// foster btree version f // 29 JAN 2014 // author: karl malbrain, malbrain@cal.berkeley.edu /* This work, including the source code, documentation and related data, is placed into the public domain. The orginal author is Karl Malbrain. THIS SOFTWARE IS PROVIDED AS-IS WITHOUT WARRANTY OF ANY KIND, NOT EVEN THE IMPLIED WARRANTY OF MERCHANTABILITY. THE AUTHOR OF THIS SOFTWARE, ASSUMES _NO_ RESPONSIBILITY FOR ANY CONSEQUENCE RESULTING FROM THE USE, MODIFICATION, OR REDISTRIBUTION OF THIS SOFTWARE. */ // Please see the project home page for documentation // code.google.com/p/high-concurrency-btree #define _FILE_OFFSET_BITS 64 #define _LARGEFILE64_SOURCE #ifdef linux #define _GNU_SOURCE #endif #ifdef unix #include #include #include #include #include #include #include #include #else #define WIN32_LEAN_AND_MEAN #include #include #include #include #include #include #include #endif #include #include typedef unsigned long long uid; #ifndef unix typedef unsigned long long off64_t; typedef unsigned short ushort; typedef unsigned int uint; #endif #define BT_ro 0x6f72 // ro #define BT_rw 0x7772 // rw #define BT_latchtable 128 // number of latch manager slots #define BT_maxbits 24 // maximum page size in bits #define BT_minbits 9 // minimum page size in bits #define BT_minpage (1 << BT_minbits) // minimum page size #define BT_maxpage (1 << BT_maxbits) // maximum page size /* There are five lock types for each node in three independent sets: 1. (set 1) AccessIntent: Sharable. Going to Read the node. Incompatible with NodeDelete. 2. (set 1) NodeDelete: Exclusive. About to release the node. Incompatible with AccessIntent. 3. (set 2) ReadLock: Sharable. Read the node. Incompatible with WriteLock. 4. (set 2) WriteLock: Exclusive. Modify the node. Incompatible with ReadLock and other WriteLocks. 5. (set 3) ParentLock: Exclusive. Have parent adopt/delete maximum foster child from the node. */ typedef enum{ BtLockAccess, BtLockDelete, BtLockRead, BtLockWrite, BtLockParent }BtLock; // Define the length of the page and key pointers #define BtId 6 // Page key slot definition. // If BT_maxbits is 15 or less, you can save 4 bytes // for each key stored by making the first two uints // into ushorts. You can also save 4 bytes by removing // the tod field from the key. // Keys are marked dead, but remain on the page until // cleanup is called. The fence key (highest key) for // the page is always present, even after cleanup. typedef struct { uint off:BT_maxbits; // page offset for key start uint dead:1; // set for deleted key uint tod; // time-stamp for key unsigned char id[BtId]; // id associated with key } BtSlot; // The key structure occupies space at the upper end of // each page. It's a length byte followed by the value // bytes. typedef struct { unsigned char len; unsigned char key[1]; } *BtKey; // The first part of an index page. // It is immediately followed // by the BtSlot array of keys. typedef struct Page { volatile uint cnt; // count of keys in page volatile uint act; // count of active keys volatile uint min; // next key offset volatile uint foster; // count of foster children unsigned char bits; // page size in bits unsigned char lvl:7; // level of page unsigned char dirty:1; // page needs to be cleaned unsigned char right[BtId]; // page number to right } *BtPage; // mode & definition for hash latch implementation enum { Mutex = 1, Write = 2, Pending = 4, Share = 8 } LockMode; // mutex locks the other fields // exclusive is set for write access // share is count of read accessors typedef struct { volatile ushort mutex:1; volatile ushort exclusive:1; volatile ushort pending:1; volatile ushort share:13; } BtSpinLatch; // hash table entries typedef struct { BtSpinLatch latch[1]; volatile ushort slot; // Latch table entry at head of chain } BtHashEntry; // latch manager table structure typedef struct { BtSpinLatch readwr[1]; // read/write page lock BtSpinLatch access[1]; // Access Intent/Page delete BtSpinLatch parent[1]; // adoption of foster children 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 volatile ushort pin; // number of outstanding locks volatile ushort hash; // hash slot entry is under volatile uid page_no; // latch set page number } BtLatchSet; // The memory mapping pool table buffer manager entry typedef struct { unsigned long long int lru; // number of times accessed uid basepage; // mapped base page number char *map; // mapped memory pointer ushort pin; // mapped page pin counter ushort slot; // slot index in this array void *hashprev; // previous pool entry for the same hash idx void *hashnext; // next pool entry for the same hash idx #ifndef unix HANDLE hmap; // Windows memory mapping handle #endif } BtPool; // structure for latch manager on ALLOC_page typedef struct { struct Page 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 ushort latchtotal; // number of page latch entries ushort latchhash; // number of latch hash table slots ushort latchvictim; // next latch entry to examine BtHashEntry table[0]; // the hash table } BtLatchMgr; // The object structure for Btree access typedef struct { uint page_size; // page size uint page_bits; // page size in bits uint seg_bits; // seg size in pages in bits uint mode; // read-write mode #ifdef unix int idx; #else HANDLE idx; #endif ushort poolcnt; // highest page pool node in use ushort poolmax; // highest page pool node allocated ushort poolmask; // total number of pages in mmap segment - 1 ushort hashsize; // size of Hash Table for pool entries ushort evicted; // last evicted hash table slot ushort *hash; // hash table of pool entries BtPool *pool; // memory pool page segments BtSpinLatch *latch; // latches for pool hash slots BtLatchMgr *latchmgr; // mapped latch page from allocation page BtLatchSet *latchsets; // mapped latch set from latch pages #ifndef unix HANDLE halloc; // allocation and latch table handle #endif } BtMgr; typedef struct { BtMgr *mgr; // buffer manager for thread 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 foster; // last search was to foster child int found; // last delete was found int err; // last error } BtDb; typedef enum { BTERR_ok = 0, BTERR_struct, BTERR_ovflw, BTERR_lock, BTERR_map, BTERR_wrt, BTERR_hash, BTERR_latch } BTERR; // 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, 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); // Helper functions to return cursor slot values extern BtKey bt_key (BtDb *bt, uint slot); extern uid bt_uid (BtDb *bt, uint slot); extern uint bt_tod (BtDb *bt, uint slot); // BTree page number constants #define ALLOC_page 0 // allocation & lock manager hash table #define ROOT_page 1 // root of the btree #define LEAF_page 2 // first page of leaves #define LATCH_page 3 // pages for lock manager // Number of levels to create in a new BTree #define MIN_lvl 2 // The page is allocated from low and hi ends. // The key offsets and row-id's are allocated // from the bottom, while the text of the key // is allocated from the top. When the two // areas meet, the page is split into two. // A key consists of a length byte, two bytes of // index number (0 - 65534), and up to 253 bytes // of key value. Duplicate keys are discarded. // Associated with each key is a 48 bit row-id. // The b-tree root is always located at page 1. // The first leaf page of level zero is always // located on page 2. // When to root page fills, it is split in two and // the tree height is raised by a new root at page // 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. // Groups of pages called segments from the btree are // cached with memory mapping. A hash table is used to keep // track of the cached segments. This behaviour is controlled // by the cache block size parameter to bt_open. // To achieve maximum concurrency one page is locked at a time // as the tree is traversed to find leaf key in question. // An adoption traversal leaves the parent node locked as the // tree is traversed to the level in quesiton. // Page 0 is dedicated to lock for new page extensions, // and chains empty pages together for reuse. // Empty pages are chained together through the ALLOC page and reused. // Access macros to address slot and key values from the page #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) { int i = BtId; while( i-- ) dest[i] = (unsigned char)id, id >>= 8; } uid bt_getid(unsigned char *src) { uid id = 0; int i; for( i = 0; i < BtId; i++ ) id <<= 8, id |= *src++; return id; } // wait until write lock mode is clear // and add 1 to the share count void bt_spinreadlock(BtSpinLatch *latch) { ushort prev; do { #ifdef unix while( __sync_fetch_and_or((ushort *)latch, Mutex) & Mutex ) sched_yield(); #else while( _InterlockedOr16((ushort *)latch, Mutex) & Mutex ) SwitchToThread(); #endif // see if exclusive request is granted or pending if( prev = !(latch->exclusive | latch->pending) ) #ifdef unix __sync_fetch_and_add((ushort *)latch, Share); #else _InterlockedExchangeAdd16 ((ushort *)latch, Share); #endif #ifdef unix __sync_fetch_and_and ((ushort *)latch, ~Mutex); #else _InterlockedAnd16((ushort *)latch, ~Mutex); #endif if( prev ) return; #ifdef unix } while( sched_yield(), 1 ); #else } while( SwitchToThread(), 1 ); #endif } // wait for other read and write latches to relinquish void bt_spinwritelock(BtSpinLatch *latch) { do { #ifdef unix while( __sync_fetch_and_or((ushort *)latch, Mutex | Pending) & Mutex ) sched_yield(); #else while( _InterlockedOr16((ushort *)latch, Mutex | Pending) & Mutex ) SwitchToThread(); #endif if( !(latch->share | latch->exclusive) ) { #ifdef unix __sync_fetch_and_or((ushort *)latch, Write); __sync_fetch_and_and ((ushort *)latch, ~(Mutex | Pending)); #else _InterlockedOr16((ushort *)latch, Write); _InterlockedAnd16((ushort *)latch, ~(Mutex | Pending)); #endif return; } #ifdef unix __sync_fetch_and_and ((ushort *)latch, ~Mutex); sched_yield(); #else _InterlockedAnd16((ushort *)latch, ~Mutex); SwitchToThread(); #endif } while( 1 ); } // try to obtain write lock // return 1 if obtained, // 0 otherwise int bt_spinwritetry(BtSpinLatch *latch) { ushort prev; #ifdef unix if( prev = __sync_fetch_and_or((ushort *)latch, Mutex), prev & Mutex ) return 0; #else if( prev = _InterlockedOr16((ushort *)latch, Mutex), prev & Mutex ) return 0; #endif // take write access if all bits are clear if( !prev ) #ifdef unix __sync_fetch_and_or ((ushort *)latch, Write); #else _InterlockedOr16((ushort *)latch, Write); #endif #ifdef unix __sync_fetch_and_and ((ushort *)latch, ~Mutex); #else _InterlockedAnd16((ushort *)latch, ~Mutex); #endif return !prev; } // clear write mode void bt_spinreleasewrite(BtSpinLatch *latch) { #ifdef unix __sync_fetch_and_and ((ushort *)latch, ~Write); #else _InterlockedAnd16((ushort *)latch, ~Write); #endif } // decrement reader count void bt_spinreleaseread(BtSpinLatch *latch) { #ifdef unix __sync_fetch_and_add((ushort *)latch, -Share); #else _InterlockedExchangeAdd16 ((ushort *)latch, -Share); #endif } // link latch table entry into latch hash table void bt_latchlink (BtDb *bt, ushort hashidx, ushort victim, uid page_no) { BtLatchSet *set = bt->mgr->latchsets + victim; if( set->next = bt->mgr->latchmgr->table[hashidx].slot ) bt->mgr->latchsets[set->next].prev = victim; bt->mgr->latchmgr->table[hashidx].slot = victim; set->page_no = page_no; set->hash = hashidx; set->prev = 0; } // release latch pin void bt_unpinlatch (BtLatchSet *set) { #ifdef unix __sync_fetch_and_add(&set->pin, -1); #else _InterlockedDecrement16 (&set->pin); #endif } // find existing latchset or inspire new one // return with latchset pinned BtLatchSet *bt_pinlatch (BtDb *bt, uid page_no) { ushort hashidx = page_no % bt->mgr->latchmgr->latchhash; ushort slot, avail = 0, victim, idx; BtLatchSet *set; // obtain read lock on hash table entry bt_spinreadlock(bt->mgr->latchmgr->table[hashidx].latch); if( slot = bt->mgr->latchmgr->table[hashidx].slot ) do { set = bt->mgr->latchsets + slot; if( page_no == set->page_no ) break; } while( slot = set->next ); if( slot ) { #ifdef unix __sync_fetch_and_add(&set->pin, 1); #else _InterlockedIncrement16 (&set->pin); #endif } bt_spinreleaseread (bt->mgr->latchmgr->table[hashidx].latch); if( slot ) return set; // try again, this time with write lock bt_spinwritelock(bt->mgr->latchmgr->table[hashidx].latch); if( slot = bt->mgr->latchmgr->table[hashidx].slot ) do { set = bt->mgr->latchsets + slot; if( page_no == set->page_no ) break; if( !set->pin && !avail ) avail = slot; } while( slot = set->next ); // found our entry, or take over an unpinned one if( slot || (slot = avail) ) { set = bt->mgr->latchsets + slot; #ifdef unix __sync_fetch_and_add(&set->pin, 1); #else _InterlockedIncrement16 (&set->pin); #endif set->page_no = page_no; bt_spinreleasewrite(bt->mgr->latchmgr->table[hashidx].latch); return set; } // see if there are any unused entries #ifdef unix victim = __sync_fetch_and_add (&bt->mgr->latchmgr->latchdeployed, 1) + 1; #else victim = _InterlockedIncrement16 (&bt->mgr->latchmgr->latchdeployed); #endif if( victim < bt->mgr->latchmgr->latchtotal ) { set = bt->mgr->latchsets + victim; #ifdef unix __sync_fetch_and_add(&set->pin, 1); #else _InterlockedIncrement16 (&set->pin); #endif bt_latchlink (bt, hashidx, victim, page_no); bt_spinreleasewrite (bt->mgr->latchmgr->table[hashidx].latch); return set; } #ifdef unix victim = __sync_fetch_and_add (&bt->mgr->latchmgr->latchdeployed, -1); #else victim = _InterlockedDecrement16 (&bt->mgr->latchmgr->latchdeployed); #endif // find and reuse previous lock entry while( 1 ) { #ifdef unix victim = __sync_fetch_and_add(&bt->mgr->latchmgr->latchvictim, 1); #else victim = _InterlockedIncrement16 (&bt->mgr->latchmgr->latchvictim) - 1; #endif // we don't use slot zero if( victim %= bt->mgr->latchmgr->latchtotal ) set = bt->mgr->latchsets + victim; else continue; // take control of our slot // from other threads if( set->pin || !bt_spinwritetry (set->busy) ) continue; idx = set->hash; // try to get write lock on hash chain // skip entry if not obtained // or has outstanding locks if( !bt_spinwritetry (bt->mgr->latchmgr->table[idx].latch) ) { bt_spinreleasewrite (set->busy); continue; } if( set->pin ) { bt_spinreleasewrite (set->busy); bt_spinreleasewrite (bt->mgr->latchmgr->table[idx].latch); continue; } // unlink our available victim from its hash chain if( set->prev ) bt->mgr->latchsets[set->prev].next = set->next; else bt->mgr->latchmgr->table[idx].slot = set->next; if( set->next ) bt->mgr->latchsets[set->next].prev = set->prev; bt_spinreleasewrite (bt->mgr->latchmgr->table[idx].latch); #ifdef unix __sync_fetch_and_add(&set->pin, 1); #else _InterlockedIncrement16 (&set->pin); #endif bt_latchlink (bt, hashidx, victim, page_no); bt_spinreleasewrite (bt->mgr->latchmgr->table[hashidx].latch); bt_spinreleasewrite (set->busy); return set; } } void bt_mgrclose (BtMgr *mgr) { BtPool *pool; uint slot; // release mapped pages // note that slot zero is never used for( slot = 1; slot < mgr->poolmax; slot++ ) { pool = mgr->pool + slot; if( pool->slot ) #ifdef unix munmap (pool->map, (mgr->poolmask+1) << mgr->page_bits); #else { FlushViewOfFile(pool->map, 0); UnmapViewOfFile(pool->map); CloseHandle(pool->hmap); } #endif } #ifdef unix munmap (mgr->latchsets, mgr->latchmgr->nlatchpage * mgr->page_size); munmap (mgr->latchmgr, mgr->page_size); #else FlushViewOfFile(mgr->latchmgr, 0); UnmapViewOfFile(mgr->latchmgr); CloseHandle(mgr->halloc); #endif #ifdef unix close (mgr->idx); free (mgr->pool); free (mgr->hash); free (mgr->latch); free (mgr); #else FlushFileBuffers(mgr->idx); CloseHandle(mgr->idx); GlobalFree (mgr->pool); GlobalFree (mgr->hash); GlobalFree (mgr->latch); GlobalFree (mgr); #endif } // close and release memory void bt_close (BtDb *bt) { #ifdef unix if ( bt->mem ) free (bt->mem); #else if ( bt->mem) VirtualFree (bt->mem, 0, MEM_RELEASE); #endif free (bt); } // open/create new btree buffer manager // call with file_name, BT_openmode, bits in page size (e.g. 16), // size of mapped page pool (e.g. 8192) BtMgr *bt_mgr (char *name, uint mode, uint bits, uint poolmax, uint segsize, uint hashsize) { uint lvl, attr, cacheblk, last, slot, idx; uint nlatchpage, latchhash; BtLatchMgr *latchmgr; off64_t size; uint amt[1]; BtMgr* mgr; BtKey key; int flag; #ifndef unix SYSTEM_INFO sysinfo[1]; #endif // determine sanity of page size and buffer pool if( bits > BT_maxbits ) bits = BT_maxbits; else if( bits < BT_minbits ) bits = BT_minbits; if( !poolmax ) return NULL; // must have buffer pool #ifdef unix mgr = calloc (1, sizeof(BtMgr)); mgr->idx = open ((char*)name, O_RDWR | O_CREAT, 0666); if( mgr->idx == -1 ) return free(mgr), NULL; cacheblk = 4096; // minimum mmap segment size for unix #else mgr = GlobalAlloc (GMEM_FIXED|GMEM_ZEROINIT, sizeof(BtMgr)); attr = FILE_ATTRIBUTE_NORMAL; mgr->idx = CreateFile(name, GENERIC_READ| GENERIC_WRITE, FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, OPEN_ALWAYS, attr, NULL); if( mgr->idx == INVALID_HANDLE_VALUE ) return GlobalFree(mgr), NULL; // normalize cacheblk to multiple of sysinfo->dwAllocationGranularity GetSystemInfo(sysinfo); cacheblk = sysinfo->dwAllocationGranularity; #endif #ifdef unix latchmgr = malloc (BT_maxpage); *amt = 0; // read minimum page size to get root info if( size = lseek (mgr->idx, 0L, 2) ) { if( pread(mgr->idx, latchmgr, BT_minpage, 0) == BT_minpage ) bits = latchmgr->alloc->bits; else return free(mgr), free(latchmgr), NULL; } else if( mode == BT_ro ) return free(latchmgr), bt_mgrclose (mgr), NULL; #else latchmgr = VirtualAlloc(NULL, BT_maxpage, MEM_COMMIT, PAGE_READWRITE); size = GetFileSize(mgr->idx, amt); if( size || *amt ) { if( !ReadFile(mgr->idx, (char *)latchmgr, BT_minpage, amt, NULL) ) return bt_mgrclose (mgr), NULL; bits = latchmgr->alloc->bits; } else if( mode == BT_ro ) return bt_mgrclose (mgr), NULL; #endif mgr->page_size = 1 << bits; mgr->page_bits = bits; mgr->poolmax = poolmax; mgr->mode = mode; if( cacheblk < mgr->page_size ) cacheblk = mgr->page_size; // mask for partial memmaps mgr->poolmask = (cacheblk >> bits) - 1; // see if requested size of pages per memmap is greater if( (1 << segsize) > mgr->poolmask ) mgr->poolmask = (1 << segsize) - 1; mgr->seg_bits = 0; while( (1 << mgr->seg_bits) <= mgr->poolmask ) mgr->seg_bits++; mgr->hashsize = hashsize; #ifdef unix mgr->pool = calloc (poolmax, sizeof(BtPool)); mgr->hash = calloc (hashsize, sizeof(ushort)); mgr->latch = calloc (hashsize, sizeof(BtSpinLatch)); #else mgr->pool = GlobalAlloc (GMEM_FIXED|GMEM_ZEROINIT, poolmax * sizeof(BtPool)); mgr->hash = GlobalAlloc (GMEM_FIXED|GMEM_ZEROINIT, hashsize * sizeof(ushort)); mgr->latch = GlobalAlloc (GMEM_FIXED|GMEM_ZEROINIT, hashsize * sizeof(BtSpinLatch)); #endif if( size || *amt ) goto mgrlatch; // initialize an empty b-tree with latch page, root page, page of leaves // and page(s) of latches memset (latchmgr, 0, 1 << bits); nlatchpage = BT_latchtable / (mgr->page_size / sizeof(BtLatchSet)) + 1; bt_putid(latchmgr->alloc->right, MIN_lvl+1+nlatchpage); latchmgr->alloc->bits = mgr->page_bits; latchmgr->nlatchpage = nlatchpage; latchmgr->latchtotal = nlatchpage * (mgr->page_size / sizeof(BtLatchSet)); // initialize latch manager latchhash = (mgr->page_size - sizeof(BtLatchMgr)) / sizeof(BtHashEntry); // size of hash table = total number of latchsets if( latchhash > latchmgr->latchtotal ) latchhash = latchmgr->latchtotal; latchmgr->latchhash = latchhash; #ifdef unix if( write (mgr->idx, latchmgr, mgr->page_size) < mgr->page_size ) return bt_mgrclose (mgr), NULL; #else if( !WriteFile (mgr->idx, (char *)latchmgr, mgr->page_size, amt, NULL) ) return bt_mgrclose (mgr), NULL; if( *amt < mgr->page_size ) return bt_mgrclose (mgr), NULL; #endif memset (latchmgr, 0, 1 << bits); latchmgr->alloc->bits = mgr->page_bits; for( lvl=MIN_lvl; lvl--; ) { slotptr(latchmgr->alloc, 1)->off = mgr->page_size - 3; 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->lvl = lvl; latchmgr->alloc->cnt = 1; latchmgr->alloc->act = 1; #ifdef unix if( write (mgr->idx, latchmgr, mgr->page_size) < mgr->page_size ) return bt_mgrclose (mgr), NULL; #else if( !WriteFile (mgr->idx, (char *)latchmgr, mgr->page_size, amt, NULL) ) return bt_mgrclose (mgr), NULL; if( *amt < mgr->page_size ) return bt_mgrclose (mgr), NULL; #endif } // clear out latch manager locks // and rest of pages to round out segment memset(latchmgr, 0, mgr->page_size); last = MIN_lvl + 1; while( last <= ((MIN_lvl + 1 + nlatchpage) | mgr->poolmask) ) { #ifdef unix pwrite(mgr->idx, latchmgr, mgr->page_size, last << mgr->page_bits); #else SetFilePointer (mgr->idx, last << mgr->page_bits, NULL, FILE_BEGIN); if( !WriteFile (mgr->idx, (char *)latchmgr, mgr->page_size, amt, NULL) ) return bt_mgrclose (mgr), NULL; if( *amt < mgr->page_size ) return bt_mgrclose (mgr), NULL; #endif last++; } mgrlatch: #ifdef unix flag = PROT_READ | PROT_WRITE; mgr->latchmgr = mmap (0, mgr->page_size, flag, MAP_SHARED, mgr->idx, ALLOC_page * mgr->page_size); if( mgr->latchmgr == MAP_FAILED ) return bt_mgrclose (mgr), NULL; mgr->latchsets = (BtLatchSet *)mmap (0, mgr->latchmgr->nlatchpage * mgr->page_size, flag, MAP_SHARED, mgr->idx, LATCH_page * mgr->page_size); if( mgr->latchsets == MAP_FAILED ) return bt_mgrclose (mgr), NULL; #else flag = PAGE_READWRITE; mgr->halloc = CreateFileMapping(mgr->idx, NULL, flag, 0, (BT_latchtable / (mgr->page_size / sizeof(BtLatchSet)) + 1 + LATCH_page) * mgr->page_size, NULL); if( !mgr->halloc ) return bt_mgrclose (mgr), NULL; flag = FILE_MAP_WRITE; mgr->latchmgr = MapViewOfFile(mgr->halloc, flag, 0, 0, (BT_latchtable / (mgr->page_size / sizeof(BtLatchSet)) + 1 + LATCH_page) * mgr->page_size); if( !mgr->latchmgr ) return GetLastError(), bt_mgrclose (mgr), NULL; mgr->latchsets = (void *)((char *)mgr->latchmgr + LATCH_page * mgr->page_size); #endif #ifdef unix free (latchmgr); #else VirtualFree (latchmgr, 0, MEM_RELEASE); #endif return mgr; } // open BTree access method // based on buffer manager BtDb *bt_open (BtMgr *mgr) { BtDb *bt = malloc (sizeof(*bt)); memset (bt, 0, sizeof(*bt)); bt->mgr = mgr; #ifdef unix bt->mem = malloc (3 *mgr->page_size); #else bt->mem = VirtualAlloc(NULL, 3 * mgr->page_size, MEM_COMMIT, PAGE_READWRITE); #endif bt->frame = (BtPage)bt->mem; bt->zero = (BtPage)(bt->mem + 1 * mgr->page_size); bt->cursor = (BtPage)(bt->mem + 2 * mgr->page_size); memset(bt->zero, 0, mgr->page_size); return bt; } // compare two keys, returning > 0, = 0, or < 0 // as the comparison value int keycmp (BtKey key1, unsigned char *key2, uint len2) { uint len1 = key1->len; int ans; if( ans = memcmp (key1->key, key2, len1 > len2 ? len2 : len1) ) return ans; if( len1 > len2 ) return 1; if( len1 < len2 ) return -1; return 0; } // Buffer Pool mgr // find segment in pool // must be called with hashslot idx locked // return NULL if not there // otherwise return node BtPool *bt_findpool(BtDb *bt, uid page_no, uint idx) { BtPool *pool; uint slot; // compute start of hash chain in pool if( slot = bt->mgr->hash[idx] ) pool = bt->mgr->pool + slot; else return NULL; page_no &= ~bt->mgr->poolmask; while( pool->basepage != page_no ) if( pool = pool->hashnext ) continue; else return NULL; return pool; } // add segment to hash table void bt_linkhash(BtDb *bt, BtPool *pool, uid page_no, int idx) { BtPool *node; uint slot; pool->hashprev = pool->hashnext = NULL; pool->basepage = page_no & ~bt->mgr->poolmask; pool->lru = 1; if( slot = bt->mgr->hash[idx] ) { node = bt->mgr->pool + slot; pool->hashnext = node; node->hashprev = pool; } bt->mgr->hash[idx] = pool->slot; } // find best segment to evict from buffer pool BtPool *bt_findlru (BtDb *bt, uint hashslot) { unsigned long long int target = ~0LL; BtPool *pool = NULL, *node; if( !hashslot ) return NULL; node = bt->mgr->pool + hashslot; // scan pool entries under hash table slot do { if( node->pin ) continue; if( node->lru > target ) continue; target = node->lru; pool = node; } while( node = node->hashnext ); return pool; } // map new buffer pool segment to virtual memory BTERR bt_mapsegment(BtDb *bt, BtPool *pool, uid page_no) { off64_t off = (page_no & ~bt->mgr->poolmask) << bt->mgr->page_bits; off64_t limit = off + ((bt->mgr->poolmask+1) << bt->mgr->page_bits); 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); if( pool->map == MAP_FAILED ) return bt->err = BTERR_map; #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); if( !pool->hmap ) return bt->err = BTERR_map; flag = ( bt->mgr->mode == BT_ro ? FILE_MAP_READ : FILE_MAP_WRITE ); pool->map = MapViewOfFile(pool->hmap, flag, (DWORD)(off >> 32), (DWORD)off, (bt->mgr->poolmask+1) << bt->mgr->page_bits); if( !pool->map ) return bt->err = BTERR_map; #endif return bt->err = 0; } // calculate page within pool BtPage bt_page (BtDb *bt, BtPool *pool, uid page_no) { uint subpage = (uint)(page_no & bt->mgr->poolmask); // page within mapping BtPage page; page = (BtPage)(pool->map + (subpage << bt->mgr->page_bits)); return page; } // release pool pin void bt_unpinpool (BtPool *pool) { #ifdef unix __sync_fetch_and_add(&pool->pin, -1); #else _InterlockedDecrement16 (&pool->pin); #endif } // find or place requested page in segment-pool // return pool table entry, incrementing pin BtPool *bt_pinpool(BtDb *bt, uid page_no) { BtPool *pool, *node, *next; uint slot, idx, victim; BtLatchSet *set; // lock hash table chain idx = (uint)(page_no >> bt->mgr->seg_bits) % bt->mgr->hashsize; bt_spinreadlock (&bt->mgr->latch[idx]); // look up in hash table if( pool = bt_findpool(bt, page_no, idx) ) { #ifdef unix __sync_fetch_and_add(&pool->pin, 1); #else _InterlockedIncrement16 (&pool->pin); #endif bt_spinreleaseread (&bt->mgr->latch[idx]); pool->lru++; return pool; } // upgrade to write lock bt_spinreleaseread (&bt->mgr->latch[idx]); bt_spinwritelock (&bt->mgr->latch[idx]); // try to find page in pool with write lock if( pool = bt_findpool(bt, page_no, idx) ) { #ifdef unix __sync_fetch_and_add(&pool->pin, 1); #else _InterlockedIncrement16 (&pool->pin); #endif bt_spinreleasewrite (&bt->mgr->latch[idx]); pool->lru++; return pool; } // allocate a new pool node // and add to hash table #ifdef unix slot = __sync_fetch_and_add(&bt->mgr->poolcnt, 1); #else slot = _InterlockedIncrement16 (&bt->mgr->poolcnt) - 1; #endif if( ++slot < bt->mgr->poolmax ) { pool = bt->mgr->pool + slot; pool->slot = slot; if( bt_mapsegment(bt, pool, page_no) ) return NULL; bt_linkhash(bt, pool, page_no, idx); #ifdef unix __sync_fetch_and_add(&pool->pin, 1); #else _InterlockedIncrement16 (&pool->pin); #endif bt_spinreleasewrite (&bt->mgr->latch[idx]); return pool; } // pool table is full // find best pool entry to evict #ifdef unix __sync_fetch_and_add(&bt->mgr->poolcnt, -1); #else _InterlockedDecrement16 (&bt->mgr->poolcnt); #endif while( 1 ) { #ifdef unix victim = __sync_fetch_and_add(&bt->mgr->evicted, 1); #else victim = _InterlockedIncrement16 (&bt->mgr->evicted) - 1; #endif victim %= bt->mgr->hashsize; // try to get write lock // skip entry if not obtained if( !bt_spinwritetry (&bt->mgr->latch[victim]) ) continue; // if cache entry is empty // or no slots are unpinned // skip this entry if( !(pool = bt_findlru(bt, bt->mgr->hash[victim])) ) { bt_spinreleasewrite (&bt->mgr->latch[victim]); continue; } // unlink victim pool node from hash table if( node = pool->hashprev ) node->hashnext = pool->hashnext; else if( node = pool->hashnext ) bt->mgr->hash[victim] = node->slot; else bt->mgr->hash[victim] = 0; if( node = pool->hashnext ) node->hashprev = pool->hashprev; bt_spinreleasewrite (&bt->mgr->latch[victim]); // remove old file mapping #ifdef unix munmap (pool->map, (bt->mgr->poolmask+1) << bt->mgr->page_bits); #else FlushViewOfFile(pool->map, 0); UnmapViewOfFile(pool->map); CloseHandle(pool->hmap); #endif pool->map = NULL; // create new pool mapping // and link into hash table if( bt_mapsegment(bt, pool, page_no) ) return NULL; bt_linkhash(bt, pool, page_no, idx); #ifdef unix __sync_fetch_and_add(&pool->pin, 1); #else _InterlockedIncrement16 (&pool->pin); #endif bt_spinreleasewrite (&bt->mgr->latch[idx]); return pool; } } // place write, read, or parent lock on requested page_no. // pin to buffer pool and return latchset pointer void bt_lockpage(BtLock mode, BtLatchSet *set) { switch( mode ) { case BtLockRead: bt_spinreadlock (set->readwr); break; case BtLockWrite: bt_spinwritelock (set->readwr); break; case BtLockAccess: bt_spinreadlock (set->access); break; case BtLockDelete: bt_spinwritelock (set->access); break; case BtLockParent: bt_spinwritelock (set->parent); break; } } // remove write, read, or parent lock on requested page_no. void bt_unlockpage(BtLock mode, BtLatchSet *set) { switch( mode ) { case BtLockRead: bt_spinreleaseread (set->readwr); break; case BtLockWrite: bt_spinreleasewrite (set->readwr); break; case BtLockAccess: bt_spinreleaseread (set->access); break; case BtLockDelete: bt_spinreleasewrite (set->access); break; case BtLockParent: bt_spinreleasewrite (set->parent); break; } } // allocate a new page and write page into it uid bt_newpage(BtDb *bt, BtPage page) { BtLatchSet *set; BtPool *pool; uid new_page; BtPage pmap; int reuse; // lock allocation page bt_spinwritelock(bt->mgr->latchmgr->lock); // use empty chain first // 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); else return 0; bt_putid(bt->mgr->latchmgr->alloc[1].right, bt_getid(pmap->right)); bt_unpinpool (pool); reuse = 1; } else { new_page = bt_getid(bt->mgr->latchmgr->alloc->right); bt_putid(bt->mgr->latchmgr->alloc->right, new_page+1); reuse = 0; } #ifdef unix // if writing first page of pool block, zero last page in the block if ( !reuse && bt->mgr->poolmask > 0 && (new_page & bt->mgr->poolmask) == 0 ) { // use zero buffer to write zeros 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; } // unlock allocation latch bt_spinreleasewrite(bt->mgr->latchmgr->lock); if ( pwrite(bt->mgr->idx, page, bt->mgr->page_size, new_page << bt->mgr->page_bits) < bt->mgr->page_size ) return bt->err = BTERR_wrt, 0; #else // unlock allocation latch bt_spinreleasewrite(bt->mgr->latchmgr->lock); // bring new page into pool and copy page. // this will extend the file into the new pages. // NB -- no latch required if( pool = bt_pinpool (bt, new_page) ) pmap = bt_page (bt, pool, new_page); else return 0; memcpy(pmap, page, bt->mgr->page_size); bt_unpinpool (pool); #endif return new_page; } // find slot in page for given key at a given level int bt_findslot (BtDb *bt, unsigned char *key, uint len) { uint diff, higher = bt->page->cnt, low = 1, slot; uint good = 0; // if no right link // make stopper key an infinite fence value // by setting the good flag if( bt_getid (bt->page->right) ) higher++; else good++; // low is the next candidate. // loop ends when they meet // if good, 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 ) low = slot + 1; else higher = slot, good++; } // return zero if key is on right link page return good ? higher : 0; } // find and load page at given level for given key // leave page rd or wr locked as requested uint bt_loadpage (BtDb *bt, unsigned char *key, uint len, uint lvl, BtLock lock) { uid page_no = ROOT_page, prevpage = 0; BtLatchSet *set, *prevset; uint drill = 0xff, slot; uint mode, prevmode; BtPool *prevpool; int foster = 0; // start at root of btree and drill down do { // determine lock mode of drill level mode = (lock == BtLockWrite) && (drill == lvl) ? BtLockWrite : BtLockRead; // obtain latch set for this page bt->set = bt_pinlatch (bt, page_no); bt->page_no = page_no; // pin page contents if( bt->pool = bt_pinpool (bt, page_no) ) bt->page = bt_page (bt, bt->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); // now unlock and unpin our (possibly foster) parent if( prevpage ) { bt_unlockpage(prevmode, prevset); bt_unpinlatch (prevset); bt_unpinpool (prevpool); prevpage = 0; } // obtain read lock using lock chaining bt_lockpage(mode, bt->set); if( page_no > ROOT_page ) bt_unlockpage(BtLockAccess, bt->set); // re-read and re-lock root after determining actual level of root if( page_no == ROOT_page ) if( bt->page->lvl != drill) { drill = bt->page->lvl; if( lock == BtLockWrite && drill == lvl ) { bt_unlockpage(mode, bt->set); bt_unpinlatch (bt->set); bt_unpinpool (bt->pool); continue; } } // find key on page at this level // and either descend to requested level // or return key slot if( slot = bt_findslot (bt, key, len) ) { // is this slot < foster child area // on the requested level? // if so, return actual slot even if dead if( slot <= bt->page->cnt - bt->page->foster ) if( drill == lvl ) return bt->foster = foster, slot; // find next active slot // note: foster children are never dead while( slotptr(bt->page, slot)->dead ) if( slot++ < bt->page->cnt ) continue; else { // we are waiting for fence key posting page_no = bt_getid(bt->page->right); goto slideright; } // is this slot < foster child area // if so, drill to next level if( slot <= bt->page->cnt - bt->page->foster ) foster = 0, drill--; else foster = 1; // continue right onto foster child // or down to next level. page_no = bt_getid(slotptr(bt->page, slot)->id); // or slide right into next page } else { page_no = bt_getid(bt->page->right); foster = 1; } slideright: prevpage = bt->page_no; prevpool = bt->pool; prevset = bt->set; prevmode = mode; } while( page_no ); // return error on end of chain bt->err = BTERR_struct; return 0; // return error } // 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_mergeright (BtDb *bt, BtPage page, BtPool *pool, BtLatchSet *set, uid page_no, uint lvl, uint slot) { BtLatchSet *rset, *pset, *rpset; BtPool *rpool, *ppool, *rppool; BtPage rpage, ppage, rppage; uid right, parent, rparent; BtKey ptr; uint idx; // cache node's parent page parent = bt->page_no; ppage = bt->page; ppool = bt->pool; pset = bt->set; // lock and map our right page // note that it cannot be our foster child // since the our node is empty // and 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; rpset = bt_pinlatch (bt, rparent); bt_lockpage (BtLockWrite, rpset); // 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; } if( idx > rppage->cnt ) return bt->err = BTERR_struct; } // now that there are no more pointers to our right node // we can wait for delete lock on it 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 not a foster child if( bt->foster ) { bt_unlockpage (BtLockWrite, pset); bt_unpinlatch (pset); bt_unpinpool (ppool); #ifdef unix sched_yield(); #else SwitchToThread(); #endif goto retry; } // find our left neighbor in our parent page for( idx = slot; --idx; ) if( !slotptr(ppage, idx)->dead ) break; // if no left neighbor, do right merge if( !idx ) return bt_mergeright (bt, page, pool, set, page_no, lvl, slot); // lock and map our left neighbor's page left = bt_getid (slotptr(ppage, idx)->id); if( lpool = bt_pinpool (bt, left) ) lpage = bt_page (bt, lpool, left); else return bt->err; lset = bt_pinlatch (bt, left); bt_lockpage(BtLockWrite, lset); // wait until foster 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; } // 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; 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); // add ourselves to free chain // lock latch mgr bt_spinwritelock(bt->mgr->latchmgr->lock); // 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); // unlock latch mgr and pages bt_spinreleasewrite(bt->mgr->latchmgr->lock); 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 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->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 bt->err = 0; } // find key in leaf level and return row-id uid bt_findkey (BtDb *bt, unsigned char *key, uint len) { uint slot; BtKey ptr; uid id; if( slot = bt_loadpage (bt, key, len, 0, BtLockRead) ) ptr = keyptr(bt->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); else id = 0; bt_unlockpage (BtLockRead, bt->set); bt_unpinlatch (bt->set); bt_unpinpool (bt->pool); return id; } // check page for space available, // clean if necessary and return // 0 - page needs splitting // >0 new slot value uint bt_cleanpage(BtDb *bt, BtPage page, uint amt, uint slot) { uint nxt = bt->mgr->page_size; uint cnt = 0, idx = 0; uint max = page->cnt; uint newslot = max; BtKey key; if( page->min >= (max+1) * sizeof(BtSlot) + sizeof(*page) + amt + 1 ) return slot; // skip cleanup if nothing to reclaim if( !page->dirty ) return 0; memcpy (bt->frame, page, bt->mgr->page_size); // skip page info and set rest of page to zero memset (page+1, 0, bt->mgr->page_size - sizeof(*page)); page->dirty = 0; page->act = 0; // try cleaning up page first // always leave fence key in the array // otherwise, remove deleted key // note: foster children are never dead while( cnt++ < max ) { if( cnt == slot ) newslot = idx + 1; 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); // 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; } 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; } // 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 // note that foster children on the page are never dead // look for next hole, but stay back from the fence key 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; } // split the root and raise the height of the btree // call with current page locked and page no of foster child // return with current page (root) unlocked BTERR bt_splitroot(BtDb *bt, uid right) { uint nxt = bt->mgr->page_size; unsigned char fencekey[256]; BtPage root = bt->page; uid new_page; BtKey key; // Obtain an empty page to use, and copy the left page // contents into it from the root. Strip foster child key. // (it's the stopper key) memset (slotptr(root, root->cnt), 0, sizeof(BtSlot)); root->dirty = 1; root->foster--; root->act--; root->cnt--; // Save left fence key. key = keyptr(root, root->cnt); memcpy (fencekey, key, key->len + 1); // copy the lower keys into a new left page if( !(new_page = bt_newpage(bt, root)) ) return bt->err; // preserve the page info at the bottom // and set rest of the root to zero memset (root+1, 0, bt->mgr->page_size - sizeof(*root)); // insert left fence key on empty newroot page nxt -= *fencekey + 1; memcpy ((unsigned char *)root + nxt, fencekey, *fencekey + 1); bt_putid(slotptr(root, 1)->id, new_page); slotptr(root, 1)->off = nxt; // insert stopper key on newroot page // and increase the root height nxt -= 3; fencekey[0] = 2; fencekey[1] = 0xff; fencekey[2] = 0xff; memcpy ((unsigned char *)root + nxt, fencekey, *fencekey + 1); bt_putid(slotptr(root, 2)->id, right); slotptr(root, 2)->off = nxt; bt_putid(root->right, 0); root->min = nxt; // reset lowest used offset and key count root->cnt = 2; root->act = 2; root->lvl++; // release and unpin root (bt->page) bt_unlockpage(BtLockWrite, bt->set); bt_unpinlatch (bt->set); bt_unpinpool (bt->pool); return 0; } // split already locked full node // return unlocked and unpinned. BTERR bt_splitpage (BtDb *bt, BtPage page, BtPool *pool, BtLatchSet *set, uid page_no) { uint slot, cnt, idx, max, nxt = bt->mgr->page_size; unsigned char fencekey[256]; uint tod = time(NULL); uint lvl = page->lvl; uid new_page; BtKey key; // initialize frame buffer for right node memset (bt->frame, 0, bt->mgr->page_size); max = page->cnt - page->foster; cnt = max / 2; idx = 0; // split higher half of keys to bt->frame // leaving old foster children in the left node, // and adding a new foster child there. 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; } // transfer right link node to new right node 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; // 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 foster child to the left node key = keyptr(bt->frame, idx); memcpy (fencekey, key, key->len + 1); // update lower keys and foster children 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 // 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; } // insert new foster child for right page in queue // before any of the current foster children nxt -= *fencekey + 1; memcpy ((unsigned char *)page + nxt, fencekey, *fencekey + 1); bt_putid (slotptr(page,++idx)->id, new_page); slotptr(page, idx)->tod = tod; slotptr(page, idx)->off = nxt; page->foster++; page->act++; // continue with old foster child keys // note that none will be dead cnt = bt->frame->cnt - bt->frame->foster; while( cnt++ < bt->frame->cnt ) { 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); slotptr(page, idx)->tod = slotptr(bt->frame, cnt)->tod; slotptr(page, idx)->off = nxt; page->act++; } 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, new_page); // release wr lock on our page bt_unlockpage (BtLockWrite, set); // obtain ParentModification lock for current page // to fix new fence key and oldest foster child on page bt_lockpage (BtLockParent, set); // get our new fence key to insert in parent node bt_lockpage (BtLockRead, set); key = keyptr(page, page->cnt-1); memcpy (fencekey, key, key->len+1); bt_unlockpage (BtLockRead, set); if( bt_insertkey (bt, fencekey + 1, *fencekey, page_no, tod, lvl + 1) ) return bt->err; // lock our page for writing bt_lockpage (BtLockRead, set); // switch old parent key from us to our oldest foster child key = keyptr(page, page->cnt); memcpy (fencekey, key, key->len+1); new_page = bt_getid (slotptr(page, page->cnt)->id); bt_unlockpage (BtLockRead, set); if( bt_insertkey (bt, fencekey + 1, *fencekey, new_page, tod, lvl + 1) ) return bt->err; // now that it has its own parent pointer, // remove oldest foster child from our page bt_lockpage (BtLockWrite, set); memset (slotptr(page, page->cnt), 0, sizeof(BtSlot)); page->dirty = 1; page->foster--; page->cnt--; page->act--; bt_unlockpage (BtLockParent, set); // if this emptied page, // undo the foster child if( !page->act ) if( bt_mergeleft (bt, page, pool, set, page_no, lvl) ) return bt->err; // unlock and unpin bt_unlockpage (BtLockWrite, set); bt_unpinlatch (set); bt_unpinpool (pool); return 0; } // Insert new key into the btree at leaf level. 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( !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; } // check if page has enough space if( slot = bt_cleanpage (bt, bt->page, len, slot) ) break; if( bt_splitpage (bt, bt->page, bt->pool, bt->set, bt->page_no) ) return bt->err; } 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; } // cache page of keys into cursor and return starting slot for given key uint bt_startkey (BtDb *bt, unsigned char *key, uint len) { 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; bt_unlockpage(BtLockRead, bt->set); bt_unpinlatch (bt->set); bt_unpinpool (bt->pool); return slot; } // return next slot for cursor page // or slide cursor right into next page uint bt_nextkey (BtDb *bt, uint slot) { BtLatchSet *set; BtPool *pool; BtPage page; uid right; do { right = bt_getid(bt->cursor->right); while( slot++ < bt->cursor->cnt - bt->cursor->foster ) if( slotptr(bt->cursor,slot)->dead ) continue; else if( right || (slot < bt->cursor->cnt - bt->cursor->foster) ) return slot; else break; if( !right ) break; bt->cursor_page = right; if( pool = bt_pinpool (bt, right) ) page = bt_page (bt, pool, right); else return 0; set = bt_pinlatch (bt, right); bt_lockpage(BtLockRead, set); memcpy (bt->cursor, page, bt->mgr->page_size); bt_unlockpage(BtLockRead, set); bt_unpinlatch (set); bt_unpinpool (pool); slot = 0; } while( 1 ); return bt->err = 0; } BtKey bt_key(BtDb *bt, uint slot) { return keyptr(bt->cursor, slot); } uid bt_uid(BtDb *bt, uint slot) { return bt_getid(slotptr(bt->cursor,slot)->id); } uint bt_tod(BtDb *bt, uint slot) { 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 } typedef struct { char type, idx; char *infile; BtMgr *mgr; int num; } ThreadArg; // standalone program to index file of keys // then list them onto std-out #ifdef unix void *index_file (void *arg) #else uint __stdcall index_file (void *arg) #endif { int line = 0, found = 0, cnt = 0; 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; time_t tod[1]; BtPool *pool; BtPage page; BtKey ptr; BtDb *bt; FILE *in; bt = bt_open (args->mgr); time (tod); 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") ) while( ch = getc(in), ch != EOF ) if( ch == '\n' ) { line++; if( args->num == 1 ) sprintf((char *)key+len, "%.9d", 1000000000 - line), len += 9; else if( args->num ) sprintf((char *)key+len, "%.9d", line + args->idx * args->num), len += 9; 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( len < 255 ) key[len++] = ch; fprintf(stderr, "finished %s for %d keys\n", args->infile, line); break; case 'd': fprintf(stderr, "started deleting keys for %s\n", args->infile); if( in = fopen (args->infile, "rb") ) while( ch = getc(in), ch != EOF ) if( ch == '\n' ) { line++; if( args->num == 1 ) sprintf((char *)key+len, "%.9d", 1000000000 - line), len += 9; else if( args->num ) sprintf((char *)key+len, "%.9d", line + args->idx * args->num), len += 9; if( bt_deletekey (bt, key, len) ) fprintf(stderr, "Error %d Line: %d\n", bt->err, line), exit(0); len = 0; } else if( len < 255 ) key[len++] = ch; fprintf(stderr, "finished %s for keys, %d \n", args->infile, line); break; case 'f': fprintf(stderr, "started finding keys for %s\n", args->infile); if( in = fopen (args->infile, "rb") ) while( ch = getc(in), ch != EOF ) if( ch == '\n' ) { line++; if( args->num == 1 ) sprintf((char *)key+len, "%.9d", 1000000000 - line), len += 9; else if( args->num ) sprintf((char *)key+len, "%.9d", line + args->idx * args->num), len += 9; if( bt_findkey (bt, key, len) ) found++; else if( bt->err ) fprintf(stderr, "Error %d Syserr %d Line: %d\n", bt->err, errno, line), exit(0); len = 0; } else if( len < 255 ) key[len++] = ch; fprintf(stderr, "finished %s for %d keys, found %d\n", args->infile, line, found); 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); } break; case 'c': fprintf(stderr, "started reading\n"); do { if( pool = bt_pinpool (bt, page_no) ) page = bt_page (bt, 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); } while( page_no = next ); cnt--; // remove stopper key fprintf(stderr, " Total keys read %d\n", cnt); break; } bt_close (bt); #ifdef unix return NULL; #else return 0; #endif } typedef struct timeval timer; int main (int argc, char **argv) { int idx, cnt, len, slot, err; int segsize, bits = 16; #ifdef unix pthread_t *threads; timer start, stop; #else time_t start[1], stop[1]; HANDLE *threads; #endif double real_time; ThreadArg *args; uint poolsize = 0; int num = 0; char key[1]; BtMgr *mgr; BtKey ptr; BtDb *bt; if( argc < 3 ) { fprintf (stderr, "Usage: %s idx_file Read/Write/Scan/Delete/Find [page_bits mapped_segments seg_bits line_numbers src_file1 src_file2 ... ]\n", argv[0]); fprintf (stderr, " where page_bits is the page size in bits\n"); fprintf (stderr, " mapped_segments is the number of mmap segments in buffer pool\n"); fprintf (stderr, " seg_bits is the size of individual segments in buffer pool in pages in bits\n"); fprintf (stderr, " line_numbers = 1 to append line numbers to keys\n"); fprintf (stderr, " src_file1 thru src_filen are files of keys separated by newline\n"); exit(0); } #ifdef unix gettimeofday(&start, NULL); #else time(start); #endif if( argc > 3 ) bits = atoi(argv[3]); if( argc > 4 ) poolsize = atoi(argv[4]); if( !poolsize ) fprintf (stderr, "Warning: no mapped_pool\n"); if( poolsize > 65535 ) fprintf (stderr, "Warning: mapped_pool > 65535 segments\n"); if( argc > 5 ) segsize = atoi(argv[5]); else segsize = 4; // 16 pages per mmap segment if( argc > 6 ) num = atoi(argv[6]); cnt = argc - 7; #ifdef unix threads = malloc (cnt * sizeof(pthread_t)); #else threads = GlobalAlloc (GMEM_FIXED|GMEM_ZEROINIT, cnt * sizeof(HANDLE)); #endif args = malloc (cnt * sizeof(ThreadArg)); mgr = bt_mgr ((argv[1]), BT_rw, bits, poolsize, segsize, poolsize / 8); if( !mgr ) { fprintf(stderr, "Index Open Error %s\n", argv[1]); exit (1); } // fire off threads for( idx = 0; idx < cnt; idx++ ) { args[idx].infile = argv[idx + 7]; args[idx].type = argv[2][0]; args[idx].mgr = mgr; args[idx].num = num; args[idx].idx = idx; #ifdef unix if( err = pthread_create (threads + idx, NULL, index_file, args + idx) ) fprintf(stderr, "Error creating thread %d\n", err); #else threads[idx] = (HANDLE)_beginthreadex(NULL, 65536, index_file, args + idx, 0, NULL); #endif } // wait for termination #ifdef unix for( idx = 0; idx < cnt; idx++ ) pthread_join (threads[idx], NULL); gettimeofday(&stop, NULL); real_time = 1000.0 * ( stop.tv_sec - start.tv_sec ) + 0.001 * (stop.tv_usec - start.tv_usec ); #else WaitForMultipleObjects (cnt, threads, TRUE, INFINITE); for( idx = 0; idx < cnt; idx++ ) CloseHandle(threads[idx]); time (stop); real_time = 1000 * (*stop - *start); #endif fprintf(stderr, " Time to complete: %.2f seconds\n", real_time/1000); bt_mgrclose (mgr); } #endif //STANDALONE