// btree version threads2h pthread rw lock version
-// 24 JAN 2014
+// 29 JAN 2014
// author: karl malbrain, malbrain@cal.berkeley.edu
typedef struct {
BtLatch readwr[1]; // read/write page lock
BtLatch access[1]; // Access Intent/Page delete
- BtLatch parent[1]; // adoption of foster children
+ BtLatch 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
uint act; // count of active keys
uint min; // next key offset
unsigned char bits; // page size in bits
- unsigned char lvl:6; // level of page
- unsigned char kill:1; // page is being deleted
+ unsigned char lvl:7; // level of page
unsigned char dirty:1; // page has deleted keys
unsigned char right[BtId]; // page number to right
- BtSlot table[0]; // array of key slots
} *BtPage;
// The memory mapping pool table buffer manager entry
void *hashprev; // previous pool entry for the same hash idx
void *hashnext; // next pool entry for the same hash idx
#ifndef unix
- HANDLE hmap;
+ HANDLE hmap; // Windows memory mapping handle
#endif
} BtPool;
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;
// B-Tree functions
extern void bt_close (BtDb *bt);
extern BtDb *bt_open (BtMgr *mgr);
-extern BTERR bt_insertkey (BtDb *bt, unsigned char *key, uint len, uint lvl, uid id, uint tod);
-extern BTERR bt_deletekey (BtDb *bt, unsigned char *key, uint len, uint lvl);
+extern BTERR bt_insertkey (BtDb *bt, unsigned char *key, uint len, uid id, uint tod, uint lvl);
+extern BTERR bt_deletekey (BtDb *bt, unsigned char *key, uint len);
extern uid bt_findkey (BtDb *bt, unsigned char *key, uint len);
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);
+
// manager functions
extern BtMgr *bt_mgr (char *name, uint mode, uint bits, uint poolsize, uint segsize, uint hashsize);
void bt_mgrclose (BtMgr *mgr);
// Access macros to address slot and key values from the page
-#define slotptr(page, slot) (page->table + slot-1)
+#define slotptr(page, slot) (((BtSlot *)(page+1)) + (slot-1))
#define keyptr(page, slot) ((BtKey)((unsigned char*)(page) + slotptr(page, slot)->off))
void bt_putid(unsigned char *dest, uid id)
uint drill = 0xff, slot;
uint mode, prevmode;
BtPool *prevpool;
+int parent = 1;
// start at root of btree and drill down
// find key on page at this level
// and descend to requested level
- if( !bt->page->kill && (slot = bt_findslot (bt, key, len)) ) {
+ if( slot = bt_findslot (bt, key, len) ) {
if( drill == lvl )
- return slot;
+ return bt->parent = parent, slot;
while( slotptr(bt->page, slot)->dead )
if( slot++ < bt->page->cnt )
continue;
else {
page_no = bt_getid(bt->page->right);
+ parent = 0;
goto slideright;
}
page_no = bt_getid(slotptr(bt->page, slot)->id);
+ parent = 1;
drill--;
}
// or slide right into next page
- // (slide left from deleted page)
- else
+ else {
page_no = bt_getid(bt->page->right);
+ parent = 0;
+ }
// continue down / right using overlapping locks
- // to protect pages being killed or split.
+ // to protect pages being split.
slideright:
prevpage = bt->page_no;
return 0; // return error
}
-// find and delete key on page by marking delete flag bit
-// when page becomes empty, delete it
+// remove empty page from the B-tree
+// by pulling our right node left over ourselves
+
+// call with bt->page, etc, set to page's locked parent
+// returns with page locked.
-BTERR bt_deletekey (BtDb *bt, unsigned char *key, uint len, uint lvl)
+BTERR bt_mergeright (BtDb *bt, BtPage page, BtPool *pool, BtLatchSet *set, uid page_no, uint lvl, uint slot)
{
-unsigned char lowerkey[256], higherkey[256];
-BtLatchSet *rset, *set;
-BtPool *pool, *rpool;
-uid page_no, right;
-uint slot, tod;
-BtPage rpage;
+BtLatchSet *rset, *pset, *rpset;
+BtPool *rpool, *ppool, *rppool;
+BtPage rpage, ppage, rppage;
+uid right, parent, rparent;
BtKey ptr;
+uint idx;
- if( slot = bt_loadpage (bt, key, len, lvl, BtLockWrite) )
- ptr = keyptr(bt->page, slot);
+ // cache node's parent page
+
+ parent = bt->page_no;
+ ppage = bt->page;
+ ppool = bt->pool;
+ pset = bt->set;
+
+ // lock and map our right page
+ // it cannot be NULL because of the stopper
+ // in the last right page
+
+ bt_lockpage (BtLockWrite, set);
+
+ // if we aren't dead yet
+
+ if( page->act )
+ goto rmergexit;
+
+ 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;
+
+ rset = bt_pinlatch (bt, right);
+
+ // find our right neighbor
+
+ if( ppage->act > 1 ) {
+ for( idx = slot; idx++ < ppage->cnt; )
+ if( !slotptr(ppage, idx)->dead )
+ break;
+
+ if( idx > ppage->cnt )
+ return bt->err = BTERR_struct;
+
+ // redirect right neighbor in parent to left node
+
+ bt_putid(slotptr(ppage,idx)->id, page_no);
+ }
+
+ // if parent has only our deleted page, e.g. no right neighbor
+ // prepare to merge parent itself
+
+ 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;
+ else
+ return bt->err = BTERR_struct;
- // if key is found delete it, otherwise ignore request
+ rpset = bt_pinlatch (bt, rparent);
+ bt_lockpage (BtLockWrite, rpset);
- if( bt->found = !keycmp (ptr, key, len) )
- if( bt->found = slotptr(bt->page, slot)->dead == 0 ) {
- slotptr(bt->page,slot)->dead = 1;
- if( slot < bt->page->cnt )
- bt->page->dirty = 1;
- bt->page->act--;
+ // find our right neighbor on right parent page
+
+ for( idx = 0; idx++ < rppage->cnt; )
+ if( !slotptr(rppage, idx)->dead ) {
+ bt_putid (slotptr(rppage, idx)->id, page_no);
+ break;
}
- // return if page is not empty, or it has no right sibling
+ if( idx > rppage->cnt )
+ return bt->err = BTERR_struct;
+ }
- right = bt_getid(bt->page->right);
- page_no = bt->page_no;
- pool = bt->pool;
- set = bt->set;
+ // now that there are no more pointers to our right node
+ // we can wait for delete lock on it
- if( !right || bt->page->act ) {
- bt_unlockpage(BtLockWrite, set);
- bt_unpinlatch (set);
- bt_unpinpool (pool);
+ bt_lockpage(BtLockDelete, rset);
+ bt_lockpage(BtLockWrite, rset);
+
+ // pull contents of right page into our empty page
+
+ memcpy (page, rpage, bt->mgr->page_size);
+
+ // ready to release right parent lock
+ // now that we have a new page in place
+
+ if( ppage->act == 1 ) {
+ bt_unlockpage (BtLockWrite, rpset);
+ bt_unpinlatch (rpset);
+ bt_unpinpool (rppool);
+ }
+
+ // add killed right block to free chain
+ // lock latch mgr
+
+ bt_spinwritelock(bt->mgr->latchmgr->lock);
+
+ // store free chain in allocation page second right
+
+ bt_putid(rpage->right, bt_getid(bt->mgr->latchmgr->alloc[1].right));
+ bt_putid(bt->mgr->latchmgr->alloc[1].right, right);
+
+ // unlock latch mgr and right page
+
+ bt_unlockpage(BtLockDelete, rset);
+ bt_unlockpage(BtLockWrite, rset);
+ bt_unpinlatch (rset);
+ bt_unpinpool (rpool);
+
+ bt_spinreleasewrite(bt->mgr->latchmgr->lock);
+
+ // delete our obsolete fence key from our parent
+
+ slotptr(ppage, slot)->dead = 1;
+ ppage->dirty = 1;
+
+ // if our parent now empty
+ // remove it from the tree
+
+ if( ppage->act-- == 1 )
+ if( bt_mergeleft (bt, ppage, ppool, pset, parent, lvl+1) )
+ return bt->err;
+
+rmergexit:
+ bt_unlockpage (BtLockWrite, pset);
+ bt_unpinlatch (pset);
+ bt_unpinpool (ppool);
+
+ bt->found = 1;
+ return bt->err = 0;
+}
+
+// remove empty page from the B-tree
+// try merging left first. If no left
+// sibling, then merge right.
+
+// call with page loaded and locked,
+// return with page locked.
+
+BTERR bt_mergeleft (BtDb *bt, BtPage page, BtPool *pool, BtLatchSet *set, uid page_no, uint lvl)
+{
+unsigned char fencekey[256], postkey[256];
+uint slot, idx, postfence = 0;
+BtLatchSet *lset, *pset;
+BtPool *lpool, *ppool;
+BtPage lpage, ppage;
+uid left, parent;
+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)) )
return bt->err;
+
+ parent = bt->page_no;
+ ppage = bt->page;
+ ppool = bt->pool;
+ pset = bt->set;
+
+ // wait until we are posted in our parent
+
+ if( !bt->parent ) {
+ bt_unlockpage (BtLockWrite, pset);
+ bt_unpinlatch (pset);
+ bt_unpinpool (ppool);
+#ifdef unix
+ sched_yield();
+#else
+ SwitchToThread();
+#endif
+ goto retry;
}
- // obtain Parent lock over write lock
+ // find our left neighbor in our parent page
- bt_lockpage(BtLockParent, set);
+ for( idx = slot; --idx; )
+ if( !slotptr(ppage, idx)->dead )
+ break;
- // keep copy of key to delete
+ // if no left neighbor, do right merge
- ptr = keyptr(bt->page, bt->page->cnt);
- memcpy(lowerkey, ptr, ptr->len + 1);
+ if( !idx )
+ return bt_mergeright (bt, page, pool, set, page_no, lvl, slot);
- // lock and map right page
+ // lock and map our left neighbor's page
- if( rpool = bt_pinpool (bt, right) )
- rpage = bt_page (bt, rpool, right);
+ left = bt_getid (slotptr(ppage, idx)->id);
+
+ if( lpool = bt_pinpool (bt, left) )
+ lpage = bt_page (bt, lpool, left);
else
return bt->err;
- rset = bt_pinlatch (bt, right);
- bt_lockpage(BtLockWrite, rset);
+ lset = bt_pinlatch (bt, left);
+ bt_lockpage(BtLockWrite, lset);
- // pull contents of next page into current empty page
+ // wait until sibling is in our parent
- memcpy (bt->page, rpage, bt->mgr->page_size);
+ 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);
+#ifdef linux
+ sched_yield();
+#else
+ SwitchToThread();
+#endif
+ goto retry;
+ }
- // keep copy of key to update
+ // since our page will have no more pointers to it,
+ // obtain Delete lock and wait for write locks to clear
- ptr = keyptr(rpage, rpage->cnt);
- memcpy(higherkey, ptr, ptr->len + 1);
+ bt_lockpage(BtLockDelete, set);
+ bt_lockpage(BtLockWrite, set);
- // Mark right page as deleted and point it to left page
- // until we can post updates at higher level.
+ // if we aren't dead yet,
+ // get ready for exit
- bt_putid(rpage->right, page_no);
- rpage->kill = 1;
- rpage->cnt = 0;
+ if( page->act ) {
+ bt_unlockpage(BtLockDelete, set);
+ bt_unlockpage(BtLockWrite, lset);
+ bt_unpinlatch (lset);
+ bt_unpinpool (lpool);
+ goto lmergexit;
+ }
- bt_unlockpage(BtLockWrite, rset);
- bt_unlockpage(BtLockWrite, set);
+ // are we are the fence key for our parent?
+ // if so, grab our old fence key
- // delete old lower key to consolidated node
+ if( postfence = slot == ppage->cnt ) {
+ ptr = keyptr (ppage, ppage->cnt);
+ memcpy(fencekey, ptr, ptr->len + 1);
+ memset(slotptr(ppage, ppage->cnt), 0, sizeof(BtSlot));
- if( bt_deletekey (bt, lowerkey + 1, *lowerkey, lvl + 1) )
- return bt->err;
+ // clear out other dead slots
- // redirect higher key directly to consolidated node
+ while( --ppage->cnt )
+ if( slotptr(ppage, ppage->cnt)->dead )
+ memset(slotptr(ppage, ppage->cnt), 0, sizeof(BtSlot));
+ else
+ break;
- tod = (uint)time(NULL);
+ ptr = keyptr (ppage, ppage->cnt);
+ memcpy(postkey, ptr, ptr->len + 1);
+ } else
+ slotptr(ppage,slot)->dead = 1;
- if( bt_insertkey (bt, higherkey+1, *higherkey, lvl + 1, page_no, tod) )
- return bt->err;
+ ppage->dirty = 1;
+ ppage->act--;
- // add killed right block to free chain
+ // push our right neighbor pointer to our left
+
+ memcpy (lpage->right, page->right, BtId);
+
+ // add ourselves to free chain
// lock latch mgr
bt_spinwritelock(bt->mgr->latchmgr->lock);
// store free chain in allocation page second right
- bt_putid(rpage->right, bt_getid(bt->mgr->latchmgr->alloc[1].right));
- bt_putid(bt->mgr->latchmgr->alloc[1].right, right);
+ bt_putid(page->right, bt_getid(bt->mgr->latchmgr->alloc[1].right));
+ bt_putid(bt->mgr->latchmgr->alloc[1].right, page_no);
- // unlock latch mgr and unpin right page
+ // unlock latch mgr and pages
bt_spinreleasewrite(bt->mgr->latchmgr->lock);
- bt_unpinlatch (rset);
- bt_unpinpool (rpool);
+ bt_unlockpage(BtLockWrite, lset);
+ bt_unpinlatch (lset);
+ bt_unpinpool (lpool);
+
+ // release our node's delete lock
+
+ bt_unlockpage(BtLockDelete, set);
+
+lmergexit:
+ bt_unlockpage (BtLockWrite, pset);
+ bt_unpinpool (ppool);
+
+ // do we need to post parent's fence key in its parent?
- // remove ParentModify lock
+ if( !postfence || parent == ROOT_page ) {
+ bt_unpinlatch (pset);
+ bt->found = 1;
+ return bt->err = 0;
+ }
+
+ // interlock parent fence post
+
+ bt_lockpage (BtLockParent, pset);
+
+ // load parent's parent page
+posttry:
+ if( !(slot = bt_loadpage (bt, fencekey+1, *fencekey, lvl+2, BtLockWrite)) )
+ 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;
+
+ page = bt->page;
+
+ 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;
+
+ bt_unlockpage (BtLockParent, pset);
+ bt_unpinlatch (pset);
+
+ bt_unlockpage (BtLockWrite, bt->set);
+ bt_unpinlatch (bt->set);
+ bt_unpinpool (bt->pool);
- bt_unlockpage(BtLockParent, set);
+ bt->found = 1;
+ return bt->err = 0;
+}
+
+// find and delete key on page by marking delete flag bit
+// if page becomes empty, delete it from the btree
+
+BTERR bt_deletekey (BtDb *bt, unsigned char *key, uint len)
+{
+BtLatchSet *set;
+BtPool *pool;
+BtPage page;
+uid page_no;
+BtKey ptr;
+uint slot;
+
+ if( !(slot = bt_loadpage (bt, key, len, 0, BtLockWrite)) )
+ 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( 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;
+ }
+
+ bt_unlockpage(BtLockWrite, set);
bt_unpinlatch (set);
bt_unpinpool (pool);
- return 0;
+ return bt->err = 0;
}
// find key in leaf level and return row-id
// if key exists, return row-id
// otherwise return 0
- if( ptr->len == len && !memcmp (ptr->key, key, len) )
+ if( slot <= bt->page->cnt && !keycmp (ptr, key, len) )
id = bt_getid(slotptr(bt->page,slot)->id);
else
id = 0;
// check page for space available,
// clean if necessary and return
-// =0 - page needs splitting
-// >0 - go ahead at returned slot
+// 0 - page needs splitting
+// >0 new slot value
-uint bt_cleanpage(BtDb *bt, uint amt, uint slot)
+uint bt_cleanpage(BtDb *bt, BtPage page, uint amt, uint slot)
{
uint nxt = bt->mgr->page_size;
-BtPage page = bt->page;
uint cnt = 0, idx = 0;
uint max = page->cnt;
-uint newslot;
+uint newslot = max;
BtKey key;
if( page->min >= (max+1) * sizeof(BtSlot) + sizeof(*page) + amt + 1 )
page->dirty = 0;
page->act = 0;
- // always leave fence key in list
+ // try cleaning up page first
+
+ // always leave fence key in the array
+ // otherwise, remove deleted key
while( cnt++ < max ) {
if( cnt == slot )
newslot = idx + 1;
- else if( cnt < max && slotptr(bt->frame,cnt)->dead )
+ if( cnt < max && slotptr(bt->frame,cnt)->dead )
continue;
// copy key
+
key = keyptr(bt->frame, cnt);
nxt -= key->len + 1;
memcpy ((unsigned char *)page + nxt, key, key->len + 1);
slotptr(page, idx)->tod = slotptr(bt->frame, cnt)->tod;
slotptr(page, idx)->off = nxt;
}
+
page->min = nxt;
page->cnt = idx;
+ // see if page has enough space now, or does it need splitting?
+
if( page->min >= (idx+1) * sizeof(BtSlot) + sizeof(*page) + amt + 1 )
return newslot;
return 0;
}
-// split the root and raise the height of the btree
+// add key to current page
+// page must already be writelocked
-BTERR bt_splitroot(BtDb *bt, unsigned char *newkey, unsigned char *oldkey, uid page_no2)
+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)
{
uint nxt = bt->mgr->page_size;
BtPage root = bt->page;
uid new_page;
// Obtain an empty page to use, and copy the current
- // root contents into it which is the lower half of
- // the old root.
+ // root contents into it
if( !(new_page = bt_newpage(bt, root)) )
return bt->err;
// insert first key on newroot page
- nxt -= *newkey + 1;
- memcpy ((unsigned char *)root + nxt, newkey, *newkey + 1);
+ nxt -= *leftkey + 1;
+ memcpy ((unsigned char *)root + nxt, leftkey, *leftkey + 1);
bt_putid(slotptr(root, 1)->id, new_page);
slotptr(root, 1)->off = nxt;
- // insert second key on newroot page
+ // insert second key (stopper key) on newroot page
// and increase the root height
- nxt -= *oldkey + 1;
- memcpy ((unsigned char *)root + nxt, oldkey, *oldkey + 1);
+ 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;
}
// split already locked full node
-// return unlocked.
+// return unlocked and unpinned.
-BTERR bt_splitpage (BtDb *bt)
+BTERR bt_splitpage (BtDb *bt, BtPage page, BtPool *pool, BtLatchSet *set, uid page_no)
{
-uint cnt = 0, idx = 0, max, nxt = bt->mgr->page_size;
-unsigned char oldkey[256], lowerkey[256];
-uid page_no = bt->page_no, right;
-BtLatchSet *nset, *set = bt->set;
-BtPool *pool = bt->pool;
-BtPage page = bt->page;
+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;
BtKey key;
-uint tod;
- // split higher half of keys to bt->frame
- // the last key (fence key) might be dead
-
- tod = (uint)time(NULL);
+ // initialize frame buffer for right node
memset (bt->frame, 0, bt->mgr->page_size);
- max = (int)page->cnt;
+ max = 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;
slotptr(bt->frame, idx)->off = nxt;
}
- // remember existing fence key for new page to the right
+ // transfer right link node to new right node
- memcpy (oldkey, key, key->len + 1);
+ if( page_no > ROOT_page )
+ memcpy (bt->frame->right, page->right, BtId);
bt->frame->bits = bt->mgr->page_bits;
bt->frame->min = nxt;
bt->frame->cnt = idx;
bt->frame->lvl = lvl;
- // link right node
-
- if( page_no > ROOT_page ) {
- right = bt_getid (page->right);
- bt_putid(bt->frame->right, right);
- }
-
- // get new free page and write frame to it.
+ // get new free page and write right frame to it.
if( !(new_page = bt_newpage(bt, bt->frame)) )
return bt->err;
+ // remember fence key for new right page to add
+ // as right sibling to the left node
+
+ key = keyptr(bt->frame, idx);
+ memcpy (rightkey, key, key->len + 1);
+
// 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));
nxt = bt->mgr->page_size;
+ page->dirty = 0;
page->act = 0;
cnt = 0;
idx = 0;
// assemble page of smaller keys
- // (they're all active 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);
+ 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;
- page->act++;
}
- // remember fence key for old page
+ // finalize left page and save fence key
- memcpy(lowerkey, key, key->len + 1);
- bt_putid(page->right, new_page);
+ memcpy(leftkey, key, key->len + 1);
page->min = nxt;
page->cnt = idx;
+ // link new right page
+
+ bt_putid (page->right, new_page);
+
// if current page is the root page, split it
if( page_no == ROOT_page )
- return bt_splitroot (bt, lowerkey, oldkey, new_page);
+ return bt_splitroot (bt, leftkey, new_page);
- // obtain Parent/Write locks
- // for left and right node pages
+ // obtain ParentModification lock for current page
- nset = bt_pinlatch (bt, new_page);
-
- bt_lockpage (BtLockParent, nset);
bt_lockpage (BtLockParent, set);
- // release wr lock on left page
- // (keep the SMO in sequence)
+ // release wr lock on our page.
+ // this will keep out another SMO
bt_unlockpage (BtLockWrite, set);
- // insert new fence for reformulated left block
+ // insert key for old page (lower keys)
- if( bt_insertkey (bt, lowerkey+1, *lowerkey, lvl + 1, page_no, tod) )
+ if( bt_insertkey (bt, leftkey + 1, *leftkey, page_no, tod, lvl + 1) )
return bt->err;
- // fix old fence for newly allocated right block page
+ // switch old parent key from us to our right page
- if( bt_insertkey (bt, oldkey+1, *oldkey, lvl + 1, new_page, tod) )
+ if( bt_insertkey (bt, rightkey + 1, *rightkey, new_page, tod, lvl + 1) )
return bt->err;
- // release Parent locks
+ // unlock and unpin
- bt_unlockpage (BtLockParent, nset);
bt_unlockpage (BtLockParent, set);
- bt_unpinlatch (nset);
bt_unpinlatch (set);
bt_unpinpool (pool);
return 0;
}
-// Insert new key into the btree at requested level.
-// Level zero pages are leaf pages. Page is unlocked at exit.
+// Insert new key into the btree at given level.
-BTERR bt_insertkey (BtDb *bt, unsigned char *key, uint len, uint lvl, uid id, uint tod)
+BTERR bt_insertkey (BtDb *bt, unsigned char *key, uint len, uid id, uint tod, uint lvl)
{
uint slot, idx;
BtPage page;
BtKey ptr;
- while( 1 ) {
- if( slot = bt_loadpage (bt, key, len, lvl, BtLockWrite) )
- ptr = keyptr(bt->page, slot);
- else
- {
- if ( !bt->err )
- bt->err = BTERR_ovflw;
- return bt->err;
- }
-
- // if key already exists, update id and return
-
- page = bt->page;
-
- if( bt->found = !keycmp (ptr, key, len) ) {
- 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;
- }
-
- // check if page has enough space
-
- if( slot = bt_cleanpage (bt, len, slot) )
- break;
-
- if( bt_splitpage (bt) )
- return bt->err;
- }
-
- // calculate next available slot and copy key into page
+ while( 1 ) {
+ if( slot = bt_loadpage (bt, key, len, lvl, BtLockWrite) )
+ ptr = keyptr(bt->page, slot);
+ else
+ {
+ if ( !bt->err )
+ bt->err = BTERR_ovflw;
+ return bt->err;
+ }
- page->min -= len + 1; // reset lowest used offset
- ((unsigned char *)page)[page->min] = len;
- memcpy ((unsigned char *)page + page->min +1, key, len );
+ // if key already exists, update id and return
- for( idx = slot; idx < page->cnt; idx++ )
- if( slotptr(page, idx)->dead )
- break;
+ page = bt->page;
- // now insert key into array before slot
- // preserving the fence slot
+ 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( idx == page->cnt )
- idx++, page->cnt++;
+ // check if page has enough space
- page->act++;
+ if( slot = bt_cleanpage (bt, bt->page, len, slot) )
+ break;
- while( idx > slot )
- *slotptr(page, idx) = *slotptr(page, idx -1), idx--;
+ if( bt_splitpage (bt, bt->page, bt->pool, bt->set, bt->page_no) )
+ return bt->err;
+ }
- bt_putid(slotptr(page,slot)->id, id);
- slotptr(page, slot)->off = page->min;
- slotptr(page, slot)->tod = tod;
- slotptr(page, slot)->dead = 0;
+ bt_addkeytopage (bt, bt->page, slot, key, len, id, tod);
- bt_unlockpage (BtLockWrite, bt->set);
- bt_unpinlatch (bt->set);
- bt_unpinpool (bt->pool);
- return 0;
+ bt_unlockpage (BtLockWrite, bt->set);
+ bt_unpinlatch (bt->set);
+ bt_unpinpool (bt->pool);
+ return 0;
}
// cache page of keys into cursor and return starting slot for given key
// 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;
+
bt_unlockpage(BtLockRead, bt->set);
bt_unpinlatch (bt->set);
bt_unpinpool (bt->pool);
uint bt_nextkey (BtDb *bt, uint slot)
{
+BtLatchSet *set;
BtPool *pool;
BtPage page;
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) )
return slot;
else
break;
break;
bt->cursor_page = right;
-
if( pool = bt_pinpool (bt, right) )
page = bt_page (bt, pool, right);
else
return 0;
- bt->set = bt_pinlatch (bt, right);
- bt_lockpage(BtLockRead, bt->set);
+ set = bt_pinlatch (bt, right);
+ bt_lockpage(BtLockRead, set);
memcpy (bt->cursor, page, bt->mgr->page_size);
- bt_unlockpage(BtLockRead, bt->set);
- bt_unpinlatch (bt->set);
+ bt_unlockpage(BtLockRead, set);
+ bt_unpinlatch (set);
bt_unpinpool (pool);
slot = 0;
} while( 1 );
return slotptr(bt->cursor,slot)->tod;
}
-#ifdef STANDALONE
-
-void bt_latchaudit (BtDb *bt)
-{
-ushort idx, hashidx;
-BtLatchSet *set;
-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;
- }
- if( set->pin ) {
- fprintf(stderr, "latchset %d pinned\n", idx);
- set->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 )
- fprintf(stderr, "latchset %d wrong hashidx\n", idx);
- if( set->pin )
- fprintf(stderr, "latchset %d pinned\n", idx);
- } while( idx = set->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);
- }
-#endif
-}
+#ifdef STANDALONE
typedef struct {
char type, idx;
unsigned char key[256];
ThreadArg *args = arg;
int ch, len = 0, slot;
+BtLatchSet *set;
time_t tod[1];
BtPool *pool;
BtPage page;
switch(args->type | 0x20)
{
- case 'a':
- fprintf(stderr, "started latch mgr audit\n");
- bt_latchaudit (bt);
- fprintf(stderr, "finished latch mgr audit\n");
- break;
-
case 'w':
fprintf(stderr, "started indexing for %s\n", args->infile);
if( in = fopen (args->infile, "rb") )
else if( args->num )
sprintf((char *)key+len, "%.9d", line + args->idx * args->num), len += 9;
- if( bt_insertkey (bt, key, len, 0, line, *tod) )
+ if( bt_insertkey (bt, key, len, line, *tod, 0) )
fprintf(stderr, "Error %d Line: %d\n", bt->err, line), exit(0);
len = 0;
}
else if( args->num )
sprintf((char *)key+len, "%.9d", line + args->idx * args->num), len += 9;
- if( bt_deletekey (bt, key, len, 0) )
+ if( bt_deletekey (bt, key, len) )
fprintf(stderr, "Error %d Line: %d\n", bt->err, line), exit(0);
len = 0;
}
fprintf(stderr, "started reading\n");
do {
- if( bt->pool = bt_pinpool (bt, page_no) )
- page = bt_page (bt, bt->pool, page_no);
+ if( pool = bt_pinpool (bt, page_no) )
+ page = bt_page (bt, pool, page_no);
else
break;
- bt->set = bt_pinlatch (bt, page_no);
- bt_lockpage (BtLockRead, bt->set);
+ set = bt_pinlatch (bt, page_no);
+ bt_lockpage (BtLockRead, set);
cnt += page->act;
next = bt_getid (page->right);
- bt_unlockpage (BtLockRead, bt->set);
- bt_unpinlatch (bt->set);
- bt_unpinpool (bt->pool);
+ bt_unlockpage (BtLockRead, set);
+ bt_unpinlatch (set);
+ bt_unpinpool (pool);
} while( page_no = next );
cnt--; // remove stopper key
// btree version threads2i sched_yield version
-// 24 JAN 2014
+// 29 JAN 2014
// author: karl malbrain, malbrain@cal.berkeley.edu
// by the BtSlot array of keys.
typedef struct Page {
- BtLatchSet latch[1]; // Set of three latches
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:6; // level of page
- unsigned char kill:1; // page is being deleted
+ unsigned char lvl:7; // level of page
unsigned char dirty:1; // page has deleted keys
unsigned char right[BtId]; // page number to right
- BtSlot table[0]; // array of key slots
} *BtPage;
// The memory mapping pool table buffer manager entry
void *hashprev; // previous pool entry for the same hash idx
void *hashnext; // next pool entry for the same hash idx
#ifndef unix
- HANDLE hmap;
+ HANDLE hmap; // Windows memory mapping handle
#endif
} BtPool;
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;
// B-Tree functions
extern void bt_close (BtDb *bt);
extern BtDb *bt_open (BtMgr *mgr);
-extern BTERR bt_insertkey (BtDb *bt, unsigned char *key, uint len, uint lvl, uid id, uint tod);
-extern BTERR bt_deletekey (BtDb *bt, unsigned char *key, uint len, uint lvl);
+extern BTERR bt_insertkey (BtDb *bt, unsigned char *key, uint len, uid id, uint tod, uint lvl);
+extern BTERR bt_deletekey (BtDb *bt, unsigned char *key, uint len);
extern uid bt_findkey (BtDb *bt, unsigned char *key, uint len);
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);
+
// manager functions
extern BtMgr *bt_mgr (char *name, uint mode, uint bits, uint poolsize, uint segsize, uint hashsize);
void bt_mgrclose (BtMgr *mgr);
// Access macros to address slot and key values from the page
-#define slotptr(page, slot) (page->table + slot-1)
+#define slotptr(page, slot) (((BtSlot *)(page+1)) + (slot-1))
#define keyptr(page, slot) ((BtKey)((unsigned char*)(page) + slotptr(page, slot)->off))
void bt_putid(unsigned char *dest, uid id)
uint drill = 0xff, slot;
uint mode, prevmode;
BtPool *prevpool;
+int parent = 1;
// start at root of btree and drill down
// find key on page at this level
// and descend to requested level
- if( !bt->page->kill && (slot = bt_findslot (bt, key, len)) ) {
+ if( slot = bt_findslot (bt, key, len) ) {
if( drill == lvl )
- return slot;
+ return bt->parent = parent, slot;
while( slotptr(bt->page, slot)->dead )
if( slot++ < bt->page->cnt )
continue;
else {
page_no = bt_getid(bt->page->right);
+ parent = 0;
goto slideright;
}
page_no = bt_getid(slotptr(bt->page, slot)->id);
+ parent = 1;
drill--;
}
// or slide right into next page
- // (slide left from deleted page)
- else
+ else {
page_no = bt_getid(bt->page->right);
+ parent = 0;
+ }
// continue down / right using overlapping locks
- // to protect pages being killed or split.
+ // to protect pages being split.
slideright:
prevpage = bt->page_no;
return 0; // return error
}
-// find and delete key on page by marking delete flag bit
-// when page becomes empty, delete it
+// remove empty page from the B-tree
+// by pulling our right node left over ourselves
+
+// call with bt->page, etc, set to page's locked parent
+// returns with page locked.
-BTERR bt_deletekey (BtDb *bt, unsigned char *key, uint len, uint lvl)
+BTERR bt_mergeright (BtDb *bt, BtPage page, BtPool *pool, BtLatchSet *set, uid page_no, uint lvl, uint slot)
{
-unsigned char lowerkey[256], higherkey[256];
-BtLatchSet *rset, *set;
-BtPool *pool, *rpool;
-uid page_no, right;
-uint slot, tod;
-BtPage rpage;
+BtLatchSet *rset, *pset, *rpset;
+BtPool *rpool, *ppool, *rppool;
+BtPage rpage, ppage, rppage;
+uid right, parent, rparent;
BtKey ptr;
+uint idx;
- if( slot = bt_loadpage (bt, key, len, lvl, BtLockWrite) )
- ptr = keyptr(bt->page, slot);
+ // cache node's parent page
+
+ parent = bt->page_no;
+ ppage = bt->page;
+ ppool = bt->pool;
+ pset = bt->set;
+
+ // lock and map our right page
+ // it cannot be NULL because of the stopper
+ // in the last right page
+
+ bt_lockpage (BtLockWrite, set);
+
+ // if we aren't dead yet
+
+ if( page->act )
+ goto rmergexit;
+
+ 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;
+
+ rset = bt_pinlatch (bt, right);
+
+ // find our right neighbor
+
+ if( ppage->act > 1 ) {
+ for( idx = slot; idx++ < ppage->cnt; )
+ if( !slotptr(ppage, idx)->dead )
+ break;
+
+ if( idx > ppage->cnt )
+ return bt->err = BTERR_struct;
+
+ // redirect right neighbor in parent to left node
+
+ bt_putid(slotptr(ppage,idx)->id, page_no);
+ }
+
+ // if parent has only our deleted page, e.g. no right neighbor
+ // prepare to merge parent itself
+
+ 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;
+ else
+ return bt->err = BTERR_struct;
- // if key is found delete it, otherwise ignore request
+ rpset = bt_pinlatch (bt, rparent);
+ bt_lockpage (BtLockWrite, rpset);
- if( bt->found = !keycmp (ptr, key, len) )
- if( bt->found = slotptr(bt->page, slot)->dead == 0 ) {
- slotptr(bt->page,slot)->dead = 1;
- if( slot < bt->page->cnt )
- bt->page->dirty = 1;
- bt->page->act--;
+ // find our right neighbor on right parent page
+
+ for( idx = 0; idx++ < rppage->cnt; )
+ if( !slotptr(rppage, idx)->dead ) {
+ bt_putid (slotptr(rppage, idx)->id, page_no);
+ break;
}
- // return if page is not empty, or it has no right sibling
+ if( idx > rppage->cnt )
+ return bt->err = BTERR_struct;
+ }
- right = bt_getid(bt->page->right);
- page_no = bt->page_no;
- pool = bt->pool;
- set = bt->set;
+ // now that there are no more pointers to our right node
+ // we can wait for delete lock on it
- if( !right || bt->page->act ) {
- bt_unlockpage(BtLockWrite, set);
- bt_unpinlatch (set);
- bt_unpinpool (pool);
+ bt_lockpage(BtLockDelete, rset);
+ bt_lockpage(BtLockWrite, rset);
+
+ // pull contents of right page into our empty page
+
+ memcpy (page, rpage, bt->mgr->page_size);
+
+ // ready to release right parent lock
+ // now that we have a new page in place
+
+ if( ppage->act == 1 ) {
+ bt_unlockpage (BtLockWrite, rpset);
+ bt_unpinlatch (rpset);
+ bt_unpinpool (rppool);
+ }
+
+ // add killed right block to free chain
+ // lock latch mgr
+
+ bt_spinwritelock(bt->mgr->latchmgr->lock);
+
+ // store free chain in allocation page second right
+
+ bt_putid(rpage->right, bt_getid(bt->mgr->latchmgr->alloc[1].right));
+ bt_putid(bt->mgr->latchmgr->alloc[1].right, right);
+
+ // unlock latch mgr and right page
+
+ bt_unlockpage(BtLockDelete, rset);
+ bt_unlockpage(BtLockWrite, rset);
+ bt_unpinlatch (rset);
+ bt_unpinpool (rpool);
+
+ bt_spinreleasewrite(bt->mgr->latchmgr->lock);
+
+ // delete our obsolete fence key from our parent
+
+ slotptr(ppage, slot)->dead = 1;
+ ppage->dirty = 1;
+
+ // if our parent now empty
+ // remove it from the tree
+
+ if( ppage->act-- == 1 )
+ if( bt_mergeleft (bt, ppage, ppool, pset, parent, lvl+1) )
+ return bt->err;
+
+rmergexit:
+ bt_unlockpage (BtLockWrite, pset);
+ bt_unpinlatch (pset);
+ bt_unpinpool (ppool);
+
+ bt->found = 1;
+ return bt->err = 0;
+}
+
+// remove empty page from the B-tree
+// try merging left first. If no left
+// sibling, then merge right.
+
+// call with page loaded and locked,
+// return with page locked.
+
+BTERR bt_mergeleft (BtDb *bt, BtPage page, BtPool *pool, BtLatchSet *set, uid page_no, uint lvl)
+{
+unsigned char fencekey[256], postkey[256];
+uint slot, idx, postfence = 0;
+BtLatchSet *lset, *pset;
+BtPool *lpool, *ppool;
+BtPage lpage, ppage;
+uid left, parent;
+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)) )
return bt->err;
+
+ parent = bt->page_no;
+ ppage = bt->page;
+ ppool = bt->pool;
+ pset = bt->set;
+
+ // wait until we are posted in our parent
+
+ if( !bt->parent ) {
+ bt_unlockpage (BtLockWrite, pset);
+ bt_unpinlatch (pset);
+ bt_unpinpool (ppool);
+#ifdef unix
+ sched_yield();
+#else
+ SwitchToThread();
+#endif
+ goto retry;
}
- // obtain Parent lock over write lock
+ // find our left neighbor in our parent page
- bt_lockpage(BtLockParent, set);
+ for( idx = slot; --idx; )
+ if( !slotptr(ppage, idx)->dead )
+ break;
- // keep copy of key to delete
+ // if no left neighbor, do right merge
- ptr = keyptr(bt->page, bt->page->cnt);
- memcpy(lowerkey, ptr, ptr->len + 1);
+ if( !idx )
+ return bt_mergeright (bt, page, pool, set, page_no, lvl, slot);
- // lock and map right page
+ // lock and map our left neighbor's page
- if( rpool = bt_pinpool (bt, right) )
- rpage = bt_page (bt, rpool, right);
+ left = bt_getid (slotptr(ppage, idx)->id);
+
+ if( lpool = bt_pinpool (bt, left) )
+ lpage = bt_page (bt, lpool, left);
else
return bt->err;
- rset = bt_pinlatch (bt, right);
- bt_lockpage(BtLockWrite, rset);
+ lset = bt_pinlatch (bt, left);
+ bt_lockpage(BtLockWrite, lset);
- // pull contents of next page into current empty page
+ // wait until sibling is in our parent
+
+ 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);
+#ifdef linux
+ sched_yield();
+#else
+ SwitchToThread();
+#endif
+ goto retry;
+ }
- memcpy (bt->page, rpage, bt->mgr->page_size);
+ // since our page will have no more pointers to it,
+ // obtain Delete lock and wait for write locks to clear
- // keep copy of key to update
+ bt_lockpage(BtLockDelete, set);
+ bt_lockpage(BtLockWrite, set);
- ptr = keyptr(rpage, rpage->cnt);
- memcpy(higherkey, ptr, ptr->len + 1);
+ // if we aren't dead yet,
+ // get ready for exit
- // Mark right page as deleted and point it to left page
- // until we can post updates at higher level.
+ if( page->act ) {
+ bt_unlockpage(BtLockDelete, set);
+ bt_unlockpage(BtLockWrite, lset);
+ bt_unpinlatch (lset);
+ bt_unpinpool (lpool);
+ goto lmergexit;
+ }
- bt_putid(rpage->right, page_no);
- rpage->kill = 1;
- rpage->cnt = 0;
+ // are we are the fence key for our parent?
+ // if so, grab our old fence key
- bt_unlockpage(BtLockWrite, rset);
- bt_unlockpage(BtLockWrite, set);
+ if( postfence = slot == ppage->cnt ) {
+ ptr = keyptr (ppage, ppage->cnt);
+ memcpy(fencekey, ptr, ptr->len + 1);
+ memset(slotptr(ppage, ppage->cnt), 0, sizeof(BtSlot));
- // delete old lower key to consolidated node
+ // clear out other dead slots
- if( bt_deletekey (bt, lowerkey + 1, *lowerkey, lvl + 1) )
- return bt->err;
+ while( --ppage->cnt )
+ if( slotptr(ppage, ppage->cnt)->dead )
+ memset(slotptr(ppage, ppage->cnt), 0, sizeof(BtSlot));
+ else
+ break;
- // redirect higher key directly to consolidated node
+ ptr = keyptr (ppage, ppage->cnt);
+ memcpy(postkey, ptr, ptr->len + 1);
+ } else
+ slotptr(ppage,slot)->dead = 1;
- tod = (uint)time(NULL);
+ ppage->dirty = 1;
+ ppage->act--;
- if( bt_insertkey (bt, higherkey+1, *higherkey, lvl + 1, page_no, tod) )
- return bt->err;
+ // push our right neighbor pointer to our left
- // add killed right block to free chain
+ memcpy (lpage->right, page->right, BtId);
+
+ // add ourselves to free chain
// lock latch mgr
bt_spinwritelock(bt->mgr->latchmgr->lock);
// store free chain in allocation page second right
- bt_putid(rpage->right, bt_getid(bt->mgr->latchmgr->alloc[1].right));
- bt_putid(bt->mgr->latchmgr->alloc[1].right, right);
+ bt_putid(page->right, bt_getid(bt->mgr->latchmgr->alloc[1].right));
+ bt_putid(bt->mgr->latchmgr->alloc[1].right, page_no);
- // unlock latch mgr and unpin right page
+ // unlock latch mgr and pages
bt_spinreleasewrite(bt->mgr->latchmgr->lock);
- bt_unpinlatch (rset);
- bt_unpinpool (rpool);
+ bt_unlockpage(BtLockWrite, lset);
+ bt_unpinlatch (lset);
+ bt_unpinpool (lpool);
+
+ // release our node's delete lock
+
+ bt_unlockpage(BtLockDelete, set);
- // remove ParentModify lock
+lmergexit:
+ bt_unlockpage (BtLockWrite, pset);
+ bt_unpinpool (ppool);
+
+ // do we need to post parent's fence key in its parent?
+
+ if( !postfence || parent == ROOT_page ) {
+ bt_unpinlatch (pset);
+ bt->found = 1;
+ return bt->err = 0;
+ }
+
+ // interlock parent fence post
+
+ bt_lockpage (BtLockParent, pset);
+
+ // load parent's parent page
+posttry:
+ if( !(slot = bt_loadpage (bt, fencekey+1, *fencekey, lvl+2, BtLockWrite)) )
+ return bt->err;
- bt_unlockpage(BtLockParent, set);
+ 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;
+
+ page = bt->page;
+
+ 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;
+
+ bt_unlockpage (BtLockParent, pset);
+ bt_unpinlatch (pset);
+
+ bt_unlockpage (BtLockWrite, bt->set);
+ bt_unpinlatch (bt->set);
+ bt_unpinpool (bt->pool);
+
+ bt->found = 1;
+ return bt->err = 0;
+}
+
+// find and delete key on page by marking delete flag bit
+// if page becomes empty, delete it from the btree
+
+BTERR bt_deletekey (BtDb *bt, unsigned char *key, uint len)
+{
+BtLatchSet *set;
+BtPool *pool;
+BtPage page;
+uid page_no;
+BtKey ptr;
+uint slot;
+
+ if( !(slot = bt_loadpage (bt, key, len, 0, BtLockWrite)) )
+ 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( 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;
+ }
+
+ bt_unlockpage(BtLockWrite, set);
bt_unpinlatch (set);
bt_unpinpool (pool);
- return 0;
+ return bt->err = 0;
}
// find key in leaf level and return row-id
// if key exists, return row-id
// otherwise return 0
- if( ptr->len == len && !memcmp (ptr->key, key, len) )
+ if( slot <= bt->page->cnt && !keycmp (ptr, key, len) )
id = bt_getid(slotptr(bt->page,slot)->id);
else
id = 0;
// check page for space available,
// clean if necessary and return
-// =0 - page needs splitting
-// >0 - go ahead at returned slot
+// 0 - page needs splitting
+// >0 new slot value
-uint bt_cleanpage(BtDb *bt, uint amt, uint slot)
+uint bt_cleanpage(BtDb *bt, BtPage page, uint amt, uint slot)
{
uint nxt = bt->mgr->page_size;
-BtPage page = bt->page;
uint cnt = 0, idx = 0;
uint max = page->cnt;
-uint newslot;
+uint newslot = max;
BtKey key;
if( page->min >= (max+1) * sizeof(BtSlot) + sizeof(*page) + amt + 1 )
page->dirty = 0;
page->act = 0;
- // always leave fence key in list
+ // try cleaning up page first
+
+ // always leave fence key in the array
+ // otherwise, remove deleted key
while( cnt++ < max ) {
if( cnt == slot )
newslot = idx + 1;
- else if( cnt < max && slotptr(bt->frame,cnt)->dead )
+ if( cnt < max && slotptr(bt->frame,cnt)->dead )
continue;
// copy key
+
key = keyptr(bt->frame, cnt);
nxt -= key->len + 1;
memcpy ((unsigned char *)page + nxt, key, key->len + 1);
slotptr(page, idx)->tod = slotptr(bt->frame, cnt)->tod;
slotptr(page, idx)->off = nxt;
}
+
page->min = nxt;
page->cnt = idx;
+ // see if page has enough space now, or does it need splitting?
+
if( page->min >= (idx+1) * sizeof(BtSlot) + sizeof(*page) + amt + 1 )
return newslot;
return 0;
}
-// split the root and raise the height of the btree
+// 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++;
+
+ // now insert key into array before slot
-BTERR bt_splitroot(BtDb *bt, unsigned char *newkey, unsigned char *oldkey, uid page_no2)
+ 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)
{
uint nxt = bt->mgr->page_size;
BtPage root = bt->page;
uid new_page;
// Obtain an empty page to use, and copy the current
- // root contents into it which is the lower half of
- // the old root.
+ // root contents into it
if( !(new_page = bt_newpage(bt, root)) )
return bt->err;
// insert first key on newroot page
- nxt -= *newkey + 1;
- memcpy ((unsigned char *)root + nxt, newkey, *newkey + 1);
+ nxt -= *leftkey + 1;
+ memcpy ((unsigned char *)root + nxt, leftkey, *leftkey + 1);
bt_putid(slotptr(root, 1)->id, new_page);
slotptr(root, 1)->off = nxt;
- // insert second key on newroot page
+ // insert second key (stopper key) on newroot page
// and increase the root height
- nxt -= *oldkey + 1;
- memcpy ((unsigned char *)root + nxt, oldkey, *oldkey + 1);
+ 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;
}
// split already locked full node
-// return unlocked.
+// return unlocked and unpinned.
-BTERR bt_splitpage (BtDb *bt)
+BTERR bt_splitpage (BtDb *bt, BtPage page, BtPool *pool, BtLatchSet *set, uid page_no)
{
-uint cnt = 0, idx = 0, max, nxt = bt->mgr->page_size;
-unsigned char oldkey[256], lowerkey[256];
-uid page_no = bt->page_no, right;
-BtLatchSet *nset, *set = bt->set;
-BtPool *pool = bt->pool;
-BtPage page = bt->page;
+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;
BtKey key;
-uint tod;
- // split higher half of keys to bt->frame
- // the last key (fence key) might be dead
-
- tod = (uint)time(NULL);
+ // initialize frame buffer for right node
memset (bt->frame, 0, bt->mgr->page_size);
- max = (int)page->cnt;
+ max = 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;
slotptr(bt->frame, idx)->off = nxt;
}
- // remember existing fence key for new page to the right
+ // transfer right link node to new right node
- memcpy (oldkey, key, key->len + 1);
+ if( page_no > ROOT_page )
+ memcpy (bt->frame->right, page->right, BtId);
bt->frame->bits = bt->mgr->page_bits;
bt->frame->min = nxt;
bt->frame->cnt = idx;
bt->frame->lvl = lvl;
- // link right node
-
- if( page_no > ROOT_page ) {
- right = bt_getid (page->right);
- bt_putid(bt->frame->right, right);
- }
-
- // get new free page and write frame to it.
+ // get new free page and write right frame to it.
if( !(new_page = bt_newpage(bt, bt->frame)) )
return bt->err;
+ // remember fence key for new right page to add
+ // as right sibling to the left node
+
+ key = keyptr(bt->frame, idx);
+ memcpy (rightkey, key, key->len + 1);
+
// 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));
nxt = bt->mgr->page_size;
+ page->dirty = 0;
page->act = 0;
cnt = 0;
idx = 0;
// assemble page of smaller keys
- // (they're all active 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);
+ 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;
- page->act++;
}
- // remember fence key for old page
+ // finalize left page and save fence key
- memcpy(lowerkey, key, key->len + 1);
- bt_putid(page->right, new_page);
+ memcpy(leftkey, key, key->len + 1);
page->min = nxt;
page->cnt = idx;
+ // link new right page
+
+ bt_putid (page->right, new_page);
+
// if current page is the root page, split it
if( page_no == ROOT_page )
- return bt_splitroot (bt, lowerkey, oldkey, new_page);
-
- // obtain Parent/Write locks
- // for left and right node pages
+ return bt_splitroot (bt, leftkey, new_page);
- nset = bt_pinlatch (bt, new_page);
+ // obtain ParentModification lock for current page
- bt_lockpage (BtLockParent, nset);
bt_lockpage (BtLockParent, set);
- // release wr lock on left page
- // (keep the SMO in sequence)
+ // release wr lock on our page.
+ // this will keep out another SMO
bt_unlockpage (BtLockWrite, set);
- // insert new fence for reformulated left block
+ // insert key for old page (lower keys)
- if( bt_insertkey (bt, lowerkey+1, *lowerkey, lvl + 1, page_no, tod) )
+ if( bt_insertkey (bt, leftkey + 1, *leftkey, page_no, tod, lvl + 1) )
return bt->err;
- // fix old fence for newly allocated right block page
+ // switch old parent key from us to our right page
- if( bt_insertkey (bt, oldkey+1, *oldkey, lvl + 1, new_page, tod) )
+ if( bt_insertkey (bt, rightkey + 1, *rightkey, new_page, tod, lvl + 1) )
return bt->err;
- // release Parent locks
+ // unlock and unpin
- bt_unlockpage (BtLockParent, nset);
bt_unlockpage (BtLockParent, set);
- bt_unpinlatch (nset);
bt_unpinlatch (set);
bt_unpinpool (pool);
return 0;
}
-// Insert new key into the btree at requested level.
-// Level zero pages are leaf pages. Page is unlocked at exit.
+// Insert new key into the btree at given level.
-BTERR bt_insertkey (BtDb *bt, unsigned char *key, uint len, uint lvl, uid id, uint tod)
+BTERR bt_insertkey (BtDb *bt, unsigned char *key, uint len, uid id, uint tod, uint lvl)
{
uint slot, idx;
BtPage page;
BtKey ptr;
- while( 1 ) {
- if( slot = bt_loadpage (bt, key, len, lvl, BtLockWrite) )
- ptr = keyptr(bt->page, slot);
- else
- {
- if ( !bt->err )
- bt->err = BTERR_ovflw;
- return bt->err;
- }
-
- // if key already exists, update id and return
-
- page = bt->page;
-
- if( bt->found = !keycmp (ptr, key, len) ) {
- 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;
- }
-
- // check if page has enough space
-
- if( slot = bt_cleanpage (bt, len, slot) )
- break;
-
- if( bt_splitpage (bt) )
- return bt->err;
- }
-
- // calculate next available slot and copy key into page
+ while( 1 ) {
+ if( slot = bt_loadpage (bt, key, len, lvl, BtLockWrite) )
+ ptr = keyptr(bt->page, slot);
+ else
+ {
+ if ( !bt->err )
+ bt->err = BTERR_ovflw;
+ return bt->err;
+ }
- page->min -= len + 1; // reset lowest used offset
- ((unsigned char *)page)[page->min] = len;
- memcpy ((unsigned char *)page + page->min +1, key, len );
+ // if key already exists, update id and return
- for( idx = slot; idx < page->cnt; idx++ )
- if( slotptr(page, idx)->dead )
- break;
+ page = bt->page;
- // now insert key into array before slot
- // preserving the fence slot
+ 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( idx == page->cnt )
- idx++, page->cnt++;
+ // check if page has enough space
- page->act++;
+ if( slot = bt_cleanpage (bt, bt->page, len, slot) )
+ break;
- while( idx > slot )
- *slotptr(page, idx) = *slotptr(page, idx -1), idx--;
+ if( bt_splitpage (bt, bt->page, bt->pool, bt->set, bt->page_no) )
+ return bt->err;
+ }
- bt_putid(slotptr(page,slot)->id, id);
- slotptr(page, slot)->off = page->min;
- slotptr(page, slot)->tod = tod;
- slotptr(page, slot)->dead = 0;
+ bt_addkeytopage (bt, bt->page, slot, key, len, id, tod);
- bt_unlockpage (BtLockWrite, bt->set);
- bt_unpinlatch (bt->set);
- bt_unpinpool (bt->pool);
- return 0;
+ bt_unlockpage (BtLockWrite, bt->set);
+ bt_unpinlatch (bt->set);
+ bt_unpinpool (bt->pool);
+ return 0;
}
// cache page of keys into cursor and return starting slot for given key
// 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;
+
bt_unlockpage(BtLockRead, bt->set);
bt_unpinlatch (bt->set);
bt_unpinpool (bt->pool);
uint bt_nextkey (BtDb *bt, uint slot)
{
+BtLatchSet *set;
BtPool *pool;
BtPage page;
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) )
return slot;
else
break;
break;
bt->cursor_page = right;
-
if( pool = bt_pinpool (bt, right) )
page = bt_page (bt, pool, right);
else
return 0;
- bt->set = bt_pinlatch (bt, right);
- bt_lockpage(BtLockRead, bt->set);
+ set = bt_pinlatch (bt, right);
+ bt_lockpage(BtLockRead, set);
memcpy (bt->cursor, page, bt->mgr->page_size);
- bt_unlockpage(BtLockRead, bt->set);
- bt_unpinlatch (bt->set);
+ bt_unlockpage(BtLockRead, set);
+ bt_unpinlatch (set);
bt_unpinpool (pool);
slot = 0;
} while( 1 );
return slotptr(bt->cursor,slot)->tod;
}
+
#ifdef STANDALONE
void bt_latchaudit (BtDb *bt)
unsigned char key[256];
ThreadArg *args = arg;
int ch, len = 0, slot;
+BtLatchSet *set;
time_t tod[1];
BtPool *pool;
BtPage page;
else if( args->num )
sprintf((char *)key+len, "%.9d", line + args->idx * args->num), len += 9;
- if( bt_insertkey (bt, key, len, 0, line, *tod) )
+ if( bt_insertkey (bt, key, len, line, *tod, 0) )
fprintf(stderr, "Error %d Line: %d\n", bt->err, line), exit(0);
len = 0;
}
else if( args->num )
sprintf((char *)key+len, "%.9d", line + args->idx * args->num), len += 9;
- if( bt_deletekey (bt, key, len, 0) )
+ if( bt_deletekey (bt, key, len) )
fprintf(stderr, "Error %d Line: %d\n", bt->err, line), exit(0);
len = 0;
}
fprintf(stderr, "started reading\n");
do {
- if( bt->pool = bt_pinpool (bt, page_no) )
- page = bt_page (bt, bt->pool, page_no);
+ if( pool = bt_pinpool (bt, page_no) )
+ page = bt_page (bt, pool, page_no);
else
break;
- bt->set = bt_pinlatch (bt, page_no);
- bt_lockpage (BtLockRead, bt->set);
+ set = bt_pinlatch (bt, page_no);
+ bt_lockpage (BtLockRead, set);
cnt += page->act;
next = bt_getid (page->right);
- bt_unlockpage (BtLockRead, bt->set);
- bt_unpinlatch (bt->set);
- bt_unpinpool (bt->pool);
+ bt_unlockpage (BtLockRead, set);
+ bt_unpinlatch (set);
+ bt_unpinpool (pool);
} while( page_no = next );
cnt--; // remove stopper key
// btree version threads2j linux futex concurrency version
-// 24 JAN 2014
+// 29 JAN 2014
// author: karl malbrain, malbrain@cal.berkeley.edu
uint act; // count of active keys
uint min; // next key offset
unsigned char bits; // page size in bits
- unsigned char lvl:6; // level of page
- unsigned char kill:1; // page is being deleted
+ unsigned char lvl:7; // level of page
unsigned char dirty:1; // page has deleted keys
unsigned char right[BtId]; // page number to right
- BtSlot table[0]; // array of key slots
} *BtPage;
// hash table entries
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;
// B-Tree functions
extern void bt_close (BtDb *bt);
extern BtDb *bt_open (BtMgr *mgr);
-extern BTERR bt_insertkey (BtDb *bt, unsigned char *key, uint len, uint lvl, uid id, uint tod);
-extern BTERR bt_deletekey (BtDb *bt, unsigned char *key, uint len, uint lvl);
+extern BTERR bt_insertkey (BtDb *bt, unsigned char *key, uint len, uid id, uint tod, uint lvl);
+extern BTERR bt_deletekey (BtDb *bt, unsigned char *key, uint len);
extern uid bt_findkey (BtDb *bt, unsigned char *key, uint len);
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);
+
// manager functions
extern BtMgr *bt_mgr (char *name, uint mode, uint bits, uint poolsize, uint segsize, uint hashsize);
void bt_mgrclose (BtMgr *mgr);
// Access macros to address slot and key values from the page
-#define slotptr(page, slot) (page->table + slot-1)
+#define slotptr(page, slot) (((BtSlot *)(page+1)) + (slot-1))
#define keyptr(page, slot) ((BtKey)((unsigned char*)(page) + slotptr(page, slot)->off))
void bt_putid(unsigned char *dest, uid id)
uint drill = 0xff, slot;
uint mode, prevmode;
BtPool *prevpool;
+int parent = 1;
// start at root of btree and drill down
// find key on page at this level
// and descend to requested level
- if( !bt->page->kill && (slot = bt_findslot (bt, key, len)) ) {
+ if( slot = bt_findslot (bt, key, len) ) {
if( drill == lvl )
- return slot;
+ return bt->parent = parent, slot;
while( slotptr(bt->page, slot)->dead )
if( slot++ < bt->page->cnt )
continue;
else {
page_no = bt_getid(bt->page->right);
+ parent = 0;
goto slideright;
}
page_no = bt_getid(slotptr(bt->page, slot)->id);
+ parent = 1;
drill--;
}
// or slide right into next page
- // (slide left from deleted page)
- else
+ else {
page_no = bt_getid(bt->page->right);
+ parent = 0;
+ }
// continue down / right using overlapping locks
- // to protect pages being killed or split.
+ // to protect pages being split.
slideright:
prevpage = bt->page_no;
return 0; // return error
}
-// find and delete key on page by marking delete flag bit
-// when page becomes empty, delete it
+// remove empty page from the B-tree
+// by pulling our right node left over ourselves
+
+// call with bt->page, etc, set to page's locked parent
+// returns with page locked.
-BTERR bt_deletekey (BtDb *bt, unsigned char *key, uint len, uint lvl)
+BTERR bt_mergeright (BtDb *bt, BtPage page, BtPool *pool, BtLatchSet *set, uid page_no, uint lvl, uint slot)
{
-unsigned char lowerkey[256], higherkey[256];
-BtLatchSet *rset, *set;
-BtPool *pool, *rpool;
-uid page_no, right;
-uint slot, tod;
-BtPage rpage;
+BtLatchSet *rset, *pset, *rpset;
+BtPool *rpool, *ppool, *rppool;
+BtPage rpage, ppage, rppage;
+uid right, parent, rparent;
BtKey ptr;
+uint idx;
- if( slot = bt_loadpage (bt, key, len, lvl, BtLockWrite) )
- ptr = keyptr(bt->page, slot);
+ // cache node's parent page
+
+ parent = bt->page_no;
+ ppage = bt->page;
+ ppool = bt->pool;
+ pset = bt->set;
+
+ // lock and map our right page
+ // it cannot be NULL because of the stopper
+ // in the last right page
+
+ bt_lockpage (BtLockWrite, set);
+
+ // if we aren't dead yet
+
+ if( page->act )
+ goto rmergexit;
+
+ 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;
+
+ rset = bt_pinlatch (bt, right);
+
+ // find our right neighbor
+
+ if( ppage->act > 1 ) {
+ for( idx = slot; idx++ < ppage->cnt; )
+ if( !slotptr(ppage, idx)->dead )
+ break;
+
+ if( idx > ppage->cnt )
+ return bt->err = BTERR_struct;
+
+ // redirect right neighbor in parent to left node
+
+ bt_putid(slotptr(ppage,idx)->id, page_no);
+ }
+
+ // if parent has only our deleted page, e.g. no right neighbor
+ // prepare to merge parent itself
+
+ 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;
+ else
+ return bt->err = BTERR_struct;
- // if key is found delete it, otherwise ignore request
+ rpset = bt_pinlatch (bt, rparent);
+ bt_lockpage (BtLockWrite, rpset);
- if( bt->found = !keycmp (ptr, key, len) )
- if( bt->found = slotptr(bt->page, slot)->dead == 0 ) {
- slotptr(bt->page,slot)->dead = 1;
- if( slot < bt->page->cnt )
- bt->page->dirty = 1;
- bt->page->act--;
+ // find our right neighbor on right parent page
+
+ for( idx = 0; idx++ < rppage->cnt; )
+ if( !slotptr(rppage, idx)->dead ) {
+ bt_putid (slotptr(rppage, idx)->id, page_no);
+ break;
}
- // return if page is not empty, or it has no right sibling
+ if( idx > rppage->cnt )
+ return bt->err = BTERR_struct;
+ }
- right = bt_getid(bt->page->right);
- page_no = bt->page_no;
- pool = bt->pool;
- set = bt->set;
+ // now that there are no more pointers to our right node
+ // we can wait for delete lock on it
- if( !right || bt->page->act ) {
- bt_unlockpage(BtLockWrite, set);
- bt_unpinlatch (set);
- bt_unpinpool (pool);
+ bt_lockpage(BtLockDelete, rset);
+ bt_lockpage(BtLockWrite, rset);
+
+ // pull contents of right page into our empty page
+
+ memcpy (page, rpage, bt->mgr->page_size);
+
+ // ready to release right parent lock
+ // now that we have a new page in place
+
+ if( ppage->act == 1 ) {
+ bt_unlockpage (BtLockWrite, rpset);
+ bt_unpinlatch (rpset);
+ bt_unpinpool (rppool);
+ }
+
+ // add killed right block to free chain
+ // lock latch mgr
+
+ bt_spinwritelock(bt->mgr->latchmgr->lock, 0);
+
+ // store free chain in allocation page second right
+
+ bt_putid(rpage->right, bt_getid(bt->mgr->latchmgr->alloc[1].right));
+ bt_putid(bt->mgr->latchmgr->alloc[1].right, right);
+
+ // unlock latch mgr and right page
+
+ bt_unlockpage(BtLockDelete, rset);
+ bt_unlockpage(BtLockWrite, rset);
+ bt_unpinlatch (rset);
+ bt_unpinpool (rpool);
+
+ bt_spinreleasewrite(bt->mgr->latchmgr->lock, 0);
+
+ // delete our obsolete fence key from our parent
+
+ slotptr(ppage, slot)->dead = 1;
+ ppage->dirty = 1;
+
+ // if our parent now empty
+ // remove it from the tree
+
+ if( ppage->act-- == 1 )
+ if( bt_mergeleft (bt, ppage, ppool, pset, parent, lvl+1) )
return bt->err;
+
+rmergexit:
+ bt_unlockpage (BtLockWrite, pset);
+ bt_unpinlatch (pset);
+ bt_unpinpool (ppool);
+
+ bt->found = 1;
+ return bt->err = 0;
+}
+
+// remove empty page from the B-tree
+// try merging left first. If no left
+// sibling, then merge right.
+
+// call with page loaded and locked,
+// return with page locked.
+
+BTERR bt_mergeleft (BtDb *bt, BtPage page, BtPool *pool, BtLatchSet *set, uid page_no, uint lvl)
+{
+unsigned char fencekey[256], postkey[256];
+uint slot, idx, postfence = 0;
+BtLatchSet *lset, *pset;
+BtPool *lpool, *ppool;
+BtPage lpage, ppage;
+uid left, parent;
+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)) )
+ return bt->err;
+
+ parent = bt->page_no;
+ ppage = bt->page;
+ ppool = bt->pool;
+ pset = bt->set;
+
+ // wait until we are posted in our parent
+
+ if( !bt->parent ) {
+ bt_unlockpage (BtLockWrite, pset);
+ bt_unpinlatch (pset);
+ bt_unpinpool (ppool);
+#ifdef unix
+ sched_yield();
+#else
+ SwitchToThread();
+#endif
+ goto retry;
}
- // obtain Parent lock over write lock
+ // find our left neighbor in our parent page
- bt_lockpage(BtLockParent, set);
+ for( idx = slot; --idx; )
+ if( !slotptr(ppage, idx)->dead )
+ break;
- // keep copy of key to delete
+ // if no left neighbor, do right merge
- ptr = keyptr(bt->page, bt->page->cnt);
- memcpy(lowerkey, ptr, ptr->len + 1);
+ if( !idx )
+ return bt_mergeright (bt, page, pool, set, page_no, lvl, slot);
- // lock and map right page
+ // lock and map our left neighbor's page
- if( rpool = bt_pinpool (bt, right) )
- rpage = bt_page (bt, rpool, right);
+ left = bt_getid (slotptr(ppage, idx)->id);
+
+ if( lpool = bt_pinpool (bt, left) )
+ lpage = bt_page (bt, lpool, left);
else
return bt->err;
- rset = bt_pinlatch (bt, right);
- bt_lockpage(BtLockWrite, rset);
+ lset = bt_pinlatch (bt, left);
+ bt_lockpage(BtLockWrite, lset);
- // pull contents of next page into current empty page
+ // wait until sibling is in our parent
- memcpy (bt->page, rpage, bt->mgr->page_size);
+ 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);
+#ifdef linux
+ sched_yield();
+#else
+ SwitchToThread();
+#endif
+ goto retry;
+ }
- // keep copy of key to update
+ // since our page will have no more pointers to it,
+ // obtain Delete lock and wait for write locks to clear
- ptr = keyptr(rpage, rpage->cnt);
- memcpy(higherkey, ptr, ptr->len + 1);
+ bt_lockpage(BtLockDelete, set);
+ bt_lockpage(BtLockWrite, set);
- // Mark right page as deleted and point it to left page
- // until we can post updates at higher level.
+ // if we aren't dead yet,
+ // get ready for exit
- bt_putid(rpage->right, page_no);
- rpage->kill = 1;
- rpage->cnt = 0;
+ if( page->act ) {
+ bt_unlockpage(BtLockDelete, set);
+ bt_unlockpage(BtLockWrite, lset);
+ bt_unpinlatch (lset);
+ bt_unpinpool (lpool);
+ goto lmergexit;
+ }
- bt_unlockpage(BtLockWrite, rset);
- bt_unlockpage(BtLockWrite, set);
+ // are we are the fence key for our parent?
+ // if so, grab our old fence key
- // delete old lower key to consolidated node
+ if( postfence = slot == ppage->cnt ) {
+ ptr = keyptr (ppage, ppage->cnt);
+ memcpy(fencekey, ptr, ptr->len + 1);
+ memset(slotptr(ppage, ppage->cnt), 0, sizeof(BtSlot));
- if( bt_deletekey (bt, lowerkey + 1, *lowerkey, lvl + 1) )
- return bt->err;
+ // clear out other dead slots
- // redirect higher key directly to consolidated node
+ while( --ppage->cnt )
+ if( slotptr(ppage, ppage->cnt)->dead )
+ memset(slotptr(ppage, ppage->cnt), 0, sizeof(BtSlot));
+ else
+ break;
- tod = (uint)time(NULL);
+ ptr = keyptr (ppage, ppage->cnt);
+ memcpy(postkey, ptr, ptr->len + 1);
+ } else
+ slotptr(ppage,slot)->dead = 1;
- if( bt_insertkey (bt, higherkey+1, *higherkey, lvl + 1, page_no, tod) )
- return bt->err;
+ ppage->dirty = 1;
+ ppage->act--;
- // add killed right block to free chain
+ // push our right neighbor pointer to our left
+
+ memcpy (lpage->right, page->right, BtId);
+
+ // add ourselves to free chain
// lock latch mgr
bt_spinwritelock(bt->mgr->latchmgr->lock, 0);
// store free chain in allocation page second right
- bt_putid(rpage->right, bt_getid(bt->mgr->latchmgr->alloc[1].right));
- bt_putid(bt->mgr->latchmgr->alloc[1].right, right);
+ bt_putid(page->right, bt_getid(bt->mgr->latchmgr->alloc[1].right));
+ bt_putid(bt->mgr->latchmgr->alloc[1].right, page_no);
- // unlock latch mgr and unpin right page
+ // unlock latch mgr and pages
bt_spinreleasewrite(bt->mgr->latchmgr->lock, 0);
- bt_unpinlatch (rset);
- bt_unpinpool (rpool);
+ bt_unlockpage(BtLockWrite, lset);
+ bt_unpinlatch (lset);
+ bt_unpinpool (lpool);
+
+ // release our node's delete lock
+
+ bt_unlockpage(BtLockDelete, set);
+
+lmergexit:
+ bt_unlockpage (BtLockWrite, pset);
+ bt_unpinpool (ppool);
+
+ // do we need to post parent's fence key in its parent?
+
+ if( !postfence || parent == ROOT_page ) {
+ bt_unpinlatch (pset);
+ bt->found = 1;
+ return bt->err = 0;
+ }
+
+ // interlock parent fence post
- // remove ParentModify lock
+ bt_lockpage (BtLockParent, pset);
- bt_unlockpage(BtLockParent, set);
+ // load parent's parent page
+posttry:
+ if( !(slot = bt_loadpage (bt, fencekey+1, *fencekey, lvl+2, BtLockWrite)) )
+ 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;
+
+ page = bt->page;
+
+ 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;
+
+ bt_unlockpage (BtLockParent, pset);
+ bt_unpinlatch (pset);
+
+ bt_unlockpage (BtLockWrite, bt->set);
+ bt_unpinlatch (bt->set);
+ bt_unpinpool (bt->pool);
+
+ bt->found = 1;
+ return bt->err = 0;
+}
+
+// find and delete key on page by marking delete flag bit
+// if page becomes empty, delete it from the btree
+
+BTERR bt_deletekey (BtDb *bt, unsigned char *key, uint len)
+{
+BtLatchSet *set;
+BtPool *pool;
+BtPage page;
+uid page_no;
+BtKey ptr;
+uint slot;
+
+ if( !(slot = bt_loadpage (bt, key, len, 0, BtLockWrite)) )
+ 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( 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;
+ }
+
+ bt_unlockpage(BtLockWrite, set);
bt_unpinlatch (set);
bt_unpinpool (pool);
- return 0;
+ return bt->err = 0;
}
// find key in leaf level and return row-id
// if key exists, return row-id
// otherwise return 0
- if( ptr->len == len && !memcmp (ptr->key, key, len) )
+ if( slot <= bt->page->cnt && !keycmp (ptr, key, len) )
id = bt_getid(slotptr(bt->page,slot)->id);
else
id = 0;
// check page for space available,
// clean if necessary and return
-// =0 - page needs splitting
-// >0 - go ahead at returned slot
+// 0 - page needs splitting
+// >0 new slot value
-uint bt_cleanpage(BtDb *bt, uint amt, uint slot)
+uint bt_cleanpage(BtDb *bt, BtPage page, uint amt, uint slot)
{
uint nxt = bt->mgr->page_size;
-BtPage page = bt->page;
uint cnt = 0, idx = 0;
uint max = page->cnt;
-uint newslot;
+uint newslot = max;
BtKey key;
if( page->min >= (max+1) * sizeof(BtSlot) + sizeof(*page) + amt + 1 )
page->dirty = 0;
page->act = 0;
- // always leave fence key in list
+ // try cleaning up page first
+
+ // always leave fence key in the array
+ // otherwise, remove deleted key
while( cnt++ < max ) {
if( cnt == slot )
newslot = idx + 1;
- else if( cnt < max && slotptr(bt->frame,cnt)->dead )
+ if( cnt < max && slotptr(bt->frame,cnt)->dead )
continue;
// copy key
+
key = keyptr(bt->frame, cnt);
nxt -= key->len + 1;
memcpy ((unsigned char *)page + nxt, key, key->len + 1);
slotptr(page, idx)->tod = slotptr(bt->frame, cnt)->tod;
slotptr(page, idx)->off = nxt;
}
+
page->min = nxt;
page->cnt = idx;
+ // see if page has enough space now, or does it need splitting?
+
if( page->min >= (idx+1) * sizeof(BtSlot) + sizeof(*page) + amt + 1 )
return newslot;
return 0;
}
-// split the root and raise the height of the btree
+// add key to current page
+// page must already be writelocked
-BTERR bt_splitroot(BtDb *bt, unsigned char *newkey, unsigned char *oldkey, uid page_no2)
+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)
{
uint nxt = bt->mgr->page_size;
BtPage root = bt->page;
uid new_page;
// Obtain an empty page to use, and copy the current
- // root contents into it which is the lower half of
- // the old root.
+ // root contents into it
if( !(new_page = bt_newpage(bt, root)) )
return bt->err;
// insert first key on newroot page
- nxt -= *newkey + 1;
- memcpy ((unsigned char *)root + nxt, newkey, *newkey + 1);
+ nxt -= *leftkey + 1;
+ memcpy ((unsigned char *)root + nxt, leftkey, *leftkey + 1);
bt_putid(slotptr(root, 1)->id, new_page);
slotptr(root, 1)->off = nxt;
- // insert second key on newroot page
+ // insert second key (stopper key) on newroot page
// and increase the root height
- nxt -= *oldkey + 1;
- memcpy ((unsigned char *)root + nxt, oldkey, *oldkey + 1);
+ 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;
}
// split already locked full node
-// return unlocked.
+// return unlocked and unpinned.
-BTERR bt_splitpage (BtDb *bt)
+BTERR bt_splitpage (BtDb *bt, BtPage page, BtPool *pool, BtLatchSet *set, uid page_no)
{
-uint cnt = 0, idx = 0, max, nxt = bt->mgr->page_size;
-unsigned char oldkey[256], lowerkey[256];
-uid page_no = bt->page_no, right;
-BtLatchSet *nset, *set = bt->set;
-BtPool *pool = bt->pool;
-BtPage page = bt->page;
+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;
BtKey key;
-uint tod;
-
- // split higher half of keys to bt->frame
- // the last key (fence key) might be dead
- tod = (uint)time(NULL);
+ // initialize frame buffer for right node
memset (bt->frame, 0, bt->mgr->page_size);
- max = (int)page->cnt;
+ max = 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;
slotptr(bt->frame, idx)->off = nxt;
}
- // remember existing fence key for new page to the right
+ // transfer right link node to new right node
- memcpy (oldkey, key, key->len + 1);
+ if( page_no > ROOT_page )
+ memcpy (bt->frame->right, page->right, BtId);
bt->frame->bits = bt->mgr->page_bits;
bt->frame->min = nxt;
bt->frame->cnt = idx;
bt->frame->lvl = lvl;
- // link right node
-
- if( page_no > ROOT_page ) {
- right = bt_getid (page->right);
- bt_putid(bt->frame->right, right);
- }
-
- // get new free page and write frame to it.
+ // get new free page and write right frame to it.
if( !(new_page = bt_newpage(bt, bt->frame)) )
return bt->err;
+ // remember fence key for new right page to add
+ // as right sibling to the left node
+
+ key = keyptr(bt->frame, idx);
+ memcpy (rightkey, key, key->len + 1);
+
// 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));
nxt = bt->mgr->page_size;
+ page->dirty = 0;
page->act = 0;
cnt = 0;
idx = 0;
// assemble page of smaller keys
- // (they're all active 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);
+ 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;
- page->act++;
}
- // remember fence key for old page
+ // finalize left page and save fence key
- memcpy(lowerkey, key, key->len + 1);
- bt_putid(page->right, new_page);
+ memcpy(leftkey, key, key->len + 1);
page->min = nxt;
page->cnt = idx;
+ // link new right page
+
+ bt_putid (page->right, new_page);
+
// if current page is the root page, split it
if( page_no == ROOT_page )
- return bt_splitroot (bt, lowerkey, oldkey, new_page);
-
- // obtain Parent/Write locks
- // for left and right node pages
+ return bt_splitroot (bt, leftkey, new_page);
- nset = bt_pinlatch (bt, new_page);
+ // obtain ParentModification lock for current page
- bt_lockpage (BtLockParent, nset);
bt_lockpage (BtLockParent, set);
- // release wr lock on left page
- // (keep the SMO in sequence)
+ // release wr lock on our page.
+ // this will keep out another SMO
bt_unlockpage (BtLockWrite, set);
- // insert new fence for reformulated left block
+ // insert key for old page (lower keys)
- if( bt_insertkey (bt, lowerkey+1, *lowerkey, lvl + 1, page_no, tod) )
+ if( bt_insertkey (bt, leftkey + 1, *leftkey, page_no, tod, lvl + 1) )
return bt->err;
- // fix old fence for newly allocated right block page
+ // switch old parent key from us to our right page
- if( bt_insertkey (bt, oldkey+1, *oldkey, lvl + 1, new_page, tod) )
+ if( bt_insertkey (bt, rightkey + 1, *rightkey, new_page, tod, lvl + 1) )
return bt->err;
- // release Parent locks
+ // unlock and unpin
- bt_unlockpage (BtLockParent, nset);
bt_unlockpage (BtLockParent, set);
- bt_unpinlatch (nset);
bt_unpinlatch (set);
bt_unpinpool (pool);
return 0;
}
-// Insert new key into the btree at requested level.
-// Level zero pages are leaf pages. Page is unlocked at exit.
+// Insert new key into the btree at given level.
-BTERR bt_insertkey (BtDb *bt, unsigned char *key, uint len, uint lvl, uid id, uint tod)
+BTERR bt_insertkey (BtDb *bt, unsigned char *key, uint len, uid id, uint tod, uint lvl)
{
uint slot, idx;
BtPage page;
BtKey ptr;
- while( 1 ) {
- if( slot = bt_loadpage (bt, key, len, lvl, BtLockWrite) )
- ptr = keyptr(bt->page, slot);
- else
- {
- if ( !bt->err )
- bt->err = BTERR_ovflw;
- return bt->err;
- }
-
- // if key already exists, update id and return
-
- page = bt->page;
-
- if( bt->found = !keycmp (ptr, key, len) ) {
- 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;
- }
-
- // check if page has enough space
-
- if( slot = bt_cleanpage (bt, len, slot) )
- break;
-
- if( bt_splitpage (bt) )
- return bt->err;
- }
-
- // calculate next available slot and copy key into page
+ while( 1 ) {
+ if( slot = bt_loadpage (bt, key, len, lvl, BtLockWrite) )
+ ptr = keyptr(bt->page, slot);
+ else
+ {
+ if ( !bt->err )
+ bt->err = BTERR_ovflw;
+ return bt->err;
+ }
- page->min -= len + 1; // reset lowest used offset
- ((unsigned char *)page)[page->min] = len;
- memcpy ((unsigned char *)page + page->min +1, key, len );
+ // if key already exists, update id and return
- for( idx = slot; idx < page->cnt; idx++ )
- if( slotptr(page, idx)->dead )
- break;
+ page = bt->page;
- // now insert key into array before slot
- // preserving the fence slot
+ 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( idx == page->cnt )
- idx++, page->cnt++;
+ // check if page has enough space
- page->act++;
+ if( slot = bt_cleanpage (bt, bt->page, len, slot) )
+ break;
- while( idx > slot )
- *slotptr(page, idx) = *slotptr(page, idx -1), idx--;
+ if( bt_splitpage (bt, bt->page, bt->pool, bt->set, bt->page_no) )
+ return bt->err;
+ }
- bt_putid(slotptr(page,slot)->id, id);
- slotptr(page, slot)->off = page->min;
- slotptr(page, slot)->tod = tod;
- slotptr(page, slot)->dead = 0;
+ bt_addkeytopage (bt, bt->page, slot, key, len, id, tod);
- bt_unlockpage (BtLockWrite, bt->set);
- bt_unpinlatch (bt->set);
- bt_unpinpool (bt->pool);
- return 0;
+ bt_unlockpage (BtLockWrite, bt->set);
+ bt_unpinlatch (bt->set);
+ bt_unpinpool (bt->pool);
+ return 0;
}
// cache page of keys into cursor and return starting slot for given key
// 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;
+
bt_unlockpage(BtLockRead, bt->set);
bt_unpinlatch (bt->set);
bt_unpinpool (bt->pool);
uint bt_nextkey (BtDb *bt, uint slot)
{
+BtLatchSet *set;
BtPool *pool;
BtPage page;
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) )
return slot;
else
break;
break;
bt->cursor_page = right;
-
if( pool = bt_pinpool (bt, right) )
page = bt_page (bt, pool, right);
else
return 0;
- bt->set = bt_pinlatch (bt, right);
- bt_lockpage(BtLockRead, bt->set);
+ set = bt_pinlatch (bt, right);
+ bt_lockpage(BtLockRead, set);
memcpy (bt->cursor, page, bt->mgr->page_size);
- bt_unlockpage(BtLockRead, bt->set);
- bt_unpinlatch (bt->set);
+ bt_unlockpage(BtLockRead, set);
+ bt_unpinlatch (set);
bt_unpinpool (pool);
slot = 0;
} while( 1 );
return slotptr(bt->cursor,slot)->tod;
}
+
#ifdef STANDALONE
void bt_latchaudit (BtDb *bt)
unsigned char key[256];
ThreadArg *args = arg;
int ch, len = 0, slot;
+BtLatchSet *set;
time_t tod[1];
BtPool *pool;
BtPage page;
else if( args->num )
sprintf((char *)key+len, "%.9d", line + args->idx * args->num), len += 9;
- if( bt_insertkey (bt, key, len, 0, line, *tod) )
+ if( bt_insertkey (bt, key, len, line, *tod, 0) )
fprintf(stderr, "Error %d Line: %d\n", bt->err, line), exit(0);
len = 0;
}
else if( args->num )
sprintf((char *)key+len, "%.9d", line + args->idx * args->num), len += 9;
- if( bt_deletekey (bt, key, len, 0) )
+ if( bt_deletekey (bt, key, len) )
fprintf(stderr, "Error %d Line: %d\n", bt->err, line), exit(0);
len = 0;
}
fprintf(stderr, "started reading\n");
do {
- if( bt->pool = bt_pinpool (bt, page_no) )
- page = bt_page (bt, bt->pool, page_no);
+ if( pool = bt_pinpool (bt, page_no) )
+ page = bt_page (bt, pool, page_no);
else
break;
- bt->set = bt_pinlatch (bt, page_no);
- bt_lockpage (BtLockRead, bt->set);
+ set = bt_pinlatch (bt, page_no);
+ bt_lockpage (BtLockRead, set);
cnt += page->act;
next = bt_getid (page->right);
- bt_unlockpage (BtLockRead, bt->set);
- bt_unpinlatch (bt->set);
- bt_unpinpool (bt->pool);
+ bt_unlockpage (BtLockRead, set);
+ bt_unpinlatch (set);
+ bt_unpinpool (pool);
} while( page_no = next );
cnt--; // remove stopper key
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