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Delay opening temporary pager files until they are first written. (CVS 4260)

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FossilOrigin-Name: 3fb97a63ef70662abdba18ce8b480e6b0badcfb1
This commit is contained in:
danielk1977
2007-08-21 14:27:01 +00:00
parent 51fc347a2e
commit 7a2b1eeb7f
4 changed files with 70 additions and 32 deletions
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61
src/pager.c
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@@ -18,7 +18,7 @@
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.363 2007/08/21 10:44:16 drh Exp $
** @(#) $Id: pager.c,v 1.364 2007/08/21 14:27:02 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
@@ -549,6 +549,16 @@ static int write32bits(sqlite3_file *fd, i64 offset, u32 val){
return sqlite3OsWrite(fd, ac, 4, offset);
}
/*
** If file pFd is open, call sqlite3OsUnlock() on it.
*/
static int osUnlock(sqlite3_file *pFd, int eLock){
if( !pFd->pMethods ){
return SQLITE_OK;
}
return sqlite3OsUnlock(pFd, eLock);
}
/*
** This function should be called when an error occurs within the pager
** code. The first argument is a pointer to the pager structure, the
@@ -930,7 +940,7 @@ static PgHdr *pager_lookup(Pager *pPager, Pgno pgno){
static void pager_unlock(Pager *pPager){
if( !pPager->exclusiveMode ){
if( !MEMDB ){
sqlite3OsUnlock(pPager->fd, NO_LOCK);
osUnlock(pPager->fd, NO_LOCK);
pPager->dbSize = -1;
IOTRACE(("UNLOCK %p\n", pPager))
}
@@ -1045,7 +1055,7 @@ static int pager_end_transaction(Pager *pPager){
}
if( !pPager->exclusiveMode ){
rc2 = sqlite3OsUnlock(pPager->fd, SHARED_LOCK);
rc2 = osUnlock(pPager->fd, SHARED_LOCK);
pPager->state = PAGER_SHARED;
}else if( pPager->state==PAGER_SYNCED ){
pPager->state = PAGER_EXCLUSIVE;
@@ -1318,7 +1328,7 @@ static void pager_truncate_cache(Pager *pPager);
*/
static int pager_truncate(Pager *pPager, int nPage){
int rc = SQLITE_OK;
if( pPager->state>=PAGER_EXCLUSIVE ){
if( pPager->state>=PAGER_EXCLUSIVE && pPager->fd->pMethods ){
rc = sqlite3OsTruncate(pPager->fd, pPager->pageSize*(i64)nPage);
}
if( rc==SQLITE_OK ){
@@ -1335,7 +1345,14 @@ static int pager_truncate(Pager *pPager, int nPage){
** by sqlite3OsSectorSize() and the pageSize.
*/
static void setSectorSize(Pager *pPager){
pPager->sectorSize = sqlite3OsSectorSize(pPager->fd);
assert(pPager->fd->pMethods||pPager->tempFile);
if( !pPager->tempFile ){
/* Sector size doesn't matter for temporary files. Also, the file
** may not have been opened yet, in whcih case the OsSectorSize()
** call will segfault.
*/
pPager->sectorSize = sqlite3OsSectorSize(pPager->fd);
}
if( pPager->sectorSize<pPager->pageSize ){
pPager->sectorSize = pPager->pageSize;
}
@@ -1823,10 +1840,13 @@ int sqlite3PagerOpen(
}
}
}else{
rc = sqlite3PagerOpentemp(pVfs, pPager->fd, pPager->zFilename);
if( rc==SQLITE_OK ){
tempFile = 1;
}
/* If a temporary file is requested, it is not opened immediately.
** In this case we accept the default page size and delay actually
** opening the file until the first call to OsWrite().
*/
/* rc = sqlite3PagerOpentemp(pVfs, pPager->fd, pPager->zFilename); */
tempFile = 1;
pPager->state = PAGER_EXCLUSIVE;
}
if( pPager && rc==SQLITE_OK ){
@@ -1887,7 +1907,7 @@ int sqlite3PagerOpen(
/* pPager->pFirstSynced = 0; */
/* pPager->pLast = 0; */
pPager->nExtra = FORCE_ALIGNMENT(nExtra);
assert(pPager->fd->pMethods||memDb);
assert(pPager->fd->pMethods||memDb||tempFile);
if( !memDb ){
setSectorSize(pPager);
}
@@ -1999,7 +2019,8 @@ void enable_simulated_io_errors(void){
int sqlite3PagerReadFileheader(Pager *pPager, int N, unsigned char *pDest){
int rc = SQLITE_OK;
memset(pDest, 0, N);
if( MEMDB==0 ){
assert(MEMDB||pPager->fd->pMethods||pPager->tempFile);
if( pPager->fd->pMethods ){
IOTRACE(("DBHDR %p 0 %d\n", pPager, N))
rc = sqlite3OsRead(pPager->fd, pDest, N, 0);
if( rc==SQLITE_IOERR_SHORT_READ ){
@@ -2019,7 +2040,7 @@ int sqlite3PagerReadFileheader(Pager *pPager, int N, unsigned char *pDest){
** file is 4096 bytes, 5 is returned instead of 4.
*/
int sqlite3PagerPagecount(Pager *pPager){
i64 n;
i64 n = 0;
int rc;
assert( pPager!=0 );
if( pPager->errCode ){
@@ -2028,7 +2049,9 @@ int sqlite3PagerPagecount(Pager *pPager){
if( pPager->dbSize>=0 ){
n = pPager->dbSize;
} else {
if( (rc = sqlite3OsFileSize(pPager->fd, &n))!=SQLITE_OK ){
assert(pPager->fd->pMethods||pPager->tempFile);
if( (pPager->fd->pMethods)
&& (rc = sqlite3OsFileSize(pPager->fd, &n))!=SQLITE_OK ){
pager_error(pPager, rc);
return 0;
}
@@ -2570,6 +2593,14 @@ static int pager_write_pagelist(PgHdr *pList){
pList = sort_pagelist(pList);
while( pList ){
/* If the file has not yet been opened, open it now. */
if( !pPager->fd->pMethods ){
assert(pPager->tempFile);
rc = sqlite3PagerOpentemp(pPager->pVfs, pPager->fd, pPager->zFilename);
if( rc ) return rc;
}
assert( pList->dirty );
/* If there are dirty pages in the page cache with page numbers greater
** than Pager.dbSize, this means sqlite3PagerTruncate() was called to
@@ -2834,6 +2865,10 @@ static int readDbPage(Pager *pPager, PgHdr *pPg, Pgno pgno){
int rc;
i64 offset;
assert( MEMDB==0 );
assert(pPager->fd->pMethods||pPager->tempFile);
if( !pPager->fd->pMethods ){
return SQLITE_IOERR_SHORT_READ;
}
offset = (pgno-1)*(i64)pPager->pageSize;
rc = sqlite3OsRead(pPager->fd, PGHDR_TO_DATA(pPg), pPager->pageSize, offset);
PAGER_INCR(sqlite3_pager_readdb_count);