bt, parent, lvl, pagefence); +} -BTERR bt_mergeleft (BtDb *bt, BtPage page, BtPool *pool, BtLatchSet *set, uid page_no, uint lvl) +// remove page from btree +// call with page unlocked +// returns with page on free list + +BTERR bt_removepage (BtDb *bt, BtPageSet *set, uint lvl, unsigned char *pagefence) { -unsigned char fencekey[256], postkey[256]; -uint slot, idx, postfence = 0; -BtLatchSet *lset, *pset; -BtPool *lpool, *ppool; -BtPage lpage, ppage; -uid left, parent; +BtPageSet parent[1], sibling[1], rparent[1]; +unsigned char newfence[256]; +uint slot, idx; BtKey ptr; - ptr = keyptr(page, page->cnt); - memcpy(fencekey, ptr, ptr->len + 1); - bt_unlockpage (BtLockWrite, set); - // load and lock our parent retry: - if( !(slot = bt_loadpage (bt, fencekey+1, *fencekey, lvl+1, BtLockWrite)) ) + if( !(slot = bt_loadpage (bt, parent, pagefence+1, *pagefence, lvl+1, BtLockWrite)) ) return bt->err; - parent = bt->page_no; - ppage = bt->page; - ppool = bt->pool; - pset = bt->set; + // can we do a simple merge entirely + // between siblings on the parent page? - // wait until we are posted in our parent + if( slot < parent->page->cnt ) { + // find our right neighbor + // right must exist because the stopper prevents + // the rightmost page from deleting - if( !bt->parent ) { - bt_unlockpage (BtLockWrite, pset); - bt_unpinlatch (pset); - bt_unpinpool (ppool); -#ifdef unix + for( idx = slot; idx++ < parent->page->cnt; ) + if( !slotptr(parent->page, idx)->dead ) + break; + + sibling->page_no = bt_getid (slotptr (parent->page, idx)->id); + + bt_lockpage (BtLockDelete, set->latch); + bt_lockpage (BtLockWrite, set->latch); + + // merge right if sibling shows up in + // our parent and is not being killed + + if( sibling->page_no == bt_getid (set->page->right) ) { + sibling->latch = bt_pinlatch (bt, sibling->page_no); + bt_lockpage (BtLockParent, sibling->latch); + bt_lockpage (BtLockDelete, sibling->latch); + bt_lockpage (BtLockWrite, sibling->latch); + + if( sibling->pool = bt_pinpool (bt, sibling->page_no) ) + sibling->page = bt_page (bt, sibling->pool, sibling->page_no); + else + return bt->err; + + if( !sibling->page->kill ) + return bt_mergeright(bt, set, parent, sibling, slot, idx); + + // try again later + + bt_unlockpage (BtLockWrite, sibling->latch); + bt_unlockpage (BtLockParent, sibling->latch); + bt_unlockpage (BtLockDelete, sibling->latch); + bt_unpinlatch (sibling->latch); + bt_unpinpool (sibling->pool); + } + + bt_unlockpage (BtLockDelete, set->latch); + bt_unlockpage (BtLockWrite, set->latch); + bt_unlockpage (BtLockWrite, parent->latch); + bt_unpinlatch (parent->latch); + bt_unpinpool (parent->pool); +#ifdef linux sched_yield(); #else SwitchToThread(); @@ -1812,35 +1909,59 @@ retry: // find our left neighbor in our parent page for( idx = slot; --idx; ) - if( !slotptr(ppage, idx)->dead ) + if( !slotptr(parent->page, idx)->dead ) break; - // if no left neighbor, do right merge + // if no left neighbor, delete ourselves and our parent - if( !idx ) - return bt_mergeright (bt, page, pool, set, page_no, lvl, slot); + if( !idx ) { + bt_lockpage (BtLockAccess, set->latch); + bt_lockpage (BtLockWrite, set->latch); + bt_unlockpage (BtLockAccess, set->latch); - // lock and map our left neighbor's page + rparent->page_no = bt_getid (parent->page->right); + rparent->latch = bt_pinlatch (bt, rparent->page_no); - left = bt_getid (slotptr(ppage, idx)->id); + bt_lockpage (BtLockAccess, rparent->latch); + bt_lockpage (BtLockWrite, rparent->latch); + bt_unlockpage (BtLockAccess, rparent->latch); - if( lpool = bt_pinpool (bt, left) ) - lpage = bt_page (bt, lpool, left); - else - return bt->err; + if( rparent->pool = bt_pinpool (bt, rparent->page_no) ) + rparent->page = bt_page (bt, rparent->pool, rparent->page_no); + else + return bt->err; + + if( !rparent->page->kill ) { + sibling->page_no = bt_getid (set->page->right); + sibling->latch = bt_pinlatch (bt, sibling->page_no); + + bt_lockpage (BtLockAccess, sibling->latch); + bt_lockpage (BtLockWrite, sibling->latch); + bt_unlockpage (BtLockAccess, sibling->latch); + + if( sibling->pool = bt_pinpool (bt, sibling->page_no) ) + sibling->page = bt_page (bt, sibling->pool, sibling->page_no); + else + return bt->err; + + if( !sibling->page->kill ) + return bt_removeparent (bt, set, parent, sibling, rparent, lvl+1); + + // try again later - lset = bt_pinlatch (bt, left); - bt_lockpage(BtLockWrite, lset); + bt_unlockpage (BtLockWrite, sibling->latch); + bt_unpinlatch (sibling->latch); + bt_unpinpool (sibling->pool); + } - // wait until sibling is in our parent + bt_unlockpage (BtLockWrite, set->latch); + bt_unlockpage (BtLockWrite, rparent->latch); + bt_unpinlatch (rparent->latch); + bt_unpinpool (rparent->pool); - if( bt_getid (lpage->right) != page_no ) { - bt_unlockpage (BtLockWrite, pset); - bt_unpinlatch (pset); - bt_unpinpool (ppool); - bt_unlockpage (BtLockWrite, lset); - bt_unpinlatch (lset); - bt_unpinpool (lpool); + bt_unlockpage (BtLockWrite, parent->latch); + bt_unpinlatch (parent->latch); + bt_unpinpool (parent->pool); #ifdef linux sched_yield(); #else @@ -1849,114 +1970,97 @@ retry: goto retry; } - // since our page will have no more pointers to it, - // obtain Delete lock and wait for write locks to clear - - bt_lockpage(BtLockDelete, set); - bt_lockpage(BtLockWrite, set); + // redirect parent to our left sibling + // lock and map our left sibling's page - // if we aren't dead yet, - // get ready for exit - - if( page->act ) { - bt_unlockpage(BtLockDelete, set); - bt_unlockpage(BtLockWrite, lset); - bt_unpinlatch (lset); - bt_unpinpool (lpool); - goto lmergexit; - } + sibling->page_no = bt_getid (slotptr(parent->page, idx)->id); + sibling->latch = bt_pinlatch (bt, sibling->page_no); - // are we are the fence key for our parent? - // if so, grab our old fence key + // wait our turn on fence key maintenance - if( postfence = slot == ppage->cnt ) { - ptr = keyptr (ppage, ppage->cnt); - memcpy(fencekey, ptr, ptr->len + 1); - memset(slotptr(ppage, ppage->cnt), 0, sizeof(BtSlot)); + bt_lockpage(BtLockParent, sibling->latch); + bt_lockpage(BtLockAccess, sibling->latch); + bt_lockpage(BtLockWrite, sibling->latch); + bt_unlockpage(BtLockAccess, sibling->latch); - // clear out other dead slots - - while( --ppage->cnt ) - if( slotptr(ppage, ppage->cnt)->dead ) - memset(slotptr(ppage, ppage->cnt), 0, sizeof(BtSlot)); - else - break; - - ptr = keyptr (ppage, ppage->cnt); - memcpy(postkey, ptr, ptr->len + 1); - } else - slotptr(ppage,slot)->dead = 1; - - ppage->dirty = 1; - ppage->act--; - - // push our right neighbor pointer to our left - - memcpy (lpage->right, page->right, BtId); + if( sibling->pool = bt_pinpool (bt, sibling->page_no) ) + sibling->page = bt_page (bt, sibling->pool, sibling->page_no); + else + return bt->err; - // add ourselves to free chain - // lock latch mgr + // wait until left sibling is in our parent - bt_spinwritelock(bt->mgr->latchmgr->lock); + if( bt_getid (sibling->page->right) != set->page_no ) { + bt_unlockpage (BtLockWrite, parent->latch); + bt_unlockpage (BtLockWrite, sibling->latch); + bt_unlockpage (BtLockParent, sibling->latch); + bt_unpinlatch (parent->latch); + bt_unpinpool (parent->pool); + bt_unpinlatch (sibling->latch); + bt_unpinpool (sibling->pool); +#ifdef linux + sched_yield(); +#else + SwitchToThread(); +#endif + goto retry; + } - // store free chain in allocation page second right - bt_putid(page->right, bt_getid(bt->mgr->latchmgr->alloc[1].right)); - bt_putid(bt->mgr->latchmgr->alloc[1].right, page_no); + // delete our left sibling from parent - // unlock latch mgr and pages + slotptr(parent->page,idx)->dead = 1; + parent->page->dirty = 1; + parent->page->act--; - bt_spinreleasewrite(bt->mgr->latchmgr->lock); - bt_unlockpage(BtLockWrite, lset); - bt_unpinlatch (lset); - bt_unpinpool (lpool); + // redirect our parent slot to our left sibling - // release our node's delete lock + bt_putid (slotptr(parent->page, slot)->id, sibling->page_no); + memcpy (sibling->page->right, set->page->right, BtId); - bt_unlockpage(BtLockDelete, set); + // collapse dead slots from parent -lmergexit: - bt_unlockpage (BtLockWrite, pset); - bt_unpinpool (ppool); + while( idx = parent->page->cnt - 1 ) + if( slotptr(parent->page, idx)->dead ) { + *slotptr(parent->page, idx) = *slotptr(parent->page, parent->page->cnt); + memset (slotptr(parent->page, parent->page->cnt--), 0, sizeof(BtSlot)); + } else + break; - // do we need to post parent's fence key in its parent? + // free our original page - if( !postfence || parent == ROOT_page ) { - bt_unpinlatch (pset); - bt->found = 1; - return bt->err = 0; - } + bt_lockpage (BtLockDelete, set->latch); + bt_lockpage (BtLockWrite, set->latch); + bt_freepage (bt, set); - // interlock parent fence post + // go down the left node's fence keys to the leaf level + // and update the fence keys in each page - bt_lockpage (BtLockParent, pset); + memcpy (newfence, parent->page->fence, 256); - // load parent's parent page -posttry: - if( !(slot = bt_loadpage (bt, fencekey+1, *fencekey, lvl+2, BtLockWrite)) ) + if( bt_fixfences (bt, sibling, newfence) ) return bt->err; - if( !(slot = bt_cleanpage (bt, bt->page, *fencekey, slot)) ) - if( bt_splitpage (bt, bt->page, bt->pool, bt->set, bt->page_no) ) - return bt->err; - else - goto posttry; + // promote sibling as new root? - page = bt->page; + if( parent->page_no == ROOT_page && parent->page->cnt == 1 ) + if( sibling->page->lvl ) { + sibling->latch = bt_pinlatch (bt, sibling->page_no); + bt_lockpage (BtLockDelete, sibling->latch); + bt_lockpage (BtLockWrite, sibling->latch); - page->min -= *postkey + 1; - ((unsigned char *)page)[page->min] = *postkey; - memcpy ((unsigned char *)page + page->min +1, postkey + 1, *postkey ); - slotptr(page, slot)->off = page->min; + if( sibling->pool = bt_pinpool (bt, sibling->page_no) ) + sibling->page = bt_page (bt, sibling->pool, sibling->page_no); + else + return bt->err; - bt_unlockpage (BtLockParent, pset); - bt_unpinlatch (pset); + return bt_removeroot (bt, parent, sibling); + } - bt_unlockpage (BtLockWrite, bt->set); - bt_unpinlatch (bt->set); - bt_unpinpool (bt->pool); + bt_unlockpage (BtLockWrite, parent->latch); + bt_unpinlatch (parent->latch); + bt_unpinpool (parent->pool); - bt->found = 1; - return bt->err = 0; + return 0; } // find and delete key on page by marking delete flag bit @@ -1964,65 +2068,79 @@ posttry: BTERR bt_deletekey (BtDb *bt, unsigned char *key, uint len) { -BtLatchSet *set; -BtPool *pool; -BtPage page; -uid page_no; +unsigned char pagefence[256]; +uint slot, idx, found; +BtPageSet set[1]; BtKey ptr; -uint slot; - if( !(slot = bt_loadpage (bt, key, len, 0, BtLockWrite)) ) + if( slot = bt_loadpage (bt, set, key, len, 0, BtLockWrite) ) + ptr = keyptr(set->page, slot); + else return bt->err; - page_no = bt->page_no; - page = bt->page; - pool = bt->pool; - set = bt->set; - // if key is found delete it, otherwise ignore request - ptr = keyptr(page, slot); + if( found = slot <= set->page->cnt ) + if( found = !keycmp (ptr, key, len) ) + if( found = slotptr(set->page, slot)->dead == 0 ) { + slotptr(set->page,slot)->dead = 1; + set->page->dirty = 1; + set->page->act--; + + // collapse empty slots - if( bt->found = !keycmp (ptr, key, len) ) - if( bt->found = slotptr(page, slot)->dead == 0 ) { - slotptr(page,slot)->dead = 1; - if( slot < page->cnt ) - page->dirty = 1; - if( !--page->act ) - if( bt_mergeleft (bt, page, pool, set, page_no, 0) ) - return bt->err; + while( idx = set->page->cnt - 1 ) + if( slotptr(set->page, idx)->dead ) { + *slotptr(set->page, idx) = *slotptr(set->page, idx + 1); + memset (slotptr(set->page, set->page->cnt--), 0, sizeof(BtSlot)); + } else + break; } - bt_unlockpage(BtLockWrite, set); - bt_unpinlatch (set); - bt_unpinpool (pool); - return bt->err = 0; + if( set->page->act ) { + bt_unlockpage(BtLockWrite, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); + return bt->found = found, 0; + } + + memcpy (pagefence, set->page->fence, 256); + set->page->kill = 1; + + bt_unlockpage (BtLockWrite, set->latch); + + if( bt_removepage (bt, set, 0, pagefence) ) + return bt->err; + + bt->found = found; + return 0; } // find key in leaf level and return row-id uid bt_findkey (BtDb *bt, unsigned char *key, uint len) { +BtPageSet set[1]; uint slot; BtKey ptr; uid id; - if( slot = bt_loadpage (bt, key, len, 0, BtLockRead) ) - ptr = keyptr(bt->page, slot); + if( slot = bt_loadpage (bt, set, key, len, 0, BtLockRead) ) + ptr = keyptr(set->page, slot); else return 0; // if key exists, return row-id // otherwise return 0 - if( slot <= bt->page->cnt && !keycmp (ptr, key, len) ) - id = bt_getid(slotptr(bt->page,slot)->id); + if( !keycmp (ptr, key, len) ) + id = bt_getid(slotptr(set->page,slot)->id); else id = 0; - bt_unlockpage (BtLockRead, bt->set); - bt_unpinlatch (bt->set); - bt_unpinpool (bt->pool); + bt_unlockpage (BtLockRead, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); return id; } @@ -2033,7 +2151,7 @@ uid id; uint bt_cleanpage(BtDb *bt, BtPage page, uint amt, uint slot) { -uint nxt = bt->mgr->page_size; +uint nxt = bt->mgr->page_size, off; uint cnt = 0, idx = 0; uint max = page->cnt; uint newslot = max; @@ -2056,28 +2174,31 @@ BtKey key; page->act = 0; // try cleaning up page first - - // always leave fence key in the array - // otherwise, remove deleted key + // by removing deleted keys while( cnt++ < max ) { if( cnt == slot ) newslot = idx + 1; - if( cnt < max && slotptr(bt->frame,cnt)->dead ) + if( slotptr(bt->frame,cnt)->dead ) continue; - // copy key + // if its not the fence key, + // copy the key across - key = keyptr(bt->frame, cnt); - nxt -= key->len + 1; - memcpy ((unsigned char *)page + nxt, key, key->len + 1); + off = slotptr(bt->frame,cnt)->off; + + if( off >= sizeof(*page) ) { + key = keyptr(bt->frame, cnt); + off = nxt -= key->len + 1; + memcpy ((unsigned char *)page + nxt, key, key->len + 1); + } // copy slot + memcpy(slotptr(page, ++idx)->id, slotptr(bt->frame, cnt)->id, BtId); - if( !(slotptr(page, idx)->dead = slotptr(bt->frame, cnt)->dead) ) - page->act++; slotptr(page, idx)->tod = slotptr(bt->frame, cnt)->tod; - slotptr(page, idx)->off = nxt; + slotptr(page, idx)->off = off; + page->act++; } page->min = nxt; @@ -2091,202 +2212,192 @@ BtKey key; return 0; } -// add key to current page -// page must already be writelocked +// split the root and raise the height of the btree -void bt_addkeytopage (BtDb *bt, BtPage page, uint slot, unsigned char *key, uint len, uid id, uint tod) -{ -uint idx; - - // find next available dead slot and copy key onto page - - for( idx = slot; idx < page->cnt; idx++ ) - if( slotptr(page, idx)->dead ) - break; - - if( idx == page->cnt ) - idx++, page->cnt++; - - page->act++; - - // now insert key into array before slot - - while( idx > slot ) - *slotptr(page, idx) = *slotptr(page, idx -1), idx--; - - page->min -= len + 1; - ((unsigned char *)page)[page->min] = len; - memcpy ((unsigned char *)page + page->min +1, key, len ); - - bt_putid(slotptr(page,slot)->id, id); - slotptr(page, slot)->off = page->min; - slotptr(page, slot)->tod = tod; - slotptr(page, slot)->dead = 0; -} - -BTERR bt_splitroot(BtDb *bt, unsigned char *leftkey, uid page_no2) +BTERR bt_splitroot(BtDb *bt, BtPageSet *root, uid page_no2) { uint nxt = bt->mgr->page_size; -BtPage root = bt->page; +unsigned char leftkey[256]; uid new_page; // Obtain an empty page to use, and copy the current - // root contents into it + // root contents into it, e.g. lower keys - if( !(new_page = bt_newpage(bt, root)) ) + memcpy (leftkey, root->page->fence, 256); + root->page->posted = 1; + + if( !(new_page = bt_newpage(bt, root->page)) ) return bt->err; // preserve the page info at the bottom - // and set rest to zero + // of higher keys and set rest to zero - memset(root+1, 0, bt->mgr->page_size - sizeof(*root)); + memset(root->page+1, 0, bt->mgr->page_size - sizeof(*root->page)); + memset(root->page->fence, 0, 256); + root->page->fence[0] = 2; + root->page->fence[1] = 0xff; + root->page->fence[2] = 0xff; - // insert first key on newroot page + // insert lower keys page fence key on newroot page nxt -= *leftkey + 1; - memcpy ((unsigned char *)root + nxt, leftkey, *leftkey + 1); - bt_putid(slotptr(root, 1)->id, new_page); - slotptr(root, 1)->off = nxt; + memcpy ((unsigned char *)root->page + nxt, leftkey, *leftkey + 1); + bt_putid(slotptr(root->page, 1)->id, new_page); + slotptr(root->page, 1)->off = nxt; - // insert second key (stopper key) on newroot page + // insert stopper key on newroot page // and increase the root height - nxt -= 3; - *((unsigned char *)root + nxt) = 2; - memset ((unsigned char *)root + nxt + 1, 0xff, 2); - bt_putid(slotptr(root, 2)->id, page_no2); - slotptr(root, 2)->off = nxt; + bt_putid(slotptr(root->page, 2)->id, page_no2); + slotptr(root->page, 2)->off = offsetof(struct BtPage_, fence); - bt_putid(root->right, 0); - root->min = nxt; // reset lowest used offset and key count - root->cnt = 2; - root->act = 2; - root->lvl++; + bt_putid(root->page->right, 0); + root->page->min = nxt; // reset lowest used offset and key count + root->page->cnt = 2; + root->page->act = 2; + root->page->lvl++; - // release and unpin root (bt->page) + // release and unpin root - bt_unlockpage(BtLockWrite, bt->set); - bt_unpinlatch (bt->set); - bt_unpinpool (bt->pool); + bt_unlockpage(BtLockWrite, root->latch); + bt_unpinlatch (root->latch); + bt_unpinpool (root->pool); return 0; } // split already locked full node -// return unlocked and unpinned. +// return unlocked. -BTERR bt_splitpage (BtDb *bt, BtPage page, BtPool *pool, BtLatchSet *set, uid page_no) +BTERR bt_splitpage (BtDb *bt, BtPageSet *set) { -uint slot, cnt, idx, max, nxt = bt->mgr->page_size; -unsigned char rightkey[256], leftkey[256]; -uint tod = time(NULL); -uint lvl = page->lvl; -uid new_page; +uint cnt = 0, idx = 0, max, nxt = bt->mgr->page_size, off; +unsigned char fencekey[256]; +uint lvl = set->page->lvl; +uid right; BtKey key; - // initialize frame buffer for right node + // split higher half of keys to bt->frame memset (bt->frame, 0, bt->mgr->page_size); - max = page->cnt; + max = set->page->cnt; cnt = max / 2; idx = 0; - // split higher half of keys to bt->frame - while( cnt++ < max ) { - key = keyptr(page, cnt); - nxt -= key->len + 1; - memcpy ((unsigned char *)bt->frame + nxt, key, key->len + 1); - memcpy(slotptr(bt->frame,++idx)->id, slotptr(page,cnt)->id, BtId); - if( !(slotptr(bt->frame, idx)->dead = slotptr(page, cnt)->dead) ) - bt->frame->act++; - slotptr(bt->frame, idx)->tod = slotptr(page, cnt)->tod; - slotptr(bt->frame, idx)->off = nxt; + if( !lvl || cnt < max ) { + key = keyptr(set->page, cnt); + off = nxt -= key->len + 1; + memcpy ((unsigned char *)bt->frame + nxt, key, key->len + 1); + } else + off = offsetof(struct BtPage_, fence); + + memcpy(slotptr(bt->frame,++idx)->id, slotptr(set->page,cnt)->id, BtId); + slotptr(bt->frame, idx)->tod = slotptr(set->page, cnt)->tod; + slotptr(bt->frame, idx)->off = off; + bt->frame->act++; } - // transfer right link node to new right node - - if( page_no > ROOT_page ) - memcpy (bt->frame->right, page->right, BtId); + if( set->page_no == ROOT_page ) + bt->frame->posted = 1; + memcpy (bt->frame->fence, set->page->fence, 256); bt->frame->bits = bt->mgr->page_bits; bt->frame->min = nxt; bt->frame->cnt = idx; bt->frame->lvl = lvl; - // get new free page and write right frame to it. + // link right node - if( !(new_page = bt_newpage(bt, bt->frame)) ) - return bt->err; + if( set->page_no > ROOT_page ) + memcpy (bt->frame->right, set->page->right, BtId); - // remember fence key for new right page to add - // as right sibling to the left node + // get new free page and write higher keys to it. - key = keyptr(bt->frame, idx); - memcpy (rightkey, key, key->len + 1); + if( !(right = bt_newpage(bt, bt->frame)) ) + return bt->err; // update lower keys to continue in old page - memcpy (bt->frame, page, bt->mgr->page_size); - memset (page+1, 0, bt->mgr->page_size - sizeof(*page)); + memcpy (bt->frame, set->page, bt->mgr->page_size); + memset (set->page+1, 0, bt->mgr->page_size - sizeof(*set->page)); nxt = bt->mgr->page_size; - page->dirty = 0; - page->act = 0; + set->page->posted = 0; + set->page->dirty = 0; + set->page->act = 0; cnt = 0; idx = 0; // assemble page of smaller keys - // to remain in the old page while( cnt++ < max / 2 ) { key = keyptr(bt->frame, cnt); - nxt -= key->len + 1; - memcpy ((unsigned char *)page + nxt, key, key->len + 1); - memcpy (slotptr(page,++idx)->id, slotptr(bt->frame,cnt)->id, BtId); - if( !(slotptr(page, idx)->dead = slotptr(bt->frame, cnt)->dead) ) - page->act++; - slotptr(page, idx)->tod = slotptr(bt->frame, cnt)->tod; - slotptr(page, idx)->off = nxt; - } - // finalize left page and save fence key + if( !lvl || cnt < max / 2 ) { + off = nxt -= key->len + 1; + memcpy ((unsigned char *)set->page + nxt, key, key->len + 1); + } else + off = offsetof(struct BtPage_, fence); - memcpy(leftkey, key, key->len + 1); - page->min = nxt; - page->cnt = idx; + memcpy(slotptr(set->page,++idx)->id, slotptr(bt->frame,cnt)->id, BtId); + slotptr(set->page, idx)->tod = slotptr(bt->frame, cnt)->tod; + slotptr(set->page, idx)->off = off; + set->page->act++; + } - // link new right page + // install fence key for smaller key page - bt_putid (page->right, new_page); + memset(set->page->fence, 0, 256); + memcpy(set->page->fence, key, key->len + 1); + + bt_putid(set->page->right, right); + set->page->min = nxt; + set->page->cnt = idx; // if current page is the root page, split it - if( page_no == ROOT_page ) - return bt_splitroot (bt, leftkey, new_page); + if( set->page_no == ROOT_page ) + return bt_splitroot (bt, set, right); + + bt_unlockpage (BtLockWrite, set->latch); - // obtain ParentModification lock for current page + // insert new fences in their parent pages + + while( 1 ) { + bt_lockpage (BtLockParent, set->latch); + bt_lockpage (BtLockWrite, set->latch); - bt_lockpage (BtLockParent, set); + memcpy (fencekey, set->page->fence, 256); + right = bt_getid (set->page->right); - // release wr lock on our page. - // this will keep out another SMO + if( set->page->posted ) { + bt_unlockpage (BtLockParent, set->latch); + bt_unlockpage (BtLockWrite, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); + return 0; + } - bt_unlockpage (BtLockWrite, set); + set->page->posted = 1; + bt_unlockpage (BtLockWrite, set->latch); - // insert key for old page (lower keys) + if( bt_insertkey (bt, fencekey+1, *fencekey, set->page_no, time(NULL), lvl+1) ) + return bt->err; - if( bt_insertkey (bt, leftkey + 1, *leftkey, page_no, tod, lvl + 1) ) - return bt->err; + bt_unlockpage (BtLockParent, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); - // switch old parent key from us to our right page + if( !(set->page_no = right) ) + break; - if( bt_insertkey (bt, rightkey + 1, *rightkey, new_page, tod, lvl + 1) ) - return bt->err; + set->latch = bt_pinlatch (bt, right); - // unlock and unpin + if( set->pool = bt_pinpool (bt, right) ) + set->page = bt_page (bt, set->pool, right); + else + return bt->err; + } - bt_unlockpage (BtLockParent, set); - bt_unpinlatch (set); - bt_unpinpool (pool); return 0; } @@ -2294,13 +2405,13 @@ BtKey key; BTERR bt_insertkey (BtDb *bt, unsigned char *key, uint len, uid id, uint tod, uint lvl) { +BtPageSet set[1]; uint slot, idx; -BtPage page; BtKey ptr; while( 1 ) { - if( slot = bt_loadpage (bt, key, len, lvl, BtLockWrite) ) - ptr = keyptr(bt->page, slot); + if( slot = bt_loadpage (bt, set, key, len, lvl, BtLockWrite) ) + ptr = keyptr(set->page, slot); else { if ( !bt->err ) @@ -2310,34 +2421,56 @@ BtKey ptr; // if key already exists, update id and return - page = bt->page; - - if( !keycmp (ptr, key, len) ) { - if( slotptr(page, slot)->dead ) - page->act++; - slotptr(page, slot)->dead = 0; - slotptr(page, slot)->tod = tod; - bt_putid(slotptr(page,slot)->id, id); - bt_unlockpage(BtLockWrite, bt->set); - bt_unpinlatch (bt->set); - bt_unpinpool (bt->pool); - return bt->err; + if( slot <= set->page->cnt ) + if( !keycmp (ptr, key, len) ) { + if( slotptr(set->page, slot)->dead ) + set->page->act++; + slotptr(set->page, slot)->dead = 0; + slotptr(set->page, slot)->tod = tod; + bt_putid(slotptr(set->page,slot)->id, id); + bt_unlockpage(BtLockWrite, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); + return 0; } // check if page has enough space - if( slot = bt_cleanpage (bt, bt->page, len, slot) ) + if( slot = bt_cleanpage (bt, set->page, len, slot) ) break; - if( bt_splitpage (bt, bt->page, bt->pool, bt->set, bt->page_no) ) + if( bt_splitpage (bt, set) ) return bt->err; } - bt_addkeytopage (bt, bt->page, slot, key, len, id, tod); + // calculate next available slot and copy key into page + + set->page->min -= len + 1; // reset lowest used offset + ((unsigned char *)set->page)[set->page->min] = len; + memcpy ((unsigned char *)set->page + set->page->min +1, key, len ); + + for( idx = slot; idx <= set->page->cnt; idx++ ) + if( slotptr(set->page, idx)->dead ) + break; + + // now insert key into array before slot - bt_unlockpage (BtLockWrite, bt->set); - bt_unpinlatch (bt->set); - bt_unpinpool (bt->pool); + if( idx > set->page->cnt ) + set->page->cnt++; + + set->page->act++; + + while( idx > slot ) + *slotptr(set->page, idx) = *slotptr(set->page, idx -1), idx--; + + bt_putid(slotptr(set->page,slot)->id, id); + slotptr(set->page, slot)->off = set->page->min; + slotptr(set->page, slot)->tod = tod; + slotptr(set->page, slot)->dead = 0; + + bt_unlockpage (BtLockWrite, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); return 0; } @@ -2345,17 +2478,21 @@ BtKey ptr; uint bt_startkey (BtDb *bt, unsigned char *key, uint len) { +BtPageSet set[1]; uint slot; // cache page for retrieval - if( slot = bt_loadpage (bt, key, len, 0, BtLockRead) ) - memcpy (bt->cursor, bt->page, bt->mgr->page_size); - bt->cursor_page = bt->page_no; + if( slot = bt_loadpage (bt, set, key, len, 0, BtLockRead) ) + memcpy (bt->cursor, set->page, bt->mgr->page_size); + else + return 0; + + bt->cursor_page = set->page_no; - bt_unlockpage(BtLockRead, bt->set); - bt_unpinlatch (bt->set); - bt_unpinpool (bt->pool); + bt_unlockpage(BtLockRead, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); return slot; } @@ -2364,9 +2501,7 @@ uint slot; uint bt_nextkey (BtDb *bt, uint slot) { -BtLatchSet *set; -BtPool *pool; -BtPage page; +BtPageSet set[1]; uid right; do { @@ -2374,7 +2509,7 @@ uid right; while( slot++ < bt->cursor->cnt ) if( slotptr(bt->cursor,slot)->dead ) continue; - else if( right || (slot < bt->cursor->cnt) ) + else if( right || (slot < bt->cursor->cnt) ) // skip infinite stopper return slot; else break; @@ -2383,19 +2518,20 @@ uid right; break; bt->cursor_page = right; - if( pool = bt_pinpool (bt, right) ) - page = bt_page (bt, pool, right); + + if( set->pool = bt_pinpool (bt, right) ) + set->page = bt_page (bt, set->pool, right); else return 0; - set = bt_pinlatch (bt, right); - bt_lockpage(BtLockRead, set); + set->latch = bt_pinlatch (bt, right); + bt_lockpage(BtLockRead, set->latch); - memcpy (bt->cursor, page, bt->mgr->page_size); + memcpy (bt->cursor, set->page, bt->mgr->page_size); - bt_unlockpage(BtLockRead, set); - bt_unpinlatch (set); - bt_unpinpool (pool); + bt_unlockpage(BtLockRead, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); slot = 0; } while( 1 ); @@ -2423,39 +2559,39 @@ uint bt_tod(BtDb *bt, uint slot) void bt_latchaudit (BtDb *bt) { ushort idx, hashidx; -BtLatchSet *set; -BtPool *pool; -BtPage page; -uid page_no; +BtPageSet set[1]; #ifdef unix for( idx = 1; idx < bt->mgr->latchmgr->latchdeployed; idx++ ) { - set = bt->mgr->latchsets + idx; - if( set->pin ) { - fprintf(stderr, "latchset %d pinned\n", idx); - set->pin = 0; + set->latch = bt->mgr->latchsets + idx; + if( set->latch->pin ) { + fprintf(stderr, "latchset %d pinned for page %.6x\n", idx, set->latch->page_no); + set->latch->pin = 0; } } for( hashidx = 0; hashidx < bt->mgr->latchmgr->latchhash; hashidx++ ) { - if( *(uint *)bt->mgr->latchmgr->table[hashidx].latch ) - fprintf(stderr, "latchmgr locked\n"); if( idx = bt->mgr->latchmgr->table[hashidx].slot ) do { - set = bt->mgr->latchsets + idx; - if( set->hash != hashidx ) + set->latch = bt->mgr->latchsets + idx; + if( set->latch->hash != hashidx ) fprintf(stderr, "latchset %d wrong hashidx\n", idx); - if( set->pin ) - fprintf(stderr, "latchset %d pinned\n", idx); - } while( idx = set->next ); + if( set->latch->pin ) + fprintf(stderr, "latchset %d pinned for page %.8x\n", idx, set->latch->page_no); + } while( idx = set->latch->next ); } - page_no = bt_getid(bt->mgr->latchmgr->alloc[1].right); - - while( page_no ) { - fprintf(stderr, "free: %.6x\n", (uint)page_no); - pool = bt_pinpool (bt, page_no); - page = bt_page (bt, pool, page_no); - page_no = bt_getid(page->right); - bt_unpinpool (pool); + + set->page_no = bt_getid(bt->mgr->latchmgr->alloc[1].right); + + while( set->page_no ) { + fprintf(stderr, "free: %.6x\n", (uint)set->page_no); + + if( set->pool = bt_pinpool (bt, set->page_no) ) + set->page = bt_page (bt, set->pool, set->page_no); + else + return; + + set->page_no = bt_getid(set->page->right); + bt_unpinpool (set->pool); } #endif } @@ -2481,10 +2617,8 @@ uid next, page_no = LEAF_page; // start on first page of leaves unsigned char key[256]; ThreadArg *args = arg; int ch, len = 0, slot; -BtLatchSet *set; +BtPageSet set[1]; time_t tod[1]; -BtPool *pool; -BtPage page; BtKey ptr; BtDb *bt; FILE *in; @@ -2570,38 +2704,49 @@ FILE *in; break; case 's': - len = key[0] = 0; - - fprintf(stderr, "started reading\n"); - - if( slot = bt_startkey (bt, key, len) ) - slot--; - else - fprintf(stderr, "Error %d in StartKey. Syserror: %d\n", bt->err, errno), exit(0); - - while( slot = bt_nextkey (bt, slot) ) { - ptr = bt_key(bt, slot); - fwrite (ptr->key, ptr->len, 1, stdout); - fputc ('\n', stdout); - } + fprintf(stderr, "started scanning\n"); + do { + if( set->pool = bt_pinpool (bt, page_no) ) + set->page = bt_page (bt, set->pool, page_no); + else + break; + set->latch = bt_pinlatch (bt, page_no); + bt_lockpage (BtLockRead, set->latch); + next = bt_getid (set->page->right); + cnt += set->page->act; + + for( slot = 0; slot++ < set->page->cnt; ) + if( next || slot < set->page->cnt ) + if( !slotptr(set->page, slot)->dead ) { + ptr = keyptr(set->page, slot); + fwrite (ptr->key, ptr->len, 1, stdout); + fputc ('\n', stdout); + } + + bt_unlockpage (BtLockRead, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); + } while( page_no = next ); + cnt--; // remove stopper key + fprintf(stderr, " Total keys read %d\n", cnt); break; case 'c': - fprintf(stderr, "started reading\n"); + fprintf(stderr, "started counting\n"); do { - if( pool = bt_pinpool (bt, page_no) ) - page = bt_page (bt, pool, page_no); + if( set->pool = bt_pinpool (bt, page_no) ) + set->page = bt_page (bt, set->pool, page_no); else break; - set = bt_pinlatch (bt, page_no); - bt_lockpage (BtLockRead, set); - cnt += page->act; - next = bt_getid (page->right); - bt_unlockpage (BtLockRead, set); - bt_unpinlatch (set); - bt_unpinpool (pool); + set->latch = bt_pinlatch (bt, page_no); + bt_lockpage (BtLockRead, set->latch); + cnt += set->page->act; + next = bt_getid (set->page->right); + bt_unlockpage (BtLockRead, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); } while( page_no = next ); cnt--; // remove stopper key diff --git a/threads2i.c b/threads2i.c index 73d7541..5f00379 100644 --- a/threads2i.c +++ b/threads2i.c @@ -1,5 +1,6 @@ // btree version threads2i sched_yield version -// 30 JAN 2014 +// with reworked bt_deletekey code +// 12 FEB 2014 // author: karl malbrain, malbrain@cal.berkeley.edu @@ -49,6 +50,7 @@ REDISTRIBUTION OF THIS SOFTWARE. #include #include +#include typedef unsigned long long uid; @@ -117,7 +119,7 @@ typedef struct { typedef struct { BtSpinLatch readwr[1]; // read/write page lock BtSpinLatch access[1]; // Access Intent/Page delete - BtSpinLatch parent[1]; // adoption of foster children + BtSpinLatch parent[1]; // Posting of fence key in parent BtSpinLatch busy[1]; // slot is being moved between chains volatile ushort next; // next entry in hash table chain volatile ushort prev; // prev entry in hash table chain @@ -161,14 +163,19 @@ typedef struct { // It is immediately followed // by the BtSlot array of keys. -typedef struct Page { +typedef struct BtPage_ { uint cnt; // count of keys in page uint act; // count of active keys uint min; // next key offset - unsigned char bits; // page size in bits - unsigned char lvl:7; // level of page + unsigned char bits:7; // page size in bits + unsigned char free:1; // page is on free chain + unsigned char lvl:4; // level of page + unsigned char kill:1; // page is being deleted unsigned char dirty:1; // page has deleted keys + unsigned char posted:1; // page fence is posted + unsigned char goright:1; // page is being deleted, go right unsigned char right[BtId]; // page number to right + unsigned char fence[256]; // page fence key } *BtPage; // The memory mapping pool table buffer manager entry @@ -186,10 +193,19 @@ typedef struct { #endif } BtPool; +// The loadpage interface object + +typedef struct { + uid page_no; // current page number + BtPage page; // current page pointer + BtPool *pool; // current page pool + BtLatchSet *latch; // current page latch set +} BtPageSet; + // structure for latch manager on ALLOC_page typedef struct { - struct Page alloc[2]; // next & free page_nos in right ptr + struct BtPage_ alloc[2]; // next & free page_nos in right ptr BtSpinLatch lock[1]; // allocation area lite latch ushort latchdeployed; // highest number of latch entries deployed ushort nlatchpage; // number of latch pages at BT_latch @@ -231,13 +247,8 @@ typedef struct { BtPage cursor; // cached frame for start/next (never mapped) BtPage frame; // spare frame for the page split (never mapped) BtPage zero; // page frame for zeroes at end of file - BtPage page; // current page - uid page_no; // current page number uid cursor_page; // current cursor page number - BtLatchSet *set; // current page latch set - BtPool *pool; // current page pool unsigned char *mem; // frame, cursor, page memory buffer - int parent; // last loadpage was from a parent level int found; // last delete or insert was found int err; // last error } BtDb; @@ -262,9 +273,7 @@ extern uint bt_startkey (BtDb *bt, unsigned char *key, uint len); extern uint bt_nextkey (BtDb *bt, uint slot); // internal functions -BTERR bt_splitpage (BtDb *bt, BtPage page, BtPool *pool, BtLatchSet *set, uid page_no); -uint bt_cleanpage(BtDb *bt, BtPage page, uint amt, uint slot); -BTERR bt_mergeleft (BtDb *bt, BtPage page, BtPool *pool, BtLatchSet *set, uid page_no, uint lvl); +BTERR bt_removepage (BtDb *bt, BtPageSet *set, uint lvl, unsigned char *pagefence); // manager functions extern BtMgr *bt_mgr (char *name, uint mode, uint bits, uint poolsize, uint segsize, uint hashsize); @@ -310,8 +319,8 @@ extern uint bt_tod (BtDb *bt, uint slot); // one with two keys. // Deleted keys are marked with a dead bit until -// page cleanup The fence key for a node is always -// present, even after deletion and cleanup. +// page cleanup. The fence key for a node is +// present in a special array // Groups of pages called segments from the btree are optionally // cached with a memory mapped pool. A hash table is used to keep @@ -326,12 +335,13 @@ extern uint bt_tod (BtDb *bt, uint slot); // Page 0 is dedicated to lock for new page extensions, // and chains empty pages together for reuse. -// The ParentModification lock on a node is obtained to prevent resplitting -// or deleting a node before its fence is posted into its upper level. +// The ParentModification lock on a node is obtained to serialize posting +// or changing the fence key for a node. // Empty pages are chained together through the ALLOC page and reused. // Access macros to address slot and key values from the page +// Page slots use 1 based indexing. #define slotptr(page, slot) (((BtSlot *)(page+1)) + (slot-1)) #define keyptr(page, slot) ((BtKey)((unsigned char*)(page) + slotptr(page, slot)->off)) @@ -872,13 +882,12 @@ SYSTEM_INFO sysinfo[1]; latchmgr->alloc->bits = mgr->page_bits; for( lvl=MIN_lvl; lvl--; ) { - slotptr(latchmgr->alloc, 1)->off = mgr->page_size - 3; + slotptr(latchmgr->alloc, 1)->off = offsetof(struct BtPage_, fence); bt_putid(slotptr(latchmgr->alloc, 1)->id, lvl ? MIN_lvl - lvl + 1 : 0); // next(lower) page number - key = keyptr(latchmgr->alloc, 1); - key->len = 2; // create stopper key - key->key[0] = 0xff; - key->key[1] = 0xff; - latchmgr->alloc->min = mgr->page_size - 3; + latchmgr->alloc->fence[0] = 2; // create stopper key + latchmgr->alloc->fence[1] = 0xff; + latchmgr->alloc->fence[2] = 0xff; + latchmgr->alloc->min = mgr->page_size; latchmgr->alloc->lvl = lvl; latchmgr->alloc->cnt = 1; latchmgr->alloc->act = 1; @@ -1071,7 +1080,7 @@ int flag; #ifdef unix flag = PROT_READ | ( bt->mgr->mode == BT_ro ? 0 : PROT_WRITE ); - pool->map = mmap (0, (bt->mgr->poolmask+1) << bt->mgr->page_bits, flag, MAP_SHARED, bt->mgr->idx, off); + pool->map = mmap (0, (bt->mgr->poolmask+1) << bt->mgr->page_bits, flag, MAP_SHARED | MAP_POPULATE, bt->mgr->idx, off); if( pool->map == MAP_FAILED ) return bt->err = BTERR_map; @@ -1304,10 +1313,8 @@ void bt_unlockpage(BtLock mode, BtLatchSet *set) uid bt_newpage(BtDb *bt, BtPage page) { -BtLatchSet *set; -BtPool *pool; +BtPageSet set[1]; uid new_page; -BtPage pmap; int reuse; // lock allocation page @@ -1318,12 +1325,13 @@ int reuse; // else allocate empty page if( new_page = bt_getid(bt->mgr->latchmgr->alloc[1].right) ) { - if( pool = bt_pinpool (bt, new_page) ) - pmap = bt_page (bt, pool, new_page); + if( set->pool = bt_pinpool (bt, new_page) ) + set->page = bt_page (bt, set->pool, new_page); else return 0; - bt_putid(bt->mgr->latchmgr->alloc[1].right, bt_getid(pmap->right)); - bt_unpinpool (pool); + + bt_putid(bt->mgr->latchmgr->alloc[1].right, bt_getid(set->page->right)); + bt_unpinpool (set->pool); reuse = 1; } else { new_page = bt_getid(bt->mgr->latchmgr->alloc->right); @@ -1339,7 +1347,6 @@ int reuse; if ( !reuse && bt->mgr->poolmask > 0 && (new_page & bt->mgr->poolmask) == 0 ) { // use zero buffer to write zeros - memset(bt->zero, 0, bt->mgr->page_size); if ( pwrite(bt->mgr->idx,bt->zero, bt->mgr->page_size, (new_page | bt->mgr->poolmask) << bt->mgr->page_bits) < bt->mgr->page_size ) return bt->err = BTERR_wrt, 0; } @@ -1347,13 +1354,13 @@ int reuse; // bring new page into pool and copy page. // this will extend the file into the new pages. - if( pool = bt_pinpool (bt, new_page) ) - pmap = bt_page (bt, pool, new_page); + if( set->pool = bt_pinpool (bt, new_page) ) + set->page = bt_page (bt, set->pool, new_page); else return 0; - memcpy(pmap, page, bt->mgr->page_size); - bt_unpinpool (pool); + memcpy(set->page, page, bt->mgr->page_size); + bt_unpinpool (set->pool); #endif // unlock allocation latch and return new page no @@ -1363,142 +1370,161 @@ int reuse; // find slot in page for given key at a given level -int bt_findslot (BtDb *bt, unsigned char *key, uint len) +int bt_findslot (BtPageSet *set, unsigned char *key, uint len) { -uint diff, higher = bt->page->cnt, low = 1, slot; -uint good = 0; +uint diff, higher = set->page->cnt, low = 1, slot; - // if no right link // make stopper key an infinite fence value - // by setting the good flag - if( bt_getid (bt->page->right) ) + if( bt_getid (set->page->right) ) higher++; - else - good++; - // low is the next candidate. + // low is the lowest candidate. // loop ends when they meet - // if good, higher is already + // higher is already // tested as .ge. the given key. while( diff = higher - low ) { slot = low + ( diff >> 1 ); - if( keycmp (keyptr(bt->page, slot), key, len) < 0 ) + if( keycmp (keyptr(set->page, slot), key, len) < 0 ) low = slot + 1; else - higher = slot, good++; + higher = slot; } + if( higher <= set->page->cnt ) + return higher; + + // if leaf page, compare against fence value + // return zero if key is on right link page + // or return slot beyond last key + + if( set->page->lvl || keycmp ((BtKey)set->page->fence, key, len) < 0 ) + return 0; - return good ? higher : 0; + return higher; } // find and load page at given level for given key // leave page rd or wr locked as requested -int bt_loadpage (BtDb *bt, unsigned char *key, uint len, uint lvl, uint lock) +int bt_loadpage (BtDb *bt, BtPageSet *set, unsigned char *key, uint len, uint lvl, uint lock) { uid page_no = ROOT_page, prevpage = 0; -BtLatchSet *set, *prevset; uint drill = 0xff, slot; +BtLatchSet *prevlatch; uint mode, prevmode; BtPool *prevpool; -int parent = 1; // start at root of btree and drill down - bt->set = NULL; - do { // determine lock mode of drill level mode = (lock == BtLockWrite) && (drill == lvl) ? BtLockWrite : BtLockRead; - bt->set = bt_pinlatch (bt, page_no); - bt->page_no = page_no; + set->latch = bt_pinlatch (bt, page_no); + set->page_no = page_no; // pin page contents - if( bt->pool = bt_pinpool (bt, page_no) ) - bt->page = bt_page (bt, bt->pool, page_no); + if( set->pool = bt_pinpool (bt, page_no) ) + set->page = bt_page (bt, set->pool, page_no); else return 0; // obtain access lock using lock chaining with Access mode if( page_no > ROOT_page ) - bt_lockpage(BtLockAccess, bt->set); + bt_lockpage(BtLockAccess, set->latch); // release & unpin parent page if( prevpage ) { - bt_unlockpage(prevmode, prevset); - bt_unpinlatch (prevset); + bt_unlockpage(prevmode, prevlatch); + bt_unpinlatch (prevlatch); bt_unpinpool (prevpool); prevpage = 0; } // obtain read lock using lock chaining - bt_lockpage(mode, bt->set); + bt_lockpage(mode, set->latch); if( page_no > ROOT_page ) - bt_unlockpage(BtLockAccess, bt->set); + bt_unlockpage(BtLockAccess, set->latch); // re-read and re-lock root after determining actual level of root - if( bt->page->lvl != drill) { - if ( bt->page_no != ROOT_page ) + if( set->page->lvl != drill) { + if ( set->page_no != ROOT_page ) return bt->err = BTERR_struct, 0; - drill = bt->page->lvl; + drill = set->page->lvl; if( lock == BtLockWrite && drill == lvl ) { - bt_unlockpage(mode, bt->set); - bt_unpinlatch (bt->set); - bt_unpinpool (bt->pool); + bt_unlockpage(mode, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); continue; } } + prevpage = set->page_no; + prevlatch = set->latch; + prevpool = set->pool; + prevmode = mode; + + // if page is being deleted and we should continue right + + if( set->page->kill && set->page->goright ) { + page_no = bt_getid (set->page->right); + continue; + } + + // otherwise, wait for deleted node to clear + + if( set->page->kill ) { + bt_unlockpage(mode, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); + page_no = ROOT_page; + prevpage = 0; + drill = 0xff; +#ifdef unix + sched_yield(); +#else + SwitchToThread(); +#endif + continue; + } + // find key on page at this level // and descend to requested level - if( slot = bt_findslot (bt, key, len) ) { + if( slot = bt_findslot (set, key, len) ) { if( drill == lvl ) - return bt->parent = parent, slot; + return slot; + + if( slot > set->page->cnt ) + return bt->err = BTERR_struct; - while( slotptr(bt->page, slot)->dead ) - if( slot++ < bt->page->cnt ) + while( slotptr(set->page, slot)->dead ) + if( slot++ < set->page->cnt ) continue; - else { - page_no = bt_getid(bt->page->right); - parent = 0; - goto slideright; - } + else + return bt->err = BTERR_struct, 0; - page_no = bt_getid(slotptr(bt->page, slot)->id); - parent = 1; + page_no = bt_getid(slotptr(set->page, slot)->id); drill--; + continue; } // or slide right into next page - else { - page_no = bt_getid(bt->page->right); - parent = 0; - } - - // continue down / right using overlapping locks - // to protect pages being split. + page_no = bt_getid(set->page->right); -slideright: - prevpage = bt->page_no; - prevpool = bt->pool; - prevset = bt->set; - prevmode = mode; } while( page_no ); // return error on end of right chain @@ -1507,189 +1533,287 @@ slideright: return 0; // return error } -// remove empty page from the B-tree -// by pulling our right node left over ourselves +// drill down fixing fence values for left sibling tree -// call with bt->page, etc, set to page's locked parent -// returns with page locked. +// call with set write locked +// return with set unlocked & unpinned. -BTERR bt_mergeright (BtDb *bt, BtPage page, BtPool *pool, BtLatchSet *set, uid page_no, uint lvl, uint slot) +BTERR bt_fixfences (BtDb *bt, BtPageSet *set, unsigned char *newfence) { -BtLatchSet *rset, *pset, *rpset; -BtPool *rpool, *ppool, *rppool; -BtPage rpage, ppage, rppage; -uid right, parent, rparent; -BtKey ptr; -uint idx; +unsigned char oldfence[256]; +BtPageSet next[1]; +int chk; + + memcpy (oldfence, set->page->fence, 256); + + while( !set->page->kill && set->page->lvl ) { + next->page_no = bt_getid(slotptr(set->page, set->page->cnt)->id); + next->latch = bt_pinlatch (bt, next->page_no); + bt_lockpage (BtLockParent, next->latch); + bt_lockpage (BtLockAccess, next->latch); + bt_lockpage (BtLockWrite, next->latch); + bt_unlockpage (BtLockAccess, next->latch); + + if( next->pool = bt_pinpool (bt, next->page_no) ) + next->page = bt_page (bt, next->pool, next->page_no); + else + return bt->err; - // cache node's parent page + chk = keycmp ((BtKey)next->page->fence, oldfence + 1, *oldfence); - parent = bt->page_no; - ppage = bt->page; - ppool = bt->pool; - pset = bt->set; + if( chk < 0 ) { + next->page_no = bt_getid (next->page->right); + bt_unlockpage (BtLockWrite, next->latch); + bt_unlockpage (BtLockParent, next->latch); + bt_unpinlatch (next->latch); + bt_unpinpool (next->pool); + continue; + } - // lock and map our right page - // it cannot be NULL because of the stopper - // in the last right page + if( chk > 0 ) + return bt->err = BTERR_struct; - bt_lockpage (BtLockWrite, set); + if( bt_fixfences (bt, next, newfence) ) + return bt->err; - // if we aren't dead yet + break; + } - if( page->act ) - goto rmergexit; + memcpy (set->page->fence, newfence, 256); - if( right = bt_getid (page->right) ) - if( rpool = bt_pinpool (bt, right) ) - rpage = bt_page (bt, rpool, right); - else - return bt->err; - else - return bt->err = BTERR_struct; + bt_unlockpage (BtLockWrite, set->latch); + bt_unlockpage (BtLockParent, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); + return 0; +} - rset = bt_pinlatch (bt, right); +// return page to free list +// page must be delete & write locked - // find our right neighbor +void bt_freepage (BtDb *bt, BtPageSet *set) +{ + // lock allocation page - if( ppage->act > 1 ) { - for( idx = slot; idx++ < ppage->cnt; ) - if( !slotptr(ppage, idx)->dead ) - break; + bt_spinwritelock (bt->mgr->latchmgr->lock); - if( idx > ppage->cnt ) - return bt->err = BTERR_struct; + // store chain in second right + bt_putid(set->page->right, bt_getid(bt->mgr->latchmgr->alloc[1].right)); + bt_putid(bt->mgr->latchmgr->alloc[1].right, set->page_no); + set->page->free = 1; - // redirect right neighbor in parent to left node + // unlock released page - bt_putid(slotptr(ppage,idx)->id, page_no); - } + bt_unlockpage (BtLockDelete, set->latch); + bt_unlockpage (BtLockWrite, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); - // if parent has only our deleted page, e.g. no right neighbor - // prepare to merge parent itself + // unlock allocation page - if( ppage->act == 1 ) { - if( rparent = bt_getid (ppage->right) ) - if( rppool = bt_pinpool (bt, rparent) ) - rppage = bt_page (bt, rppool, rparent); - else - return bt->err; + bt_spinreleasewrite (bt->mgr->latchmgr->lock); +} + +// remove the root level by promoting its only child +// call with parent and child pages + +BTERR bt_removeroot (BtDb *bt, BtPageSet *root, BtPageSet *child) +{ +uid next = 0; + + do { + if( next ) { + child->latch = bt_pinlatch (bt, next); + bt_lockpage (BtLockDelete, child->latch); + bt_lockpage (BtLockWrite, child->latch); + + if( child->pool = bt_pinpool (bt, next) ) + child->page = bt_page (bt, child->pool, next); else - return bt->err = BTERR_struct; + return bt->err; + + child->page_no = next; + } + + memcpy (root->page, child->page, bt->mgr->page_size); + next = bt_getid (slotptr(child->page, child->page->cnt)->id); + bt_freepage (bt, child); + } while( root->page->lvl > 1 && root->page->cnt == 1 ); + + bt_unlockpage (BtLockWrite, root->latch); + bt_unpinlatch (root->latch); + bt_unpinpool (root->pool); + return 0; +} + +// pull right page over ourselves in simple merge + +BTERR bt_mergeright (BtDb *bt, BtPageSet *set, BtPageSet *parent, BtPageSet *right, uint slot, uint idx) +{ + // install ourselves as child page + // and delete ourselves from parent - rpset = bt_pinlatch (bt, rparent); - bt_lockpage (BtLockWrite, rpset); + bt_putid (slotptr(parent->page, idx)->id, set->page_no); + slotptr(parent->page, slot)->dead = 1; + parent->page->act--; - // find our right neighbor on right parent page + // collapse any empty slots - for( idx = 0; idx++ < rppage->cnt; ) - if( !slotptr(rppage, idx)->dead ) { - bt_putid (slotptr(rppage, idx)->id, page_no); + while( idx = parent->page->cnt - 1 ) + if( slotptr(parent->page, idx)->dead ) { + *slotptr(parent->page, idx) = *slotptr(parent->page, idx + 1); + memset (slotptr(parent->page, parent->page->cnt--), 0, sizeof(BtSlot)); + } else break; - } - if( idx > rppage->cnt ) - return bt->err = BTERR_struct; - } + memcpy (set->page, right->page, bt->mgr->page_size); + bt_unlockpage (BtLockParent, right->latch); - // now that there are no more pointers to our right node - // we can wait for delete lock on it + bt_freepage (bt, right); - bt_lockpage(BtLockDelete, rset); - bt_lockpage(BtLockWrite, rset); + // do we need to remove a btree level? + // (leave the first page of leaves alone) - // pull contents of right page into our empty page + if( parent->page_no == ROOT_page && parent->page->cnt == 1 ) + if( set->page->lvl ) + return bt_removeroot (bt, parent, set); - memcpy (page, rpage, bt->mgr->page_size); + bt_unlockpage (BtLockWrite, parent->latch); + bt_unlockpage (BtLockDelete, set->latch); + bt_unlockpage (BtLockWrite, set->latch); + bt_unpinlatch (parent->latch); + bt_unpinpool (parent->pool); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); + return 0; +} - // ready to release right parent lock - // now that we have a new page in place +// remove both child and parent from the btree +// from the fence position in the parent +// call with both pages locked for writing - if( ppage->act == 1 ) { - bt_unlockpage (BtLockWrite, rpset); - bt_unpinlatch (rpset); - bt_unpinpool (rppool); - } +BTERR bt_removeparent (BtDb *bt, BtPageSet *child, BtPageSet *parent, BtPageSet *right, BtPageSet *rparent, uint lvl) +{ +unsigned char pagefence[256]; +uint idx; - // add killed right block to free chain - // lock latch mgr + // pull right sibling over ourselves and unlock - bt_spinwritelock(bt->mgr->latchmgr->lock); + memcpy (child->page, right->page, bt->mgr->page_size); - // store free chain in allocation page second right + bt_unlockpage (BtLockWrite, child->latch); + bt_unpinlatch (child->latch); + bt_unpinpool (child->pool); - bt_putid(rpage->right, bt_getid(bt->mgr->latchmgr->alloc[1].right)); - bt_putid(bt->mgr->latchmgr->alloc[1].right, right); + // install ourselves into right link of old right page - // unlock latch mgr and right page + bt_putid (right->page->right, child->page_no); + right->page->goright = 1; // tell bt_loadpage to go right to us + right->page->kill = 1; - bt_unlockpage(BtLockDelete, rset); - bt_unlockpage(BtLockWrite, rset); - bt_unpinlatch (rset); - bt_unpinpool (rpool); + bt_unlockpage (BtLockWrite, right->latch); - bt_spinreleasewrite(bt->mgr->latchmgr->lock); + // remove our slot from our parent + // signal to move right - // delete our obsolete fence key from our parent + parent->page->goright = 1; // tell bt_loadpage to go right to rparent + parent->page->kill = 1; + parent->page->act--; - slotptr(ppage, slot)->dead = 1; - ppage->dirty = 1; + // redirect right page pointer in right parent to us - // if our parent now empty - // remove it from the tree + for( idx = 0; idx++ < rparent->page->cnt; ) + if( !slotptr(rparent->page, idx)->dead ) + break; - if( ppage->act-- == 1 ) - if( bt_mergeleft (bt, ppage, ppool, pset, parent, lvl+1) ) - return bt->err; + if( bt_getid (slotptr(rparent->page, idx)->id) != right->page_no ) + return bt->err = BTERR_struct; -rmergexit: - bt_unlockpage (BtLockWrite, pset); - bt_unpinlatch (pset); - bt_unpinpool (ppool); + bt_putid (slotptr(rparent->page, idx)->id, child->page_no); + bt_unlockpage (BtLockWrite, rparent->latch); + bt_unpinlatch (rparent->latch); + bt_unpinpool (rparent->pool); - bt->found = 1; - return bt->err = 0; -} + // free the right page + + bt_lockpage (BtLockDelete, right->latch); + bt_lockpage (BtLockWrite, right->latch); + bt_freepage (bt, right); + + // save parent page fence value -// remove empty page from the B-tree -// try merging left first. If no left -// sibling, then merge right. + memcpy (pagefence, parent->page->fence, 256); + bt_unlockpage (BtLockWrite, parent->latch); -// call with page loaded and locked, -// return with page locked. + return bt_removepage (bt, parent, lvl, pagefence); +} + +// remove page from btree +// call with page unlocked +// returns with page on free list -BTERR bt_mergeleft (BtDb *bt, BtPage page, BtPool *pool, BtLatchSet *set, uid page_no, uint lvl) +BTERR bt_removepage (BtDb *bt, BtPageSet *set, uint lvl, unsigned char *pagefence) { -unsigned char fencekey[256], postkey[256]; -uint slot, idx, postfence = 0; -BtLatchSet *lset, *pset; -BtPool *lpool, *ppool; -BtPage lpage, ppage; -uid left, parent; +BtPageSet parent[1], sibling[1], rparent[1]; +unsigned char newfence[256]; +uint slot, idx; BtKey ptr; - ptr = keyptr(page, page->cnt); - memcpy(fencekey, ptr, ptr->len + 1); - bt_unlockpage (BtLockWrite, set); - // load and lock our parent retry: - if( !(slot = bt_loadpage (bt, fencekey+1, *fencekey, lvl+1, BtLockWrite)) ) + if( !(slot = bt_loadpage (bt, parent, pagefence+1, *pagefence, lvl+1, BtLockWrite)) ) return bt->err; - parent = bt->page_no; - ppage = bt->page; - ppool = bt->pool; - pset = bt->set; + // can we do a simple merge entirely + // between siblings on the parent page? - // wait until we are posted in our parent + if( slot < parent->page->cnt ) { + // find our right neighbor + // right must exist because the stopper prevents + // the rightmost page from deleting - if( !bt->parent ) { - bt_unlockpage (BtLockWrite, pset); - bt_unpinlatch (pset); - bt_unpinpool (ppool); -#ifdef unix + for( idx = slot; idx++ < parent->page->cnt; ) + if( !slotptr(parent->page, idx)->dead ) + break; + + sibling->page_no = bt_getid (slotptr (parent->page, idx)->id); + + bt_lockpage (BtLockDelete, set->latch); + bt_lockpage (BtLockWrite, set->latch); + + // merge right if sibling shows up in + // our parent and is not being killed + + if( sibling->page_no == bt_getid (set->page->right) ) { + sibling->latch = bt_pinlatch (bt, sibling->page_no); + bt_lockpage (BtLockParent, sibling->latch); + bt_lockpage (BtLockDelete, sibling->latch); + bt_lockpage (BtLockWrite, sibling->latch); + + if( sibling->pool = bt_pinpool (bt, sibling->page_no) ) + sibling->page = bt_page (bt, sibling->pool, sibling->page_no); + else + return bt->err; + + if( !sibling->page->kill ) + return bt_mergeright(bt, set, parent, sibling, slot, idx); + + // try again later + + bt_unlockpage (BtLockWrite, sibling->latch); + bt_unlockpage (BtLockParent, sibling->latch); + bt_unlockpage (BtLockDelete, sibling->latch); + bt_unpinlatch (sibling->latch); + bt_unpinpool (sibling->pool); + } + + bt_unlockpage (BtLockDelete, set->latch); + bt_unlockpage (BtLockWrite, set->latch); + bt_unlockpage (BtLockWrite, parent->latch); + bt_unpinlatch (parent->latch); + bt_unpinpool (parent->pool); +#ifdef linux sched_yield(); #else SwitchToThread(); @@ -1700,35 +1824,59 @@ retry: // find our left neighbor in our parent page for( idx = slot; --idx; ) - if( !slotptr(ppage, idx)->dead ) + if( !slotptr(parent->page, idx)->dead ) break; - // if no left neighbor, do right merge + // if no left neighbor, delete ourselves and our parent - if( !idx ) - return bt_mergeright (bt, page, pool, set, page_no, lvl, slot); + if( !idx ) { + bt_lockpage (BtLockAccess, set->latch); + bt_lockpage (BtLockWrite, set->latch); + bt_unlockpage (BtLockAccess, set->latch); - // lock and map our left neighbor's page + rparent->page_no = bt_getid (parent->page->right); + rparent->latch = bt_pinlatch (bt, rparent->page_no); - left = bt_getid (slotptr(ppage, idx)->id); + bt_lockpage (BtLockAccess, rparent->latch); + bt_lockpage (BtLockWrite, rparent->latch); + bt_unlockpage (BtLockAccess, rparent->latch); - if( lpool = bt_pinpool (bt, left) ) - lpage = bt_page (bt, lpool, left); - else - return bt->err; + if( rparent->pool = bt_pinpool (bt, rparent->page_no) ) + rparent->page = bt_page (bt, rparent->pool, rparent->page_no); + else + return bt->err; + + if( !rparent->page->kill ) { + sibling->page_no = bt_getid (set->page->right); + sibling->latch = bt_pinlatch (bt, sibling->page_no); - lset = bt_pinlatch (bt, left); - bt_lockpage(BtLockWrite, lset); + bt_lockpage (BtLockAccess, sibling->latch); + bt_lockpage (BtLockWrite, sibling->latch); + bt_unlockpage (BtLockAccess, sibling->latch); - // wait until sibling is in our parent + if( sibling->pool = bt_pinpool (bt, sibling->page_no) ) + sibling->page = bt_page (bt, sibling->pool, sibling->page_no); + else + return bt->err; + + if( !sibling->page->kill ) + return bt_removeparent (bt, set, parent, sibling, rparent, lvl+1); + + // try again later - if( bt_getid (lpage->right) != page_no ) { - bt_unlockpage (BtLockWrite, pset); - bt_unpinlatch (pset); - bt_unpinpool (ppool); - bt_unlockpage (BtLockWrite, lset); - bt_unpinlatch (lset); - bt_unpinpool (lpool); + bt_unlockpage (BtLockWrite, sibling->latch); + bt_unpinlatch (sibling->latch); + bt_unpinpool (sibling->pool); + } + + bt_unlockpage (BtLockWrite, set->latch); + bt_unlockpage (BtLockWrite, rparent->latch); + bt_unpinlatch (rparent->latch); + bt_unpinpool (rparent->pool); + + bt_unlockpage (BtLockWrite, parent->latch); + bt_unpinlatch (parent->latch); + bt_unpinpool (parent->pool); #ifdef linux sched_yield(); #else @@ -1737,114 +1885,97 @@ retry: goto retry; } - // since our page will have no more pointers to it, - // obtain Delete lock and wait for write locks to clear - - bt_lockpage(BtLockDelete, set); - bt_lockpage(BtLockWrite, set); - - // if we aren't dead yet, - // get ready for exit - - if( page->act ) { - bt_unlockpage(BtLockDelete, set); - bt_unlockpage(BtLockWrite, lset); - bt_unpinlatch (lset); - bt_unpinpool (lpool); - goto lmergexit; - } - - // are we are the fence key for our parent? - // if so, grab our old fence key + // redirect parent to our left sibling + // lock and map our left sibling's page - if( postfence = slot == ppage->cnt ) { - ptr = keyptr (ppage, ppage->cnt); - memcpy(fencekey, ptr, ptr->len + 1); - memset(slotptr(ppage, ppage->cnt), 0, sizeof(BtSlot)); - - // clear out other dead slots - - while( --ppage->cnt ) - if( slotptr(ppage, ppage->cnt)->dead ) - memset(slotptr(ppage, ppage->cnt), 0, sizeof(BtSlot)); - else - break; + sibling->page_no = bt_getid (slotptr(parent->page, idx)->id); + sibling->latch = bt_pinlatch (bt, sibling->page_no); - ptr = keyptr (ppage, ppage->cnt); - memcpy(postkey, ptr, ptr->len + 1); - } else - slotptr(ppage,slot)->dead = 1; + // wait our turn on fence key maintenance - ppage->dirty = 1; - ppage->act--; + bt_lockpage(BtLockParent, sibling->latch); + bt_lockpage(BtLockAccess, sibling->latch); + bt_lockpage(BtLockWrite, sibling->latch); + bt_unlockpage(BtLockAccess, sibling->latch); - // push our right neighbor pointer to our left - - memcpy (lpage->right, page->right, BtId); + if( sibling->pool = bt_pinpool (bt, sibling->page_no) ) + sibling->page = bt_page (bt, sibling->pool, sibling->page_no); + else + return bt->err; - // add ourselves to free chain - // lock latch mgr + // wait until left sibling is in our parent - bt_spinwritelock(bt->mgr->latchmgr->lock); + if( bt_getid (sibling->page->right) != set->page_no ) { + bt_unlockpage (BtLockWrite, parent->latch); + bt_unlockpage (BtLockWrite, sibling->latch); + bt_unlockpage (BtLockParent, sibling->latch); + bt_unpinlatch (parent->latch); + bt_unpinpool (parent->pool); + bt_unpinlatch (sibling->latch); + bt_unpinpool (sibling->pool); +#ifdef linux + sched_yield(); +#else + SwitchToThread(); +#endif + goto retry; + } - // store free chain in allocation page second right - bt_putid(page->right, bt_getid(bt->mgr->latchmgr->alloc[1].right)); - bt_putid(bt->mgr->latchmgr->alloc[1].right, page_no); + // delete our left sibling from parent - // unlock latch mgr and pages + slotptr(parent->page,idx)->dead = 1; + parent->page->dirty = 1; + parent->page->act--; - bt_spinreleasewrite(bt->mgr->latchmgr->lock); - bt_unlockpage(BtLockWrite, lset); - bt_unpinlatch (lset); - bt_unpinpool (lpool); + // redirect our parent slot to our left sibling - // release our node's delete lock + bt_putid (slotptr(parent->page, slot)->id, sibling->page_no); + memcpy (sibling->page->right, set->page->right, BtId); - bt_unlockpage(BtLockDelete, set); + // collapse dead slots from parent -lmergexit: - bt_unlockpage (BtLockWrite, pset); - bt_unpinpool (ppool); + while( idx = parent->page->cnt - 1 ) + if( slotptr(parent->page, idx)->dead ) { + *slotptr(parent->page, idx) = *slotptr(parent->page, parent->page->cnt); + memset (slotptr(parent->page, parent->page->cnt--), 0, sizeof(BtSlot)); + } else + break; - // do we need to post parent's fence key in its parent? + // free our original page - if( !postfence || parent == ROOT_page ) { - bt_unpinlatch (pset); - bt->found = 1; - return bt->err = 0; - } + bt_lockpage (BtLockDelete, set->latch); + bt_lockpage (BtLockWrite, set->latch); + bt_freepage (bt, set); - // interlock parent fence post + // go down the left node's fence keys to the leaf level + // and update the fence keys in each page - bt_lockpage (BtLockParent, pset); + memcpy (newfence, parent->page->fence, 256); - // load parent's parent page -posttry: - if( !(slot = bt_loadpage (bt, fencekey+1, *fencekey, lvl+2, BtLockWrite)) ) + if( bt_fixfences (bt, sibling, newfence) ) return bt->err; - if( !(slot = bt_cleanpage (bt, bt->page, *fencekey, slot)) ) - if( bt_splitpage (bt, bt->page, bt->pool, bt->set, bt->page_no) ) - return bt->err; - else - goto posttry; + // promote sibling as new root? - page = bt->page; + if( parent->page_no == ROOT_page && parent->page->cnt == 1 ) + if( sibling->page->lvl ) { + sibling->latch = bt_pinlatch (bt, sibling->page_no); + bt_lockpage (BtLockDelete, sibling->latch); + bt_lockpage (BtLockWrite, sibling->latch); - page->min -= *postkey + 1; - ((unsigned char *)page)[page->min] = *postkey; - memcpy ((unsigned char *)page + page->min +1, postkey + 1, *postkey ); - slotptr(page, slot)->off = page->min; + if( sibling->pool = bt_pinpool (bt, sibling->page_no) ) + sibling->page = bt_page (bt, sibling->pool, sibling->page_no); + else + return bt->err; - bt_unlockpage (BtLockParent, pset); - bt_unpinlatch (pset); + return bt_removeroot (bt, parent, sibling); + } - bt_unlockpage (BtLockWrite, bt->set); - bt_unpinlatch (bt->set); - bt_unpinpool (bt->pool); + bt_unlockpage (BtLockWrite, parent->latch); + bt_unpinlatch (parent->latch); + bt_unpinpool (parent->pool); - bt->found = 1; - return bt->err = 0; + return 0; } // find and delete key on page by marking delete flag bit @@ -1852,65 +1983,79 @@ posttry: BTERR bt_deletekey (BtDb *bt, unsigned char *key, uint len) { -BtLatchSet *set; -BtPool *pool; -BtPage page; -uid page_no; +unsigned char pagefence[256]; +uint slot, idx, found; +BtPageSet set[1]; BtKey ptr; -uint slot; - if( !(slot = bt_loadpage (bt, key, len, 0, BtLockWrite)) ) + if( slot = bt_loadpage (bt, set, key, len, 0, BtLockWrite) ) + ptr = keyptr(set->page, slot); + else return bt->err; - page_no = bt->page_no; - page = bt->page; - pool = bt->pool; - set = bt->set; - // if key is found delete it, otherwise ignore request - ptr = keyptr(page, slot); + if( found = slot <= set->page->cnt ) + if( found = !keycmp (ptr, key, len) ) + if( found = slotptr(set->page, slot)->dead == 0 ) { + slotptr(set->page,slot)->dead = 1; + set->page->dirty = 1; + set->page->act--; + + // collapse empty slots - if( bt->found = !keycmp (ptr, key, len) ) - if( bt->found = slotptr(page, slot)->dead == 0 ) { - slotptr(page,slot)->dead = 1; - if( slot < page->cnt ) - page->dirty = 1; - if( !--page->act ) - if( bt_mergeleft (bt, page, pool, set, page_no, 0) ) - return bt->err; + while( idx = set->page->cnt - 1 ) + if( slotptr(set->page, idx)->dead ) { + *slotptr(set->page, idx) = *slotptr(set->page, idx + 1); + memset (slotptr(set->page, set->page->cnt--), 0, sizeof(BtSlot)); + } else + break; } - bt_unlockpage(BtLockWrite, set); - bt_unpinlatch (set); - bt_unpinpool (pool); - return bt->err = 0; + if( set->page->act ) { + bt_unlockpage(BtLockWrite, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); + return bt->found = found, 0; + } + + memcpy (pagefence, set->page->fence, 256); + set->page->kill = 1; + + bt_unlockpage (BtLockWrite, set->latch); + + if( bt_removepage (bt, set, 0, pagefence) ) + return bt->err; + + bt->found = found; + return 0; } // find key in leaf level and return row-id uid bt_findkey (BtDb *bt, unsigned char *key, uint len) { +BtPageSet set[1]; uint slot; BtKey ptr; uid id; - if( slot = bt_loadpage (bt, key, len, 0, BtLockRead) ) - ptr = keyptr(bt->page, slot); + if( slot = bt_loadpage (bt, set, key, len, 0, BtLockRead) ) + ptr = keyptr(set->page, slot); else return 0; // if key exists, return row-id // otherwise return 0 - if( slot <= bt->page->cnt && !keycmp (ptr, key, len) ) - id = bt_getid(slotptr(bt->page,slot)->id); + if( !keycmp (ptr, key, len) ) + id = bt_getid(slotptr(set->page,slot)->id); else id = 0; - bt_unlockpage (BtLockRead, bt->set); - bt_unpinlatch (bt->set); - bt_unpinpool (bt->pool); + bt_unlockpage (BtLockRead, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); return id; } @@ -1921,7 +2066,7 @@ uid id; uint bt_cleanpage(BtDb *bt, BtPage page, uint amt, uint slot) { -uint nxt = bt->mgr->page_size; +uint nxt = bt->mgr->page_size, off; uint cnt = 0, idx = 0; uint max = page->cnt; uint newslot = max; @@ -1944,28 +2089,31 @@ BtKey key; page->act = 0; // try cleaning up page first - - // always leave fence key in the array - // otherwise, remove deleted key + // by removing deleted keys while( cnt++ < max ) { if( cnt == slot ) newslot = idx + 1; - if( cnt < max && slotptr(bt->frame,cnt)->dead ) + if( slotptr(bt->frame,cnt)->dead ) continue; - // copy key + // if its not the fence key, + // copy the key across - key = keyptr(bt->frame, cnt); - nxt -= key->len + 1; - memcpy ((unsigned char *)page + nxt, key, key->len + 1); + off = slotptr(bt->frame,cnt)->off; + + if( off >= sizeof(*page) ) { + key = keyptr(bt->frame, cnt); + off = nxt -= key->len + 1; + memcpy ((unsigned char *)page + nxt, key, key->len + 1); + } // copy slot + memcpy(slotptr(page, ++idx)->id, slotptr(bt->frame, cnt)->id, BtId); - if( !(slotptr(page, idx)->dead = slotptr(bt->frame, cnt)->dead) ) - page->act++; slotptr(page, idx)->tod = slotptr(bt->frame, cnt)->tod; - slotptr(page, idx)->off = nxt; + slotptr(page, idx)->off = off; + page->act++; } page->min = nxt; @@ -1979,202 +2127,192 @@ BtKey key; return 0; } -// add key to current page -// page must already be writelocked - -void bt_addkeytopage (BtDb *bt, BtPage page, uint slot, unsigned char *key, uint len, uid id, uint tod) -{ -uint idx; - - // find next available dead slot and copy key onto page - - for( idx = slot; idx < page->cnt; idx++ ) - if( slotptr(page, idx)->dead ) - break; - - if( idx == page->cnt ) - idx++, page->cnt++; - - page->act++; +// split the root and raise the height of the btree - // now insert key into array before slot - - while( idx > slot ) - *slotptr(page, idx) = *slotptr(page, idx -1), idx--; - - page->min -= len + 1; - ((unsigned char *)page)[page->min] = len; - memcpy ((unsigned char *)page + page->min +1, key, len ); - - bt_putid(slotptr(page,slot)->id, id); - slotptr(page, slot)->off = page->min; - slotptr(page, slot)->tod = tod; - slotptr(page, slot)->dead = 0; -} - -BTERR bt_splitroot(BtDb *bt, unsigned char *leftkey, uid page_no2) +BTERR bt_splitroot(BtDb *bt, BtPageSet *root, uid page_no2) { uint nxt = bt->mgr->page_size; -BtPage root = bt->page; +unsigned char leftkey[256]; uid new_page; // Obtain an empty page to use, and copy the current - // root contents into it + // root contents into it, e.g. lower keys + + memcpy (leftkey, root->page->fence, 256); + root->page->posted = 1; - if( !(new_page = bt_newpage(bt, root)) ) + if( !(new_page = bt_newpage(bt, root->page)) ) return bt->err; // preserve the page info at the bottom - // and set rest to zero + // of higher keys and set rest to zero - memset(root+1, 0, bt->mgr->page_size - sizeof(*root)); + memset(root->page+1, 0, bt->mgr->page_size - sizeof(*root->page)); + memset(root->page->fence, 0, 256); + root->page->fence[0] = 2; + root->page->fence[1] = 0xff; + root->page->fence[2] = 0xff; - // insert first key on newroot page + // insert lower keys page fence key on newroot page nxt -= *leftkey + 1; - memcpy ((unsigned char *)root + nxt, leftkey, *leftkey + 1); - bt_putid(slotptr(root, 1)->id, new_page); - slotptr(root, 1)->off = nxt; + memcpy ((unsigned char *)root->page + nxt, leftkey, *leftkey + 1); + bt_putid(slotptr(root->page, 1)->id, new_page); + slotptr(root->page, 1)->off = nxt; - // insert second key (stopper key) on newroot page + // insert stopper key on newroot page // and increase the root height - nxt -= 3; - *((unsigned char *)root + nxt) = 2; - memset ((unsigned char *)root + nxt + 1, 0xff, 2); - bt_putid(slotptr(root, 2)->id, page_no2); - slotptr(root, 2)->off = nxt; + bt_putid(slotptr(root->page, 2)->id, page_no2); + slotptr(root->page, 2)->off = offsetof(struct BtPage_, fence); - bt_putid(root->right, 0); - root->min = nxt; // reset lowest used offset and key count - root->cnt = 2; - root->act = 2; - root->lvl++; + bt_putid(root->page->right, 0); + root->page->min = nxt; // reset lowest used offset and key count + root->page->cnt = 2; + root->page->act = 2; + root->page->lvl++; - // release and unpin root (bt->page) + // release and unpin root - bt_unlockpage(BtLockWrite, bt->set); - bt_unpinlatch (bt->set); - bt_unpinpool (bt->pool); + bt_unlockpage(BtLockWrite, root->latch); + bt_unpinlatch (root->latch); + bt_unpinpool (root->pool); return 0; } // split already locked full node -// return unlocked and unpinned. +// return unlocked. -BTERR bt_splitpage (BtDb *bt, BtPage page, BtPool *pool, BtLatchSet *set, uid page_no) +BTERR bt_splitpage (BtDb *bt, BtPageSet *set) { -uint slot, cnt, idx, max, nxt = bt->mgr->page_size; -unsigned char rightkey[256], leftkey[256]; -uint tod = time(NULL); -uint lvl = page->lvl; -uid new_page; +uint cnt = 0, idx = 0, max, nxt = bt->mgr->page_size, off; +unsigned char fencekey[256]; +uint lvl = set->page->lvl; +uid right; BtKey key; - // initialize frame buffer for right node + // split higher half of keys to bt->frame memset (bt->frame, 0, bt->mgr->page_size); - max = page->cnt; + max = set->page->cnt; cnt = max / 2; idx = 0; - // split higher half of keys to bt->frame - while( cnt++ < max ) { - key = keyptr(page, cnt); - nxt -= key->len + 1; - memcpy ((unsigned char *)bt->frame + nxt, key, key->len + 1); - memcpy(slotptr(bt->frame,++idx)->id, slotptr(page,cnt)->id, BtId); - if( !(slotptr(bt->frame, idx)->dead = slotptr(page, cnt)->dead) ) - bt->frame->act++; - slotptr(bt->frame, idx)->tod = slotptr(page, cnt)->tod; - slotptr(bt->frame, idx)->off = nxt; + if( !lvl || cnt < max ) { + key = keyptr(set->page, cnt); + off = nxt -= key->len + 1; + memcpy ((unsigned char *)bt->frame + nxt, key, key->len + 1); + } else + off = offsetof(struct BtPage_, fence); + + memcpy(slotptr(bt->frame,++idx)->id, slotptr(set->page,cnt)->id, BtId); + slotptr(bt->frame, idx)->tod = slotptr(set->page, cnt)->tod; + slotptr(bt->frame, idx)->off = off; + bt->frame->act++; } - // transfer right link node to new right node - - if( page_no > ROOT_page ) - memcpy (bt->frame->right, page->right, BtId); + if( set->page_no == ROOT_page ) + bt->frame->posted = 1; + memcpy (bt->frame->fence, set->page->fence, 256); bt->frame->bits = bt->mgr->page_bits; bt->frame->min = nxt; bt->frame->cnt = idx; bt->frame->lvl = lvl; - // get new free page and write right frame to it. + // link right node - if( !(new_page = bt_newpage(bt, bt->frame)) ) - return bt->err; + if( set->page_no > ROOT_page ) + memcpy (bt->frame->right, set->page->right, BtId); - // remember fence key for new right page to add - // as right sibling to the left node + // get new free page and write higher keys to it. - key = keyptr(bt->frame, idx); - memcpy (rightkey, key, key->len + 1); + if( !(right = bt_newpage(bt, bt->frame)) ) + return bt->err; // update lower keys to continue in old page - memcpy (bt->frame, page, bt->mgr->page_size); - memset (page+1, 0, bt->mgr->page_size - sizeof(*page)); + memcpy (bt->frame, set->page, bt->mgr->page_size); + memset (set->page+1, 0, bt->mgr->page_size - sizeof(*set->page)); nxt = bt->mgr->page_size; - page->dirty = 0; - page->act = 0; + set->page->posted = 0; + set->page->dirty = 0; + set->page->act = 0; cnt = 0; idx = 0; // assemble page of smaller keys - // to remain in the old page while( cnt++ < max / 2 ) { key = keyptr(bt->frame, cnt); - nxt -= key->len + 1; - memcpy ((unsigned char *)page + nxt, key, key->len + 1); - memcpy (slotptr(page,++idx)->id, slotptr(bt->frame,cnt)->id, BtId); - if( !(slotptr(page, idx)->dead = slotptr(bt->frame, cnt)->dead) ) - page->act++; - slotptr(page, idx)->tod = slotptr(bt->frame, cnt)->tod; - slotptr(page, idx)->off = nxt; - } - // finalize left page and save fence key + if( !lvl || cnt < max / 2 ) { + off = nxt -= key->len + 1; + memcpy ((unsigned char *)set->page + nxt, key, key->len + 1); + } else + off = offsetof(struct BtPage_, fence); - memcpy(leftkey, key, key->len + 1); - page->min = nxt; - page->cnt = idx; + memcpy(slotptr(set->page,++idx)->id, slotptr(bt->frame,cnt)->id, BtId); + slotptr(set->page, idx)->tod = slotptr(bt->frame, cnt)->tod; + slotptr(set->page, idx)->off = off; + set->page->act++; + } + + // install fence key for smaller key page - // link new right page + memset(set->page->fence, 0, 256); + memcpy(set->page->fence, key, key->len + 1); - bt_putid (page->right, new_page); + bt_putid(set->page->right, right); + set->page->min = nxt; + set->page->cnt = idx; // if current page is the root page, split it - if( page_no == ROOT_page ) - return bt_splitroot (bt, leftkey, new_page); + if( set->page_no == ROOT_page ) + return bt_splitroot (bt, set, right); - // obtain ParentModification lock for current page + bt_unlockpage (BtLockWrite, set->latch); - bt_lockpage (BtLockParent, set); + // insert new fences in their parent pages - // release wr lock on our page. - // this will keep out another SMO + while( 1 ) { + bt_lockpage (BtLockParent, set->latch); + bt_lockpage (BtLockWrite, set->latch); - bt_unlockpage (BtLockWrite, set); + memcpy (fencekey, set->page->fence, 256); + right = bt_getid (set->page->right); - // insert key for old page (lower keys) + if( set->page->posted ) { + bt_unlockpage (BtLockParent, set->latch); + bt_unlockpage (BtLockWrite, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); + return 0; + } - if( bt_insertkey (bt, leftkey + 1, *leftkey, page_no, tod, lvl + 1) ) - return bt->err; + set->page->posted = 1; + bt_unlockpage (BtLockWrite, set->latch); - // switch old parent key from us to our right page + if( bt_insertkey (bt, fencekey+1, *fencekey, set->page_no, time(NULL), lvl+1) ) + return bt->err; - if( bt_insertkey (bt, rightkey + 1, *rightkey, new_page, tod, lvl + 1) ) - return bt->err; + bt_unlockpage (BtLockParent, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); - // unlock and unpin + if( !(set->page_no = right) ) + break; + + set->latch = bt_pinlatch (bt, right); + + if( set->pool = bt_pinpool (bt, right) ) + set->page = bt_page (bt, set->pool, right); + else + return bt->err; + } - bt_unlockpage (BtLockParent, set); - bt_unpinlatch (set); - bt_unpinpool (pool); return 0; } @@ -2182,13 +2320,13 @@ BtKey key; BTERR bt_insertkey (BtDb *bt, unsigned char *key, uint len, uid id, uint tod, uint lvl) { +BtPageSet set[1]; uint slot, idx; -BtPage page; BtKey ptr; while( 1 ) { - if( slot = bt_loadpage (bt, key, len, lvl, BtLockWrite) ) - ptr = keyptr(bt->page, slot); + if( slot = bt_loadpage (bt, set, key, len, lvl, BtLockWrite) ) + ptr = keyptr(set->page, slot); else { if ( !bt->err ) @@ -2198,34 +2336,56 @@ BtKey ptr; // if key already exists, update id and return - page = bt->page; - - if( !keycmp (ptr, key, len) ) { - if( slotptr(page, slot)->dead ) - page->act++; - slotptr(page, slot)->dead = 0; - slotptr(page, slot)->tod = tod; - bt_putid(slotptr(page,slot)->id, id); - bt_unlockpage(BtLockWrite, bt->set); - bt_unpinlatch (bt->set); - bt_unpinpool (bt->pool); - return bt->err; + if( slot <= set->page->cnt ) + if( !keycmp (ptr, key, len) ) { + if( slotptr(set->page, slot)->dead ) + set->page->act++; + slotptr(set->page, slot)->dead = 0; + slotptr(set->page, slot)->tod = tod; + bt_putid(slotptr(set->page,slot)->id, id); + bt_unlockpage(BtLockWrite, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); + return 0; } // check if page has enough space - if( slot = bt_cleanpage (bt, bt->page, len, slot) ) + if( slot = bt_cleanpage (bt, set->page, len, slot) ) break; - if( bt_splitpage (bt, bt->page, bt->pool, bt->set, bt->page_no) ) + if( bt_splitpage (bt, set) ) return bt->err; } - bt_addkeytopage (bt, bt->page, slot, key, len, id, tod); + // calculate next available slot and copy key into page + + set->page->min -= len + 1; // reset lowest used offset + ((unsigned char *)set->page)[set->page->min] = len; + memcpy ((unsigned char *)set->page + set->page->min +1, key, len ); + + for( idx = slot; idx <= set->page->cnt; idx++ ) + if( slotptr(set->page, idx)->dead ) + break; + + // now insert key into array before slot + + if( idx > set->page->cnt ) + set->page->cnt++; + + set->page->act++; - bt_unlockpage (BtLockWrite, bt->set); - bt_unpinlatch (bt->set); - bt_unpinpool (bt->pool); + while( idx > slot ) + *slotptr(set->page, idx) = *slotptr(set->page, idx -1), idx--; + + bt_putid(slotptr(set->page,slot)->id, id); + slotptr(set->page, slot)->off = set->page->min; + slotptr(set->page, slot)->tod = tod; + slotptr(set->page, slot)->dead = 0; + + bt_unlockpage (BtLockWrite, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); return 0; } @@ -2233,17 +2393,21 @@ BtKey ptr; uint bt_startkey (BtDb *bt, unsigned char *key, uint len) { +BtPageSet set[1]; uint slot; // cache page for retrieval - if( slot = bt_loadpage (bt, key, len, 0, BtLockRead) ) - memcpy (bt->cursor, bt->page, bt->mgr->page_size); - bt->cursor_page = bt->page_no; + if( slot = bt_loadpage (bt, set, key, len, 0, BtLockRead) ) + memcpy (bt->cursor, set->page, bt->mgr->page_size); + else + return 0; + + bt->cursor_page = set->page_no; - bt_unlockpage(BtLockRead, bt->set); - bt_unpinlatch (bt->set); - bt_unpinpool (bt->pool); + bt_unlockpage(BtLockRead, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); return slot; } @@ -2252,9 +2416,7 @@ uint slot; uint bt_nextkey (BtDb *bt, uint slot) { -BtLatchSet *set; -BtPool *pool; -BtPage page; +BtPageSet set[1]; uid right; do { @@ -2262,7 +2424,7 @@ uid right; while( slot++ < bt->cursor->cnt ) if( slotptr(bt->cursor,slot)->dead ) continue; - else if( right || (slot < bt->cursor->cnt) ) + else if( right || (slot < bt->cursor->cnt) ) // skip infinite stopper return slot; else break; @@ -2271,19 +2433,20 @@ uid right; break; bt->cursor_page = right; - if( pool = bt_pinpool (bt, right) ) - page = bt_page (bt, pool, right); + + if( set->pool = bt_pinpool (bt, right) ) + set->page = bt_page (bt, set->pool, right); else return 0; - set = bt_pinlatch (bt, right); - bt_lockpage(BtLockRead, set); + set->latch = bt_pinlatch (bt, right); + bt_lockpage(BtLockRead, set->latch); - memcpy (bt->cursor, page, bt->mgr->page_size); + memcpy (bt->cursor, set->page, bt->mgr->page_size); - bt_unlockpage(BtLockRead, set); - bt_unpinlatch (set); - bt_unpinpool (pool); + bt_unlockpage(BtLockRead, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); slot = 0; } while( 1 ); @@ -2311,45 +2474,56 @@ uint bt_tod(BtDb *bt, uint slot) void bt_latchaudit (BtDb *bt) { ushort idx, hashidx; -BtLatchSet *set; +BtLatchSet *latch; BtPool *pool; BtPage page; uid page_no; #ifdef unix for( idx = 1; idx < bt->mgr->latchmgr->latchdeployed; idx++ ) { - set = bt->mgr->latchsets + idx; - if( *(ushort *)set->readwr || *(ushort *)set->access || *(ushort *)set->parent ) { - fprintf(stderr, "latchset %d locked for page %6x\n", idx, set->page_no); - *(ushort *)set->readwr = 0; - *(ushort *)set->access = 0; - *(ushort *)set->parent = 0; + latch = bt->mgr->latchsets + idx; + if( *(ushort *)latch->readwr ) { + fprintf(stderr, "latchset %d r/w locked for page %.8x\n", idx, latch->page_no); + *(ushort *)latch->readwr = 0; + } + if( *(ushort *)latch->access ) { + fprintf(stderr, "latchset %d access locked for page %.8x\n", idx, latch->page_no); + *(ushort *)latch->access = 0; + } + if( *(ushort *)latch->parent ) { + fprintf(stderr, "latchset %d parent locked for page %.8x\n", idx, latch->page_no); + *(ushort *)latch->parent = 0; } - if( set->pin ) { - fprintf(stderr, "latchset %d pinned\n", idx); - set->pin = 0; + if( *(ushort *)latch->busy ) { + fprintf(stderr, "latchset %d busy locked for page %.8x\n", idx, latch->page_no); + *(ushort *)latch->parent = 0; + } + if( latch->pin ) { + fprintf(stderr, "latchset %d pinned for page %.8x\n", idx, latch->page_no); + latch->pin = 0; } } for( hashidx = 0; hashidx < bt->mgr->latchmgr->latchhash; hashidx++ ) { - if( *(uint *)bt->mgr->latchmgr->table[hashidx].latch ) - fprintf(stderr, "latchmgr locked\n"); if( idx = bt->mgr->latchmgr->table[hashidx].slot ) do { - set = bt->mgr->latchsets + idx; - if( *(uint *)set->readwr || *(ushort *)set->access || *(ushort *)set->parent ) - fprintf(stderr, "latchset %d locked\n", idx); - if( set->hash != hashidx ) + latch = bt->mgr->latchsets + idx; + if( latch->hash != hashidx ) { fprintf(stderr, "latchset %d wrong hashidx\n", idx); - if( set->pin ) - fprintf(stderr, "latchset %d pinned\n", idx); - } while( idx = set->next ); + latch->hash = hashidx; + } + } while( idx = latch->next ); } + page_no = bt_getid(bt->mgr->latchmgr->alloc[1].right); while( page_no ) { fprintf(stderr, "free: %.6x\n", (uint)page_no); - pool = bt_pinpool (bt, page_no); - page = bt_page (bt, pool, page_no); + + if( pool = bt_pinpool (bt, page_no) ) + page = bt_page (bt, pool, page_no); + else + return; + page_no = bt_getid(page->right); bt_unpinpool (pool); } @@ -2377,10 +2551,8 @@ uid next, page_no = LEAF_page; // start on first page of leaves unsigned char key[256]; ThreadArg *args = arg; int ch, len = 0, slot; -BtLatchSet *set; +BtPageSet set[1]; time_t tod[1]; -BtPool *pool; -BtPage page; BtKey ptr; BtDb *bt; FILE *in; @@ -2466,38 +2638,49 @@ FILE *in; break; case 's': - len = key[0] = 0; - - fprintf(stderr, "started reading\n"); - - if( slot = bt_startkey (bt, key, len) ) - slot--; - else - fprintf(stderr, "Error %d in StartKey. Syserror: %d\n", bt->err, errno), exit(0); - - while( slot = bt_nextkey (bt, slot) ) { - ptr = bt_key(bt, slot); - fwrite (ptr->key, ptr->len, 1, stdout); - fputc ('\n', stdout); - } + fprintf(stderr, "started scanning\n"); + do { + if( set->pool = bt_pinpool (bt, page_no) ) + set->page = bt_page (bt, set->pool, page_no); + else + break; + set->latch = bt_pinlatch (bt, page_no); + bt_lockpage (BtLockRead, set->latch); + next = bt_getid (set->page->right); + cnt += set->page->act; + + for( slot = 0; slot++ < set->page->cnt; ) + if( next || slot < set->page->cnt ) + if( !slotptr(set->page, slot)->dead ) { + ptr = keyptr(set->page, slot); + fwrite (ptr->key, ptr->len, 1, stdout); + fputc ('\n', stdout); + } + + bt_unlockpage (BtLockRead, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); + } while( page_no = next ); + cnt--; // remove stopper key + fprintf(stderr, " Total keys read %d\n", cnt); break; case 'c': - fprintf(stderr, "started reading\n"); + fprintf(stderr, "started counting\n"); do { - if( pool = bt_pinpool (bt, page_no) ) - page = bt_page (bt, pool, page_no); + if( set->pool = bt_pinpool (bt, page_no) ) + set->page = bt_page (bt, set->pool, page_no); else break; - set = bt_pinlatch (bt, page_no); - bt_lockpage (BtLockRead, set); - cnt += page->act; - next = bt_getid (page->right); - bt_unlockpage (BtLockRead, set); - bt_unpinlatch (set); - bt_unpinpool (pool); + set->latch = bt_pinlatch (bt, page_no); + bt_lockpage (BtLockRead, set->latch); + cnt += set->page->act; + next = bt_getid (set->page->right); + bt_unlockpage (BtLockRead, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); } while( page_no = next ); cnt--; // remove stopper key diff --git a/threads2j.c b/threads2j.c index e9aa1e7..70052ee 100644 --- a/threads2j.c +++ b/threads2j.c @@ -1,5 +1,6 @@ // btree version threads2j linux futex concurrency version -// 30 JAN 2014 +// with reworked bt_deletekey +// 12 FEB 2014 // author: karl malbrain, malbrain@cal.berkeley.edu @@ -52,6 +53,7 @@ REDISTRIBUTION OF THIS SOFTWARE. #include #include +#include typedef unsigned long long uid; @@ -149,14 +151,19 @@ typedef struct { // It is immediately followed // by the BtSlot array of keys. -typedef struct Page { +typedef struct BtPage_ { uint cnt; // count of keys in page uint act; // count of active keys uint min; // next key offset - unsigned char bits; // page size in bits - unsigned char lvl:7; // level of page + unsigned char bits:7; // page size in bits + unsigned char free:1; // page is on free list + unsigned char lvl:4; // level of page + unsigned char kill:1; // page is being deleted unsigned char dirty:1; // page has deleted keys + unsigned char posted:1; // page fence has posted + unsigned char goright:1; // page is being killed, continue to right unsigned char right[BtId]; // page number to right + unsigned char fence[256]; // page fence key } *BtPage; // hash table entries @@ -195,10 +202,19 @@ typedef struct { #endif } BtPool; +// The loadpage interface object + +typedef struct { + uid page_no; // current page number + BtPage page; // current page pointer + BtPool *pool; // current page pool + BtLatchSet *latch; // current page latch set +} BtPageSet; + // structure for latch manager on ALLOC_page typedef struct { - struct Page alloc[2]; // next & free page_nos in right ptr + struct BtPage_ alloc[2]; // next & free page_nos in right ptr BtLatch lock[1]; // allocation area lite latch ushort latchdeployed; // highest number of latch entries deployed ushort nlatchpage; // number of latch pages at BT_latch @@ -240,13 +256,8 @@ typedef struct { BtPage cursor; // cached frame for start/next (never mapped) BtPage frame; // spare frame for the page split (never mapped) BtPage zero; // page of zeroes to extend the file (never mapped) - BtPage page; // current page mapped from file - uid page_no; // current page number uid cursor_page; // current cursor page number - BtLatchSet *set; // current page latchset - BtPool *pool; // current page pool unsigned char *mem; // frame, cursor, page memory buffer - int parent; // last loadpage was from a parent level int found; // last delete or insert was found int err; // last error } BtDb; @@ -271,9 +282,7 @@ extern uint bt_startkey (BtDb *bt, unsigned char *key, uint len); extern uint bt_nextkey (BtDb *bt, uint slot); // internal functions -BTERR bt_splitpage (BtDb *bt, BtPage page, BtPool *pool, BtLatchSet *set, uid page_no); -uint bt_cleanpage(BtDb *bt, BtPage page, uint amt, uint slot); -BTERR bt_mergeleft (BtDb *bt, BtPage page, BtPool *pool, BtLatchSet *set, uid page_no, uint lvl); +BTERR bt_removepage (BtDb *bt, BtPageSet *set, uint lvl, unsigned char *pagefence); // manager functions extern BtMgr *bt_mgr (char *name, uint mode, uint bits, uint poolsize, uint segsize, uint hashsize); @@ -319,8 +328,8 @@ extern uint bt_tod (BtDb *bt, uint slot); // one with two keys. // Deleted keys are marked with a dead bit until -// page cleanup The fence key for a node is always -// present, even after deletion and cleanup. +// page cleanup. The fence key for a node is +// present in a special array. // Groups of pages called segments from the btree are optionally // cached with a memory mapped pool. A hash table is used to keep @@ -335,12 +344,13 @@ extern uint bt_tod (BtDb *bt, uint slot); // Page 0 is dedicated to lock for new page extensions, // and chains empty pages together for reuse. -// The ParentModification lock on a node is obtained to prevent resplitting -// or deleting a node before its fence is posted into its upper level. +// The ParentModification lock on a node is obtained to serialize posting +// or changing the fence key for a node. // Empty pages are chained together through the ALLOC page and reused. // Access macros to address slot and key values from the page +// Page slots use 1 based indexing. #define slotptr(page, slot) (((BtSlot *)(page+1)) + (slot-1)) #define keyptr(page, slot) ((BtKey)((unsigned char*)(page) + slotptr(page, slot)->off)) @@ -907,13 +917,12 @@ SYSTEM_INFO sysinfo[1]; latchmgr->alloc->bits = mgr->page_bits; for( lvl=MIN_lvl; lvl--; ) { - slotptr(latchmgr->alloc, 1)->off = mgr->page_size - 3; + slotptr(latchmgr->alloc, 1)->off = offsetof(struct BtPage_, fence); bt_putid(slotptr(latchmgr->alloc, 1)->id, lvl ? MIN_lvl - lvl + 1 : 0); // next(lower) page number - key = keyptr(latchmgr->alloc, 1); - key->len = 2; // create stopper key - key->key[0] = 0xff; - key->key[1] = 0xff; - latchmgr->alloc->min = mgr->page_size - 3; + latchmgr->alloc->fence[0] = 2; // create stopper key + latchmgr->alloc->fence[1] = 0xff; + latchmgr->alloc->fence[2] = 0xff; + latchmgr->alloc->min = mgr->page_size; latchmgr->alloc->lvl = lvl; latchmgr->alloc->cnt = 1; latchmgr->alloc->act = 1; @@ -1106,7 +1115,7 @@ int flag; #ifdef unix flag = PROT_READ | ( bt->mgr->mode == BT_ro ? 0 : PROT_WRITE ); - pool->map = mmap (0, (bt->mgr->poolmask+1) << bt->mgr->page_bits, flag, MAP_SHARED, bt->mgr->idx, off); + pool->map = mmap (0, (bt->mgr->poolmask+1) << bt->mgr->page_bits, flag, MAP_SHARED | MAP_POPULATE, bt->mgr->idx, off); if( pool->map == MAP_FAILED ) return bt->err = BTERR_map; @@ -1339,10 +1348,8 @@ void bt_unlockpage(BtLock mode, BtLatchSet *set) uid bt_newpage(BtDb *bt, BtPage page) { -BtLatchSet *set; -BtPool *pool; +BtPageSet set[1]; uid new_page; -BtPage pmap; int reuse; // lock allocation page @@ -1353,12 +1360,13 @@ int reuse; // else allocate empty page if( new_page = bt_getid(bt->mgr->latchmgr->alloc[1].right) ) { - if( pool = bt_pinpool (bt, new_page) ) - pmap = bt_page (bt, pool, new_page); + if( set->pool = bt_pinpool (bt, new_page) ) + set->page = bt_page (bt, set->pool, new_page); else return 0; - bt_putid(bt->mgr->latchmgr->alloc[1].right, bt_getid(pmap->right)); - bt_unpinpool (pool); + + bt_putid(bt->mgr->latchmgr->alloc[1].right, bt_getid(set->page->right)); + bt_unpinpool (set->pool); reuse = 1; } else { new_page = bt_getid(bt->mgr->latchmgr->alloc->right); @@ -1374,7 +1382,6 @@ int reuse; if ( !reuse && bt->mgr->poolmask > 0 && (new_page & bt->mgr->poolmask) == 0 ) { // use zero buffer to write zeros - memset(bt->zero, 0, bt->mgr->page_size); if ( pwrite(bt->mgr->idx,bt->zero, bt->mgr->page_size, (new_page | bt->mgr->poolmask) << bt->mgr->page_bits) < bt->mgr->page_size ) return bt->err = BTERR_wrt, 0; } @@ -1382,13 +1389,13 @@ int reuse; // bring new page into pool and copy page. // this will extend the file into the new pages. - if( pool = bt_pinpool (bt, new_page) ) - pmap = bt_page (bt, pool, new_page); + if( set->pool = bt_pinpool (bt, new_page) ) + set->page = bt_page (bt, set->pool, new_page); else return 0; - memcpy(pmap, page, bt->mgr->page_size); - bt_unpinpool (pool); + memcpy(set->page, page, bt->mgr->page_size); + bt_unpinpool (set->pool); #endif // unlock allocation latch and return new page no @@ -1398,142 +1405,161 @@ int reuse; // find slot in page for given key at a given level -int bt_findslot (BtDb *bt, unsigned char *key, uint len) +int bt_findslot (BtPageSet *set, unsigned char *key, uint len) { -uint diff, higher = bt->page->cnt, low = 1, slot; -uint good = 0; +uint diff, higher = set->page->cnt, low = 1, slot; - // if no right link // make stopper key an infinite fence value - // by setting the good flag - if( bt_getid (bt->page->right) ) + if( bt_getid (set->page->right) ) higher++; - else - good++; - // low is the next candidate. + // low is the lowest candidate. // loop ends when they meet - // if good, higher is already + // higher is already // tested as .ge. the given key. while( diff = higher - low ) { slot = low + ( diff >> 1 ); - if( keycmp (keyptr(bt->page, slot), key, len) < 0 ) + if( keycmp (keyptr(set->page, slot), key, len) < 0 ) low = slot + 1; else - higher = slot, good++; + higher = slot; } + if( higher <= set->page->cnt ) + return higher; + + // if leaf page, compare against fence value + // return zero if key is on right link page + // or return slot beyond last key + + if( set->page->lvl || keycmp ((BtKey)set->page->fence, key, len) < 0 ) + return 0; - return good ? higher : 0; + return higher; } // find and load page at given level for given key // leave page rd or wr locked as requested -int bt_loadpage (BtDb *bt, unsigned char *key, uint len, uint lvl, uint lock) +int bt_loadpage (BtDb *bt, BtPageSet *set, unsigned char *key, uint len, uint lvl, uint lock) { uid page_no = ROOT_page, prevpage = 0; -BtLatchSet *set, *prevset; uint drill = 0xff, slot; +BtLatchSet *prevlatch; uint mode, prevmode; BtPool *prevpool; -int parent = 1; // start at root of btree and drill down - bt->set = NULL; - do { // determine lock mode of drill level mode = (lock == BtLockWrite) && (drill == lvl) ? BtLockWrite : BtLockRead; - bt->set = bt_pinlatch (bt, page_no); - bt->page_no = page_no; + set->latch = bt_pinlatch (bt, page_no); + set->page_no = page_no; // pin page contents - if( bt->pool = bt_pinpool (bt, page_no) ) - bt->page = bt_page (bt, bt->pool, page_no); + if( set->pool = bt_pinpool (bt, page_no) ) + set->page = bt_page (bt, set->pool, page_no); else return 0; // obtain access lock using lock chaining with Access mode if( page_no > ROOT_page ) - bt_lockpage(BtLockAccess, bt->set); + bt_lockpage(BtLockAccess, set->latch); // release & unpin parent page if( prevpage ) { - bt_unlockpage(prevmode, prevset); - bt_unpinlatch (prevset); + bt_unlockpage(prevmode, prevlatch); + bt_unpinlatch (prevlatch); bt_unpinpool (prevpool); prevpage = 0; } // obtain read lock using lock chaining - bt_lockpage(mode, bt->set); + bt_lockpage(mode, set->latch); if( page_no > ROOT_page ) - bt_unlockpage(BtLockAccess, bt->set); + bt_unlockpage(BtLockAccess, set->latch); // re-read and re-lock root after determining actual level of root - if( bt->page->lvl != drill) { - if ( bt->page_no != ROOT_page ) + if( set->page->lvl != drill) { + if ( set->page_no != ROOT_page ) return bt->err = BTERR_struct, 0; - drill = bt->page->lvl; + drill = set->page->lvl; if( lock == BtLockWrite && drill == lvl ) { - bt_unlockpage(mode, bt->set); - bt_unpinlatch (bt->set); - bt_unpinpool (bt->pool); + bt_unlockpage(mode, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); continue; } } + prevpage = set->page_no; + prevlatch = set->latch; + prevpool = set->pool; + prevmode = mode; + + // if page is being deleted and we should continue right + + if( set->page->kill && set->page->goright ) { + page_no = bt_getid (set->page->right); + continue; + } + + // otherwise, wait for deleted node to clear + + if( set->page->kill ) { + bt_unlockpage(mode, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); + page_no = ROOT_page; + prevpage = 0; + drill = 0xff; +#ifdef unix + sched_yield(); +#else + SwitchToThread(); +#endif + continue; + } + // find key on page at this level // and descend to requested level - if( slot = bt_findslot (bt, key, len) ) { + if( slot = bt_findslot (set, key, len) ) { if( drill == lvl ) - return bt->parent = parent, slot; + return slot; + + if( slot > set->page->cnt ) + return bt->err = BTERR_struct; - while( slotptr(bt->page, slot)->dead ) - if( slot++ < bt->page->cnt ) + while( slotptr(set->page, slot)->dead ) + if( slot++ < set->page->cnt ) continue; - else { - page_no = bt_getid(bt->page->right); - parent = 0; - goto slideright; - } + else + return bt->err = BTERR_struct, 0; - page_no = bt_getid(slotptr(bt->page, slot)->id); - parent = 1; + page_no = bt_getid(slotptr(set->page, slot)->id); drill--; + continue; } // or slide right into next page - else { - page_no = bt_getid(bt->page->right); - parent = 0; - } - - // continue down / right using overlapping locks - // to protect pages being split. + page_no = bt_getid(set->page->right); -slideright: - prevpage = bt->page_no; - prevpool = bt->pool; - prevset = bt->set; - prevmode = mode; } while( page_no ); // return error on end of right chain @@ -1542,189 +1568,287 @@ slideright: return 0; // return error } -// remove empty page from the B-tree -// by pulling our right node left over ourselves +// drill down fixing fence values for left sibling tree -// call with bt->page, etc, set to page's locked parent -// returns with page locked. +// call with set write locked +// return with set unlocked & unpinned. -BTERR bt_mergeright (BtDb *bt, BtPage page, BtPool *pool, BtLatchSet *set, uid page_no, uint lvl, uint slot) +BTERR bt_fixfences (BtDb *bt, BtPageSet *set, unsigned char *newfence) { -BtLatchSet *rset, *pset, *rpset; -BtPool *rpool, *ppool, *rppool; -BtPage rpage, ppage, rppage; -uid right, parent, rparent; -BtKey ptr; -uint idx; +unsigned char oldfence[256]; +BtPageSet next[1]; +int chk; + + memcpy (oldfence, set->page->fence, 256); + + while( !set->page->kill && set->page->lvl ) { + next->page_no = bt_getid(slotptr(set->page, set->page->cnt)->id); + next->latch = bt_pinlatch (bt, next->page_no); + bt_lockpage (BtLockParent, next->latch); + bt_lockpage (BtLockAccess, next->latch); + bt_lockpage (BtLockWrite, next->latch); + bt_unlockpage (BtLockAccess, next->latch); + + if( next->pool = bt_pinpool (bt, next->page_no) ) + next->page = bt_page (bt, next->pool, next->page_no); + else + return bt->err; - // cache node's parent page + chk = keycmp ((BtKey)next->page->fence, oldfence + 1, *oldfence); - parent = bt->page_no; - ppage = bt->page; - ppool = bt->pool; - pset = bt->set; + if( chk < 0 ) { + next->page_no = bt_getid (next->page->right); + bt_unlockpage (BtLockWrite, next->latch); + bt_unlockpage (BtLockParent, next->latch); + bt_unpinlatch (next->latch); + bt_unpinpool (next->pool); + continue; + } - // lock and map our right page - // it cannot be NULL because of the stopper - // in the last right page + if( chk > 0 ) + return bt->err = BTERR_struct; - bt_lockpage (BtLockWrite, set); + if( bt_fixfences (bt, next, newfence) ) + return bt->err; - // if we aren't dead yet + break; + } - if( page->act ) - goto rmergexit; + memcpy (set->page->fence, newfence, 256); - if( right = bt_getid (page->right) ) - if( rpool = bt_pinpool (bt, right) ) - rpage = bt_page (bt, rpool, right); - else - return bt->err; - else - return bt->err = BTERR_struct; + bt_unlockpage (BtLockWrite, set->latch); + bt_unlockpage (BtLockParent, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); + return 0; +} - rset = bt_pinlatch (bt, right); +// return page to free list +// page must be delete & write locked - // find our right neighbor +void bt_freepage (BtDb *bt, BtPageSet *set) +{ + // lock allocation page - if( ppage->act > 1 ) { - for( idx = slot; idx++ < ppage->cnt; ) - if( !slotptr(ppage, idx)->dead ) - break; + bt_spinwritelock (bt->mgr->latchmgr->lock, 0); - if( idx > ppage->cnt ) - return bt->err = BTERR_struct; + // store chain in second right + bt_putid(set->page->right, bt_getid(bt->mgr->latchmgr->alloc[1].right)); + bt_putid(bt->mgr->latchmgr->alloc[1].right, set->page_no); + set->page->free = 1; - // redirect right neighbor in parent to left node + // unlock released page - bt_putid(slotptr(ppage,idx)->id, page_no); - } + bt_unlockpage (BtLockDelete, set->latch); + bt_unlockpage (BtLockWrite, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); - // if parent has only our deleted page, e.g. no right neighbor - // prepare to merge parent itself + // unlock allocation page - if( ppage->act == 1 ) { - if( rparent = bt_getid (ppage->right) ) - if( rppool = bt_pinpool (bt, rparent) ) - rppage = bt_page (bt, rppool, rparent); - else - return bt->err; + bt_spinreleasewrite (bt->mgr->latchmgr->lock, 0); +} + +// remove the root level by promoting its only child +// call with parent and child pages + +BTERR bt_removeroot (BtDb *bt, BtPageSet *root, BtPageSet *child) +{ +uid next = 0; + + do { + if( next ) { + child->latch = bt_pinlatch (bt, next); + bt_lockpage (BtLockDelete, child->latch); + bt_lockpage (BtLockWrite, child->latch); + + if( child->pool = bt_pinpool (bt, next) ) + child->page = bt_page (bt, child->pool, next); else - return bt->err = BTERR_struct; + return bt->err; + + child->page_no = next; + } + + memcpy (root->page, child->page, bt->mgr->page_size); + next = bt_getid (slotptr(child->page, child->page->cnt)->id); + bt_freepage (bt, child); + } while( root->page->lvl > 1 && root->page->cnt == 1 ); + + bt_unlockpage (BtLockWrite, root->latch); + bt_unpinlatch (root->latch); + bt_unpinpool (root->pool); + return 0; +} + +// pull right page over ourselves in simple merge + +BTERR bt_mergeright (BtDb *bt, BtPageSet *set, BtPageSet *parent, BtPageSet *right, uint slot, uint idx) +{ + // install ourselves as child page + // and delete ourselves from parent - rpset = bt_pinlatch (bt, rparent); - bt_lockpage (BtLockWrite, rpset); + bt_putid (slotptr(parent->page, idx)->id, set->page_no); + slotptr(parent->page, slot)->dead = 1; + parent->page->act--; - // find our right neighbor on right parent page + // collapse any empty slots - for( idx = 0; idx++ < rppage->cnt; ) - if( !slotptr(rppage, idx)->dead ) { - bt_putid (slotptr(rppage, idx)->id, page_no); + while( idx = parent->page->cnt - 1 ) + if( slotptr(parent->page, idx)->dead ) { + *slotptr(parent->page, idx) = *slotptr(parent->page, idx + 1); + memset (slotptr(parent->page, parent->page->cnt--), 0, sizeof(BtSlot)); + } else break; - } - if( idx > rppage->cnt ) - return bt->err = BTERR_struct; - } + memcpy (set->page, right->page, bt->mgr->page_size); + bt_unlockpage (BtLockParent, right->latch); - // now that there are no more pointers to our right node - // we can wait for delete lock on it + bt_freepage (bt, right); - bt_lockpage(BtLockDelete, rset); - bt_lockpage(BtLockWrite, rset); + // do we need to remove a btree level? + // (leave the first page of leaves alone) - // pull contents of right page into our empty page + if( parent->page_no == ROOT_page && parent->page->cnt == 1 ) + if( set->page->lvl ) + return bt_removeroot (bt, parent, set); - memcpy (page, rpage, bt->mgr->page_size); + bt_unlockpage (BtLockWrite, parent->latch); + bt_unlockpage (BtLockDelete, set->latch); + bt_unlockpage (BtLockWrite, set->latch); + bt_unpinlatch (parent->latch); + bt_unpinpool (parent->pool); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); + return 0; +} - // ready to release right parent lock - // now that we have a new page in place +// remove both child and parent from the btree +// from the fence position in the parent +// call with both pages locked for writing - if( ppage->act == 1 ) { - bt_unlockpage (BtLockWrite, rpset); - bt_unpinlatch (rpset); - bt_unpinpool (rppool); - } +BTERR bt_removeparent (BtDb *bt, BtPageSet *child, BtPageSet *parent, BtPageSet *right, BtPageSet *rparent, uint lvl) +{ +unsigned char pagefence[256]; +uint idx; - // add killed right block to free chain - // lock latch mgr + // pull right sibling over ourselves and unlock - bt_spinwritelock(bt->mgr->latchmgr->lock, 0); + memcpy (child->page, right->page, bt->mgr->page_size); - // store free chain in allocation page second right + bt_unlockpage (BtLockWrite, child->latch); + bt_unpinlatch (child->latch); + bt_unpinpool (child->pool); - bt_putid(rpage->right, bt_getid(bt->mgr->latchmgr->alloc[1].right)); - bt_putid(bt->mgr->latchmgr->alloc[1].right, right); + // install ourselves into right link of old right page - // unlock latch mgr and right page + bt_putid (right->page->right, child->page_no); + right->page->goright = 1; // tell bt_loadpage to go right to us + right->page->kill = 1; - bt_unlockpage(BtLockDelete, rset); - bt_unlockpage(BtLockWrite, rset); - bt_unpinlatch (rset); - bt_unpinpool (rpool); + bt_unlockpage (BtLockWrite, right->latch); - bt_spinreleasewrite(bt->mgr->latchmgr->lock, 0); + // remove our slot from our parent + // signal to move right - // delete our obsolete fence key from our parent + parent->page->goright = 1; // tell bt_loadpage to go right to rparent + parent->page->kill = 1; + parent->page->act--; - slotptr(ppage, slot)->dead = 1; - ppage->dirty = 1; + // redirect right page pointer in right parent to us - // if our parent now empty - // remove it from the tree + for( idx = 0; idx++ < rparent->page->cnt; ) + if( !slotptr(rparent->page, idx)->dead ) + break; - if( ppage->act-- == 1 ) - if( bt_mergeleft (bt, ppage, ppool, pset, parent, lvl+1) ) - return bt->err; + if( bt_getid (slotptr(rparent->page, idx)->id) != right->page_no ) + return bt->err = BTERR_struct; -rmergexit: - bt_unlockpage (BtLockWrite, pset); - bt_unpinlatch (pset); - bt_unpinpool (ppool); + bt_putid (slotptr(rparent->page, idx)->id, child->page_no); + bt_unlockpage (BtLockWrite, rparent->latch); + bt_unpinlatch (rparent->latch); + bt_unpinpool (rparent->pool); - bt->found = 1; - return bt->err = 0; -} + // free the right page + + bt_lockpage (BtLockDelete, right->latch); + bt_lockpage (BtLockWrite, right->latch); + bt_freepage (bt, right); + + // save parent page fence value -// remove empty page from the B-tree -// try merging left first. If no left -// sibling, then merge right. + memcpy (pagefence, parent->page->fence, 256); + bt_unlockpage (BtLockWrite, parent->latch); -// call with page loaded and locked, -// return with page locked. + return bt_removepage (bt, parent, lvl, pagefence); +} + +// remove page from btree +// call with page unlocked +// returns with page on free list -BTERR bt_mergeleft (BtDb *bt, BtPage page, BtPool *pool, BtLatchSet *set, uid page_no, uint lvl) +BTERR bt_removepage (BtDb *bt, BtPageSet *set, uint lvl, unsigned char *pagefence) { -unsigned char fencekey[256], postkey[256]; -uint slot, idx, postfence = 0; -BtLatchSet *lset, *pset; -BtPool *lpool, *ppool; -BtPage lpage, ppage; -uid left, parent; +BtPageSet parent[1], sibling[1], rparent[1]; +unsigned char newfence[256]; +uint slot, idx; BtKey ptr; - ptr = keyptr(page, page->cnt); - memcpy(fencekey, ptr, ptr->len + 1); - bt_unlockpage (BtLockWrite, set); - // load and lock our parent retry: - if( !(slot = bt_loadpage (bt, fencekey+1, *fencekey, lvl+1, BtLockWrite)) ) + if( !(slot = bt_loadpage (bt, parent, pagefence+1, *pagefence, lvl+1, BtLockWrite)) ) return bt->err; - parent = bt->page_no; - ppage = bt->page; - ppool = bt->pool; - pset = bt->set; + // can we do a simple merge entirely + // between siblings on the parent page? - // wait until we are posted in our parent + if( slot < parent->page->cnt ) { + // find our right neighbor + // right must exist because the stopper prevents + // the rightmost page from deleting - if( !bt->parent ) { - bt_unlockpage (BtLockWrite, pset); - bt_unpinlatch (pset); - bt_unpinpool (ppool); -#ifdef unix + for( idx = slot; idx++ < parent->page->cnt; ) + if( !slotptr(parent->page, idx)->dead ) + break; + + sibling->page_no = bt_getid (slotptr (parent->page, idx)->id); + + bt_lockpage (BtLockDelete, set->latch); + bt_lockpage (BtLockWrite, set->latch); + + // merge right if sibling shows up in + // our parent and is not being killed + + if( sibling->page_no == bt_getid (set->page->right) ) { + sibling->latch = bt_pinlatch (bt, sibling->page_no); + bt_lockpage (BtLockParent, sibling->latch); + bt_lockpage (BtLockDelete, sibling->latch); + bt_lockpage (BtLockWrite, sibling->latch); + + if( sibling->pool = bt_pinpool (bt, sibling->page_no) ) + sibling->page = bt_page (bt, sibling->pool, sibling->page_no); + else + return bt->err; + + if( !sibling->page->kill ) + return bt_mergeright(bt, set, parent, sibling, slot, idx); + + // try again later + + bt_unlockpage (BtLockWrite, sibling->latch); + bt_unlockpage (BtLockParent, sibling->latch); + bt_unlockpage (BtLockDelete, sibling->latch); + bt_unpinlatch (sibling->latch); + bt_unpinpool (sibling->pool); + } + + bt_unlockpage (BtLockDelete, set->latch); + bt_unlockpage (BtLockWrite, set->latch); + bt_unlockpage (BtLockWrite, parent->latch); + bt_unpinlatch (parent->latch); + bt_unpinpool (parent->pool); +#ifdef linux sched_yield(); #else SwitchToThread(); @@ -1735,35 +1859,59 @@ retry: // find our left neighbor in our parent page for( idx = slot; --idx; ) - if( !slotptr(ppage, idx)->dead ) + if( !slotptr(parent->page, idx)->dead ) break; - // if no left neighbor, do right merge + // if no left neighbor, delete ourselves and our parent - if( !idx ) - return bt_mergeright (bt, page, pool, set, page_no, lvl, slot); + if( !idx ) { + bt_lockpage (BtLockAccess, set->latch); + bt_lockpage (BtLockWrite, set->latch); + bt_unlockpage (BtLockAccess, set->latch); - // lock and map our left neighbor's page + rparent->page_no = bt_getid (parent->page->right); + rparent->latch = bt_pinlatch (bt, rparent->page_no); - left = bt_getid (slotptr(ppage, idx)->id); + bt_lockpage (BtLockAccess, rparent->latch); + bt_lockpage (BtLockWrite, rparent->latch); + bt_unlockpage (BtLockAccess, rparent->latch); - if( lpool = bt_pinpool (bt, left) ) - lpage = bt_page (bt, lpool, left); - else - return bt->err; + if( rparent->pool = bt_pinpool (bt, rparent->page_no) ) + rparent->page = bt_page (bt, rparent->pool, rparent->page_no); + else + return bt->err; + + if( !rparent->page->kill ) { + sibling->page_no = bt_getid (set->page->right); + sibling->latch = bt_pinlatch (bt, sibling->page_no); - lset = bt_pinlatch (bt, left); - bt_lockpage(BtLockWrite, lset); + bt_lockpage (BtLockAccess, sibling->latch); + bt_lockpage (BtLockWrite, sibling->latch); + bt_unlockpage (BtLockAccess, sibling->latch); - // wait until sibling is in our parent + if( sibling->pool = bt_pinpool (bt, sibling->page_no) ) + sibling->page = bt_page (bt, sibling->pool, sibling->page_no); + else + return bt->err; + + if( !sibling->page->kill ) + return bt_removeparent (bt, set, parent, sibling, rparent, lvl+1); + + // try again later - if( bt_getid (lpage->right) != page_no ) { - bt_unlockpage (BtLockWrite, pset); - bt_unpinlatch (pset); - bt_unpinpool (ppool); - bt_unlockpage (BtLockWrite, lset); - bt_unpinlatch (lset); - bt_unpinpool (lpool); + bt_unlockpage (BtLockWrite, sibling->latch); + bt_unpinlatch (sibling->latch); + bt_unpinpool (sibling->pool); + } + + bt_unlockpage (BtLockWrite, set->latch); + bt_unlockpage (BtLockWrite, rparent->latch); + bt_unpinlatch (rparent->latch); + bt_unpinpool (rparent->pool); + + bt_unlockpage (BtLockWrite, parent->latch); + bt_unpinlatch (parent->latch); + bt_unpinpool (parent->pool); #ifdef linux sched_yield(); #else @@ -1772,114 +1920,97 @@ retry: goto retry; } - // since our page will have no more pointers to it, - // obtain Delete lock and wait for write locks to clear - - bt_lockpage(BtLockDelete, set); - bt_lockpage(BtLockWrite, set); - - // if we aren't dead yet, - // get ready for exit - - if( page->act ) { - bt_unlockpage(BtLockDelete, set); - bt_unlockpage(BtLockWrite, lset); - bt_unpinlatch (lset); - bt_unpinpool (lpool); - goto lmergexit; - } - - // are we are the fence key for our parent? - // if so, grab our old fence key - - if( postfence = slot == ppage->cnt ) { - ptr = keyptr (ppage, ppage->cnt); - memcpy(fencekey, ptr, ptr->len + 1); - memset(slotptr(ppage, ppage->cnt), 0, sizeof(BtSlot)); - - // clear out other dead slots - - while( --ppage->cnt ) - if( slotptr(ppage, ppage->cnt)->dead ) - memset(slotptr(ppage, ppage->cnt), 0, sizeof(BtSlot)); - else - break; + // redirect parent to our left sibling + // lock and map our left sibling's page - ptr = keyptr (ppage, ppage->cnt); - memcpy(postkey, ptr, ptr->len + 1); - } else - slotptr(ppage,slot)->dead = 1; + sibling->page_no = bt_getid (slotptr(parent->page, idx)->id); + sibling->latch = bt_pinlatch (bt, sibling->page_no); - ppage->dirty = 1; - ppage->act--; + // wait our turn on fence key maintenance - // push our right neighbor pointer to our left + bt_lockpage(BtLockParent, sibling->latch); + bt_lockpage(BtLockAccess, sibling->latch); + bt_lockpage(BtLockWrite, sibling->latch); + bt_unlockpage(BtLockAccess, sibling->latch); - memcpy (lpage->right, page->right, BtId); + if( sibling->pool = bt_pinpool (bt, sibling->page_no) ) + sibling->page = bt_page (bt, sibling->pool, sibling->page_no); + else + return bt->err; - // add ourselves to free chain - // lock latch mgr + // wait until left sibling is in our parent - bt_spinwritelock(bt->mgr->latchmgr->lock, 0); + if( bt_getid (sibling->page->right) != set->page_no ) { + bt_unlockpage (BtLockWrite, parent->latch); + bt_unlockpage (BtLockWrite, sibling->latch); + bt_unlockpage (BtLockParent, sibling->latch); + bt_unpinlatch (parent->latch); + bt_unpinpool (parent->pool); + bt_unpinlatch (sibling->latch); + bt_unpinpool (sibling->pool); +#ifdef linux + sched_yield(); +#else + SwitchToThread(); +#endif + goto retry; + } - // store free chain in allocation page second right - bt_putid(page->right, bt_getid(bt->mgr->latchmgr->alloc[1].right)); - bt_putid(bt->mgr->latchmgr->alloc[1].right, page_no); + // delete our left sibling from parent - // unlock latch mgr and pages + slotptr(parent->page,idx)->dead = 1; + parent->page->dirty = 1; + parent->page->act--; - bt_spinreleasewrite(bt->mgr->latchmgr->lock, 0); - bt_unlockpage(BtLockWrite, lset); - bt_unpinlatch (lset); - bt_unpinpool (lpool); + // redirect our parent slot to our left sibling - // release our node's delete lock + bt_putid (slotptr(parent->page, slot)->id, sibling->page_no); + memcpy (sibling->page->right, set->page->right, BtId); - bt_unlockpage(BtLockDelete, set); + // collapse dead slots from parent -lmergexit: - bt_unlockpage (BtLockWrite, pset); - bt_unpinpool (ppool); + while( idx = parent->page->cnt - 1 ) + if( slotptr(parent->page, idx)->dead ) { + *slotptr(parent->page, idx) = *slotptr(parent->page, parent->page->cnt); + memset (slotptr(parent->page, parent->page->cnt--), 0, sizeof(BtSlot)); + } else + break; - // do we need to post parent's fence key in its parent? + // free our original page - if( !postfence || parent == ROOT_page ) { - bt_unpinlatch (pset); - bt->found = 1; - return bt->err = 0; - } + bt_lockpage (BtLockDelete, set->latch); + bt_lockpage (BtLockWrite, set->latch); + bt_freepage (bt, set); - // interlock parent fence post + // go down the left node's fence keys to the leaf level + // and update the fence keys in each page - bt_lockpage (BtLockParent, pset); + memcpy (newfence, parent->page->fence, 256); - // load parent's parent page -posttry: - if( !(slot = bt_loadpage (bt, fencekey+1, *fencekey, lvl+2, BtLockWrite)) ) + if( bt_fixfences (bt, sibling, newfence) ) return bt->err; - if( !(slot = bt_cleanpage (bt, bt->page, *fencekey, slot)) ) - if( bt_splitpage (bt, bt->page, bt->pool, bt->set, bt->page_no) ) - return bt->err; - else - goto posttry; + // promote sibling as new root? - page = bt->page; + if( parent->page_no == ROOT_page && parent->page->cnt == 1 ) + if( sibling->page->lvl ) { + sibling->latch = bt_pinlatch (bt, sibling->page_no); + bt_lockpage (BtLockDelete, sibling->latch); + bt_lockpage (BtLockWrite, sibling->latch); - page->min -= *postkey + 1; - ((unsigned char *)page)[page->min] = *postkey; - memcpy ((unsigned char *)page + page->min +1, postkey + 1, *postkey ); - slotptr(page, slot)->off = page->min; + if( sibling->pool = bt_pinpool (bt, sibling->page_no) ) + sibling->page = bt_page (bt, sibling->pool, sibling->page_no); + else + return bt->err; - bt_unlockpage (BtLockParent, pset); - bt_unpinlatch (pset); + return bt_removeroot (bt, parent, sibling); + } - bt_unlockpage (BtLockWrite, bt->set); - bt_unpinlatch (bt->set); - bt_unpinpool (bt->pool); + bt_unlockpage (BtLockWrite, parent->latch); + bt_unpinlatch (parent->latch); + bt_unpinpool (parent->pool); - bt->found = 1; - return bt->err = 0; + return 0; } // find and delete key on page by marking delete flag bit @@ -1887,65 +2018,79 @@ posttry: BTERR bt_deletekey (BtDb *bt, unsigned char *key, uint len) { -BtLatchSet *set; -BtPool *pool; -BtPage page; -uid page_no; +unsigned char pagefence[256]; +uint slot, idx, found; +BtPageSet set[1]; BtKey ptr; -uint slot; - if( !(slot = bt_loadpage (bt, key, len, 0, BtLockWrite)) ) + if( slot = bt_loadpage (bt, set, key, len, 0, BtLockWrite) ) + ptr = keyptr(set->page, slot); + else return bt->err; - page_no = bt->page_no; - page = bt->page; - pool = bt->pool; - set = bt->set; - // if key is found delete it, otherwise ignore request - ptr = keyptr(page, slot); + if( found = slot <= set->page->cnt ) + if( found = !keycmp (ptr, key, len) ) + if( found = slotptr(set->page, slot)->dead == 0 ) { + slotptr(set->page,slot)->dead = 1; + set->page->dirty = 1; + set->page->act--; - if( bt->found = !keycmp (ptr, key, len) ) - if( bt->found = slotptr(page, slot)->dead == 0 ) { - slotptr(page,slot)->dead = 1; - if( slot < page->cnt ) - page->dirty = 1; - if( !--page->act ) - if( bt_mergeleft (bt, page, pool, set, page_no, 0) ) - return bt->err; + // collapse empty slots + + while( idx = set->page->cnt - 1 ) + if( slotptr(set->page, idx)->dead ) { + *slotptr(set->page, idx) = *slotptr(set->page, idx + 1); + memset (slotptr(set->page, set->page->cnt--), 0, sizeof(BtSlot)); + } else + break; } - bt_unlockpage(BtLockWrite, set); - bt_unpinlatch (set); - bt_unpinpool (pool); - return bt->err = 0; + if( set->page->act ) { + bt_unlockpage(BtLockWrite, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); + return bt->found = found, 0; + } + + memcpy (pagefence, set->page->fence, 256); + set->page->kill = 1; + + bt_unlockpage (BtLockWrite, set->latch); + + if( bt_removepage (bt, set, 0, pagefence) ) + return bt->err; + + bt->found = found; + return 0; } // find key in leaf level and return row-id uid bt_findkey (BtDb *bt, unsigned char *key, uint len) { +BtPageSet set[1]; uint slot; BtKey ptr; uid id; - if( slot = bt_loadpage (bt, key, len, 0, BtLockRead) ) - ptr = keyptr(bt->page, slot); + if( slot = bt_loadpage (bt, set, key, len, 0, BtLockRead) ) + ptr = keyptr(set->page, slot); else return 0; // if key exists, return row-id // otherwise return 0 - if( slot <= bt->page->cnt && !keycmp (ptr, key, len) ) - id = bt_getid(slotptr(bt->page,slot)->id); + if( !keycmp (ptr, key, len) ) + id = bt_getid(slotptr(set->page,slot)->id); else id = 0; - bt_unlockpage (BtLockRead, bt->set); - bt_unpinlatch (bt->set); - bt_unpinpool (bt->pool); + bt_unlockpage (BtLockRead, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); return id; } @@ -1956,7 +2101,7 @@ uid id; uint bt_cleanpage(BtDb *bt, BtPage page, uint amt, uint slot) { -uint nxt = bt->mgr->page_size; +uint nxt = bt->mgr->page_size, off; uint cnt = 0, idx = 0; uint max = page->cnt; uint newslot = max; @@ -1979,28 +2124,31 @@ BtKey key; page->act = 0; // try cleaning up page first - - // always leave fence key in the array - // otherwise, remove deleted key + // by removing deleted keys while( cnt++ < max ) { if( cnt == slot ) newslot = idx + 1; - if( cnt < max && slotptr(bt->frame,cnt)->dead ) + if( slotptr(bt->frame,cnt)->dead ) continue; - // copy key + // if its not the fence key, + // copy the key across - key = keyptr(bt->frame, cnt); - nxt -= key->len + 1; - memcpy ((unsigned char *)page + nxt, key, key->len + 1); + off = slotptr(bt->frame,cnt)->off; + + if( off >= sizeof(*page) ) { + key = keyptr(bt->frame, cnt); + off = nxt -= key->len + 1; + memcpy ((unsigned char *)page + nxt, key, key->len + 1); + } // copy slot + memcpy(slotptr(page, ++idx)->id, slotptr(bt->frame, cnt)->id, BtId); - if( !(slotptr(page, idx)->dead = slotptr(bt->frame, cnt)->dead) ) - page->act++; slotptr(page, idx)->tod = slotptr(bt->frame, cnt)->tod; - slotptr(page, idx)->off = nxt; + slotptr(page, idx)->off = off; + page->act++; } page->min = nxt; @@ -2014,202 +2162,192 @@ BtKey key; return 0; } -// add key to current page -// page must already be writelocked +// split the root and raise the height of the btree -void bt_addkeytopage (BtDb *bt, BtPage page, uint slot, unsigned char *key, uint len, uid id, uint tod) -{ -uint idx; - - // find next available dead slot and copy key onto page - - for( idx = slot; idx < page->cnt; idx++ ) - if( slotptr(page, idx)->dead ) - break; - - if( idx == page->cnt ) - idx++, page->cnt++; - - page->act++; - - // now insert key into array before slot - - while( idx > slot ) - *slotptr(page, idx) = *slotptr(page, idx -1), idx--; - - page->min -= len + 1; - ((unsigned char *)page)[page->min] = len; - memcpy ((unsigned char *)page + page->min +1, key, len ); - - bt_putid(slotptr(page,slot)->id, id); - slotptr(page, slot)->off = page->min; - slotptr(page, slot)->tod = tod; - slotptr(page, slot)->dead = 0; -} - -BTERR bt_splitroot(BtDb *bt, unsigned char *leftkey, uid page_no2) +BTERR bt_splitroot(BtDb *bt, BtPageSet *root, uid page_no2) { uint nxt = bt->mgr->page_size; -BtPage root = bt->page; +unsigned char leftkey[256]; uid new_page; // Obtain an empty page to use, and copy the current - // root contents into it + // root contents into it, e.g. lower keys + + memcpy (leftkey, root->page->fence, 256); + root->page->posted = 1; - if( !(new_page = bt_newpage(bt, root)) ) + if( !(new_page = bt_newpage(bt, root->page)) ) return bt->err; // preserve the page info at the bottom - // and set rest to zero + // of higher keys and set rest to zero - memset(root+1, 0, bt->mgr->page_size - sizeof(*root)); + memset(root->page+1, 0, bt->mgr->page_size - sizeof(*root->page)); + memset(root->page->fence, 0, 256); + root->page->fence[0] = 2; + root->page->fence[1] = 0xff; + root->page->fence[2] = 0xff; - // insert first key on newroot page + // insert lower keys page fence key on newroot page nxt -= *leftkey + 1; - memcpy ((unsigned char *)root + nxt, leftkey, *leftkey + 1); - bt_putid(slotptr(root, 1)->id, new_page); - slotptr(root, 1)->off = nxt; + memcpy ((unsigned char *)root->page + nxt, leftkey, *leftkey + 1); + bt_putid(slotptr(root->page, 1)->id, new_page); + slotptr(root->page, 1)->off = nxt; - // insert second key (stopper key) on newroot page + // insert stopper key on newroot page // and increase the root height - nxt -= 3; - *((unsigned char *)root + nxt) = 2; - memset ((unsigned char *)root + nxt + 1, 0xff, 2); - bt_putid(slotptr(root, 2)->id, page_no2); - slotptr(root, 2)->off = nxt; + bt_putid(slotptr(root->page, 2)->id, page_no2); + slotptr(root->page, 2)->off = offsetof(struct BtPage_, fence); - bt_putid(root->right, 0); - root->min = nxt; // reset lowest used offset and key count - root->cnt = 2; - root->act = 2; - root->lvl++; + bt_putid(root->page->right, 0); + root->page->min = nxt; // reset lowest used offset and key count + root->page->cnt = 2; + root->page->act = 2; + root->page->lvl++; - // release and unpin root (bt->page) + // release and unpin root - bt_unlockpage(BtLockWrite, bt->set); - bt_unpinlatch (bt->set); - bt_unpinpool (bt->pool); + bt_unlockpage(BtLockWrite, root->latch); + bt_unpinlatch (root->latch); + bt_unpinpool (root->pool); return 0; } // split already locked full node -// return unlocked and unpinned. +// return unlocked. -BTERR bt_splitpage (BtDb *bt, BtPage page, BtPool *pool, BtLatchSet *set, uid page_no) +BTERR bt_splitpage (BtDb *bt, BtPageSet *set) { -uint slot, cnt, idx, max, nxt = bt->mgr->page_size; -unsigned char rightkey[256], leftkey[256]; -uint tod = time(NULL); -uint lvl = page->lvl; -uid new_page; +uint cnt = 0, idx = 0, max, nxt = bt->mgr->page_size, off; +unsigned char fencekey[256]; +uint lvl = set->page->lvl; +uid right; BtKey key; - // initialize frame buffer for right node + // split higher half of keys to bt->frame memset (bt->frame, 0, bt->mgr->page_size); - max = page->cnt; + max = set->page->cnt; cnt = max / 2; idx = 0; - // split higher half of keys to bt->frame - while( cnt++ < max ) { - key = keyptr(page, cnt); - nxt -= key->len + 1; - memcpy ((unsigned char *)bt->frame + nxt, key, key->len + 1); - memcpy(slotptr(bt->frame,++idx)->id, slotptr(page,cnt)->id, BtId); - if( !(slotptr(bt->frame, idx)->dead = slotptr(page, cnt)->dead) ) - bt->frame->act++; - slotptr(bt->frame, idx)->tod = slotptr(page, cnt)->tod; - slotptr(bt->frame, idx)->off = nxt; + if( !lvl || cnt < max ) { + key = keyptr(set->page, cnt); + off = nxt -= key->len + 1; + memcpy ((unsigned char *)bt->frame + nxt, key, key->len + 1); + } else + off = offsetof(struct BtPage_, fence); + + memcpy(slotptr(bt->frame,++idx)->id, slotptr(set->page,cnt)->id, BtId); + slotptr(bt->frame, idx)->tod = slotptr(set->page, cnt)->tod; + slotptr(bt->frame, idx)->off = off; + bt->frame->act++; } - // transfer right link node to new right node - - if( page_no > ROOT_page ) - memcpy (bt->frame->right, page->right, BtId); + if( set->page_no == ROOT_page ) + bt->frame->posted = 1; + memcpy (bt->frame->fence, set->page->fence, 256); bt->frame->bits = bt->mgr->page_bits; bt->frame->min = nxt; bt->frame->cnt = idx; bt->frame->lvl = lvl; - // get new free page and write right frame to it. + // link right node - if( !(new_page = bt_newpage(bt, bt->frame)) ) - return bt->err; + if( set->page_no > ROOT_page ) + memcpy (bt->frame->right, set->page->right, BtId); - // remember fence key for new right page to add - // as right sibling to the left node + // get new free page and write higher keys to it. - key = keyptr(bt->frame, idx); - memcpy (rightkey, key, key->len + 1); + if( !(right = bt_newpage(bt, bt->frame)) ) + return bt->err; // update lower keys to continue in old page - memcpy (bt->frame, page, bt->mgr->page_size); - memset (page+1, 0, bt->mgr->page_size - sizeof(*page)); + memcpy (bt->frame, set->page, bt->mgr->page_size); + memset (set->page+1, 0, bt->mgr->page_size - sizeof(*set->page)); nxt = bt->mgr->page_size; - page->dirty = 0; - page->act = 0; + set->page->posted = 0; + set->page->dirty = 0; + set->page->act = 0; cnt = 0; idx = 0; // assemble page of smaller keys - // to remain in the old page while( cnt++ < max / 2 ) { key = keyptr(bt->frame, cnt); - nxt -= key->len + 1; - memcpy ((unsigned char *)page + nxt, key, key->len + 1); - memcpy (slotptr(page,++idx)->id, slotptr(bt->frame,cnt)->id, BtId); - if( !(slotptr(page, idx)->dead = slotptr(bt->frame, cnt)->dead) ) - page->act++; - slotptr(page, idx)->tod = slotptr(bt->frame, cnt)->tod; - slotptr(page, idx)->off = nxt; - } - // finalize left page and save fence key + if( !lvl || cnt < max / 2 ) { + off = nxt -= key->len + 1; + memcpy ((unsigned char *)set->page + nxt, key, key->len + 1); + } else + off = offsetof(struct BtPage_, fence); - memcpy(leftkey, key, key->len + 1); - page->min = nxt; - page->cnt = idx; + memcpy(slotptr(set->page,++idx)->id, slotptr(bt->frame,cnt)->id, BtId); + slotptr(set->page, idx)->tod = slotptr(bt->frame, cnt)->tod; + slotptr(set->page, idx)->off = off; + set->page->act++; + } + + // install fence key for smaller key page - // link new right page + memset(set->page->fence, 0, 256); + memcpy(set->page->fence, key, key->len + 1); - bt_putid (page->right, new_page); + bt_putid(set->page->right, right); + set->page->min = nxt; + set->page->cnt = idx; // if current page is the root page, split it - if( page_no == ROOT_page ) - return bt_splitroot (bt, leftkey, new_page); + if( set->page_no == ROOT_page ) + return bt_splitroot (bt, set, right); - // obtain ParentModification lock for current page + bt_unlockpage (BtLockWrite, set->latch); - bt_lockpage (BtLockParent, set); + // insert new fences in their parent pages - // release wr lock on our page. - // this will keep out another SMO + while( 1 ) { + bt_lockpage (BtLockParent, set->latch); + bt_lockpage (BtLockWrite, set->latch); - bt_unlockpage (BtLockWrite, set); + memcpy (fencekey, set->page->fence, 256); + right = bt_getid (set->page->right); - // insert key for old page (lower keys) + if( set->page->posted ) { + bt_unlockpage (BtLockParent, set->latch); + bt_unlockpage (BtLockWrite, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); + return 0; + } - if( bt_insertkey (bt, leftkey + 1, *leftkey, page_no, tod, lvl + 1) ) - return bt->err; + set->page->posted = 1; + bt_unlockpage (BtLockWrite, set->latch); - // switch old parent key from us to our right page + if( bt_insertkey (bt, fencekey+1, *fencekey, set->page_no, time(NULL), lvl+1) ) + return bt->err; - if( bt_insertkey (bt, rightkey + 1, *rightkey, new_page, tod, lvl + 1) ) - return bt->err; + bt_unlockpage (BtLockParent, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); - // unlock and unpin + if( !(set->page_no = right) ) + break; + + set->latch = bt_pinlatch (bt, right); + + if( set->pool = bt_pinpool (bt, right) ) + set->page = bt_page (bt, set->pool, right); + else + return bt->err; + } - bt_unlockpage (BtLockParent, set); - bt_unpinlatch (set); - bt_unpinpool (pool); return 0; } @@ -2217,13 +2355,13 @@ BtKey key; BTERR bt_insertkey (BtDb *bt, unsigned char *key, uint len, uid id, uint tod, uint lvl) { +BtPageSet set[1]; uint slot, idx; -BtPage page; BtKey ptr; while( 1 ) { - if( slot = bt_loadpage (bt, key, len, lvl, BtLockWrite) ) - ptr = keyptr(bt->page, slot); + if( slot = bt_loadpage (bt, set, key, len, lvl, BtLockWrite) ) + ptr = keyptr(set->page, slot); else { if ( !bt->err ) @@ -2233,34 +2371,56 @@ BtKey ptr; // if key already exists, update id and return - page = bt->page; - - if( !keycmp (ptr, key, len) ) { - if( slotptr(page, slot)->dead ) - page->act++; - slotptr(page, slot)->dead = 0; - slotptr(page, slot)->tod = tod; - bt_putid(slotptr(page,slot)->id, id); - bt_unlockpage(BtLockWrite, bt->set); - bt_unpinlatch (bt->set); - bt_unpinpool (bt->pool); - return bt->err; + if( slot <= set->page->cnt ) + if( !keycmp (ptr, key, len) ) { + if( slotptr(set->page, slot)->dead ) + set->page->act++; + slotptr(set->page, slot)->dead = 0; + slotptr(set->page, slot)->tod = tod; + bt_putid(slotptr(set->page,slot)->id, id); + bt_unlockpage(BtLockWrite, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); + return 0; } // check if page has enough space - if( slot = bt_cleanpage (bt, bt->page, len, slot) ) + if( slot = bt_cleanpage (bt, set->page, len, slot) ) break; - if( bt_splitpage (bt, bt->page, bt->pool, bt->set, bt->page_no) ) + if( bt_splitpage (bt, set) ) return bt->err; } - bt_addkeytopage (bt, bt->page, slot, key, len, id, tod); + // calculate next available slot and copy key into page + + set->page->min -= len + 1; // reset lowest used offset + ((unsigned char *)set->page)[set->page->min] = len; + memcpy ((unsigned char *)set->page + set->page->min +1, key, len ); + + for( idx = slot; idx <= set->page->cnt; idx++ ) + if( slotptr(set->page, idx)->dead ) + break; + + // now insert key into array before slot + + if( idx > set->page->cnt ) + set->page->cnt++; + + set->page->act++; - bt_unlockpage (BtLockWrite, bt->set); - bt_unpinlatch (bt->set); - bt_unpinpool (bt->pool); + while( idx > slot ) + *slotptr(set->page, idx) = *slotptr(set->page, idx -1), idx--; + + bt_putid(slotptr(set->page,slot)->id, id); + slotptr(set->page, slot)->off = set->page->min; + slotptr(set->page, slot)->tod = tod; + slotptr(set->page, slot)->dead = 0; + + bt_unlockpage (BtLockWrite, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); return 0; } @@ -2268,17 +2428,21 @@ BtKey ptr; uint bt_startkey (BtDb *bt, unsigned char *key, uint len) { +BtPageSet set[1]; uint slot; // cache page for retrieval - if( slot = bt_loadpage (bt, key, len, 0, BtLockRead) ) - memcpy (bt->cursor, bt->page, bt->mgr->page_size); - bt->cursor_page = bt->page_no; + if( slot = bt_loadpage (bt, set, key, len, 0, BtLockRead) ) + memcpy (bt->cursor, set->page, bt->mgr->page_size); + else + return 0; + + bt->cursor_page = set->page_no; - bt_unlockpage(BtLockRead, bt->set); - bt_unpinlatch (bt->set); - bt_unpinpool (bt->pool); + bt_unlockpage(BtLockRead, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); return slot; } @@ -2287,9 +2451,7 @@ uint slot; uint bt_nextkey (BtDb *bt, uint slot) { -BtLatchSet *set; -BtPool *pool; -BtPage page; +BtPageSet set[1]; uid right; do { @@ -2297,7 +2459,7 @@ uid right; while( slot++ < bt->cursor->cnt ) if( slotptr(bt->cursor,slot)->dead ) continue; - else if( right || (slot < bt->cursor->cnt) ) + else if( right || (slot < bt->cursor->cnt) ) // skip infinite stopper return slot; else break; @@ -2306,19 +2468,20 @@ uid right; break; bt->cursor_page = right; - if( pool = bt_pinpool (bt, right) ) - page = bt_page (bt, pool, right); + + if( set->pool = bt_pinpool (bt, right) ) + set->page = bt_page (bt, set->pool, right); else return 0; - set = bt_pinlatch (bt, right); - bt_lockpage(BtLockRead, set); + set->latch = bt_pinlatch (bt, right); + bt_lockpage(BtLockRead, set->latch); - memcpy (bt->cursor, page, bt->mgr->page_size); + memcpy (bt->cursor, set->page, bt->mgr->page_size); - bt_unlockpage(BtLockRead, set); - bt_unpinlatch (set); - bt_unpinpool (pool); + bt_unlockpage(BtLockRead, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); slot = 0; } while( 1 ); @@ -2346,45 +2509,56 @@ uint bt_tod(BtDb *bt, uint slot) void bt_latchaudit (BtDb *bt) { ushort idx, hashidx; -BtLatchSet *set; +BtLatchSet *latch; BtPool *pool; BtPage page; uid page_no; #ifdef unix for( idx = 1; idx < bt->mgr->latchmgr->latchdeployed; idx++ ) { - set = bt->mgr->latchsets + idx; - if( *(ushort *)set->readwr || *(ushort *)set->access || *(ushort *)set->parent ) { - fprintf(stderr, "latchset %d locked for page %6x\n", idx, set->page_no); - *(ushort *)set->readwr = 0; - *(ushort *)set->access = 0; - *(ushort *)set->parent = 0; + latch = bt->mgr->latchsets + idx; + if( *(uint *)latch->readwr ) { + fprintf(stderr, "latchset %d r/w locked for page %.8x\n", idx, latch->page_no); + *(uint *)latch->readwr = 0; + } + if( *(uint *)latch->access ) { + fprintf(stderr, "latchset %d access locked for page %.8x\n", idx, latch->page_no); + *(uint *)latch->access = 0; + } + if( *(uint *)latch->parent ) { + fprintf(stderr, "latchset %d parent locked for page %.8x\n", idx, latch->page_no); + *(uint *)latch->parent = 0; } - if( set->pin ) { - fprintf(stderr, "latchset %d pinned\n", idx); - set->pin = 0; + if( *(uint *)latch->busy ) { + fprintf(stderr, "latchset %d busy locked for page %.8x\n", idx, latch->page_no); + *(uint *)latch->parent = 0; + } + if( latch->pin ) { + fprintf(stderr, "latchset %d pinned for page %.8x\n", idx, latch->page_no); + latch->pin = 0; } } for( hashidx = 0; hashidx < bt->mgr->latchmgr->latchhash; hashidx++ ) { - if( *(uint *)bt->mgr->latchmgr->table[hashidx].latch ) - fprintf(stderr, "latchmgr locked\n"); if( idx = bt->mgr->latchmgr->table[hashidx].slot ) do { - set = bt->mgr->latchsets + idx; - if( *(uint *)set->readwr || *(ushort *)set->access || *(ushort *)set->parent ) - fprintf(stderr, "latchset %d locked\n", idx); - if( set->hash != hashidx ) + latch = bt->mgr->latchsets + idx; + if( latch->hash != hashidx ) { fprintf(stderr, "latchset %d wrong hashidx\n", idx); - if( set->pin ) - fprintf(stderr, "latchset %d pinned\n", idx); - } while( idx = set->next ); + latch->hash = hashidx; + } + } while( idx = latch->next ); } + page_no = bt_getid(bt->mgr->latchmgr->alloc[1].right); while( page_no ) { fprintf(stderr, "free: %.6x\n", (uint)page_no); - pool = bt_pinpool (bt, page_no); - page = bt_page (bt, pool, page_no); + + if( pool = bt_pinpool (bt, page_no) ) + page = bt_page (bt, pool, page_no); + else + return; + page_no = bt_getid(page->right); bt_unpinpool (pool); } @@ -2412,10 +2586,8 @@ uid next, page_no = LEAF_page; // start on first page of leaves unsigned char key[256]; ThreadArg *args = arg; int ch, len = 0, slot; -BtLatchSet *set; +BtPageSet set[1]; time_t tod[1]; -BtPool *pool; -BtPage page; BtKey ptr; BtDb *bt; FILE *in; @@ -2501,38 +2673,49 @@ FILE *in; break; case 's': - len = key[0] = 0; - - fprintf(stderr, "started reading\n"); - - if( slot = bt_startkey (bt, key, len) ) - slot--; - else - fprintf(stderr, "Error %d in StartKey. Syserror: %d\n", bt->err, errno), exit(0); - - while( slot = bt_nextkey (bt, slot) ) { - ptr = bt_key(bt, slot); - fwrite (ptr->key, ptr->len, 1, stdout); - fputc ('\n', stdout); - } + fprintf(stderr, "started scanning\n"); + do { + if( set->pool = bt_pinpool (bt, page_no) ) + set->page = bt_page (bt, set->pool, page_no); + else + break; + set->latch = bt_pinlatch (bt, page_no); + bt_lockpage (BtLockRead, set->latch); + next = bt_getid (set->page->right); + cnt += set->page->act; + + for( slot = 0; slot++ < set->page->cnt; ) + if( next || slot < set->page->cnt ) + if( !slotptr(set->page, slot)->dead ) { + ptr = keyptr(set->page, slot); + fwrite (ptr->key, ptr->len, 1, stdout); + fputc ('\n', stdout); + } + + bt_unlockpage (BtLockRead, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); + } while( page_no = next ); + cnt--; // remove stopper key + fprintf(stderr, " Total keys read %d\n", cnt); break; case 'c': - fprintf(stderr, "started reading\n"); + fprintf(stderr, "started counting\n"); do { - if( pool = bt_pinpool (bt, page_no) ) - page = bt_page (bt, pool, page_no); + if( set->pool = bt_pinpool (bt, page_no) ) + set->page = bt_page (bt, set->pool, page_no); else break; - set = bt_pinlatch (bt, page_no); - bt_lockpage (BtLockRead, set); - cnt += page->act; - next = bt_getid (page->right); - bt_unlockpage (BtLockRead, set); - bt_unpinlatch (set); - bt_unpinpool (pool); + set->latch = bt_pinlatch (bt, page_no); + bt_lockpage (BtLockRead, set->latch); + cnt += set->page->act; + next = bt_getid (set->page->right); + bt_unlockpage (BtLockRead, set->latch); + bt_unpinlatch (set->latch); + bt_unpinpool (set->pool); } while( page_no = next ); cnt--; // remove stopper key