X-Git-Url: https://pd.if.org/git/?a=blobdiff_plain;f=fosterbtreef.c;h=e4592d2d2611a5911fa4006ba67c0532d41db766;hb=0c15ab64c54d597779331be5002e2e0ba839a749;hp=2b3eecbfb16535fba9f888fe9894f888f836e3fb;hpb=48501624b8372fa9c781c6f89f41b58d91338bb8;p=btree

diff --git a/fosterbtreef.c b/fosterbtreef.c
index 2b3eecb..e4592d2 100644
--- a/fosterbtreef.c
+++ b/fosterbtreef.c
@@ -1,5 +1,5 @@
-// foster btree version f
-// 30 DEC 2013
+// foster btree version f2
+// 18 JAN 2014
 
 // author: karl malbrain, malbrain@cal.berkeley.edu
 
@@ -121,18 +121,17 @@ typedef struct {
 //	by the BtSlot array of keys.
 
 typedef struct Page {
-	uint cnt;					// count of keys in page
-	uint act;					// count of active keys
-	uint min;					// next key offset
-	uint foster;				// count of foster children
+	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:6;		// level of page
-	unsigned char kill:1;		// page is being deleted
+	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 spin latch implementation
+//	mode & definition for hash latch implementation
 
 enum {
 	Mutex = 1,
@@ -159,10 +158,12 @@ typedef struct {
 	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 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
@@ -214,29 +215,31 @@ typedef struct {
 #endif
 	ushort poolcnt;				// highest page pool node in use
 	ushort poolmax;				// highest page pool node allocated
-	ushort poolmask;			// total size of pages in mmap segment - 1
+	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 *latchset;		// first mapped latch set from latch pages
+	BtLatchSet *latchsets;		// mapped latch set from latch pages
 #ifndef unix
-	HANDLE halloc;				// allocation and latch table
+	HANDLE halloc;				// allocation and latch table handle
 #endif
 } BtMgr;
 
 typedef struct {
 	BtMgr *mgr;			// buffer manager for thread
-	BtPage temp;		// temporary frame buffer (memory mapped/file IO)
 	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 found;			// last delete was found
 	int err;			// last error
 } BtDb;
 
@@ -254,8 +257,8 @@ typedef enum {
 // 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);
-extern BTERR  bt_deletekey (BtDb *bt, unsigned char *key, uint len, uint lvl);
+extern BTERR  bt_insertkey (BtDb *bt, unsigned char *key, uint len, uid id, uint tod, uint lvl);
+extern BTERR  bt_deletekey (BtDb *bt, unsigned char *key, uint len);
 extern uid bt_findkey    (BtDb *bt, unsigned char *key, uint len);
 extern uint bt_startkey  (BtDb *bt, unsigned char *key, uint len);
 extern uint bt_nextkey   (BtDb *bt, uint slot);
@@ -373,7 +376,6 @@ ushort prev;
 #else
 	_InterlockedAnd16((ushort *)latch, ~Mutex);
 #endif
-
 	if( prev )
 		return;
 #ifdef  unix
@@ -387,8 +389,6 @@ ushort prev;
 
 void bt_spinwritelock(BtSpinLatch *latch)
 {
-ushort prev;
-
   do {
 #ifdef  unix
 	while( __sync_fetch_and_or((ushort *)latch, Mutex | Pending) & Mutex )
@@ -397,23 +397,22 @@ ushort prev;
 	while( _InterlockedOr16((ushort *)latch, Mutex | Pending) & Mutex )
 		SwitchToThread();
 #endif
-	if( prev = !(latch->share | latch->exclusive) )
+	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 | Pending));
-#else
-	_InterlockedAnd16((ushort *)latch, ~(Mutex | Pending));
-#endif
-	if( prev )
-		return;
-#ifdef  unix
+	__sync_fetch_and_and ((ushort *)latch, ~Mutex);
 	sched_yield();
 #else
+	_InterlockedAnd16((ushort *)latch, ~Mutex);
 	SwitchToThread();
 #endif
   } while( 1 );
@@ -478,10 +477,10 @@ void bt_spinreleaseread(BtSpinLatch *latch)
 
 void bt_latchlink (BtDb *bt, ushort hashidx, ushort victim, uid page_no)
 {
-BtLatchSet *set = bt->mgr->latchset + victim;
+BtLatchSet *set = bt->mgr->latchsets + victim;
 
 	if( set->next = bt->mgr->latchmgr->table[hashidx].slot )
-		bt->mgr->latchset[set->next].prev = victim;
+		bt->mgr->latchsets[set->next].prev = victim;
 
 	bt->mgr->latchmgr->table[hashidx].slot = victim;
 	set->page_no = page_no;
@@ -489,10 +488,21 @@ BtLatchSet *set = bt->mgr->latchset + victim;
 	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_bindlatch (BtDb *bt, uid page_no, int incr)
+BtLatchSet *bt_pinlatch (BtDb *bt, uid page_no)
 {
 ushort hashidx = page_no % bt->mgr->latchmgr->latchhash;
 ushort slot, avail = 0, victim, idx;
@@ -504,12 +514,12 @@ BtLatchSet *set;
 
 	if( slot = bt->mgr->latchmgr->table[hashidx].slot ) do
 	{
-		set = bt->mgr->latchset + slot;
+		set = bt->mgr->latchsets + slot;
 		if( page_no == set->page_no )
 			break;
 	} while( slot = set->next );
 
-	if( slot && incr ) {
+	if( slot ) {
 #ifdef unix
 		__sync_fetch_and_add(&set->pin, 1);
 #else
@@ -528,7 +538,7 @@ BtLatchSet *set;
 
   if( slot = bt->mgr->latchmgr->table[hashidx].slot ) do
   {
-	set = bt->mgr->latchset + slot;
+	set = bt->mgr->latchsets + slot;
 	if( page_no == set->page_no )
 		break;
 	if( !set->pin && !avail )
@@ -538,14 +548,12 @@ BtLatchSet *set;
   //  found our entry, or take over an unpinned one
 
   if( slot || (slot = avail) ) {
-	set = bt->mgr->latchset + slot;
-	if( incr ) {
+	set = bt->mgr->latchsets + slot;
 #ifdef unix
-		__sync_fetch_and_add(&set->pin, 1);
+	__sync_fetch_and_add(&set->pin, 1);
 #else
-		_InterlockedIncrement16 (&set->pin);
+	_InterlockedIncrement16 (&set->pin);
 #endif
-	}
 	set->page_no = page_no;
 	bt_spinreleasewrite(bt->mgr->latchmgr->table[hashidx].latch);
 	return set;
@@ -559,7 +567,7 @@ BtLatchSet *set;
 #endif
 
 	if( victim < bt->mgr->latchmgr->latchtotal ) {
-		set = bt->mgr->latchset + victim;
+		set = bt->mgr->latchsets + victim;
 #ifdef unix
 		__sync_fetch_and_add(&set->pin, 1);
 #else
@@ -586,7 +594,7 @@ BtLatchSet *set;
 	//	we don't use slot zero
 
 	if( victim %= bt->mgr->latchmgr->latchtotal )
-		set = bt->mgr->latchset + victim;
+		set = bt->mgr->latchsets + victim;
 	else
 		continue;
 
@@ -616,18 +624,19 @@ BtLatchSet *set;
 	//  unlink our available victim from its hash chain
 
 	if( set->prev )
-		bt->mgr->latchset[set->prev].next = set->next;
+		bt->mgr->latchsets[set->prev].next = set->next;
 	else
 		bt->mgr->latchmgr->table[idx].slot = set->next;
 
 	if( set->next )
-		bt->mgr->latchset[set->next].prev = set->prev;
+		bt->mgr->latchsets[set->next].prev = set->prev;
 
 	bt_spinreleasewrite (bt->mgr->latchmgr->table[idx].latch);
-
-	if( incr )
-		set->pin++;
-
+#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);
@@ -657,6 +666,14 @@ uint slot;
 #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);
@@ -698,7 +715,6 @@ BtMgr *bt_mgr (char *name, uint mode, uint bits, uint poolmax, uint segsize, uin
 uint lvl, attr, cacheblk, last, slot, idx;
 uint nlatchpage, latchhash;
 BtLatchMgr *latchmgr;
-int lockmode;
 off64_t size;
 uint amt[1];
 BtMgr* mgr;
@@ -722,19 +738,8 @@ SYSTEM_INFO sysinfo[1];
 #ifdef unix
 	mgr = calloc (1, sizeof(BtMgr));
 
-	switch (mode & 0x7fff)
-	{
-	case BT_rw:
-		mgr->idx = open ((char*)name, O_RDWR | O_CREAT, 0666);
-		lockmode = 1;
-		break;
+	mgr->idx = open ((char*)name, O_RDWR | O_CREAT, 0666);
 
-	case BT_ro:
-	default:
-		mgr->idx = open ((char*)name, O_RDONLY);
-		lockmode = 0;
-		break;
-	}
 	if( mgr->idx == -1 )
 		return free(mgr), NULL;
 	
@@ -743,19 +748,8 @@ SYSTEM_INFO sysinfo[1];
 #else
 	mgr = GlobalAlloc (GMEM_FIXED|GMEM_ZEROINIT, sizeof(BtMgr));
 	attr = FILE_ATTRIBUTE_NORMAL;
-	switch (mode & 0x7fff)
-	{
-	case BT_rw:
-		mgr->idx = CreateFile(name, GENERIC_READ| GENERIC_WRITE, FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, OPEN_ALWAYS, attr, NULL);
-		lockmode = 1;
-		break;
+	mgr->idx = CreateFile(name, GENERIC_READ| GENERIC_WRITE, FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, OPEN_ALWAYS, attr, NULL);
 
-	case BT_ro:
-	default:
-		mgr->idx = CreateFile(name, GENERIC_READ, FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, OPEN_EXISTING, attr, NULL);
-		lockmode = 0;
-		break;
-	}
 	if( mgr->idx == INVALID_HANDLE_VALUE )
 		return GlobalFree(mgr), NULL;
 
@@ -776,7 +770,7 @@ SYSTEM_INFO sysinfo[1];
 		else
 			return free(mgr), free(latchmgr), NULL;
 	} else if( mode == BT_ro )
-		return bt_mgrclose (mgr), NULL;
+		return free(latchmgr), bt_mgrclose (mgr), NULL;
 #else
 	latchmgr = VirtualAlloc(NULL, BT_maxpage, MEM_COMMIT, PAGE_READWRITE);
 	size = GetFileSize(mgr->idx, amt);
@@ -908,25 +902,25 @@ SYSTEM_INFO sysinfo[1];
 
 mgrlatch:
 #ifdef unix
-	flag = PROT_READ | ( mgr->mode == BT_ro ? 0 : PROT_WRITE );
+	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->latchset = (BtLatchSet *)mmap (0, mgr->latchmgr->nlatchpage * mgr->page_size, flag, MAP_SHARED, mgr->idx, LATCH_page * mgr->page_size);
-	if( mgr->latchset == MAP_FAILED )
+	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 = ( mgr->mode == BT_ro ? PAGE_READONLY : PAGE_READWRITE );
+	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 = ( mgr->mode == BT_ro ? FILE_MAP_READ : FILE_MAP_WRITE );
+	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->latchset = (void *)((char *)mgr->latchmgr + LATCH_page * mgr->page_size);
+	mgr->latchsets = (void *)((char *)mgr->latchmgr + LATCH_page * mgr->page_size);
 #endif
 
 #ifdef unix
@@ -954,6 +948,8 @@ BtDb *bt = malloc (sizeof(*bt));
 	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;
 }
 
@@ -1081,10 +1077,43 @@ int flag;
  	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));
+#ifdef unix
+	{
+	uint idx = subpage / 8;
+	uint bit = subpage % 8;
+
+		if( ~((bt->mgr->pooladvise + pool->slot * ((bt->mgr->poolmask + 8)/8))[idx] >> bit) & 1 ) {
+		  madvise (page, bt->mgr->page_size, MADV_WILLNEED);
+		  (bt->mgr->pooladvise + pool->slot * ((bt->mgr->poolmask + 8)/8))[idx] |= 1 << bit;
+		}
+	}
+#endif
+	return page;
+}
+
+//  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_pinpage(BtDb *bt, uid page_no)
+BtPool *bt_pinpool(BtDb *bt, uid page_no)
 {
 BtPool *pool, *node, *next;
 uint slot, idx, victim;
@@ -1226,41 +1255,10 @@ BtLatchSet *set;
 }
 
 // place write, read, or parent lock on requested page_no.
-//	pin to buffer pool and return page pointer
+//	pin to buffer pool and return latchset pointer
 
-BTERR bt_lockpage(BtDb *bt, uid page_no, BtLock mode, BtPage *pageptr)
+void bt_lockpage(BtLock mode, BtLatchSet *set)
 {
-BtLatchSet *set;
-BtPool *pool;
-uint subpage;
-BtPage page;
-
-	//	find/create maping in pool table
-	//	  and pin our pool slot
-
-	if( pool = bt_pinpage(bt, page_no) )
-		subpage = (uint)(page_no & bt->mgr->poolmask); // page within mapping
-	else
-		return bt->err;
-
-	if( !(set = bt_bindlatch (bt, page_no, 1)) )
-		return bt->err;
-
-	page = (BtPage)(pool->map + (subpage << bt->mgr->page_bits));
-
-#ifdef unix
-	{
-	uint idx = subpage / 8;
-	uint bit = subpage % 8;
-
-	  if( mode == BtLockRead || mode == BtLockWrite )
-		if( ~((bt->mgr->pooladvise + pool->slot * ((bt->mgr->poolmask + 8)/8))[idx] >> bit) & 1 ) {
-		  madvise (page, bt->mgr->page_size, MADV_WILLNEED);
-		  (bt->mgr->pooladvise + pool->slot * ((bt->mgr->poolmask + 8)/8))[idx] |= 1 << bit;
-		}
-	}
-#endif
-
 	switch( mode ) {
 	case BtLockRead:
 		bt_spinreadlock (set->readwr);
@@ -1277,39 +1275,13 @@ BtPage page;
 	case BtLockParent:
 		bt_spinwritelock (set->parent);
 		break;
-	default:
-		return bt->err = BTERR_lock;
 	}
-
-	if( pageptr )
-		*pageptr = page;
-
-	return bt->err = 0;
 }
 
 // remove write, read, or parent lock on requested page_no.
 
-BTERR bt_unlockpage(BtDb *bt, uid page_no, BtLock mode)
+void bt_unlockpage(BtLock mode, BtLatchSet *set)
 {
-BtLatchSet *set;
-BtPool *pool;
-uint idx;
-
-	//	since page is pinned
-	//	it should still be in the buffer pool
-	//	and is in no danger of being a victim for reuse
-
-	if( !(set = bt_bindlatch (bt, page_no, 0)) )
-		return bt->err = BTERR_latch;
-
-	idx = (uint)(page_no >> bt->mgr->seg_bits) % bt->mgr->hashsize;
- 	bt_spinreadlock (&bt->mgr->latch[idx]);
-
-	if( !(pool = bt_findpool(bt, page_no, idx)) )
-		return bt->err = BTERR_hash;
-
- 	bt_spinreleaseread (&bt->mgr->latch[idx]);
-
 	switch( mode ) {
 	case BtLockRead:
 		bt_spinreleaseread (set->readwr);
@@ -1326,65 +1298,15 @@ uint idx;
 	case BtLockParent:
 		bt_spinreleasewrite (set->parent);
 		break;
-	default:
-		return bt->err = BTERR_lock;
 	}
-
-#ifdef  unix
-	__sync_fetch_and_add(&pool->pin, -1);
-	__sync_fetch_and_add (&set->pin, -1);
-#else
-	_InterlockedDecrement16 (&pool->pin);
-	_InterlockedDecrement16 (&set->pin);
-#endif
-	return bt->err = 0;
-}
-
-//	deallocate a deleted page
-//	place on free chain out of allocator page
-//  fence key must already be removed from parent
-
-BTERR bt_freepage(BtDb *bt, uid page_no)
-{
-	//  obtain delete lock on deleted page
-
-	if( bt_lockpage(bt, page_no, BtLockDelete, NULL) )
-		return bt->err;
-
-	//  obtain write lock on deleted page
-
-	if( bt_lockpage(bt, page_no, BtLockWrite, &bt->temp) )
-		return bt->err;
-
-	//	lock allocation page
-
-	bt_spinwritelock(bt->mgr->latchmgr->lock);
-
-	//	store free chain in allocation page second right
-	bt_putid(bt->temp->right, bt_getid(bt->mgr->latchmgr->alloc[1].right));
-	bt_putid(bt->mgr->latchmgr->alloc[1].right, page_no);
-
-	// unlock page zero 
-
-	bt_spinreleasewrite(bt->mgr->latchmgr->lock);
-
-	//  remove write lock on deleted node
-
-	if( bt_unlockpage(bt, page_no, BtLockWrite) )
-		return bt->err;
-
-	//  remove delete lock on deleted node
-
-	if( bt_unlockpage(bt, page_no, BtLockDelete) )
-		return bt->err;
-
-	return 0;
 }
 
 //	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;
@@ -1397,11 +1319,12 @@ int reuse;
 	// else allocate empty page
 
 	if( new_page = bt_getid(bt->mgr->latchmgr->alloc[1].right) ) {
-		if( bt_lockpage (bt, new_page, BtLockWrite, &bt->temp) )
-			return 0;
-		bt_putid(bt->mgr->latchmgr->alloc[1].right, bt_getid(bt->temp->right));
-		if( bt_unlockpage (bt, new_page, BtLockWrite) )
+		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);
@@ -1409,33 +1332,39 @@ int reuse;
 		reuse = 0;
 	}
 #ifdef unix
-	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;
-
 	// 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
-		memset(bt->zero, 0, bt->mgr->page_size);
 		if ( pwrite(bt->mgr->idx,bt->zero, bt->mgr->page_size, (new_page | bt->mgr->poolmask) << bt->mgr->page_bits) < bt->mgr->page_size )
 			return bt->err = BTERR_wrt, 0;
 	}
+
+	// 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( bt_lockpage(bt, new_page, BtLockWrite, &pmap) )
+	if( pool = bt_pinpool (bt, new_page) )
+		pmap = bt_page (bt, pool, new_page);
+	else
 		return 0;
 
 	memcpy(pmap, page, bt->mgr->page_size);
-
-	if( bt_unlockpage (bt, new_page, BtLockWrite) )
-		return 0;
+	bt_unpinpool (pool);
 #endif
-	// unlock allocation latch and return new page no
-
-	bt_spinreleasewrite(bt->mgr->latchmgr->lock);
 	return new_page;
 }
 
@@ -1462,11 +1391,13 @@ uint diff, higher = bt->page->cnt, low = 1, slot;
 //  find and load page at given level for given key
 //	leave page rd or wr locked as requested
 
-int bt_loadpage (BtDb *bt, unsigned char *key, uint len, uint lvl, uint lock)
+int bt_loadpage (BtDb *bt, 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;
 
   //  start at root of btree and drill down
 
@@ -1474,84 +1405,94 @@ uint mode, prevmode;
 	// 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 )
-	  if( bt_lockpage(bt, page_no, BtLockAccess, NULL) )
-		return 0;									
+	  bt_lockpage(BtLockAccess, bt->set);
 
-	//  now unlock our (possibly foster) parent
+	//  now unlock and unpin our (possibly foster) parent
 
-	if( prevpage )
-	  if( bt_unlockpage(bt, prevpage, prevmode) )
-		return 0;
-	  else
-		prevpage = 0;
+	if( prevpage ) {
+	  bt_unlockpage(prevmode, prevset);
+	  bt_unpinlatch (prevset);
+	  bt_unpinpool (prevpool);
+	  prevpage = 0;
+	}
 
  	// obtain read lock using lock chaining
-	// and pin page contents
 
-	if( bt_lockpage(bt, page_no, mode, &bt->page) )
-		return 0;									
+	bt_lockpage(mode, bt->set);
 
 	if( page_no > ROOT_page )
-	  if( bt_unlockpage(bt, page_no, BtLockAccess) )
-		return 0;									
+	  bt_unlockpage(BtLockAccess, bt->set);
 
 	// re-read and re-lock root after determining actual level of root
 
-	if( bt->page_no == ROOT_page )
+	if( page_no == ROOT_page )
 	  if( bt->page->lvl != drill) {
 		drill = bt->page->lvl;
 
-	    if( lock == BtLockWrite && drill == lvl )
-		  if( bt_unlockpage(bt, page_no, mode) )
-			return 0;
-		  else
-			continue;
+	    if( lock == BtLockWrite && drill == lvl ) {
+		  bt_unlockpage(mode, bt->set);
+		  bt_unpinlatch (bt->set);
+		  bt_unpinpool (bt->pool);
+		  continue;
+		}
 	  }
 
 	prevpage = bt->page_no;
+	prevpool = bt->pool;
+	prevset = bt->set;
 	prevmode = mode;
 
-	//	if page is being deleted,
-	//	move back to preceeding page
-
-	if( bt->page->kill ) {
-		page_no = bt_getid (bt->page->right);
-		continue;
-	}
-
 	//  find key on page at this level
-	//  and descend to requested level
+	//  and either descend to requested level
+	//	or return key slot
 
 	slot = bt_findslot (bt, key, len);
 
-	//	is this slot a foster child?
+	//	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 slot;
 
+	//	find next active slot
+
+	//	note: foster children are never dead
+	//	nor fence keys for interiour nodes
+
 	while( slotptr(bt->page, slot)->dead )
 	  if( slot++ < bt->page->cnt )
 		continue;
 	  else
-		goto slideright;
+		return bt->err = BTERR_struct, 0;	// last key shouldn't be deleted
+
+	//	is this slot < foster child area
+	//	if so, drill to next level
 
 	if( slot <= bt->page->cnt - bt->page->foster )
 		drill--;
 
-	//  continue down / right using overlapping locks
-	//  to protect pages being killed or split.
+	//  continue right onto foster child
+	//	or down to next level.
 
 	page_no = bt_getid(slotptr(bt->page, slot)->id);
-	continue;
-
-slideright:
-	page_no = bt_getid(bt->page->right);
 
   } while( page_no );
 
@@ -1562,108 +1503,182 @@ slideright:
 }
 
 //  find and delete key on page by marking delete flag bit
-//  when page becomes empty, delete it from the btree
+//  when leaf page becomes empty, delete it from the btree
 
-BTERR bt_deletekey (BtDb *bt, unsigned char *key, uint len, uint lvl)
+BTERR bt_deletekey (BtDb *bt, unsigned char *key, uint len)
 {
-unsigned char leftkey[256], rightkey[256];
+unsigned char leftkey[256];
+BtLatchSet *rset, *set;
+BtPool *pool, *rpool;
+BtPage rpage, page;
 uid page_no, right;
 uint slot, tod;
 BtKey ptr;
 
-	if( slot = bt_loadpage (bt, key, len, lvl, BtLockWrite) )
+	if( slot = bt_loadpage (bt, key, len, 0, BtLockWrite) )
 		ptr = keyptr(bt->page, slot);
 	else
 		return bt->err;
 
 	// if key is found delete it, otherwise ignore request
+	// note that fence keys of interiour nodes are not deleted.
 
-	if( !keycmp (ptr, key, len) )
-		if( slotptr(bt->page, slot)->dead == 0 ) {
+	if( bt->found = !keycmp (ptr, key, len) )
+		if( bt->found = slotptr(bt->page, slot)->dead == 0 ) {
  			slotptr(bt->page,slot)->dead = 1;
 			if( slot < bt->page->cnt )
  				bt->page->dirty = 1;
  			bt->page->act--;
 		}
 
-	// return if page is not empty, or it has no right sibling
-
-	right = bt_getid(bt->page->right);
 	page_no = bt->page_no;
+	pool = bt->pool;
+	page = bt->page;
+	set = bt->set;
 
-	if( !right || bt->page->act )
-		return bt_unlockpage(bt, page_no, BtLockWrite);
+	// return if page is not empty or not found
 
-	// obtain Parent lock over write lock
-
-	if( bt_lockpage(bt, page_no, BtLockParent, NULL) )
+	if( page->act || !bt->found ) {
+		bt_unlockpage(BtLockWrite, set);
+		bt_unpinlatch (set);
+		bt_unpinpool (pool);
 		return bt->err;
+	}
 
-	// cache copy of key to delete
+	// cache copy of fence key of empty node
 
-	ptr = keyptr(bt->page, bt->page->cnt);
+	ptr = keyptr(page, page->cnt);
 	memcpy(leftkey, ptr, ptr->len + 1);
 
-	// lock and map right page
+	//	release write lock on empty node
+	//	obtain Parent lock
 
-	if( bt_lockpage(bt, right, BtLockWrite, &bt->temp) )
-		return bt->err;
+	bt_unlockpage(BtLockWrite, set);
+	bt_lockpage(BtLockParent, set);
 
-	// pull contents of next page into current empty page 
-	memcpy (bt->page, bt->temp, bt->mgr->page_size);
+	//	load and lock parent to see
+	//  if delete of empty node is OK
+	//	ie, not a fence key of parent
 
-	//	cache copy of key to update
-	ptr = keyptr(bt->temp, bt->temp->cnt);
-	memcpy(rightkey, ptr, ptr->len + 1);
+	while( 1 ) {
+	  if( slot = bt_loadpage (bt, leftkey+1, *leftkey, 1, BtLockWrite) )
+		ptr = keyptr(bt->page, slot);
+	  else
+		return bt->err;
 
-	//  Mark right page as deleted and point it to left page
-	//	until we can post updates at higher level.
+	  // does parent level contain our fence key yet?
+	  // and is it free of foster children?
 
-	bt_putid(bt->temp->right, page_no);
-	bt->temp->kill = 1;
-	bt->temp->cnt = 0;
+	  if( !bt->page->foster )
+	   if( !keycmp (ptr, leftkey+1, *leftkey) )
+		break;
 
-	if( bt_unlockpage(bt, right, BtLockWrite) )
-		return bt->err;
-	if( bt_unlockpage(bt, page_no, BtLockWrite) )
-		return bt->err;
+	  bt_unlockpage(BtLockWrite, bt->set);
+	  bt_unpinlatch (bt->set);
+	  bt_unpinpool (bt->pool);
+#ifdef unix
+	  sched_yield();
+#else
+	  SwitchToThread();
+#endif
+	}
 
-	//  delete old lower key to consolidated node
+	//	find our left fence key
 
-	if( bt_deletekey (bt, leftkey + 1, *leftkey, lvl + 1) )
+	while( slotptr(bt->page, slot)->dead )
+	  if( slot++ < bt->page->cnt )
+		continue;
+	  else
+		return bt->err = BTERR_struct;	// last key shouldn't be deleted
+
+	//	now we have both parent and child
+
+	bt_lockpage(BtLockDelete, set);
+	bt_lockpage(BtLockWrite, set);
+
+	// return if page has no right sibling within parent
+	//	 or if empty node is no longer empty
+
+	if( page->act || slot == bt->page->cnt ) {
+		// unpin parent
+		bt_unlockpage(BtLockWrite, bt->set);
+		bt_unpinlatch (bt->set);
+		bt_unpinpool (bt->pool);
+		// unpin empty node
+		bt_unlockpage(BtLockParent, set);
+		bt_unlockpage(BtLockDelete, set);
+		bt_unlockpage(BtLockWrite, set);
+		bt_unpinlatch (set);
+		bt_unpinpool (pool);
 		return bt->err;
+	}
 
-	//  redirect higher key directly to consolidated node
+	// lock and map our right page
+	// note that it cannot be our foster child
+	// since the our node is empty
 
-	if( slot = bt_loadpage (bt, rightkey+1, *rightkey, lvl+1, BtLockWrite) )
-		ptr = keyptr(bt->page, slot);
+	right = bt_getid(page->right);
+
+	if( rpool = bt_pinpool (bt, right) )
+		rpage = bt_page (bt, rpool, right);
 	else
 		return bt->err;
 
-	// since key already exists, update id
+	rset = bt_pinlatch (bt, right);
+	bt_lockpage(BtLockWrite, rset);
+	bt_lockpage(BtLockDelete, rset);
+
+	// pull contents of right page into empty page 
 
-	if( keycmp (ptr, rightkey+1, *rightkey) )
-		return bt->err = BTERR_struct;
+	memcpy (page, rpage, bt->mgr->page_size);
+
+	//	delete left parent slot for old empty page
+	//	and redirect right parent slot to it
+
+	bt->page->act--;
+	bt->page->dirty = 1;
+	slotptr(bt->page, slot)->dead = 1;
+
+	while( slot++ < bt->page->cnt )
+	  if( !slotptr(bt->page, slot)->dead )
+		break;
 
-	slotptr(bt->page, slot)->dead = 0;
 	bt_putid(slotptr(bt->page,slot)->id, page_no);
 
-	if( bt_unlockpage(bt, bt->page_no, BtLockWrite) )
-		return bt->err;
+	// release parent level lock
+	//	and our empty node lock
 
-	//	obtain write lock and
-	//	add right block to free chain
+	bt_unlockpage(BtLockWrite, set);
+	bt_unlockpage(BtLockWrite, bt->set);
+	bt_unpinlatch (bt->set);
+	bt_unpinpool (bt->pool);
 
-	if( bt_freepage (bt, right) )
-		return bt->err;
+	//	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_spinreleasewrite(bt->mgr->latchmgr->lock);
+
+	bt_unlockpage(BtLockWrite, rset);
+	bt_unlockpage(BtLockDelete, rset);
+	bt_unpinlatch (rset);
+	bt_unpinpool (rpool);
 
 	// 	remove ParentModify lock
 
-	if( bt_unlockpage(bt, page_no, BtLockParent) )
-		return bt->err;
-	
+	bt_unlockpage(BtLockParent, set);
+	bt_unlockpage(BtLockDelete, set);
+	bt_unpinlatch (set);
+	bt_unpinpool (pool);
 	return 0;
-}
+} 
 
 //	find key in leaf level and return row-id
 
@@ -1681,32 +1696,33 @@ uid id;
 	// if key exists, return row-id
 	//	otherwise return 0
 
-	if( ptr->len == len && !memcmp (ptr->key, key, len) )
+	if( slot <= bt->page->cnt && !keycmp (ptr, key, len) )
 		id = bt_getid(slotptr(bt->page,slot)->id);
 	else
 		id = 0;
 
-	if( bt_unlockpage (bt, bt->page_no, BtLockRead) )
-		return 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
-//	1 - go ahead
+//	>0  new slot value
 
-uint bt_cleanpage(BtDb *bt, uint amt)
+uint bt_cleanpage(BtDb *bt, uint amt, uint slot)
 {
 uint nxt = bt->mgr->page_size;
 BtPage page = bt->page;
 uint cnt = 0, idx = 0;
 uint max = page->cnt;
+uint newslot;
 BtKey key;
 
 	if( page->min >= (max+1) * sizeof(BtSlot) + sizeof(*page) + amt + 1 )
-		return 1;
+		return slot;
 
 	//	skip cleanup if nothing to reclaim
 
@@ -1723,12 +1739,20 @@ BtKey key;
 
 	// try cleaning up page first
 
+	// always leave fence key in the array
+	// otherwise, remove deleted key
+
+	// note: foster children are never dead
+	//	nor are fence keys for interiour nodes
+
 	while( cnt++ < max ) {
-		// always leave fence key and foster children in list
-		if( cnt < max - page->foster && slotptr(bt->frame,cnt)->dead )
+		if( cnt == slot )
+			newslot = idx + 1;
+		else 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);
@@ -1747,7 +1771,7 @@ BtKey key;
 	//	see if page has enough space now, or does it need splitting?
 
 	if( page->min >= (idx+1) * sizeof(BtSlot) + sizeof(*page) + amt + 1 )
-		return 1;
+		return newslot;
 
 	return 0;
 }
@@ -1760,27 +1784,29 @@ void bt_addkeytopage (BtDb *bt, uint slot, unsigned char *key, uint len, uid id,
 BtPage page = bt->page;
 uint idx;
 
-	// calculate next available slot and copy key into page
+	// find next available dead slot and copy key onto page
+	// note that foster children on the page are never dead
 
-	page->min -= len + 1;
-	((unsigned char *)page)[page->min] = len;
-	memcpy ((unsigned char *)page + page->min +1, key, len );
+	// look for next hole, but stay back from the fence key
 
 	for( idx = slot; idx < page->cnt; idx++ )
 	  if( slotptr(page, idx)->dead )
 		break;
 
-	// now insert key into array before slot
-	// preserving the fence slot
-
 	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;
@@ -1803,9 +1829,11 @@ BtKey key;
 	//  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--;
-	root->foster--;
 
 	//	Save left fence key.
 
@@ -1846,27 +1874,32 @@ BtKey key;
 	root->act = 2;
 	root->lvl++;
 
-	// release root (bt->page)
+	// release and unpin root (bt->page)
 
-	return bt_unlockpage(bt, ROOT_page, BtLockWrite);
+	bt_unlockpage(BtLockWrite, bt->set);
+	bt_unpinlatch (bt->set);
+	bt_unpinpool (bt->pool);
+	return 0;
 }
 
 //  split already locked full node
 //	in current page variables
-//	return unlocked.
+//	return unlocked and unpinned.
 
 BTERR bt_splitpage (BtDb *bt)
 {
 uint slot, cnt, idx, max, nxt = bt->mgr->page_size;
 unsigned char fencekey[256];
 uid page_no = bt->page_no;
+BtLatchSet *set = bt->set;
+BtPool *pool = bt->pool;
 BtPage page = bt->page;
 uint tod = time(NULL);
 uint lvl = page->lvl;
 uid new_page, right;
 BtKey key;
 
-	//	initialize frame buffer
+	//	initialize frame buffer for right node
 
 	memset (bt->frame, 0, bt->mgr->page_size);
 	max = page->cnt - page->foster;
@@ -1875,19 +1908,21 @@ BtKey key;
 	idx = 0;
 
 	//  split higher half of keys to bt->frame
-	//	leaving foster children in the left node.
+	//	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;
-		bt->frame->act++;
 	}
 
-	// transfer right link node
+	// transfer right link node to new right node
 
 	if( page_no > ROOT_page ) {
 		right = bt_getid (page->right);
@@ -1899,13 +1934,13 @@ BtKey key;
 	bt->frame->cnt = idx;
 	bt->frame->lvl = lvl;
 
-	//	get new free page and write frame to it.
+	//	get new free page and write right frame to it.
 
 	if( !(new_page = bt_newpage(bt, bt->frame)) )
 		return bt->err;
 
-	//	remember fence key for new page to add
-	//	as foster child
+	//	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);
@@ -1915,6 +1950,7 @@ BtKey key;
 	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;
@@ -1927,22 +1963,26 @@ BtKey key;
 		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;
-		page->act++;
 	}
 
-	//	insert new foster child at beginning of the current foster children
+	//	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 if any
+	//  continue with old foster child keys
+	//	note that none will be dead
 
 	cnt = bt->frame->cnt - bt->frame->foster;
 
@@ -1970,109 +2010,69 @@ BtKey key;
 
 	//  release wr lock on our page
 
-	if( bt_unlockpage (bt, page_no, BtLockWrite) )
-		return bt->err;
+	bt_unlockpage (BtLockWrite, set);
 
 	//  obtain ParentModification lock for current page
-	//	to fix fence key and highest foster child on page
+	//	to fix new fence key and oldest foster child on page
 
-	if( bt_lockpage (bt, page_no, BtLockParent, NULL) )
-		return bt->err;
+	bt_lockpage (BtLockParent, set);
 
-	//  get our highest foster child key to find in parent node
+	//  get our new fence key to insert in parent node
 
-	if( bt_lockpage (bt, page_no, BtLockRead, &page) )
-		return bt->err;
+	bt_lockpage (BtLockRead, set);
 
-	key = keyptr(page, page->cnt);
+	key = keyptr(page, page->cnt-1);
 	memcpy (fencekey, key, key->len+1);
 
-	if( bt_unlockpage (bt, page_no, BtLockRead) )
-		return bt->err;
-
-	  //  update our parent
-try_again:
-
-	do {
-	  slot = bt_loadpage (bt, fencekey + 1, *fencekey, lvl + 1, BtLockWrite);
-
-	  if( !slot )
-		return bt->err;
-
-	  // check if parent page has enough space for any possible key
+	bt_unlockpage (BtLockRead, set);
 
-	  if( bt_cleanpage (bt, 256) )
-		break;
-
-	  if( bt_splitpage (bt) )
+	if( bt_insertkey (bt, fencekey + 1, *fencekey, page_no, tod, lvl + 1) )
 		return bt->err;
-	} while( 1 );
 
-	//  see if we are still a foster child from another node
+	//	lock our page for writing
 
-	if( bt_getid (slotptr(bt->page, slot)->id) != page_no ) {
-		if( bt_unlockpage (bt, bt->page_no, BtLockWrite) )
-			return bt->err;
-#ifdef  unix
-		sched_yield();
-#else
-		SwitchToThread();
-#endif
-		goto try_again;
-	}
+	bt_lockpage (BtLockRead, set);
 
-	//	wait until readers from parent get their locks
-	//	on our page
+	//	switch old parent key from us to our oldest foster child
 
-	if( bt_lockpage (bt, page_no, BtLockDelete, NULL) )
-		return bt->err;
+	key = keyptr(page, page->cnt);
+	memcpy (fencekey, key, key->len+1);
 
-	//	lock our page for writing
+	new_page = bt_getid (slotptr(page, page->cnt)->id);
+	bt_unlockpage (BtLockRead, set);
 
-	if( bt_lockpage (bt, page_no, BtLockWrite, &page) )
+	if( bt_insertkey (bt, fencekey + 1, *fencekey, new_page, tod, lvl + 1) )
 		return bt->err;
 
-	//	switch parent fence key to foster child
-
-	if( slotptr(page, page->cnt)->dead )
-		slotptr(bt->page, slot)->dead = 1;
-	else
-		bt_putid (slotptr(bt->page, slot)->id, bt_getid(slotptr(page, page->cnt)->id));
-
-	//	remove highest foster child from our page
+	//	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--;
-	page->foster--;
-	page->dirty = 1;
-	key = keyptr(page, page->cnt);
-
-	//	add our new fence key for foster child to our parent
-
-	bt_addkeytopage (bt, slot, key->key, key->len, page_no, tod);
-
-	if( bt_unlockpage (bt, bt->page_no, BtLockWrite) )
-		return bt->err;
 
-	if( bt_unlockpage (bt, page_no, BtLockDelete) )
-		return bt->err;
+	//	unlock and unpin
 
-	if( bt_unlockpage (bt, page_no, BtLockWrite) )
-		return bt->err;
-
-	return bt_unlockpage (bt, page_no, BtLockParent);
+	bt_unlockpage (BtLockWrite, set);
+	bt_unlockpage (BtLockParent, 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)
+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, 0, BtLockWrite) )
+		if( slot = bt_loadpage (bt, key, len, lvl, BtLockWrite) )
 			ptr = keyptr(bt->page, slot);
 		else
 		{
@@ -2086,15 +2086,20 @@ BtKey ptr;
 		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);
-			return bt_unlockpage(bt, bt->page_no, BtLockWrite);
+			bt_unlockpage(BtLockWrite, bt->set);
+			bt_unpinlatch (bt->set);
+			bt_unpinpool (bt->pool);
+			return bt->err;
 		}
 
 		// check if page has enough space
 
- 		if( bt_cleanpage (bt, len) )
+ 		if( slot = bt_cleanpage (bt, len, slot) )
 			break;
 
 		if( bt_splitpage (bt) )
@@ -2103,7 +2108,10 @@ BtKey ptr;
 
   	bt_addkeytopage (bt, slot, key, len, id, tod);
 
-	return bt_unlockpage (bt, bt->page_no, BtLockWrite);
+	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
@@ -2115,10 +2123,12 @@ uint slot;
 	// cache page for retrieval
 	if( slot = bt_loadpage (bt, key, len, 0, BtLockRead) )
 		memcpy (bt->cursor, bt->page, bt->mgr->page_size);
+
 	bt->cursor_page = bt->page_no;
-	if ( bt_unlockpage(bt, bt->page_no, BtLockRead) )
-		return 0;
 
+	bt_unlockpage(BtLockRead, bt->set);
+	bt_unpinlatch (bt->set);
+	bt_unpinpool (bt->pool);
 	return slot;
 }
 
@@ -2127,6 +2137,8 @@ uint slot;
 
 uint bt_nextkey (BtDb *bt, uint slot)
 {
+BtLatchSet *set;
+BtPool *pool;
 BtPage page;
 uid right;
 
@@ -2144,15 +2156,19 @@ uid right;
 		break;
 
 	bt->cursor_page = right;
-
-    if( bt_lockpage(bt, right, BtLockRead, &page) )
+	if( pool = bt_pinpool (bt, right) )
+		page = bt_page (bt, pool, right);
+	else
 		return 0;
 
-	memcpy (bt->cursor, page, bt->mgr->page_size);
+	set = bt_pinlatch (bt, right);
+    bt_lockpage(BtLockRead, set);
 
-	if ( bt_unlockpage(bt, right, BtLockRead) )
-		return 0;
+	memcpy (bt->cursor, page, bt->mgr->page_size);
 
+	bt_unlockpage(BtLockRead, set);
+	bt_unpinlatch (set);
+	bt_unpinpool (pool);
 	slot = 0;
   } while( 1 );
 
@@ -2177,6 +2193,54 @@ uint bt_tod(BtDb *bt, uint slot)
 
 #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( *(ushort *)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( *(ushort *)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;
@@ -2198,7 +2262,9 @@ 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;
@@ -2209,6 +2275,11 @@ FILE *in;
 
 	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") )
@@ -2223,7 +2294,7 @@ FILE *in;
 			  else if( args->num )
 		  		sprintf((char *)key+len, "%.9d", line + args->idx * args->num), len += 9;
 
-			  if( bt_insertkey (bt, key, len, line, *tod) )
+			  if( bt_insertkey (bt, key, len, line, *tod, 0) )
 				fprintf(stderr, "Error %d Line: %d\n", bt->err, line), exit(0);
 			  len = 0;
 			}
@@ -2245,7 +2316,7 @@ FILE *in;
 			  else if( args->num )
 		  		sprintf((char *)key+len, "%.9d", line + args->idx * args->num), len += 9;
 
-			  if( bt_deletekey (bt, key, len, 0) )
+			  if( bt_deletekey (bt, key, len) )
 				fprintf(stderr, "Error %d Line: %d\n", bt->err, line), exit(0);
 			  len = 0;
 			}
@@ -2300,10 +2371,17 @@ FILE *in;
 		fprintf(stderr, "started reading\n");
 
 	  	do {
-			bt_lockpage (bt, page_no, BtLockRead, &page);
+			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 (bt, page_no, BtLockRead);
+			bt_unlockpage (BtLockRead, set);
+			bt_unpinlatch (set);
+			bt_unpinpool (pool);
 	  	} while( page_no = next );
 
 	  	cnt--;	// remove stopper key