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Delay opening the sub-journal until SQLite actually needs to write data to it.

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FossilOrigin-Name: c43deb33ae5f191ea2e054181759beeeb9ea71bf
This commit is contained in:
dan
2010-06-03 12:35:28 +00:00
parent f83dc1ef3f
commit 459564f43f
6 changed files with 89 additions and 79 deletions
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75
src/pager.c
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@@ -3407,6 +3407,26 @@ static int pager_write_pagelist(PgHdr *pList){
return rc;
}
/*
** Ensure that the sub-journal file is open. If it is already open, this
** function is a no-op.
**
** SQLITE_OK is returned if everything goes according to plan. An
** SQLITE_IOERR_XXX error code is returned if a call to sqlite3OsOpen()
** fails.
*/
static int openSubJournal(Pager *pPager){
int rc = SQLITE_OK;
if( !isOpen(pPager->sjfd) ){
if( pPager->journalMode==PAGER_JOURNALMODE_MEMORY || pPager->subjInMemory ){
sqlite3MemJournalOpen(pPager->sjfd);
}else{
rc = pagerOpentemp(pPager, pPager->sjfd, SQLITE_OPEN_SUBJOURNAL);
}
}
return rc;
}
/*
** Append a record of the current state of page pPg to the sub-journal.
** It is the callers responsibility to use subjRequiresPage() to check
@@ -3423,21 +3443,31 @@ static int pager_write_pagelist(PgHdr *pList){
static int subjournalPage(PgHdr *pPg){
int rc = SQLITE_OK;
Pager *pPager = pPg->pPager;
if( isOpen(pPager->sjfd) ){
void *pData = pPg->pData;
i64 offset = pPager->nSubRec*(4+pPager->pageSize);
char *pData2;
if( pPager->journalMode!=PAGER_JOURNALMODE_OFF ){
CODEC2(pPager, pData, pPg->pgno, 7, return SQLITE_NOMEM, pData2);
PAGERTRACE(("STMT-JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno));
/* Open the sub-journal, if it has not already been opened */
assert( pPager->useJournal );
assert( isOpen(pPager->jfd) || pagerUseWal(pPager) );
assert( isOpen(pPager->sjfd) || pPager->nSubRec==0 );
assert( pagerUseWal(pPager)
|| pageInJournal(pPg)
|| pPg->pgno>pPager->dbOrigSize
);
rc = write32bits(pPager->sjfd, offset, pPg->pgno);
rc = openSubJournal(pPager);
/* If the sub-journal was opened successfully (or was already open),
** write the journal record into the file. */
if( rc==SQLITE_OK ){
rc = sqlite3OsWrite(pPager->sjfd, pData2, pPager->pageSize, offset+4);
void *pData = pPg->pData;
i64 offset = pPager->nSubRec*(4+pPager->pageSize);
char *pData2;
CODEC2(pPager, pData, pPg->pgno, 7, return SQLITE_NOMEM, pData2);
PAGERTRACE(("STMT-JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno));
rc = write32bits(pPager->sjfd, offset, pPg->pgno);
if( rc==SQLITE_OK ){
rc = sqlite3OsWrite(pPager->sjfd, pData2, pPager->pageSize, offset+4);
}
}
}
if( rc==SQLITE_OK ){
@@ -4400,27 +4430,6 @@ void sqlite3PagerUnref(DbPage *pPg){
}
}
/*
** If the main journal file has already been opened, ensure that the
** sub-journal file is open too. If the main journal is not open,
** this function is a no-op.
**
** SQLITE_OK is returned if everything goes according to plan.
** An SQLITE_IOERR_XXX error code is returned if a call to
** sqlite3OsOpen() fails.
*/
static int openSubJournal(Pager *pPager){
int rc = SQLITE_OK;
if( (pagerUseWal(pPager) || isOpen(pPager->jfd)) && !isOpen(pPager->sjfd) ){
if( pPager->journalMode==PAGER_JOURNALMODE_MEMORY || pPager->subjInMemory ){
sqlite3MemJournalOpen(pPager->sjfd);
}else{
rc = pagerOpentemp(pPager, pPager->sjfd, SQLITE_OPEN_SUBJOURNAL);
}
}
return rc;
}
/*
** This function is called at the start of every write transaction.
** There must already be a RESERVED or EXCLUSIVE lock on the database
@@ -4503,9 +4512,6 @@ static int pager_open_journal(Pager *pPager){
pPager->journalHdr = 0;
rc = writeJournalHdr(pPager);
}
if( rc==SQLITE_OK && pPager->nSavepoint ){
rc = openSubJournal(pPager);
}
if( rc!=SQLITE_OK ){
sqlite3BitvecDestroy(pPager->pInJournal);
@@ -5469,9 +5475,6 @@ int sqlite3PagerOpenSavepoint(Pager *pPager, int nSavepoint){
pPager->nSavepoint = ii+1;
}
assert( pPager->nSavepoint==nSavepoint );
/* Open the sub-journal, if it is not already opened. */
rc = openSubJournal(pPager);
assertTruncateConstraint(pPager);
}