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Defer the exclusive db lock until the pager cache is flushed to disk. 41

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tests now fail. (CVS 1528)

FossilOrigin-Name: d2f69e5ef2f261a00bb8427a4e2a1638ecfd17a9
This commit is contained in:
danielk1977
2004-06-04 10:38:30 +00:00
parent 24162fe668
commit 9eed505701
5 changed files with 84 additions and 68 deletions
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109
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 1.111 2004/06/04 06:22:01 danielk1977 Exp $
** @(#) $Id: pager.c,v 1.112 2004/06/04 10:38:31 danielk1977 Exp $
*/
#include "os.h" /* Must be first to enable large file support */
#include "sqliteInt.h"
@@ -522,7 +522,7 @@ static int pager_unwritelock(Pager *pPager){
}else{
assert( pPager->dirtyFile==0 || pPager->useJournal==0 );
}
rc = sqlite3OsReadLock(&pPager->fd);
rc = sqlite3OsLock(&pPager->fd, SHARED_LOCK);
if( rc==SQLITE_OK ){
pPager->state = SQLITE_READLOCK;
}else{
@@ -658,15 +658,28 @@ static int pager_delmaster(const char *zMaster){
*/
OsFile journal;
int nMaster;
off_t jsz;
rc = sqlite3OsOpenReadOnly(zJournal, &journal);
sqliteFree(zJournal);
if( rc!=SQLITE_OK ){
sqlite3OsClose(&journal);
sqliteFree(zJournal);
goto delmaster_out;
}
sqlite3OsClose(&journal);
/* Check if the file is big enough to be a format 3 journal file
** with the required master journal name. If not, ignore it.
*/
rc = sqlite3OsFileSize(&journal, &jsz);
if( rc!=SQLITE_OK ){
sqlite3OsClose(&journal);
goto delmaster_out;
}
if( jsz<(sizeof(aJournalMagic3)+4*sizeof(u32)+strlen(zMaster)+1) ){
sqlite3OsClose(&journal);
continue;
}
/* Seek to the point in the journal where the master journal name
** is stored. Read the master journal name into memory obtained
** from malloc.
@@ -1532,9 +1545,40 @@ static int syncJournal(Pager *pPager, const char *zMaster){
static int pager_write_pagelist(PgHdr *pList){
Pager *pPager;
int rc;
int busy = 1;
if( pList==0 ) return SQLITE_OK;
pPager = pList->pPager;
/* At this point there may be either a RESERVED or EXCLUSIVE lock on the
** database file. If there is already an EXCLUSIVE lock, the following
** calls to sqlite3OsLock() are no-ops.
**
** The upgrade from a RESERVED to PENDING lock cannot return SQLITE_BUSY,
** unless someone is not following the locking protocol.
**
** The upgrade from PENDING to EXCLUSIVE can return SQLITE_BUSY. It's
** not totally clear that the busy-callback should be invoked here
** though. (?)
*/
rc = sqlite3OsLock(&pPager->fd, PENDING_LOCK);
if( rc==SQLITE_BUSY ){
return SQLITE_PROTOCOL;
}
if( rc!=SQLITE_OK ){
return rc;
}
do {
rc = sqlite3OsLock(&pPager->fd, EXCLUSIVE_LOCK);
}while( rc==SQLITE_BUSY &&
pPager->pBusyHandler &&
pPager->pBusyHandler->xFunc &&
pPager->pBusyHandler->xFunc(pPager->pBusyHandler->pArg, "", busy++)
);
if( rc!=SQLITE_OK ){
return rc;
}
while( pList ){
assert( pList->dirty );
sqlite3OsSeek(&pPager->fd, (pList->pgno-1)*(off_t)SQLITE_PAGE_SIZE);
@@ -1607,20 +1651,15 @@ int sqlite3pager_get(Pager *pPager, Pgno pgno, void **ppPage){
*/
if( pPager->nRef==0 && !pPager->memDb ){
int busy = 1;
while( busy ){
rc = sqlite3OsReadLock(&pPager->fd);
if( rc==SQLITE_BUSY &&
pPager->pBusyHandler &&
pPager->pBusyHandler->xFunc &&
pPager->pBusyHandler->xFunc(pPager->pBusyHandler->pArg, "", busy++)
){
rc = SQLITE_OK;
}else{
busy = 0;
}
if( rc!=SQLITE_OK ){
return rc;
}
do {
rc = sqlite3OsLock(&pPager->fd, SHARED_LOCK);
}while( rc==SQLITE_BUSY &&
pPager->pBusyHandler &&
pPager->pBusyHandler->xFunc &&
pPager->pBusyHandler->xFunc(pPager->pBusyHandler->pArg, "", busy++)
);
if( rc!=SQLITE_OK ){
return rc;
}
pPager->state = SQLITE_READLOCK;
@@ -1906,7 +1945,7 @@ static int pager_open_journal(Pager *pPager){
sqlite3pager_pagecount(pPager);
pPager->aInJournal = sqliteMalloc( pPager->dbSize/8 + 1 );
if( pPager->aInJournal==0 ){
sqlite3OsReadLock(&pPager->fd);
sqlite3OsLock(&pPager->fd, SHARED_LOCK);
pPager->state = SQLITE_READLOCK;
return SQLITE_NOMEM;
}
@@ -1914,7 +1953,7 @@ static int pager_open_journal(Pager *pPager){
if( rc!=SQLITE_OK ){
sqliteFree(pPager->aInJournal);
pPager->aInJournal = 0;
sqlite3OsReadLock(&pPager->fd);
sqlite3OsLock(&pPager->fd, SHARED_LOCK);
pPager->state = SQLITE_READLOCK;
return SQLITE_CANTOPEN;
}
@@ -2020,20 +2059,20 @@ int sqlite3pager_begin(void *pData, int nMaster){
pPager->origDbSize = pPager->dbSize;
}else{
int busy = 1;
while( busy ){
rc = sqlite3OsWriteLock(&pPager->fd);
if( rc==SQLITE_BUSY &&
pPager->pBusyHandler &&
pPager->pBusyHandler->xFunc &&
pPager->pBusyHandler->xFunc(pPager->pBusyHandler->pArg, "", busy++)
){
rc = SQLITE_OK;
}else{
busy = 0;
}
if( rc!=SQLITE_OK ){
return rc;
}
do {
/* If the library grabs an EXCLUSIVE lock here, as in the commented
** out line, then it exhibits the old locking behaviour - a writer
** excludes all readers, not just other writers.
*/
/* rc = sqlite3OsLock(&pPager->fd, EXCLUSIVE_LOCK); */
rc = sqlite3OsLock(&pPager->fd, RESERVED_LOCK);
}while( rc==SQLITE_BUSY &&
pPager->pBusyHandler &&
pPager->pBusyHandler->xFunc &&
pPager->pBusyHandler->xFunc(pPager->pBusyHandler->pArg, "", busy++)
);
if( rc!=SQLITE_OK ){
return rc;
}
pPager->nMaster = nMaster;
pPager->state = SQLITE_WRITELOCK;
@@ -2515,7 +2554,7 @@ int sqlite3pager_stmt_begin(Pager *pPager){
assert( pPager->journalOpen );
pPager->aInStmt = sqliteMalloc( pPager->dbSize/8 + 1 );
if( pPager->aInStmt==0 ){
sqlite3OsReadLock(&pPager->fd);
sqlite3OsLock(&pPager->fd, SHARED_LOCK);
return SQLITE_NOMEM;
}
#ifndef NDEBUG