Change the BTree so that it uses the Pagers temporary page space when

reorganizing the rows on a page, rather than mallocing for space of
its own.  In this way, we avoid having to deal with a malloc failure
deep down inside the page reorganizer.  Ticket #2806 (CVS 4577)

FossilOrigin-Name: 98960132dc082da61652201f4bd2b559725350c0

manifest

@@ -1,5 +1,5 @@
-C Reorganize\sthe\scode\sfor\sthe\shomegrown\srecursive\smutexes.\s\sFix\sa\splace\nin\sthe\sprevious\scheck-in\swhere\sthe\s#ifdef\slabel\swas\sincorrect.\nTicket\s#2804.\s(CVS\s4576)
-D 2007-11-28T14:04:57
+C Change\sthe\sBTree\sso\sthat\sit\suses\sthe\sPagers\stemporary\spage\sspace\swhen\nreorganizing\sthe\srows\son\sa\spage,\srather\sthan\smallocing\sfor\sspace\sof\nits\sown.\s\sIn\sthis\sway,\swe\savoid\shaving\sto\sdeal\swith\sa\smalloc\sfailure\ndeep\sdown\sinside\sthe\spage\sreorganizer.\s\sTicket\s#2806\s(CVS\s4577)
+D 2007-11-28T16:19:56
 F Makefile.arm-wince-mingw32ce-gcc ac5f7b2cef0cd850d6f755ba6ee4ab961b1fadf7
 F Makefile.in 35396fd58890420b29edcf27b6c0e2d054862a6b
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -83,7 +83,7 @@ F src/analyze.c fd1a3d756c1a20fca3c505bed0398f4cdca83cb8
 F src/attach.c a01d55157d46a1234909f3a7f21fb09549c947bd
 F src/auth.c c8b2ab5c8bad4bd90ed7c294694f48269162c627
 F src/btmutex.c 442be6f068d77ca9ffd69899cf0a3943c244548c
-F src/btree.c 008ce6b6bbcf00dfa3b1eca41bd3560fb287fd52
+F src/btree.c c5844bb4bbe997a7c8400a714fcf304d91855383
 F src/btree.h d0736ebca4b6eafbdd823c46a8de574cea078211
 F src/btreeInt.h 4330c19b8314545fdb209cc77e2a57f6a5290e9c
 F src/build.c b58dd7c7a763a228196022ec0d51781ed6995cde
@@ -123,8 +123,8 @@ F src/os_unix.c db6755454c84004d0041eb1b2194c90b35db0a5b
 F src/os_unix.h 5768d56d28240d3fe4537fac08cc85e4fb52279e
 F src/os_win.c 1fb40eb62fb0719ea578d69edcb1a2974f04d214
 F src/os_win.h 41a946bea10f61c158ce8645e7646b29d44f122b
-F src/pager.c b1eaca429cf9a4e35bed12f6f326d39a82ee8a33
-F src/pager.h d783e7f184afdc33adff37ba58d4e029bd8793b3
+F src/pager.c bb524fe4b501a60762d07d6d0d33fd548b176cf6
+F src/pager.h f504f7ae84060fee0416a853e368d3d113c3d6fa
 F src/parse.y a780b33ef45dd7b3272319cf91e609d6f109a31c
 F src/pragma.c cb1486e76dbcad757968afc4083d3472032e62b5
 F src/prepare.c f811fdb6fd4a82cca673a6e1d5b041d6caf567f1
@@ -593,7 +593,7 @@ F www/tclsqlite.tcl 8be95ee6dba05eabcd27a9d91331c803f2ce2130
 F www/vdbe.tcl 87a31ace769f20d3627a64fa1fade7fed47b90d0
 F www/version3.tcl 890248cf7b70e60c383b0e84d77d5132b3ead42b
 F www/whentouse.tcl fc46eae081251c3c181bd79c5faef8195d7991a5
-P 80299eebddba9aac4c1bc36ffa2b440bffbf1751
-R 91aabeff7afc14d1c39bb734a20c5788
+P 542e11f954983ae26fef4ea850c8b2a20f738edd
+R 21c1d3a78e0cb66c070fb743696cb747
 U drh
-Z 5760708bd767145f7cd934d8b8502186
+Z 6091ee38d7896a754234ddd4a74396ad

manifest.uuid

@@ -1 +1 @@
-542e11f954983ae26fef4ea850c8b2a20f738edd
+98960132dc082da61652201f4bd2b559725350c0

src/btree.c

@@ -9,7 +9,7 @@
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
-** $Id: btree.c,v 1.430 2007/11/05 15:30:13 danielk1977 Exp $
+** $Id: btree.c,v 1.431 2007/11/28 16:19:56 drh Exp $
 **
 ** This file implements a external (disk-based) database using BTrees.
 ** See the header comment on "btreeInt.h" for additional information.
@@ -677,8 +677,7 @@ static int defragmentPage(MemPage *pPage){
   assert( pPage->pBt->usableSize <= SQLITE_MAX_PAGE_SIZE );
   assert( pPage->nOverflow==0 );
   assert( sqlite3_mutex_held(pPage->pBt->mutex) );
-  temp = sqlite3_malloc( pPage->pBt->pageSize );
-  if( temp==0 ) return SQLITE_NOMEM;
+  temp = sqlite3PagerTempSpace(pPage->pBt->pPager);
   data = pPage->aData;
   hdr = pPage->hdrOffset;
   cellOffset = pPage->cellOffset;
@@ -705,7 +704,6 @@ static int defragmentPage(MemPage *pPage){
   data[hdr+7] = 0;
   addr = cellOffset+2*nCell;
   memset(&data[addr], 0, brk-addr);
-  sqlite3_free(temp);
   return SQLITE_OK;
 }
 

src/pager.c

@@ -18,7 +18,7 @@
 ** file simultaneously, or one process from reading the database while
 ** another is writing.
 **
-** @(#) $Id: pager.c,v 1.395 2007/11/27 16:55:08 drh Exp $
+** @(#) $Id: pager.c,v 1.396 2007/11/28 16:19:56 drh Exp $
 */
 #ifndef SQLITE_OMIT_DISKIO
 #include "sqliteInt.h"
@@ -2332,6 +2332,18 @@ int sqlite3PagerSetPagesize(Pager *pPager, u16 *pPageSize){
   return rc;
 }
 
+/*
+** Return a pointer to the "temporary page" buffer held internally
+** by the pager.  This is a buffer that is big enough to hold the
+** entire content of a database page.  This buffer is used internally
+** during rollback and will be overwritten whenever a rollback
+** occurs.  But other modules are free to use it too, as long as
+** no rollbacks are happening.
+*/
+void *sqlite3PagerTempSpace(Pager *pPager){
+  return pPager->pTmpSpace;
+}
+
 /*
 ** Attempt to set the maximum database page count if mxPage is positive. 
 ** Make no changes if mxPage is zero or negative.  And never reduce the

src/pager.h

@@ -13,7 +13,7 @@
 ** subsystem.  The page cache subsystem reads and writes a file a page
 ** at a time and provides a journal for rollback.
 **
-** @(#) $Id: pager.h,v 1.67 2007/09/03 15:19:35 drh Exp $
+** @(#) $Id: pager.h,v 1.68 2007/11/28 16:19:56 drh Exp $
 */
 
 #ifndef _PAGER_H_
@@ -94,6 +94,7 @@ int sqlite3PagerMovepage(Pager*,DbPage*,Pgno);
 void *sqlite3PagerGetData(DbPage *); 
 void *sqlite3PagerGetExtra(DbPage *); 
 int sqlite3PagerLockingMode(Pager *, int);
+void *sqlite3PagerTempSpace(Pager*);
 
 #if defined(SQLITE_ENABLE_MEMORY_MANAGEMENT) && !defined(SQLITE_OMIT_DISKIO)
   int sqlite3PagerReleaseMemory(int);