From: drh <drh@noemail.net>
Date: Thu, 7 Apr 2011 14:47:01 +0000 (+0000)
Subject: When searching a list of freelist trunk pages looking for a specific page
X-Git-Tag: version-3.7.6~20
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=93b4fc78cf8a32f0b9c4563a77706034e56c6093;p=thirdparty%2Fsqlite.git

When searching a list of freelist trunk pages looking for a specific page
to allocate, avoid unnecessary journalling of the unchanged trunk pages towards
the start of the list.

FossilOrigin-Name: d03d63d77ed144ac2c02a0245c4b4b070b79c88e
---

diff --git a/manifest b/manifest
index 518827889c..097db8a15d 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Avoid\srunning\sthread1.test\sor\sthread2.test\sif\sSQLITE_MUTEX_NOOP\sis\sdefined.
-D 2011-04-07T14:05:47.844
+C When\ssearching\sa\slist\sof\sfreelist\strunk\spages\slooking\sfor\sa\sspecific\spage\nto\sallocate,\savoid\sunnecessary\sjournalling\sof\sthe\sunchanged\strunk\spages\stowards\nthe\sstart\sof\sthe\slist.
+D 2011-04-07T14:47:01.943
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in 7a4d9524721d40ef9ee26f93f9bd6a51dba106f2
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -121,7 +121,7 @@ F src/auth.c 523da7fb4979469955d822ff9298352d6b31de34
 F src/backup.c b7529a6691f0fd534ae8ff622203c46a7f1b626b
 F src/bitvec.c af50f1c8c0ff54d6bdb7a80e2fceca5a93670bef
 F src/btmutex.c 976f45a12e37293e32cae0281b15a21d48a8aaa7
-F src/btree.c 4fcad108b612a4d33dac568b11d26e4d38ccbe35
+F src/btree.c 6a9164af8a2ef4612ee30b253635a9bd8e5e1b1b
 F src/btree.h 11753dd46597a20702bca8746cb4caa4486a82b5
 F src/btreeInt.h 67978c014fa4f7cc874032dd3aacadd8db656bc3
 F src/build.c b7c993274ee2a029937b0bc4815bdef80b330017
@@ -927,7 +927,7 @@ F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
 F tool/split-sqlite3c.tcl d9be87f1c340285a3e081eb19b4a247981ed290c
 F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
-P e4e99606fdf1f1cecf914dc865b066bf07793d1f
-R 42c41e910cfc7e1c1b9040c4c34f5e86
-U dan
-Z e11fdaaab64fe55fe7338be760f5f876
+P 532ae32ea0f5e821dac643cbc4b041c103cadfdc
+R ada284aaaa309102c01ae8aa530bb601
+U drh
+Z 52b476a7ff4c3a8d80844592d209d819
diff --git a/manifest.uuid b/manifest.uuid
index 4b9265b79f..ada919f6d9 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-532ae32ea0f5e821dac643cbc4b041c103cadfdc
\ No newline at end of file
+d03d63d77ed144ac2c02a0245c4b4b070b79c88e
\ No newline at end of file
diff --git a/src/btree.c b/src/btree.c
index bfdc3d98a8..103a1f3230 100644
--- a/src/btree.c
+++ b/src/btree.c
@@ -4819,7 +4819,7 @@ static int allocateBtreePage(
         goto end_allocate_page;
       }
 
-      k = get4byte(&pTrunk->aData[4]);
+      k = get4byte(&pTrunk->aData[4]); /* # of leaves on this trunk page */
       if( k==0 && !searchList ){
         /* The trunk has no leaves and the list is not being searched. 
         ** So extract the trunk page itself and use it as the newly 
@@ -4904,10 +4904,6 @@ static int allocateBtreePage(
         u32 closest;
         Pgno iPage;
         unsigned char *aData = pTrunk->aData;
-        rc = sqlite3PagerWrite(pTrunk->pDbPage);
-        if( rc ){
-          goto end_allocate_page;
-        }
         if( nearby>0 ){
           u32 i;
           int dist;
@@ -4937,11 +4933,12 @@ static int allocateBtreePage(
           TRACE(("ALLOCATE: %d was leaf %d of %d on trunk %d"
                  ": %d more free pages\n",
                  *pPgno, closest+1, k, pTrunk->pgno, n-1));
+          rc = sqlite3PagerWrite(pTrunk->pDbPage);
+          if( rc ) goto end_allocate_page;
           if( closest<k-1 ){
             memcpy(&aData[8+closest*4], &aData[4+k*4], 4);
           }
           put4byte(&aData[4], k-1);
-          assert( sqlite3PagerIswriteable(pTrunk->pDbPage) );
           noContent = !btreeGetHasContent(pBt, *pPgno);
           rc = btreeGetPage(pBt, *pPgno, ppPage, noContent);
           if( rc==SQLITE_OK ){
@@ -5010,6 +5007,7 @@ end_allocate_page:
   }else{
     *ppPage = 0;
   }
+  assert( rc!=SQLITE_OK || sqlite3PagerIswriteable((*ppPage)->pDbPage) );
   return rc;
 }