From: drh <drh@noemail.net>
Date: Mon, 29 Jun 2015 19:08:18 +0000 (+0000)
Subject: Combine subjRequiresPage() and subjournalPage() into a single
X-Git-Tag: version-3.8.11~95
X-Git-Url: http://git.ipfire.org/gitweb/gitweb.cgi?a=commitdiff_plain;h=60e32edba5b50692af25ad56f849d6b41c2b2c72;p=thirdparty%2Fsqlite.git

Combine subjRequiresPage() and subjournalPage() into a single
subjournalPageIfRequired() routine.

FossilOrigin-Name: 3b65eb56c422855ca47f709247205f0c77d98a5c
---

diff --git a/manifest b/manifest
index 38f44bf307..97944da70e 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Add\sthe\sPGHDR_WRITEABLE\sbit\sfor\sPgHdr.flags\swhich\sis\sused\sto\s\ndistinguish\sbetween\spages\sthat\sare\son\sthe\sdirty\slist\sand\spages\sthat\sare\nsafe\sto\smodify.
-D 2015-06-29T18:29:10.051
+C Combine\ssubjRequiresPage()\sand\ssubjournalPage()\sinto\sa\ssingle\nsubjournalPageIfRequired()\sroutine.
+D 2015-06-29T19:08:18.213
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in 285a0a234ed7610d431d91671c136098c2bd86a9
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -314,7 +314,7 @@ F src/os_setup.h c9d4553b5aaa6f73391448b265b89bed0b890faa
 F src/os_unix.c 23eb5f56fac54d8fe0cb204291f3b3b2d94f23fc
 F src/os_win.c 27cc135e2d0b8b1e2e4944db1e2669a6a18fa0f8
 F src/os_win.h eb7a47aa17b26b77eb97e4823f20a00b8bda12ca
-F src/pager.c 349cc089392bd0111e575bb0abacae0038a193c9
+F src/pager.c 4cf1b151727f5f12898927c6688b167fd4999d14
 F src/pager.h c3476e7c89cdf1c6914e50a11f3714e30b4e0a77
 F src/parse.y 6d60dda8f8d418b6dc034f1fbccd816c459983a8
 F src/pcache.c 379fd77feb732b39750eb733260d9c227d8a4314
@@ -1364,7 +1364,7 @@ F tool/vdbe_profile.tcl 67746953071a9f8f2f668b73fe899074e2c6d8c1
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh 48bd54594752d5be3337f12c72f28d2080cb630b
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P 14de3d39267a4005a0fa900bab4adc4c104e4084
-R 87e4d0501eab929e3fc91ca03b341d4f
+P 7c4ef7b7c8744af19075bb96d1e0b63e35978ed1
+R f62d201ad6eea9a89949366a04424df3
 U drh
-Z 78f063c06b61cea5c0d3875d2ce428dd
+Z d7a21ab6fd66c107b4716f65f30e363a
diff --git a/manifest.uuid b/manifest.uuid
index 4c09287aba..76f6ffe525 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-7c4ef7b7c8744af19075bb96d1e0b63e35978ed1
\ No newline at end of file
+3b65eb56c422855ca47f709247205f0c77d98a5c
\ No newline at end of file
diff --git a/src/pager.c b/src/pager.c
index 7fe8c92def..bf6f8f4d69 100644
--- a/src/pager.c
+++ b/src/pager.c
@@ -4320,8 +4320,6 @@ static int openSubJournal(Pager *pPager){
 
 /*
 ** Append a record of the current state of page pPg to the sub-journal. 
-** It is the callers responsibility to use subjRequiresPage() to check 
-** that it is really required before calling this function.
 **
 ** If successful, set the bit corresponding to pPg->pgno in the bitvecs
 ** for all open savepoints before returning.
@@ -4368,6 +4366,13 @@ static int subjournalPage(PgHdr *pPg){
   }
   return rc;
 }
+static int subjournalPageIfRequired(PgHdr *pPg){
+  if( subjRequiresPage(pPg) ){
+    return subjournalPage(pPg);
+  }else{
+    return SQLITE_OK;
+  }
+}
 
 /*
 ** This function is called by the pcache layer when it has reached some
@@ -4425,9 +4430,7 @@ static int pagerStress(void *p, PgHdr *pPg){
   pPg->pDirty = 0;
   if( pagerUseWal(pPager) ){
     /* Write a single frame for this page to the log. */
-    if( subjRequiresPage(pPg) ){ 
-      rc = subjournalPage(pPg); 
-    }
+    rc = subjournalPageIfRequired(pPg); 
     if( rc==SQLITE_OK ){
       rc = pagerWalFrames(pPager, pPg, 0, 0);
     }
@@ -4440,39 +4443,6 @@ static int pagerStress(void *p, PgHdr *pPg){
       rc = syncJournal(pPager, 1);
     }
   
-    /* If the page number of this page is larger than the current size of
-    ** the database image, it may need to be written to the sub-journal.
-    ** This is because the call to pager_write_pagelist() below will not
-    ** actually write data to the file in this case.
-    **
-    ** Consider the following sequence of events:
-    **
-    **   BEGIN;
-    **     <journal page X>
-    **     <modify page X>
-    **     SAVEPOINT sp;
-    **       <shrink database file to Y pages>
-    **       pagerStress(page X)
-    **     ROLLBACK TO sp;
-    **
-    ** If (X>Y), then when pagerStress is called page X will not be written
-    ** out to the database file, but will be dropped from the cache. Then,
-    ** following the "ROLLBACK TO sp" statement, reading page X will read
-    ** data from the database file. This will be the copy of page X as it
-    ** was when the transaction started, not as it was when "SAVEPOINT sp"
-    ** was executed.
-    **
-    ** The solution is to write the current data for page X into the 
-    ** sub-journal file now (if it is not already there), so that it will
-    ** be restored to its current value when the "ROLLBACK TO sp" is 
-    ** executed.
-    */
-    if( NEVER(
-        rc==SQLITE_OK && pPg->pgno>pPager->dbSize && subjRequiresPage(pPg)
-    ) ){
-      rc = subjournalPage(pPg);
-    }
-  
     /* Write the contents of the page out to the database file. */
     if( rc==SQLITE_OK ){
       assert( (pPg->flags&PGHDR_NEED_SYNC)==0 );
@@ -5781,8 +5751,8 @@ static int pager_write(PgHdr *pPg){
   /* If the statement journal is open and the page is not in it,
   ** then write the page into the statement journal.
   */
-  if( pPager->nSavepoint>0 && subjRequiresPage(pPg) ){
-    rc = subjournalPage(pPg);
+  if( pPager->nSavepoint>0 ){
+    rc = subjournalPageIfRequired(pPg);
   }
 
   /* Update the database size and return. */
@@ -6772,9 +6742,8 @@ int sqlite3PagerMovepage(Pager *pPager, DbPage *pPg, Pgno pgno, int isCommit){
   ** one or more savepoint bitvecs. This is the reason this function
   ** may return SQLITE_NOMEM.
   */
-  if( pPg->flags&PGHDR_DIRTY
-   && subjRequiresPage(pPg)
-   && SQLITE_OK!=(rc = subjournalPage(pPg))
+  if( (pPg->flags & PGHDR_DIRTY)!=0
+   && SQLITE_OK!=(rc = subjournalPageIfRequired(pPg))
   ){
     return rc;
   }