Add code to reduce rollback journal i/o based on IOCAP flags. As yet untested. (CVS 4278)
FossilOrigin-Name: 595568492e63822caed5b6970542dcee4615dc4d
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danielk1977
parent
863c0f9b87
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12
manifest
12
manifest
@ -1,5 +1,5 @@
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C Ensure\stemporary\sfiles\sare\sdeleted\swhen\sthey\sare\sclosed.\s(CVS\s4277)
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D 2007-08-23T11:47:59
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C Add\scode\sto\sreduce\srollback\sjournal\si/o\sbased\son\sIOCAP\sflags.\sAs\syet\suntested.\s(CVS\s4278)
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D 2007-08-23T14:48:24
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F Makefile.in 0c0e53720f658c7a551046442dd7afba0b72bfbe
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F Makefile.linux-gcc 65241babba6faf1152bf86574477baab19190499
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F README 9c4e2d6706bdcc3efdd773ce752a8cdab4f90028
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@ -115,7 +115,7 @@ F src/os_unix.c 3ff776e03535b64df12dcc272a913a52d69f3e4a
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F src/os_unix.h 5768d56d28240d3fe4537fac08cc85e4fb52279e
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F src/os_win.c 29c0e19c1072679a4c7818c49fab2f35d2ad7747
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F src/os_win.h 41a946bea10f61c158ce8645e7646b29d44f122b
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F src/pager.c 896e95aa2dcb74d5b951a87be4eec811617c835b
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F src/pager.c 0879439873a9da769ee400b3b8c0967afd786fe8
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F src/pager.h 53087c6fb9db01aed17c7fd044662a27507e89b8
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F src/parse.y 2d2ce439dc6184621fb0b86f4fc5aca7f391a590
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F src/pragma.c 9b989506a1b7c8aecd6befb8235e2f57a4aba7e5
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@ -560,7 +560,7 @@ F www/tclsqlite.tcl 8be95ee6dba05eabcd27a9d91331c803f2ce2130
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F www/vdbe.tcl 87a31ace769f20d3627a64fa1fade7fed47b90d0
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F www/version3.tcl 890248cf7b70e60c383b0e84d77d5132b3ead42b
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F www/whentouse.tcl fc46eae081251c3c181bd79c5faef8195d7991a5
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P 5f0fb894f44069c4aa9b8dba62b4d8a262c991de
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R 22b54f8709250bd737f996dad2021c82
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P cf4e3c158aa71afc91f263a314c2e750d191fb41
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R 48618499cdb378fd88ded4f7882609ca
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U danielk1977
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Z fa59609801ef669b738463099d997068
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Z c7849b12c2cdd0aee60800e4b6323c91
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@ -1 +1 @@
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cf4e3c158aa71afc91f263a314c2e750d191fb41
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595568492e63822caed5b6970542dcee4615dc4d
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84
src/pager.c
84
src/pager.c
@ -18,7 +18,7 @@
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** file simultaneously, or one process from reading the database while
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** another is writing.
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**
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** @(#) $Id: pager.c,v 1.370 2007/08/23 11:47:59 danielk1977 Exp $
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** @(#) $Id: pager.c,v 1.371 2007/08/23 14:48:24 danielk1977 Exp $
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*/
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#ifndef SQLITE_OMIT_DISKIO
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#include "sqliteInt.h"
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@ -822,17 +822,37 @@ static int writeJournalHdr(Pager *pPager){
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seekJournalHdr(pPager);
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pPager->journalHdr = pPager->journalOff;
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/* FIX ME:
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**
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** Possibly for a pager not in no-sync mode, the journal magic should not
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** be written until nRec is filled in as part of next syncJournal().
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**
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** Actually maybe the whole journal header should be delayed until that
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** point. Think about this.
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*/
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memcpy(zHeader, aJournalMagic, sizeof(aJournalMagic));
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/* The nRec Field. 0xFFFFFFFF for no-sync journals. */
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put32bits(&zHeader[sizeof(aJournalMagic)], pPager->noSync ? 0xffffffff : 0);
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/*
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** Write the nRec Field - the number of page records that follow this
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** journal header. Normally, zero is written to this value at this time.
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** After the records are added to the journal (and the journal synced,
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** if in full-sync mode), the zero is overwritten with the true number
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** of records (see syncJournal()).
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**
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** A faster alternative is to write 0xFFFFFFFF to the nRec field. When
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** reading the journal this value tells SQLite to assume that the
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** rest of the journal file contains valid page records. This assumption
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** is dangerous, as if a failure occured whilst writing to the journal
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** file it may contain some garbage data. There are two scenarios
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** where this risk can be ignored:
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**
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** * When the pager is in no-sync mode. Corruption can follow a
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** power failure in this case anyway.
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**
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** * When the SQLITE_IOCAP_SAFE_APPEND flag is set. This guarantees
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** that garbage data is never appended to the journal file.
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*/
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assert(pPager->fd->pMethods||pPager->noSync);
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if( (pPager->noSync)
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|| (sqlite3OsDeviceCharacteristics(pPager->fd)&SQLITE_IOCAP_SAFE_APPEND)
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){
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put32bits(&zHeader[sizeof(aJournalMagic)], 0xffffffff);
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}else{
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put32bits(&zHeader[sizeof(aJournalMagic)], 0);
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}
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/* The random check-hash initialiser */
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sqlite3Randomness(sizeof(pPager->cksumInit), &pPager->cksumInit);
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put32bits(&zHeader[sizeof(aJournalMagic)+4], pPager->cksumInit);
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@ -2484,7 +2504,12 @@ int sqlite3PagerRef(DbPage *pPg){
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** is synced, then the nRec field is updated, then a second sync occurs.
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**
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** For temporary databases, we do not care if we are able to rollback
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** after a power failure, so sync occurs.
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** after a power failure, so no sync occurs.
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**
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** If the IOCAP_SEQUENTIAL flag is set for the persistent media on which
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** the database is stored, then OsSync() is never called on the journal
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** file. In this case all that is required is to update the nRec field in
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** the journal header.
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**
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** This routine clears the needSync field of every page current held in
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** memory.
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@ -2493,12 +2518,15 @@ static int syncJournal(Pager *pPager){
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PgHdr *pPg;
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int rc = SQLITE_OK;
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/* Sync the journal before modifying the main database
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** (assuming there is a journal and it needs to be synced.)
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*/
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if( pPager->needSync ){
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if( !pPager->tempFile ){
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int iDc = sqlite3OsDeviceCharacteristics(pPager->fd);
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assert( pPager->journalOpen );
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/* assert( !pPager->noSync ); // noSync might be set if synchronous
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** was turned off after the transaction was started. Ticket #615 */
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#ifndef NDEBUG
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@ -2512,15 +2540,20 @@ static int syncJournal(Pager *pPager){
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assert( pPager->journalOff==jSz );
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}
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#endif
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{
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i64 jrnlOff;
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if( 0==(iDc&SQLITE_IOCAP_SAFE_APPEND) ){
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/* Write the nRec value into the journal file header. If in
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** full-synchronous mode, sync the journal first. This ensures that
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** all data has really hit the disk before nRec is updated to mark
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** it as a candidate for rollback.
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** it as a candidate for rollback.
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**
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** This is not required if the persistent media supports the
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** SAFE_APPEND property. Because in this case it is not possible
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** for garbage data to be appended to the file, the nRec field
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** is populated with 0xFFFFFFFF when the journal header is written
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** and never needs to be updated.
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*/
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if( pPager->fullSync ){
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i64 jrnlOff;
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if( pPager->fullSync && 0==(iDc&SQLITE_IOCAP_SEQUENTIAL) ){
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PAGERTRACE2("SYNC journal of %d\n", PAGERID(pPager));
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IOTRACE(("JSYNC %p\n", pPager))
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rc = sqlite3OsSync(pPager->jfd, pPager->sync_flags);
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@ -2532,12 +2565,14 @@ static int syncJournal(Pager *pPager){
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rc = write32bits(pPager->jfd, jrnlOff, pPager->nRec);
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if( rc ) return rc;
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}
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PAGERTRACE2("SYNC journal of %d\n", PAGERID(pPager));
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IOTRACE(("JSYNC %p\n", pPager))
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rc = sqlite3OsSync(pPager->jfd, pPager->sync_flags|
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(pPager->sync_flags==SQLITE_SYNC_FULL?SQLITE_SYNC_DATAONLY:0)
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);
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if( rc!=0 ) return rc;
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if( 0==(iDc&SQLITE_IOCAP_SEQUENTIAL) ){
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PAGERTRACE2("SYNC journal of %d\n", PAGERID(pPager));
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IOTRACE(("JSYNC %p\n", pPager))
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rc = sqlite3OsSync(pPager->jfd, pPager->sync_flags|
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(pPager->sync_flags==SQLITE_SYNC_FULL?SQLITE_SYNC_DATAONLY:0)
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);
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if( rc!=0 ) return rc;
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}
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pPager->journalStarted = 1;
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}
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pPager->needSync = 0;
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@ -2774,11 +2809,12 @@ static int pager_recycle(Pager *pPager, int syncOk, PgHdr **ppPg){
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** it can't be helped.
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*/
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if( pPg==0 && pPager->pFirst && syncOk && !MEMDB){
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int iDc = sqlite3OsDeviceCharacteristics(pPager->fd);
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int rc = syncJournal(pPager);
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if( rc!=0 ){
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return rc;
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}
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if( pPager->fullSync ){
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if( pPager->fullSync && 0==(iDc&SQLITE_IOCAP_SAFE_APPEND) ){
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/* If in full-sync mode, write a new journal header into the
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** journal file. This is done to avoid ever modifying a journal
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** header that is involved in the rollback of pages that have
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