1 // btree version threads2h pthread rw lock/SRW version
2 // with fixed bt_deletekey code
5 // author: karl malbrain, malbrain@cal.berkeley.edu
8 This work, including the source code, documentation
9 and related data, is placed into the public domain.
11 The orginal author is Karl Malbrain.
13 THIS SOFTWARE IS PROVIDED AS-IS WITHOUT WARRANTY
14 OF ANY KIND, NOT EVEN THE IMPLIED WARRANTY OF
15 MERCHANTABILITY. THE AUTHOR OF THIS SOFTWARE,
16 ASSUMES _NO_ RESPONSIBILITY FOR ANY CONSEQUENCE
17 RESULTING FROM THE USE, MODIFICATION, OR
18 REDISTRIBUTION OF THIS SOFTWARE.
21 // Please see the project home page for documentation
22 // code.google.com/p/high-concurrency-btree
24 #define _FILE_OFFSET_BITS 64
25 #define _LARGEFILE64_SOURCE
41 #define WIN32_LEAN_AND_MEAN
55 typedef unsigned long long uid;
58 typedef unsigned long long off64_t;
59 typedef unsigned short ushort;
60 typedef unsigned int uint;
63 #define BT_latchtable 128 // number of latch manager slots
65 #define BT_ro 0x6f72 // ro
66 #define BT_rw 0x7772 // rw
68 #define BT_maxbits 24 // maximum page size in bits
69 #define BT_minbits 9 // minimum page size in bits
70 #define BT_minpage (1 << BT_minbits) // minimum page size
71 #define BT_maxpage (1 << BT_maxbits) // maximum page size
74 There are five lock types for each node in three independent sets:
75 1. (set 1) AccessIntent: Sharable. Going to Read the node. Incompatible with NodeDelete.
76 2. (set 1) NodeDelete: Exclusive. About to release the node. Incompatible with AccessIntent.
77 3. (set 2) ReadLock: Sharable. Read the node. Incompatible with WriteLock.
78 4. (set 2) WriteLock: Exclusive. Modify the node. Incompatible with ReadLock and other WriteLocks.
79 5. (set 3) ParentModification: Exclusive. Change the node's parent keys. Incompatible with another ParentModification.
90 // mode & definition for latch implementation
92 // exclusive is set for write access
93 // share is count of read accessors
94 // grant write lock when share == 0
97 volatile unsigned char mutex;
98 volatile unsigned char exclusive:1;
99 volatile unsigned char pending:1;
100 volatile ushort share;
103 // hash table entries
106 BtSpinLatch latch[1];
107 volatile ushort slot; // Latch table entry at head of chain
110 // latch manager table structure
114 pthread_rwlock_t lock[1];
121 BtLatch readwr[1]; // read/write page lock
122 BtLatch access[1]; // Access Intent/Page delete
123 BtLatch parent[1]; // Posting of fence key in parent
124 BtSpinLatch busy[1]; // slot is being moved between chains
125 volatile ushort next; // next entry in hash table chain
126 volatile ushort prev; // prev entry in hash table chain
127 volatile ushort pin; // number of outstanding locks
128 volatile ushort hash; // hash slot entry is under
129 volatile uid page_no; // latch set page number
132 // Define the length of the page and key pointers
136 // Page key slot definition.
138 // If BT_maxbits is 15 or less, you can save 4 bytes
139 // for each key stored by making the first two uints
140 // into ushorts. You can also save 4 bytes by removing
141 // the tod field from the key.
143 // Keys are marked dead, but remain on the page until
144 // it cleanup is called. The fence key (highest key) for
145 // the page is always present, even after cleanup.
148 uint off:BT_maxbits; // page offset for key start
149 uint dead:1; // set for deleted key
150 uint tod; // time-stamp for key
151 unsigned char id[BtId]; // id associated with key
154 // The key structure occupies space at the upper end of
155 // each page. It's a length byte followed by the value
160 unsigned char key[1];
163 // The first part of an index page.
164 // It is immediately followed
165 // by the BtSlot array of keys.
167 typedef struct BtPage_ {
168 uint cnt; // count of keys in page
169 uint act; // count of active keys
170 uint min; // next key offset
171 unsigned char bits:7; // page size in bits
172 unsigned char free:1; // page is on free list
173 unsigned char lvl:5; // level of page
174 unsigned char kill:1; // page is being killed
175 unsigned char dirty:1; // page has deleted keys
176 unsigned char posted:1; // page fence is posted
177 unsigned char right[BtId]; // page number to right
180 // The memory mapping pool table buffer manager entry
183 unsigned long long int lru; // number of times accessed
184 uid basepage; // mapped base page number
185 char *map; // mapped memory pointer
186 ushort slot; // slot index in this array
187 ushort pin; // mapped page pin counter
188 void *hashprev; // previous pool entry for the same hash idx
189 void *hashnext; // next pool entry for the same hash idx
191 HANDLE hmap; // Windows memory mapping handle
195 // The loadpage interface object
198 uid page_no; // current page number
199 BtPage page; // current page pointer
200 BtPool *pool; // current page pool
201 BtLatchSet *latch; // current page latch set
204 // structure for latch manager on ALLOC_page
207 struct BtPage_ alloc[2]; // next & free page_nos in right ptr
208 BtSpinLatch lock[1]; // allocation area lite latch
209 ushort latchdeployed; // highest number of latch entries deployed
210 ushort nlatchpage; // number of latch pages at BT_latch
211 ushort latchtotal; // number of page latch entries
212 ushort latchhash; // number of latch hash table slots
213 ushort latchvictim; // next latch entry to examine
214 BtHashEntry table[0]; // the hash table
217 // The object structure for Btree access
220 uint page_size; // page size
221 uint page_bits; // page size in bits
222 uint seg_bits; // seg size in pages in bits
223 uint mode; // read-write mode
229 ushort poolcnt; // highest page pool node in use
230 ushort poolmax; // highest page pool node allocated
231 ushort poolmask; // total number of pages in mmap segment - 1
232 ushort hashsize; // size of Hash Table for pool entries
233 volatile uint evicted; // last evicted hash table slot
234 ushort *hash; // pool index for hash entries
235 BtSpinLatch *latch; // latches for hash table slots
236 BtLatchMgr *latchmgr; // mapped latch page from allocation page
237 BtLatchSet *latchsets; // mapped latch set from latch pages
238 BtPool *pool; // memory pool page segments
240 HANDLE halloc; // allocation and latch table handle
245 BtMgr *mgr; // buffer manager for thread
246 BtPage cursor; // cached frame for start/next (never mapped)
247 BtPage frame; // spare frame for the page split (never mapped)
248 BtPage zero; // page frame for zeroes at end of file
249 uid cursor_page; // current cursor page number
250 unsigned char *mem; // frame, cursor, page memory buffer
251 int found; // last delete or insert was found
252 int err; // last error
266 extern void bt_close (BtDb *bt);
267 extern BtDb *bt_open (BtMgr *mgr);
268 extern BTERR bt_insertkey (BtDb *bt, unsigned char *key, uint len, uint lvl, uid id, uint tod);
269 extern BTERR bt_deletekey (BtDb *bt, unsigned char *key, uint len, uint lvl);
270 extern uid bt_findkey (BtDb *bt, unsigned char *key, uint len);
271 extern uint bt_startkey (BtDb *bt, unsigned char *key, uint len);
272 extern uint bt_nextkey (BtDb *bt, uint slot);
275 extern BtMgr *bt_mgr (char *name, uint mode, uint bits, uint poolsize, uint segsize, uint hashsize);
276 void bt_mgrclose (BtMgr *mgr);
278 // Helper functions to return slot values
280 extern BtKey bt_key (BtDb *bt, uint slot);
281 extern uid bt_uid (BtDb *bt, uint slot);
282 extern uint bt_tod (BtDb *bt, uint slot);
284 // BTree page number constants
285 #define ALLOC_page 0 // allocation & lock manager hash table
286 #define ROOT_page 1 // root of the btree
287 #define LEAF_page 2 // first page of leaves
288 #define LATCH_page 3 // pages for lock manager
290 // Number of levels to create in a new BTree
294 // The page is allocated from low and hi ends.
295 // The key offsets and row-id's are allocated
296 // from the bottom, while the text of the key
297 // is allocated from the top. When the two
298 // areas meet, the page is split into two.
300 // A key consists of a length byte, two bytes of
301 // index number (0 - 65534), and up to 253 bytes
302 // of key value. Duplicate keys are discarded.
303 // Associated with each key is a 48 bit row-id.
305 // The b-tree root is always located at page 1.
306 // The first leaf page of level zero is always
307 // located on page 2.
309 // The b-tree pages are linked with next
310 // pointers to facilitate enumerators,
311 // and provide for concurrency.
313 // When to root page fills, it is split in two and
314 // the tree height is raised by a new root at page
315 // one with two keys.
317 // Deleted keys are marked with a dead bit until
318 // page cleanup The fence key for a node is
319 // present in a special array.
321 // Groups of pages called segments from the btree are optionally
322 // cached with a memory mapped pool. A hash table is used to keep
323 // track of the cached segments. This behaviour is controlled
324 // by the cache block size parameter to bt_open.
326 // To achieve maximum concurrency one page is locked at a time
327 // as the tree is traversed to find leaf key in question. The right
328 // page numbers are used in cases where the page is being split,
331 // Page 0 is dedicated to lock for new page extensions,
332 // and chains empty pages together for reuse.
334 // The ParentModification lock on a node is obtained to serialize posting
335 // or changing the fence key for a node.
337 // Empty pages are chained together through the ALLOC page and reused.
339 // Access macros to address slot and key values from the page.
340 // Page slots use 1 based indexing.
342 #define slotptr(page, slot) (((BtSlot *)(page+1)) + (slot-1))
343 #define keyptr(page, slot) ((BtKey)((unsigned char*)(page) + slotptr(page, slot)->off))
345 void bt_putid(unsigned char *dest, uid id)
350 dest[i] = (unsigned char)id, id >>= 8;
353 uid bt_getid(unsigned char *src)
358 for( i = 0; i < BtId; i++ )
359 id <<= 8, id |= *src++;
366 // wait until write lock mode is clear
367 // and add 1 to the share count
369 void bt_spinreadlock(BtSpinLatch *latch)
374 // obtain latch mutex
376 if( __sync_lock_test_and_set(&latch->mutex, 1) )
379 if( _InterlockedExchange8(&latch->mutex, 1) )
382 // see if exclusive request is granted or pending
384 if( prev = !(latch->exclusive | latch->pending) )
388 __sync_lock_release (&latch->mutex);
390 _InterlockedExchange8(&latch->mutex, 0);
397 } while( sched_yield(), 1 );
399 } while( SwitchToThread(), 1 );
403 // wait for other read and write latches to relinquish
405 void bt_spinwritelock(BtSpinLatch *latch)
411 if( __sync_lock_test_and_set(&latch->mutex, 1) )
414 if( _InterlockedExchange8(&latch->mutex, 1) )
417 if( prev = !(latch->share | latch->exclusive) )
418 latch->exclusive = 1, latch->pending = 0;
422 __sync_lock_release (&latch->mutex);
424 _InterlockedExchange8(&latch->mutex, 0);
429 } while( sched_yield(), 1 );
431 } while( SwitchToThread(), 1 );
435 // try to obtain write lock
437 // return 1 if obtained,
440 int bt_spinwritetry(BtSpinLatch *latch)
445 if( __sync_lock_test_and_set(&latch->mutex, 1) )
448 if( _InterlockedExchange8(&latch->mutex, 1) )
451 // take write access if all bits are clear
453 if( prev = !(latch->exclusive | latch->share) )
454 latch->exclusive = 1;
457 __sync_lock_release (&latch->mutex);
459 _InterlockedExchange8(&latch->mutex, 0);
466 void bt_spinreleasewrite(BtSpinLatch *latch)
468 // obtain latch mutex
470 while( __sync_lock_test_and_set(&latch->mutex, 1) )
473 while( _InterlockedExchange8(&latch->mutex, 1) )
476 latch->exclusive = 0;
478 __sync_lock_release (&latch->mutex);
480 _InterlockedExchange8(&latch->mutex, 0);
484 // decrement reader count
486 void bt_spinreleaseread(BtSpinLatch *latch)
489 while( __sync_lock_test_and_set(&latch->mutex, 1) )
492 while( _InterlockedExchange8(&latch->mutex, 1) )
497 __sync_lock_release (&latch->mutex);
499 _InterlockedExchange8(&latch->mutex, 0);
503 void bt_readlock(BtLatch *latch)
506 pthread_rwlock_rdlock (latch->lock);
508 AcquireSRWLockShared (latch->srw);
512 // wait for other read and write latches to relinquish
514 void bt_writelock(BtLatch *latch)
517 pthread_rwlock_wrlock (latch->lock);
519 AcquireSRWLockExclusive (latch->srw);
523 // try to obtain write lock
525 // return 1 if obtained,
526 // 0 if already write or read locked
528 int bt_writetry(BtLatch *latch)
533 result = !pthread_rwlock_trywrlock (latch->lock);
535 result = TryAcquireSRWLockExclusive (latch->srw);
542 void bt_releasewrite(BtLatch *latch)
545 pthread_rwlock_unlock (latch->lock);
547 ReleaseSRWLockExclusive (latch->srw);
551 // decrement reader count
553 void bt_releaseread(BtLatch *latch)
556 pthread_rwlock_unlock (latch->lock);
558 ReleaseSRWLockShared (latch->srw);
562 void bt_initlockset (BtLatchSet *set)
565 pthread_rwlockattr_t rwattr[1];
567 pthread_rwlockattr_init (rwattr);
568 pthread_rwlockattr_setpshared (rwattr, PTHREAD_PROCESS_SHARED);
570 pthread_rwlock_init (set->readwr->lock, rwattr);
571 pthread_rwlock_init (set->access->lock, rwattr);
572 pthread_rwlock_init (set->parent->lock, rwattr);
573 pthread_rwlockattr_destroy (rwattr);
575 InitializeSRWLock (set->readwr->srw);
576 InitializeSRWLock (set->access->srw);
577 InitializeSRWLock (set->parent->srw);
581 // link latch table entry into latch hash table
583 void bt_latchlink (BtDb *bt, ushort hashidx, ushort victim, uid page_no)
585 BtLatchSet *set = bt->mgr->latchsets + victim;
587 if( set->next = bt->mgr->latchmgr->table[hashidx].slot )
588 bt->mgr->latchsets[set->next].prev = victim;
590 bt->mgr->latchmgr->table[hashidx].slot = victim;
591 set->page_no = page_no;
598 void bt_unpinlatch (BtLatchSet *set)
601 __sync_fetch_and_add(&set->pin, -1);
603 _InterlockedDecrement16 (&set->pin);
607 // find existing latchset or inspire new one
608 // return with latchset pinned
610 BtLatchSet *bt_pinlatch (BtDb *bt, uid page_no)
612 ushort hashidx = page_no % bt->mgr->latchmgr->latchhash;
613 ushort slot, avail = 0, victim, idx;
616 // obtain read lock on hash table entry
618 bt_spinreadlock(bt->mgr->latchmgr->table[hashidx].latch);
620 if( slot = bt->mgr->latchmgr->table[hashidx].slot ) do
622 set = bt->mgr->latchsets + slot;
623 if( page_no == set->page_no )
625 } while( slot = set->next );
629 __sync_fetch_and_add(&set->pin, 1);
631 _InterlockedIncrement16 (&set->pin);
635 bt_spinreleaseread (bt->mgr->latchmgr->table[hashidx].latch);
640 // try again, this time with write lock
642 bt_spinwritelock(bt->mgr->latchmgr->table[hashidx].latch);
644 if( slot = bt->mgr->latchmgr->table[hashidx].slot ) do
646 set = bt->mgr->latchsets + slot;
647 if( page_no == set->page_no )
649 if( !set->pin && !avail )
651 } while( slot = set->next );
653 // found our entry, or take over an unpinned one
655 if( slot || (slot = avail) ) {
656 set = bt->mgr->latchsets + slot;
658 __sync_fetch_and_add(&set->pin, 1);
660 _InterlockedIncrement16 (&set->pin);
662 set->page_no = page_no;
663 bt_spinreleasewrite(bt->mgr->latchmgr->table[hashidx].latch);
667 // see if there are any unused entries
669 victim = __sync_fetch_and_add (&bt->mgr->latchmgr->latchdeployed, 1) + 1;
671 victim = _InterlockedIncrement16 (&bt->mgr->latchmgr->latchdeployed);
674 if( victim < bt->mgr->latchmgr->latchtotal ) {
675 set = bt->mgr->latchsets + victim;
677 __sync_fetch_and_add(&set->pin, 1);
679 _InterlockedIncrement16 (&set->pin);
681 bt_initlockset (set);
682 bt_latchlink (bt, hashidx, victim, page_no);
683 bt_spinreleasewrite (bt->mgr->latchmgr->table[hashidx].latch);
688 victim = __sync_fetch_and_add (&bt->mgr->latchmgr->latchdeployed, -1);
690 victim = _InterlockedDecrement16 (&bt->mgr->latchmgr->latchdeployed);
692 // find and reuse previous lock entry
696 victim = __sync_fetch_and_add(&bt->mgr->latchmgr->latchvictim, 1);
698 victim = _InterlockedIncrement16 (&bt->mgr->latchmgr->latchvictim) - 1;
700 // we don't use slot zero
702 if( victim %= bt->mgr->latchmgr->latchtotal )
703 set = bt->mgr->latchsets + victim;
707 // take control of our slot
708 // from other threads
710 if( set->pin || !bt_spinwritetry (set->busy) )
715 // try to get write lock on hash chain
716 // skip entry if not obtained
717 // or has outstanding locks
719 if( !bt_spinwritetry (bt->mgr->latchmgr->table[idx].latch) ) {
720 bt_spinreleasewrite (set->busy);
725 bt_spinreleasewrite (set->busy);
726 bt_spinreleasewrite (bt->mgr->latchmgr->table[idx].latch);
730 // unlink our available victim from its hash chain
733 bt->mgr->latchsets[set->prev].next = set->next;
735 bt->mgr->latchmgr->table[idx].slot = set->next;
738 bt->mgr->latchsets[set->next].prev = set->prev;
740 bt_spinreleasewrite (bt->mgr->latchmgr->table[idx].latch);
742 __sync_fetch_and_add(&set->pin, 1);
744 _InterlockedIncrement16 (&set->pin);
746 bt_latchlink (bt, hashidx, victim, page_no);
747 bt_spinreleasewrite (bt->mgr->latchmgr->table[hashidx].latch);
748 bt_spinreleasewrite (set->busy);
753 void bt_mgrclose (BtMgr *mgr)
758 // release mapped pages
759 // note that slot zero is never used
761 for( slot = 1; slot < mgr->poolmax; slot++ ) {
762 pool = mgr->pool + slot;
765 munmap (pool->map, (mgr->poolmask+1) << mgr->page_bits);
768 FlushViewOfFile(pool->map, 0);
769 UnmapViewOfFile(pool->map);
770 CloseHandle(pool->hmap);
776 munmap (mgr->latchsets, mgr->latchmgr->nlatchpage * mgr->page_size);
777 munmap (mgr->latchmgr, mgr->page_size);
779 FlushViewOfFile(mgr->latchmgr, 0);
780 UnmapViewOfFile(mgr->latchmgr);
781 CloseHandle(mgr->halloc);
790 FlushFileBuffers(mgr->idx);
791 CloseHandle(mgr->idx);
792 GlobalFree (mgr->pool);
793 GlobalFree (mgr->hash);
794 GlobalFree (mgr->latch);
799 // close and release memory
801 void bt_close (BtDb *bt)
808 VirtualFree (bt->mem, 0, MEM_RELEASE);
813 // open/create new btree buffer manager
815 // call with file_name, BT_openmode, bits in page size (e.g. 16),
816 // size of mapped page pool (e.g. 8192)
818 BtMgr *bt_mgr (char *name, uint mode, uint bits, uint poolmax, uint segsize, uint hashsize)
820 uint lvl, attr, cacheblk, last, slot, idx;
821 uint nlatchpage, latchhash;
822 BtLatchMgr *latchmgr;
830 SYSTEM_INFO sysinfo[1];
833 // determine sanity of page size and buffer pool
835 if( bits > BT_maxbits )
837 else if( bits < BT_minbits )
841 return NULL; // must have buffer pool
844 mgr = calloc (1, sizeof(BtMgr));
846 mgr->idx = open ((char*)name, O_RDWR | O_CREAT, 0666);
849 return free(mgr), NULL;
851 cacheblk = 4096; // minimum mmap segment size for unix
854 mgr = GlobalAlloc (GMEM_FIXED|GMEM_ZEROINIT, sizeof(BtMgr));
855 attr = FILE_ATTRIBUTE_NORMAL;
856 mgr->idx = CreateFile(name, GENERIC_READ| GENERIC_WRITE, FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, OPEN_ALWAYS, attr, NULL);
858 if( mgr->idx == INVALID_HANDLE_VALUE )
859 return GlobalFree(mgr), NULL;
861 // normalize cacheblk to multiple of sysinfo->dwAllocationGranularity
862 GetSystemInfo(sysinfo);
863 cacheblk = sysinfo->dwAllocationGranularity;
867 latchmgr = malloc (BT_maxpage);
870 // read minimum page size to get root info
872 if( size = lseek (mgr->idx, 0L, 2) ) {
873 if( pread(mgr->idx, latchmgr, BT_minpage, 0) == BT_minpage )
874 bits = latchmgr->alloc->bits;
876 return free(mgr), free(latchmgr), NULL;
877 } else if( mode == BT_ro )
878 return free(latchmgr), bt_mgrclose (mgr), NULL;
880 latchmgr = VirtualAlloc(NULL, BT_maxpage, MEM_COMMIT, PAGE_READWRITE);
881 size = GetFileSize(mgr->idx, amt);
884 if( !ReadFile(mgr->idx, (char *)latchmgr, BT_minpage, amt, NULL) )
885 return bt_mgrclose (mgr), NULL;
886 bits = latchmgr->alloc->bits;
887 } else if( mode == BT_ro )
888 return bt_mgrclose (mgr), NULL;
891 mgr->page_size = 1 << bits;
892 mgr->page_bits = bits;
894 mgr->poolmax = poolmax;
897 if( cacheblk < mgr->page_size )
898 cacheblk = mgr->page_size;
900 // mask for partial memmaps
902 mgr->poolmask = (cacheblk >> bits) - 1;
904 // see if requested size of pages per memmap is greater
906 if( (1 << segsize) > mgr->poolmask )
907 mgr->poolmask = (1 << segsize) - 1;
911 while( (1 << mgr->seg_bits) <= mgr->poolmask )
914 mgr->hashsize = hashsize;
917 mgr->pool = calloc (poolmax, sizeof(BtPool));
918 mgr->hash = calloc (hashsize, sizeof(ushort));
919 mgr->latch = calloc (hashsize, sizeof(BtSpinLatch));
921 mgr->pool = GlobalAlloc (GMEM_FIXED|GMEM_ZEROINIT, poolmax * sizeof(BtPool));
922 mgr->hash = GlobalAlloc (GMEM_FIXED|GMEM_ZEROINIT, hashsize * sizeof(ushort));
923 mgr->latch = GlobalAlloc (GMEM_FIXED|GMEM_ZEROINIT, hashsize * sizeof(BtSpinLatch));
929 // initialize an empty b-tree with latch page, root page, page of leaves
930 // and page(s) of latches
932 memset (latchmgr, 0, 1 << bits);
933 nlatchpage = BT_latchtable / (mgr->page_size / sizeof(BtLatchSet)) + 1;
934 bt_putid(latchmgr->alloc->right, MIN_lvl+1+nlatchpage);
935 latchmgr->alloc->bits = mgr->page_bits;
937 latchmgr->nlatchpage = nlatchpage;
938 latchmgr->latchtotal = nlatchpage * (mgr->page_size / sizeof(BtLatchSet));
940 // initialize latch manager
942 latchhash = (mgr->page_size - sizeof(BtLatchMgr)) / sizeof(BtHashEntry);
944 // size of hash table = total number of latchsets
946 if( latchhash > latchmgr->latchtotal )
947 latchhash = latchmgr->latchtotal;
949 latchmgr->latchhash = latchhash;
952 if( write (mgr->idx, latchmgr, mgr->page_size) < mgr->page_size )
953 return bt_mgrclose (mgr), NULL;
955 if( !WriteFile (mgr->idx, (char *)latchmgr, mgr->page_size, amt, NULL) )
956 return bt_mgrclose (mgr), NULL;
958 if( *amt < mgr->page_size )
959 return bt_mgrclose (mgr), NULL;
962 memset (latchmgr, 0, 1 << bits);
963 latchmgr->alloc->bits = mgr->page_bits;
965 for( lvl=MIN_lvl; lvl--; ) {
966 slotptr(latchmgr->alloc, 1)->off = mgr->page_size - 3;
967 bt_putid(slotptr(latchmgr->alloc, 1)->id, lvl ? MIN_lvl - lvl + 1 : 0); // next(lower) page number
968 key = keyptr(latchmgr->alloc, 1);
969 key->len = 2; // create stopper key
972 latchmgr->alloc->min = mgr->page_size - 3;
973 latchmgr->alloc->lvl = lvl;
974 latchmgr->alloc->cnt = 1;
975 latchmgr->alloc->act = 1;
977 if( write (mgr->idx, latchmgr, mgr->page_size) < mgr->page_size )
978 return bt_mgrclose (mgr), NULL;
980 if( !WriteFile (mgr->idx, (char *)latchmgr, mgr->page_size, amt, NULL) )
981 return bt_mgrclose (mgr), NULL;
983 if( *amt < mgr->page_size )
984 return bt_mgrclose (mgr), NULL;
988 // clear out latch manager locks
989 // and rest of pages to round out segment
991 memset(latchmgr, 0, mgr->page_size);
994 while( last <= ((MIN_lvl + 1 + nlatchpage) | mgr->poolmask) ) {
996 pwrite(mgr->idx, latchmgr, mgr->page_size, last << mgr->page_bits);
998 SetFilePointer (mgr->idx, last << mgr->page_bits, NULL, FILE_BEGIN);
999 if( !WriteFile (mgr->idx, (char *)latchmgr, mgr->page_size, amt, NULL) )
1000 return bt_mgrclose (mgr), NULL;
1001 if( *amt < mgr->page_size )
1002 return bt_mgrclose (mgr), NULL;
1009 flag = PROT_READ | PROT_WRITE;
1010 mgr->latchmgr = mmap (0, mgr->page_size, flag, MAP_SHARED, mgr->idx, ALLOC_page * mgr->page_size);
1011 if( mgr->latchmgr == MAP_FAILED )
1012 return bt_mgrclose (mgr), NULL;
1013 mgr->latchsets = (BtLatchSet *)mmap (0, mgr->latchmgr->nlatchpage * mgr->page_size, flag, MAP_SHARED, mgr->idx, LATCH_page * mgr->page_size);
1014 if( mgr->latchsets == MAP_FAILED )
1015 return bt_mgrclose (mgr), NULL;
1017 flag = PAGE_READWRITE;
1018 mgr->halloc = CreateFileMapping(mgr->idx, NULL, flag, 0, (BT_latchtable / (mgr->page_size / sizeof(BtLatchSet)) + 1 + LATCH_page) * mgr->page_size, NULL);
1020 return bt_mgrclose (mgr), NULL;
1022 flag = FILE_MAP_WRITE;
1023 mgr->latchmgr = MapViewOfFile(mgr->halloc, flag, 0, 0, (BT_latchtable / (mgr->page_size / sizeof(BtLatchSet)) + 1 + LATCH_page) * mgr->page_size);
1024 if( !mgr->latchmgr )
1025 return GetLastError(), bt_mgrclose (mgr), NULL;
1027 mgr->latchsets = (void *)((char *)mgr->latchmgr + LATCH_page * mgr->page_size);
1033 VirtualFree (latchmgr, 0, MEM_RELEASE);
1038 // open BTree access method
1039 // based on buffer manager
1041 BtDb *bt_open (BtMgr *mgr)
1043 BtDb *bt = malloc (sizeof(*bt));
1045 memset (bt, 0, sizeof(*bt));
1048 bt->mem = malloc (3 *mgr->page_size);
1050 bt->mem = VirtualAlloc(NULL, 3 * mgr->page_size, MEM_COMMIT, PAGE_READWRITE);
1052 bt->frame = (BtPage)bt->mem;
1053 bt->zero = (BtPage)(bt->mem + 1 * mgr->page_size);
1054 bt->cursor = (BtPage)(bt->mem + 2 * mgr->page_size);
1056 memset (bt->zero, 0, mgr->page_size);
1060 // compare two keys, returning > 0, = 0, or < 0
1061 // as the comparison value
1063 int keycmp (BtKey key1, unsigned char *key2, uint len2)
1065 uint len1 = key1->len;
1068 if( ans = memcmp (key1->key, key2, len1 > len2 ? len2 : len1) )
1081 // find segment in pool
1082 // must be called with hashslot idx locked
1083 // return NULL if not there
1084 // otherwise return node
1086 BtPool *bt_findpool(BtDb *bt, uid page_no, uint idx)
1091 // compute start of hash chain in pool
1093 if( slot = bt->mgr->hash[idx] )
1094 pool = bt->mgr->pool + slot;
1098 page_no &= ~bt->mgr->poolmask;
1100 while( pool->basepage != page_no )
1101 if( pool = pool->hashnext )
1109 // add segment to hash table
1111 void bt_linkhash(BtDb *bt, BtPool *pool, uid page_no, int idx)
1116 pool->hashprev = pool->hashnext = NULL;
1117 pool->basepage = page_no & ~bt->mgr->poolmask;
1120 if( slot = bt->mgr->hash[idx] ) {
1121 node = bt->mgr->pool + slot;
1122 pool->hashnext = node;
1123 node->hashprev = pool;
1126 bt->mgr->hash[idx] = pool->slot;
1129 // find best segment to evict from buffer pool
1131 BtPool *bt_findlru (BtDb *bt, uint hashslot)
1133 unsigned long long int target = ~0LL;
1134 BtPool *pool = NULL, *node;
1139 node = bt->mgr->pool + hashslot;
1141 // scan pool entries under hash table slot
1146 if( node->lru > target )
1150 } while( node = node->hashnext );
1155 // map new buffer pool segment to virtual memory
1157 BTERR bt_mapsegment(BtDb *bt, BtPool *pool, uid page_no)
1159 off64_t off = (page_no & ~bt->mgr->poolmask) << bt->mgr->page_bits;
1160 off64_t limit = off + ((bt->mgr->poolmask+1) << bt->mgr->page_bits);
1164 flag = PROT_READ | ( bt->mgr->mode == BT_ro ? 0 : PROT_WRITE );
1165 pool->map = mmap (0, (bt->mgr->poolmask+1) << bt->mgr->page_bits, flag, MAP_SHARED, bt->mgr->idx, off);
1166 if( pool->map == MAP_FAILED )
1167 return bt->err = BTERR_map;
1169 flag = ( bt->mgr->mode == BT_ro ? PAGE_READONLY : PAGE_READWRITE );
1170 pool->hmap = CreateFileMapping(bt->mgr->idx, NULL, flag, (DWORD)(limit >> 32), (DWORD)limit, NULL);
1172 return bt->err = BTERR_map;
1174 flag = ( bt->mgr->mode == BT_ro ? FILE_MAP_READ : FILE_MAP_WRITE );
1175 pool->map = MapViewOfFile(pool->hmap, flag, (DWORD)(off >> 32), (DWORD)off, (bt->mgr->poolmask+1) << bt->mgr->page_bits);
1177 return bt->err = BTERR_map;
1182 // calculate page within pool
1184 BtPage bt_page (BtDb *bt, BtPool *pool, uid page_no)
1186 uint subpage = (uint)(page_no & bt->mgr->poolmask); // page within mapping
1189 page = (BtPage)(pool->map + (subpage << bt->mgr->page_bits));
1195 void bt_unpinpool (BtPool *pool)
1198 __sync_fetch_and_add(&pool->pin, -1);
1200 _InterlockedDecrement16 (&pool->pin);
1204 // find or place requested page in segment-pool
1205 // return pool table entry, incrementing pin
1207 BtPool *bt_pinpool(BtDb *bt, uid page_no)
1209 BtPool *pool, *node, *next;
1210 uint slot, idx, victim;
1212 // lock hash table chain
1214 idx = (uint)(page_no >> bt->mgr->seg_bits) % bt->mgr->hashsize;
1215 bt_spinreadlock (&bt->mgr->latch[idx]);
1217 // look up in hash table
1219 if( pool = bt_findpool(bt, page_no, idx) ) {
1221 __sync_fetch_and_add(&pool->pin, 1);
1223 _InterlockedIncrement16 (&pool->pin);
1225 bt_spinreleaseread (&bt->mgr->latch[idx]);
1230 // upgrade to write lock
1232 bt_spinreleaseread (&bt->mgr->latch[idx]);
1233 bt_spinwritelock (&bt->mgr->latch[idx]);
1235 // try to find page in pool with write lock
1237 if( pool = bt_findpool(bt, page_no, idx) ) {
1239 __sync_fetch_and_add(&pool->pin, 1);
1241 _InterlockedIncrement16 (&pool->pin);
1243 bt_spinreleasewrite (&bt->mgr->latch[idx]);
1248 // allocate a new pool node
1249 // and add to hash table
1252 slot = __sync_fetch_and_add(&bt->mgr->poolcnt, 1);
1254 slot = _InterlockedIncrement16 (&bt->mgr->poolcnt) - 1;
1257 if( ++slot < bt->mgr->poolmax ) {
1258 pool = bt->mgr->pool + slot;
1261 if( bt_mapsegment(bt, pool, page_no) )
1264 bt_linkhash(bt, pool, page_no, idx);
1266 __sync_fetch_and_add(&pool->pin, 1);
1268 _InterlockedIncrement16 (&pool->pin);
1270 bt_spinreleasewrite (&bt->mgr->latch[idx]);
1274 // pool table is full
1275 // find best pool entry to evict
1278 __sync_fetch_and_add(&bt->mgr->poolcnt, -1);
1280 _InterlockedDecrement16 (&bt->mgr->poolcnt);
1285 victim = __sync_fetch_and_add(&bt->mgr->evicted, 1);
1287 victim = _InterlockedIncrement (&bt->mgr->evicted) - 1;
1289 victim %= bt->mgr->hashsize;
1291 // try to get write lock
1292 // skip entry if not obtained
1294 if( !bt_spinwritetry (&bt->mgr->latch[victim]) )
1297 // if pool entry is empty
1298 // or any pages are pinned
1301 if( !(pool = bt_findlru(bt, bt->mgr->hash[victim])) ) {
1302 bt_spinreleasewrite (&bt->mgr->latch[victim]);
1306 // unlink victim pool node from hash table
1308 if( node = pool->hashprev )
1309 node->hashnext = pool->hashnext;
1310 else if( node = pool->hashnext )
1311 bt->mgr->hash[victim] = node->slot;
1313 bt->mgr->hash[victim] = 0;
1315 if( node = pool->hashnext )
1316 node->hashprev = pool->hashprev;
1318 bt_spinreleasewrite (&bt->mgr->latch[victim]);
1320 // remove old file mapping
1322 munmap (pool->map, (bt->mgr->poolmask+1) << bt->mgr->page_bits);
1324 FlushViewOfFile(pool->map, 0);
1325 UnmapViewOfFile(pool->map);
1326 CloseHandle(pool->hmap);
1330 // create new pool mapping
1331 // and link into hash table
1333 if( bt_mapsegment(bt, pool, page_no) )
1336 bt_linkhash(bt, pool, page_no, idx);
1338 __sync_fetch_and_add(&pool->pin, 1);
1340 _InterlockedIncrement16 (&pool->pin);
1342 bt_spinreleasewrite (&bt->mgr->latch[idx]);
1347 // place write, read, or parent lock on requested page_no.
1349 void bt_lockpage(BtLock mode, BtLatchSet *set)
1353 bt_readlock (set->readwr);
1356 bt_writelock (set->readwr);
1359 bt_readlock (set->access);
1362 bt_writelock (set->access);
1365 bt_writelock (set->parent);
1370 // remove write, read, or parent lock on requested page
1372 void bt_unlockpage(BtLock mode, BtLatchSet *set)
1376 bt_releaseread (set->readwr);
1379 bt_releasewrite (set->readwr);
1382 bt_releaseread (set->access);
1385 bt_releasewrite (set->access);
1388 bt_releasewrite (set->parent);
1393 // allocate a new page and write page into it
1395 uid bt_newpage(BtDb *bt, BtPage page)
1401 // lock allocation page
1403 bt_spinwritelock(bt->mgr->latchmgr->lock);
1405 // use empty chain first
1406 // else allocate empty page
1408 if( new_page = bt_getid(bt->mgr->latchmgr->alloc[1].right) ) {
1409 if( set->pool = bt_pinpool (bt, new_page) )
1410 set->page = bt_page (bt, set->pool, new_page);
1414 bt_putid(bt->mgr->latchmgr->alloc[1].right, bt_getid(set->page->right));
1415 bt_unpinpool (set->pool);
1418 new_page = bt_getid(bt->mgr->latchmgr->alloc->right);
1419 bt_putid(bt->mgr->latchmgr->alloc->right, new_page+1);
1423 if ( pwrite(bt->mgr->idx, page, bt->mgr->page_size, new_page << bt->mgr->page_bits) < bt->mgr->page_size )
1424 return bt->err = BTERR_wrt, 0;
1426 // if writing first page of pool block, zero last page in the block
1428 if ( !reuse && bt->mgr->poolmask > 0 && (new_page & bt->mgr->poolmask) == 0 )
1430 // use zero buffer to write zeros
1431 if ( pwrite(bt->mgr->idx,bt->zero, bt->mgr->page_size, (new_page | bt->mgr->poolmask) << bt->mgr->page_bits) < bt->mgr->page_size )
1432 return bt->err = BTERR_wrt, 0;
1435 // bring new page into pool and copy page.
1436 // this will extend the file into the new pages.
1438 if( set->pool = bt_pinpool (bt, new_page) )
1439 set->page = bt_page (bt, set->pool, new_page);
1443 memcpy(set->page, page, bt->mgr->page_size);
1444 bt_unpinpool (set->pool);
1446 // unlock allocation latch and return new page no
1448 bt_spinreleasewrite(bt->mgr->latchmgr->lock);
1452 // find slot in page for given key at a given level
1454 int bt_findslot (BtPageSet *set, unsigned char *key, uint len)
1456 uint diff, higher = set->page->cnt, low = 1, slot;
1459 // make stopper key an infinite fence value
1461 if( bt_getid (set->page->right) )
1466 // low is the lowest candidate.
1467 // loop ends when they meet
1469 // higher is already
1470 // tested as .ge. the passed key.
1472 while( diff = higher - low ) {
1473 slot = low + ( diff >> 1 );
1474 if( keycmp (keyptr(set->page, slot), key, len) < 0 )
1477 higher = slot, good++;
1480 // return zero if key is on right link page
1482 return good ? higher : 0;
1485 // find and load page at given level for given key
1486 // leave page rd or wr locked as requested
1488 int bt_loadpage (BtDb *bt, BtPageSet *set, unsigned char *key, uint len, uint lvl, BtLock lock)
1490 uid page_no = ROOT_page, prevpage = 0;
1491 uint drill = 0xff, slot;
1492 BtLatchSet *prevlatch;
1493 uint mode, prevmode;
1496 // start at root of btree and drill down
1499 // determine lock mode of drill level
1500 mode = (drill == lvl) ? lock : BtLockRead;
1502 set->latch = bt_pinlatch (bt, page_no);
1503 set->page_no = page_no;
1505 // pin page contents
1507 if( set->pool = bt_pinpool (bt, page_no) )
1508 set->page = bt_page (bt, set->pool, page_no);
1512 // obtain access lock using lock chaining with Access mode
1514 if( page_no > ROOT_page )
1515 bt_lockpage(BtLockAccess, set->latch);
1517 // release & unpin parent page
1520 bt_unlockpage(prevmode, prevlatch);
1521 bt_unpinlatch (prevlatch);
1522 bt_unpinpool (prevpool);
1526 // obtain read lock using lock chaining
1528 bt_lockpage(mode, set->latch);
1530 if( set->page->free )
1531 return bt->err = BTERR_struct, 0;
1533 if( page_no > ROOT_page )
1534 bt_unlockpage(BtLockAccess, set->latch);
1536 // re-read and re-lock root after determining actual level of root
1538 if( set->page->lvl != drill) {
1539 if ( set->page_no != ROOT_page )
1540 return bt->err = BTERR_struct, 0;
1542 drill = set->page->lvl;
1544 if( lock != BtLockRead && drill == lvl ) {
1545 bt_unlockpage(mode, set->latch);
1546 bt_unpinlatch (set->latch);
1547 bt_unpinpool (set->pool);
1552 prevpage = set->page_no;
1553 prevlatch = set->latch;
1554 prevpool = set->pool;
1557 // find key on page at this level
1558 // and descend to requested level
1560 if( !set->page->kill )
1561 if( slot = bt_findslot (set, key, len) ) {
1565 while( slotptr(set->page, slot)->dead )
1566 if( slot++ < set->page->cnt )
1571 page_no = bt_getid(slotptr(set->page, slot)->id);
1576 // or slide right into next page
1579 page_no = bt_getid(set->page->right);
1583 // return error on end of right chain
1585 bt->err = BTERR_struct;
1586 return 0; // return error
1589 // return page to free list
1590 // page must be delete & write locked
1592 void bt_freepage (BtDb *bt, BtPageSet *set)
1594 // lock allocation page
1596 bt_spinwritelock (bt->mgr->latchmgr->lock);
1598 // store chain in second right
1599 bt_putid(set->page->right, bt_getid(bt->mgr->latchmgr->alloc[1].right));
1600 bt_putid(bt->mgr->latchmgr->alloc[1].right, set->page_no);
1601 set->page->free = 1;
1603 // unlock released page
1605 bt_unlockpage (BtLockDelete, set->latch);
1606 bt_unlockpage (BtLockWrite, set->latch);
1607 bt_unpinlatch (set->latch);
1608 bt_unpinpool (set->pool);
1610 // unlock allocation page
1612 bt_spinreleasewrite (bt->mgr->latchmgr->lock);
1615 // a fence key was deleted from a page
1616 // push new fence value upwards
1618 BTERR bt_fixfence (BtDb *bt, BtPageSet *set, uint lvl)
1620 unsigned char leftkey[256], rightkey[256];
1624 // remove the old fence value
1626 ptr = keyptr(set->page, set->page->cnt);
1627 memcpy (rightkey, ptr, ptr->len + 1);
1629 memset (slotptr(set->page, set->page->cnt--), 0, sizeof(BtSlot));
1630 set->page->dirty = 1;
1632 ptr = keyptr(set->page, set->page->cnt);
1633 memcpy (leftkey, ptr, ptr->len + 1);
1634 page_no = set->page_no;
1636 bt_lockpage (BtLockParent, set->latch);
1637 bt_unlockpage (BtLockWrite, set->latch);
1639 // insert new (now smaller) fence key
1641 if( bt_insertkey (bt, leftkey+1, *leftkey, lvl+1, page_no, time(NULL)) )
1644 // now delete old fence key
1646 if( bt_deletekey (bt, rightkey+1, *rightkey, lvl+1) )
1649 bt_unlockpage (BtLockParent, set->latch);
1650 bt_unpinlatch(set->latch);
1651 bt_unpinpool (set->pool);
1655 // root has a single child
1656 // collapse a level from the tree
1658 BTERR bt_collapseroot (BtDb *bt, BtPageSet *root)
1663 // find the child entry and promote as new root contents
1666 for( idx = 0; idx++ < root->page->cnt; )
1667 if( !slotptr(root->page, idx)->dead )
1670 child->page_no = bt_getid (slotptr(root->page, idx)->id);
1672 child->latch = bt_pinlatch (bt, child->page_no);
1673 bt_lockpage (BtLockDelete, child->latch);
1674 bt_lockpage (BtLockWrite, child->latch);
1676 if( child->pool = bt_pinpool (bt, child->page_no) )
1677 child->page = bt_page (bt, child->pool, child->page_no);
1681 memcpy (root->page, child->page, bt->mgr->page_size);
1682 bt_freepage (bt, child);
1684 } while( root->page->lvl > 1 && root->page->act == 1 );
1686 bt_unlockpage (BtLockWrite, root->latch);
1687 bt_unpinlatch (root->latch);
1688 bt_unpinpool (root->pool);
1692 // find and delete key on page by marking delete flag bit
1693 // if page becomes empty, delete it from the btree
1695 BTERR bt_deletekey (BtDb *bt, unsigned char *key, uint len, uint lvl)
1697 unsigned char lowerfence[256], higherfence[256];
1698 uint slot, idx, dirty = 0, fence, found;
1699 BtPageSet set[1], right[1];
1702 if( slot = bt_loadpage (bt, set, key, len, lvl, BtLockWrite) )
1703 ptr = keyptr(set->page, slot);
1707 // are we deleting a fence slot?
1709 fence = slot == set->page->cnt;
1711 // if key is found delete it, otherwise ignore request
1713 if( found = !keycmp (ptr, key, len) )
1714 if( found = slotptr(set->page, slot)->dead == 0 ) {
1715 dirty = slotptr(set->page, slot)->dead = 1;
1716 set->page->dirty = 1;
1719 // collapse empty slots
1721 while( idx = set->page->cnt - 1 )
1722 if( slotptr(set->page, idx)->dead ) {
1723 *slotptr(set->page, idx) = *slotptr(set->page, idx + 1);
1724 memset (slotptr(set->page, set->page->cnt--), 0, sizeof(BtSlot));
1729 // did we delete a fence key in an upper level?
1731 if( dirty && lvl && set->page->act && fence )
1732 if( bt_fixfence (bt, set, lvl) )
1735 return bt->found = found, 0;
1737 // is this a collapsed root?
1739 if( lvl > 1 && set->page_no == ROOT_page && set->page->act == 1 )
1740 if( bt_collapseroot (bt, set) )
1743 return bt->found = found, 0;
1745 // return if page is not empty
1747 if( set->page->act ) {
1748 bt_unlockpage(BtLockWrite, set->latch);
1749 bt_unpinlatch (set->latch);
1750 bt_unpinpool (set->pool);
1751 return bt->found = found, 0;
1754 // cache copy of fence key
1755 // to post in parent
1757 ptr = keyptr(set->page, set->page->cnt);
1758 memcpy (lowerfence, ptr, ptr->len + 1);
1760 // obtain lock on right page
1762 right->page_no = bt_getid(set->page->right);
1763 right->latch = bt_pinlatch (bt, right->page_no);
1764 bt_lockpage (BtLockWrite, right->latch);
1766 // pin page contents
1768 if( right->pool = bt_pinpool (bt, right->page_no) )
1769 right->page = bt_page (bt, right->pool, right->page_no);
1773 if( right->page->kill )
1774 return bt->err = BTERR_struct;
1776 // pull contents of right peer into our empty page
1778 memcpy (set->page, right->page, bt->mgr->page_size);
1780 // cache copy of key to update
1782 ptr = keyptr(right->page, right->page->cnt);
1783 memcpy (higherfence, ptr, ptr->len + 1);
1785 // mark right page deleted and point it to left page
1786 // until we can post parent updates
1788 bt_putid (right->page->right, set->page_no);
1789 right->page->kill = 1;
1791 bt_lockpage (BtLockParent, right->latch);
1792 bt_unlockpage (BtLockWrite, right->latch);
1794 bt_lockpage (BtLockParent, set->latch);
1795 bt_unlockpage (BtLockWrite, set->latch);
1797 // redirect higher key directly to our new node contents
1799 if( bt_insertkey (bt, higherfence+1, *higherfence, lvl+1, set->page_no, time(NULL)) )
1802 // delete old lower key to our node
1804 if( bt_deletekey (bt, lowerfence+1, *lowerfence, lvl+1) )
1807 // obtain delete and write locks to right node
1809 bt_unlockpage (BtLockParent, right->latch);
1810 bt_lockpage (BtLockDelete, right->latch);
1811 bt_lockpage (BtLockWrite, right->latch);
1812 bt_freepage (bt, right);
1814 bt_unlockpage (BtLockParent, set->latch);
1815 bt_unpinlatch (set->latch);
1816 bt_unpinpool (set->pool);
1821 // find key in leaf level and return row-id
1823 uid bt_findkey (BtDb *bt, unsigned char *key, uint len)
1830 if( slot = bt_loadpage (bt, set, key, len, 0, BtLockRead) )
1831 ptr = keyptr(set->page, slot);
1835 // if key exists, return row-id
1836 // otherwise return 0
1838 if( slot <= set->page->cnt )
1839 if( !keycmp (ptr, key, len) )
1840 id = bt_getid(slotptr(set->page,slot)->id);
1842 bt_unlockpage (BtLockRead, set->latch);
1843 bt_unpinlatch (set->latch);
1844 bt_unpinpool (set->pool);
1848 // check page for space available,
1849 // clean if necessary and return
1850 // 0 - page needs splitting
1851 // >0 new slot value
1853 uint bt_cleanpage(BtDb *bt, BtPage page, uint amt, uint slot)
1855 uint nxt = bt->mgr->page_size;
1856 uint cnt = 0, idx = 0;
1857 uint max = page->cnt;
1861 if( page->min >= (max+1) * sizeof(BtSlot) + sizeof(*page) + amt + 1 )
1864 // skip cleanup if nothing to reclaim
1869 memcpy (bt->frame, page, bt->mgr->page_size);
1871 // skip page info and set rest of page to zero
1873 memset (page+1, 0, bt->mgr->page_size - sizeof(*page));
1877 // try cleaning up page first
1878 // by removing deleted keys
1880 while( cnt++ < max ) {
1883 if( cnt < max && slotptr(bt->frame,cnt)->dead )
1886 // copy the key across
1888 key = keyptr(bt->frame, cnt);
1889 nxt -= key->len + 1;
1890 memcpy ((unsigned char *)page + nxt, key, key->len + 1);
1894 memcpy(slotptr(page, ++idx)->id, slotptr(bt->frame, cnt)->id, BtId);
1895 if( !(slotptr(page, idx)->dead = slotptr(bt->frame, cnt)->dead) )
1897 slotptr(page, idx)->tod = slotptr(bt->frame, cnt)->tod;
1898 slotptr(page, idx)->off = nxt;
1904 // see if page has enough space now, or does it need splitting?
1906 if( page->min >= (idx+1) * sizeof(BtSlot) + sizeof(*page) + amt + 1 )
1912 // split the root and raise the height of the btree
1914 BTERR bt_splitroot(BtDb *bt, BtPageSet *root, unsigned char *leftkey, uid page_no2)
1916 uint nxt = bt->mgr->page_size;
1919 // Obtain an empty page to use, and copy the current
1920 // root contents into it, e.g. lower keys
1922 if( !(left = bt_newpage(bt, root->page)) )
1925 // preserve the page info at the bottom
1926 // of higher keys and set rest to zero
1928 memset(root->page+1, 0, bt->mgr->page_size - sizeof(*root->page));
1930 // insert lower keys page fence key on newroot page as first key
1932 nxt -= *leftkey + 1;
1933 memcpy ((unsigned char *)root->page + nxt, leftkey, *leftkey + 1);
1934 bt_putid(slotptr(root->page, 1)->id, left);
1935 slotptr(root->page, 1)->off = nxt;
1937 // insert stopper key on newroot page
1938 // and increase the root height
1941 ((unsigned char *)root->page)[nxt] = 2;
1942 ((unsigned char *)root->page)[nxt+1] = 0xff;
1943 ((unsigned char *)root->page)[nxt+2] = 0xff;
1944 bt_putid(slotptr(root->page, 2)->id, page_no2);
1945 slotptr(root->page, 2)->off = nxt;
1947 bt_putid(root->page->right, 0);
1948 root->page->min = nxt; // reset lowest used offset and key count
1949 root->page->cnt = 2;
1950 root->page->act = 2;
1953 // release and unpin root
1955 bt_unlockpage(BtLockWrite, root->latch);
1956 bt_unpinlatch (root->latch);
1957 bt_unpinpool (root->pool);
1961 // split already locked full node
1964 BTERR bt_splitpage (BtDb *bt, BtPageSet *set)
1966 uint cnt = 0, idx = 0, max, nxt = bt->mgr->page_size;
1967 unsigned char fencekey[256];
1968 uint lvl = set->page->lvl;
1973 // split higher half of keys to bt->frame
1975 memset (bt->frame, 0, bt->mgr->page_size);
1976 max = set->page->cnt;
1980 while( cnt++ < max ) {
1981 key = keyptr(set->page, cnt);
1982 nxt -= key->len + 1;
1983 memcpy ((unsigned char *)bt->frame + nxt, key, key->len + 1);
1985 memcpy(slotptr(bt->frame,++idx)->id, slotptr(set->page,cnt)->id, BtId);
1986 if( !(slotptr(bt->frame, idx)->dead = slotptr(set->page, cnt)->dead) )
1988 slotptr(bt->frame, idx)->tod = slotptr(set->page, cnt)->tod;
1989 slotptr(bt->frame, idx)->off = nxt;
1992 bt->frame->bits = bt->mgr->page_bits;
1993 bt->frame->min = nxt;
1994 bt->frame->cnt = idx;
1995 bt->frame->lvl = lvl;
1999 if( set->page_no > ROOT_page )
2000 memcpy (bt->frame->right, set->page->right, BtId);
2002 // get new free page and write higher keys to it.
2004 if( !(right = bt_newpage(bt, bt->frame)) )
2007 // update lower keys to continue in old page
2009 memcpy (bt->frame, set->page, bt->mgr->page_size);
2010 memset (set->page+1, 0, bt->mgr->page_size - sizeof(*set->page));
2011 nxt = bt->mgr->page_size;
2012 set->page->posted = 0;
2013 set->page->dirty = 0;
2018 // assemble page of smaller keys
2020 while( cnt++ < max / 2 ) {
2021 key = keyptr(bt->frame, cnt);
2022 nxt -= key->len + 1;
2023 memcpy ((unsigned char *)set->page + nxt, key, key->len + 1);
2024 memcpy(slotptr(set->page,++idx)->id, slotptr(bt->frame,cnt)->id, BtId);
2025 slotptr(set->page, idx)->tod = slotptr(bt->frame, cnt)->tod;
2026 slotptr(set->page, idx)->off = nxt;
2030 // remember fence key for smaller page
2032 memcpy(fencekey, key, key->len + 1);
2033 bt_putid(set->page->right, right);
2034 set->page->min = nxt;
2035 set->page->cnt = idx;
2037 // if current page is the root page, split it
2039 if( set->page_no == ROOT_page )
2040 return bt_splitroot (bt, set, fencekey, right);
2044 // insert new fences in their parent pages
2047 bt_lockpage (BtLockParent, set->latch);
2049 key = keyptr (set->page, set->page->cnt);
2050 memcpy (fencekey, key, key->len + 1);
2051 prev = set->page->posted;
2053 if( right && prev ) {
2054 bt_unlockpage (BtLockParent, set->latch);
2055 bt_unlockpage (BtLockWrite, set->latch);
2056 bt_unpinlatch (set->latch);
2057 bt_unpinpool (set->pool);
2061 right = bt_getid (set->page->right);
2062 set->page->posted = 1;
2064 bt_unlockpage (BtLockWrite, set->latch);
2066 // insert new fence for reformulated left block of smaller keys
2069 if( bt_insertkey (bt, fencekey+1, *fencekey, lvl+1, set->page_no, time(NULL)) )
2072 bt_unlockpage (BtLockParent, set->latch);
2073 bt_unpinlatch (set->latch);
2074 bt_unpinpool (set->pool);
2076 if( !(set->page_no = right) )
2079 set->latch = bt_pinlatch (bt, right);
2081 if( set->pool = bt_pinpool (bt, right) )
2082 set->page = bt_page (bt, set->pool, right);
2086 bt_lockpage (BtLockWrite, set->latch);
2092 // Insert new key into the btree at given level.
2094 BTERR bt_insertkey (BtDb *bt, unsigned char *key, uint len, uint lvl, uid id, uint tod)
2101 if( slot = bt_loadpage (bt, set, key, len, lvl, BtLockWrite) )
2102 ptr = keyptr(set->page, slot);
2106 bt->err = BTERR_ovflw;
2110 // if key already exists, update id and return
2112 if( !keycmp (ptr, key, len) ) {
2113 if( slotptr(set->page, slot)->dead )
2115 slotptr(set->page, slot)->dead = 0;
2116 slotptr(set->page, slot)->tod = tod;
2117 bt_putid(slotptr(set->page,slot)->id, id);
2118 bt_unlockpage(BtLockWrite, set->latch);
2119 bt_unpinlatch (set->latch);
2120 bt_unpinpool (set->pool);
2124 // check if page has enough space
2126 if( slot = bt_cleanpage (bt, set->page, len, slot) )
2129 if( bt_splitpage (bt, set) )
2133 // calculate next available slot and copy key into page
2135 set->page->min -= len + 1; // reset lowest used offset
2136 ((unsigned char *)set->page)[set->page->min] = len;
2137 memcpy ((unsigned char *)set->page + set->page->min +1, key, len );
2139 for( idx = slot; idx < set->page->cnt; idx++ )
2140 if( slotptr(set->page, idx)->dead )
2143 // now insert key into array before slot
2145 if( idx == set->page->cnt )
2146 idx++, set->page->cnt++;
2151 *slotptr(set->page, idx) = *slotptr(set->page, idx -1), idx--;
2153 bt_putid(slotptr(set->page,slot)->id, id);
2154 slotptr(set->page, slot)->off = set->page->min;
2155 slotptr(set->page, slot)->tod = tod;
2156 slotptr(set->page, slot)->dead = 0;
2158 bt_unlockpage (BtLockWrite, set->latch);
2159 bt_unpinlatch (set->latch);
2160 bt_unpinpool (set->pool);
2164 // cache page of keys into cursor and return starting slot for given key
2166 uint bt_startkey (BtDb *bt, unsigned char *key, uint len)
2171 // cache page for retrieval
2173 if( slot = bt_loadpage (bt, set, key, len, 0, BtLockRead) )
2174 memcpy (bt->cursor, set->page, bt->mgr->page_size);
2178 bt->cursor_page = set->page_no;
2180 bt_unlockpage(BtLockRead, set->latch);
2181 bt_unpinlatch (set->latch);
2182 bt_unpinpool (set->pool);
2186 // return next slot for cursor page
2187 // or slide cursor right into next page
2189 uint bt_nextkey (BtDb *bt, uint slot)
2195 right = bt_getid(bt->cursor->right);
2197 while( slot++ < bt->cursor->cnt )
2198 if( slotptr(bt->cursor,slot)->dead )
2200 else if( right || (slot < bt->cursor->cnt) ) // skip infinite stopper
2208 bt->cursor_page = right;
2210 if( set->pool = bt_pinpool (bt, right) )
2211 set->page = bt_page (bt, set->pool, right);
2215 set->latch = bt_pinlatch (bt, right);
2216 bt_lockpage(BtLockRead, set->latch);
2218 memcpy (bt->cursor, set->page, bt->mgr->page_size);
2220 bt_unlockpage(BtLockRead, set->latch);
2221 bt_unpinlatch (set->latch);
2222 bt_unpinpool (set->pool);
2230 BtKey bt_key(BtDb *bt, uint slot)
2232 return keyptr(bt->cursor, slot);
2235 uid bt_uid(BtDb *bt, uint slot)
2237 return bt_getid(slotptr(bt->cursor,slot)->id);
2240 uint bt_tod(BtDb *bt, uint slot)
2242 return slotptr(bt->cursor,slot)->tod;
2248 void bt_latchaudit (BtDb *bt)
2250 ushort idx, hashidx;
2256 for( idx = 1; idx < bt->mgr->latchmgr->latchdeployed; idx++ ) {
2257 set->latch = bt->mgr->latchsets + idx;
2258 if( set->latch->pin ) {
2259 fprintf(stderr, "latchset %d pinned for page %.6x\n", idx, set->latch->page_no);
2260 set->latch->pin = 0;
2264 for( hashidx = 0; hashidx < bt->mgr->latchmgr->latchhash; hashidx++ ) {
2265 if( idx = bt->mgr->latchmgr->table[hashidx].slot ) do {
2266 set->latch = bt->mgr->latchsets + idx;
2267 if( set->latch->hash != hashidx )
2268 fprintf(stderr, "latchset %d wrong hashidx\n", idx);
2269 if( set->latch->pin )
2270 fprintf(stderr, "latchset %d pinned for page %.8x\n", idx, set->latch->page_no);
2271 } while( idx = set->latch->next );
2274 next = bt->mgr->latchmgr->nlatchpage + LATCH_page;
2275 page_no = LEAF_page;
2277 while( page_no < bt_getid(bt->mgr->latchmgr->alloc->right) ) {
2278 pread (bt->mgr->idx, bt->frame, bt->mgr->page_size, page_no << bt->mgr->page_bits);
2279 if( !bt->frame->free )
2280 for( idx = 0; idx++ < bt->frame->cnt - 1; ) {
2281 ptr = keyptr(bt->frame, idx+1);
2282 if( keycmp (keyptr(bt->frame, idx), ptr->key, ptr->len) >= 0 )
2283 fprintf(stderr, "page %.8x idx %.2x out of order\n", page_no, idx);
2286 if( page_no > LEAF_page )
2300 // standalone program to index file of keys
2301 // then list them onto std-out
2304 void *index_file (void *arg)
2306 uint __stdcall index_file (void *arg)
2309 int line = 0, found = 0, cnt = 0;
2310 uid next, page_no = LEAF_page; // start on first page of leaves
2311 unsigned char key[256];
2312 ThreadArg *args = arg;
2313 int ch, len = 0, slot;
2320 bt = bt_open (args->mgr);
2323 switch(args->type | 0x20)
2326 fprintf(stderr, "started latch mgr audit\n");
2328 fprintf(stderr, "finished latch mgr audit\n");
2332 fprintf(stderr, "started indexing for %s\n", args->infile);
2333 if( in = fopen (args->infile, "rb") )
2334 while( ch = getc(in), ch != EOF )
2339 if( args->num == 1 )
2340 sprintf((char *)key+len, "%.9d", 1000000000 - line), len += 9;
2342 else if( args->num )
2343 sprintf((char *)key+len, "%.9d", line + args->idx * args->num), len += 9;
2345 if( bt_insertkey (bt, key, len, 0, line, *tod) )
2346 fprintf(stderr, "Error %d Line: %d\n", bt->err, line), exit(0);
2349 else if( len < 255 )
2351 fprintf(stderr, "finished %s for %d keys\n", args->infile, line);
2355 fprintf(stderr, "started deleting keys for %s\n", args->infile);
2356 if( in = fopen (args->infile, "rb") )
2357 while( ch = getc(in), ch != EOF )
2361 if( args->num == 1 )
2362 sprintf((char *)key+len, "%.9d", 1000000000 - line), len += 9;
2364 else if( args->num )
2365 sprintf((char *)key+len, "%.9d", line + args->idx * args->num), len += 9;
2367 if( bt_deletekey (bt, key, len, 0) )
2368 fprintf(stderr, "Error %d Line: %d\n", bt->err, line), exit(0);
2371 else if( len < 255 )
2373 fprintf(stderr, "finished %s for keys, %d \n", args->infile, line);
2377 fprintf(stderr, "started finding keys for %s\n", args->infile);
2378 if( in = fopen (args->infile, "rb") )
2379 while( ch = getc(in), ch != EOF )
2383 if( args->num == 1 )
2384 sprintf((char *)key+len, "%.9d", 1000000000 - line), len += 9;
2386 else if( args->num )
2387 sprintf((char *)key+len, "%.9d", line + args->idx * args->num), len += 9;
2389 if( bt_findkey (bt, key, len) )
2392 fprintf(stderr, "Error %d Syserr %d Line: %d\n", bt->err, errno, line), exit(0);
2394 fprintf(stderr, "Unable to find key %.*s line %d\n", len, key, line);
2397 else if( len < 255 )
2399 fprintf(stderr, "finished %s for %d keys, found %d\n", args->infile, line, found);
2403 fprintf(stderr, "started scanning\n");
2405 if( set->pool = bt_pinpool (bt, page_no) )
2406 set->page = bt_page (bt, set->pool, page_no);
2409 set->latch = bt_pinlatch (bt, page_no);
2410 bt_lockpage (BtLockRead, set->latch);
2411 next = bt_getid (set->page->right);
2412 cnt += set->page->act;
2414 for( slot = 0; slot++ < set->page->cnt; )
2415 if( next || slot < set->page->cnt )
2416 if( !slotptr(set->page, slot)->dead ) {
2417 ptr = keyptr(set->page, slot);
2418 fwrite (ptr->key, ptr->len, 1, stdout);
2419 fputc ('\n', stdout);
2422 bt_unlockpage (BtLockRead, set->latch);
2423 bt_unpinlatch (set->latch);
2424 bt_unpinpool (set->pool);
2425 } while( page_no = next );
2427 cnt--; // remove stopper key
2428 fprintf(stderr, " Total keys read %d\n", cnt);
2432 fprintf(stderr, "started counting\n");
2433 next = bt->mgr->latchmgr->nlatchpage + LATCH_page;
2434 page_no = LEAF_page;
2436 while( page_no < bt_getid(bt->mgr->latchmgr->alloc->right) ) {
2437 uid off = page_no << bt->mgr->page_bits;
2439 pread (bt->mgr->idx, bt->frame, bt->mgr->page_size, off);
2443 SetFilePointer (bt->mgr->idx, (long)off, (long*)(&off)+1, FILE_BEGIN);
2445 if( !ReadFile(bt->mgr->idx, bt->frame, bt->mgr->page_size, amt, NULL))
2446 return bt->err = BTERR_map;
2448 if( *amt < bt->mgr->page_size )
2449 return bt->err = BTERR_map;
2451 if( !bt->frame->free && !bt->frame->lvl )
2452 cnt += bt->frame->act;
2453 if( page_no > LEAF_page )
2458 cnt--; // remove stopper key
2459 fprintf(stderr, " Total keys read %d\n", cnt);
2471 typedef struct timeval timer;
2473 int main (int argc, char **argv)
2475 int idx, cnt, len, slot, err;
2476 int segsize, bits = 16;
2481 time_t start[1], stop[1];
2494 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]);
2495 fprintf (stderr, " where page_bits is the page size in bits\n");
2496 fprintf (stderr, " mapped_segments is the number of mmap segments in buffer pool\n");
2497 fprintf (stderr, " seg_bits is the size of individual segments in buffer pool in pages in bits\n");
2498 fprintf (stderr, " line_numbers = 1 to append line numbers to keys\n");
2499 fprintf (stderr, " src_file1 thru src_filen are files of keys separated by newline\n");
2504 gettimeofday(&start, NULL);
2510 bits = atoi(argv[3]);
2513 poolsize = atoi(argv[4]);
2516 fprintf (stderr, "Warning: no mapped_pool\n");
2518 if( poolsize > 65535 )
2519 fprintf (stderr, "Warning: mapped_pool > 65535 segments\n");
2522 segsize = atoi(argv[5]);
2524 segsize = 4; // 16 pages per mmap segment
2527 num = atoi(argv[6]);
2531 threads = malloc (cnt * sizeof(pthread_t));
2533 threads = GlobalAlloc (GMEM_FIXED|GMEM_ZEROINIT, cnt * sizeof(HANDLE));
2535 args = malloc (cnt * sizeof(ThreadArg));
2537 mgr = bt_mgr ((argv[1]), BT_rw, bits, poolsize, segsize, poolsize / 8);
2540 fprintf(stderr, "Index Open Error %s\n", argv[1]);
2546 for( idx = 0; idx < cnt; idx++ ) {
2547 args[idx].infile = argv[idx + 7];
2548 args[idx].type = argv[2][0];
2549 args[idx].mgr = mgr;
2550 args[idx].num = num;
2551 args[idx].idx = idx;
2553 if( err = pthread_create (threads + idx, NULL, index_file, args + idx) )
2554 fprintf(stderr, "Error creating thread %d\n", err);
2556 threads[idx] = (HANDLE)_beginthreadex(NULL, 65536, index_file, args + idx, 0, NULL);
2560 // wait for termination
2563 for( idx = 0; idx < cnt; idx++ )
2564 pthread_join (threads[idx], NULL);
2565 gettimeofday(&stop, NULL);
2566 real_time = 1000.0 * ( stop.tv_sec - start.tv_sec ) + 0.001 * (stop.tv_usec - start.tv_usec );
2568 WaitForMultipleObjects (cnt, threads, TRUE, INFINITE);
2570 for( idx = 0; idx < cnt; idx++ )
2571 CloseHandle(threads[idx]);
2574 real_time = 1000 * (*stop - *start);
2576 fprintf(stderr, " Time to complete: %.2f seconds\n", real_time/1000);