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Add automatic recovery from the pager "error-state". Also add a new error code - SQLITE_IOERR_NOMEM. (CVS 4454)

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FossilOrigin-Name: 12eca32a6a3d68d5b20eed03afdffe7599e66014
This commit is contained in:
danielk1977
2007-10-03 08:46:44 +00:00
parent ae1463b941
commit ae72d98252
21 changed files with 319 additions and 132 deletions
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204
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 1.390 2007/09/17 07:02:57 danielk1977 Exp $
** @(#) $Id: pager.c,v 1.391 2007/10/03 08:46:45 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
@@ -809,9 +809,17 @@ static int jrnlBufferSize(Pager *pPager){
** The value returned is a copy of the second argument to this function.
**
** If the second argument is SQLITE_IOERR, SQLITE_CORRUPT, or SQLITE_FULL
** the error becomes persistent. All subsequent API calls on this Pager
** will immediately return the same error code.
** the error becomes persistent. Until the persisten error is cleared,
** subsequent API calls on this Pager will immediately return the same
** error code.
**
** A persistent error indicates that the contents of the pager-cache
** cannot be trusted. This state can be cleared by completely discarding
** the contents of the pager-cache. If a transaction was active when
** the persistent error occured, then the rollback journal may need
** to be replayed.
*/
static void pager_unlock(Pager *pPager);
static int pager_error(Pager *pPager, int rc){
int rc2 = rc & 0xff;
assert(
@@ -825,6 +833,13 @@ static int pager_error(Pager *pPager, int rc){
rc2==SQLITE_CORRUPT
){
pPager->errCode = rc;
if( pPager->state==PAGER_UNLOCK && pPager->nRef==0 ){
/* If the pager is already unlocked, call pager_unlock() now to
** clear the error state and ensure that the pager-cache is
** completely empty.
*/
pager_unlock(pPager);
}
}
return rc;
}
@@ -1198,38 +1213,6 @@ static PgHdr *pager_lookup(Pager *pPager, Pgno pgno){
return p;
}
/*
** Unlock the database file.
*/
static void pager_unlock(Pager *pPager){
if( !pPager->exclusiveMode ){
if( !MEMDB ){
osUnlock(pPager->fd, NO_LOCK);
pPager->dbSize = -1;
IOTRACE(("UNLOCK %p\n", pPager))
}
pPager->state = PAGER_UNLOCK;
pPager->changeCountDone = 0;
}
}
/*
** Execute a rollback if a transaction is active and unlock the
** database file. This is a no-op if the pager has already entered
** the error-state.
*/
static void pagerUnlockAndRollback(Pager *p){
if( p->errCode ) return;
assert( p->state>=PAGER_RESERVED || p->journalOpen==0 );
if( p->state>=PAGER_RESERVED ){
sqlite3PagerRollback(p);
}
pager_unlock(p);
assert( p->errCode || !p->journalOpen || (p->exclusiveMode&&!p->journalOff) );
assert( p->errCode || !p->stmtOpen || p->exclusiveMode );
}
/*
** Clear the in-memory cache. This routine
** sets the state of the pager back to what it was when it was first
@@ -1252,6 +1235,7 @@ static void pager_reset(Pager *pPager){
assert(pPager->lru.pLast==0);
pPager->pStmt = 0;
pPager->pAll = 0;
pPager->pDirty = 0;
pPager->nHash = 0;
sqlite3_free(pPager->aHash);
pPager->nPage = 0;
@@ -1259,6 +1243,69 @@ static void pager_reset(Pager *pPager){
pPager->nRef = 0;
}
/*
** Unlock the database file.
**
** If the pager is currently in error state, discard the contents of
** the cache and reset the Pager structure internal state. If there is
** an open journal-file, then the next time a shared-lock is obtained
** on the pager file (by this or any other process), it will be
** treated as a hot-journal and rolled back.
*/
static void pager_unlock(Pager *pPager){
if( !pPager->exclusiveMode ){
if( !MEMDB ){
if( pPager->fd->pMethods ){
osUnlock(pPager->fd, NO_LOCK);
}
pPager->dbSize = -1;
IOTRACE(("UNLOCK %p\n", pPager))
/* If Pager.errCode is set, the contents of the pager cache cannot be
** trusted. Now that the pager file is unlocked, the contents of the
** cache can be discarded and the error code safely cleared.
*/
if( pPager->errCode ){
pPager->errCode = SQLITE_OK;
pager_reset(pPager);
if( pPager->stmtOpen ){
sqlite3OsClose(pPager->stfd);
}
if( pPager->journalOpen ){
sqlite3OsClose(pPager->jfd);
pPager->journalOpen = 0;
}
pPager->stmtOpen = 0;
pPager->stmtInUse = 0;
pPager->journalOff = 0;
pPager->journalStarted = 0;
pPager->stmtAutoopen = 0;
pPager->origDbSize = 0;
}
}
if( !MEMDB || pPager->errCode==SQLITE_OK ){
pPager->state = PAGER_UNLOCK;
pPager->changeCountDone = 0;
}
}
}
/*
** Execute a rollback if a transaction is active and unlock the
** database file. If the pager has already entered the error state,
** do not attempt the rollback.
*/
static void pagerUnlockAndRollback(Pager *p){
assert( p->state>=PAGER_RESERVED || p->journalOpen==0 );
if( p->errCode==SQLITE_OK && p->state>=PAGER_RESERVED ){
sqlite3PagerRollback(p);
}
pager_unlock(p);
assert( p->errCode || !p->journalOpen || (p->exclusiveMode&&!p->journalOff) );
assert( p->errCode || !p->stmtOpen || p->exclusiveMode );
}
/*
** This routine ends a transaction. A transaction is ended by either
** a COMMIT or a ROLLBACK.
@@ -2367,7 +2414,9 @@ int sqlite3PagerPagecount(Pager *pPager){
assert(pPager->fd->pMethods||pPager->tempFile);
if( (pPager->fd->pMethods)
&& (rc = sqlite3OsFileSize(pPager->fd, &n))!=SQLITE_OK ){
pPager->nRef++;
pager_error(pPager, rc);
pPager->nRef--;
return 0;
}
if( n>0 && n<pPager->pageSize ){
@@ -3215,8 +3264,30 @@ static int readDbPage(Pager *pPager, PgHdr *pPg, Pgno pgno){
*/
static int pagerSharedLock(Pager *pPager){
int rc = SQLITE_OK;
int isHot = 0;
if( pPager->state==PAGER_UNLOCK ){
/* If this database is opened for exclusive access, has no outstanding
** page references and is in an error-state, now is the chance to clear
** the error. Discard the contents of the pager-cache and treat any
** open journal file as a hot-journal.
*/
if( !MEMDB && pPager->exclusiveMode && pPager->nRef==0 && pPager->errCode ){
if( pPager->journalOpen ){
isHot = 1;
}
pager_reset(pPager);
pPager->errCode = SQLITE_OK;
}
/* If the pager is still in an error state, do not proceed. The error
** state will be cleared at some point in the future when all page
** references are dropped and the cache can be discarded.
*/
if( pPager->errCode && pPager->errCode!=SQLITE_FULL ){
return pPager->errCode;
}
if( pPager->state==PAGER_UNLOCK || isHot ){
sqlite3_vfs *pVfs = pPager->pVfs;
if( !MEMDB ){
assert( pPager->nRef==0 );
@@ -3231,7 +3302,7 @@ static int pagerSharedLock(Pager *pPager){
/* If a journal file exists, and there is no RESERVED lock on the
** database file, then it either needs to be played back or deleted.
*/
if( hasHotJournal(pPager) ){
if( hasHotJournal(pPager) || isHot ){
/* Get an EXCLUSIVE lock on the database file. At this point it is
** important that a RESERVED lock is not obtained on the way to the
** EXCLUSIVE lock. If it were, another process might open the
@@ -3243,12 +3314,14 @@ static int pagerSharedLock(Pager *pPager){
** second process will get to this point in the code and fail to
** obtain it's own EXCLUSIVE lock on the database file.
*/
rc = sqlite3OsLock(pPager->fd, EXCLUSIVE_LOCK);
if( rc!=SQLITE_OK ){
pager_unlock(pPager);
return pager_error(pPager, rc);
if( pPager->state<EXCLUSIVE_LOCK ){
rc = sqlite3OsLock(pPager->fd, EXCLUSIVE_LOCK);
if( rc!=SQLITE_OK ){
pager_unlock(pPager);
return pager_error(pPager, rc);
}
pPager->state = PAGER_EXCLUSIVE;
}
pPager->state = PAGER_EXCLUSIVE;
/* Open the journal for reading only. Return SQLITE_BUSY if
** we are unable to open the journal file.
@@ -3264,21 +3337,23 @@ static int pagerSharedLock(Pager *pPager){
** OsTruncate() call used in exclusive-access mode also requires
** a read/write file handle.
*/
rc = SQLITE_BUSY;
if( sqlite3OsAccess(pVfs, pPager->zJournal, SQLITE_ACCESS_EXISTS) ){
int fout = 0;
int flags = SQLITE_OPEN_READWRITE|SQLITE_OPEN_MAIN_JOURNAL;
assert( !pPager->tempFile );
rc = sqlite3OsOpen(pVfs, pPager->zJournal, pPager->jfd, flags, &fout);
assert( rc!=SQLITE_OK || pPager->jfd->pMethods );
if( fout&SQLITE_OPEN_READONLY ){
rc = SQLITE_BUSY;
sqlite3OsClose(pPager->jfd);
if( !isHot ){
rc = SQLITE_BUSY;
if( sqlite3OsAccess(pVfs, pPager->zJournal, SQLITE_ACCESS_EXISTS) ){
int fout = 0;
int f = SQLITE_OPEN_READWRITE|SQLITE_OPEN_MAIN_JOURNAL;
assert( !pPager->tempFile );
rc = sqlite3OsOpen(pVfs, pPager->zJournal, pPager->jfd, f, &fout);
assert( rc!=SQLITE_OK || pPager->jfd->pMethods );
if( fout&SQLITE_OPEN_READONLY ){
rc = SQLITE_BUSY;
sqlite3OsClose(pPager->jfd);
}
}
}
if( rc!=SQLITE_OK ){
pager_unlock(pPager);
return (rc==SQLITE_NOMEM?rc:SQLITE_BUSY);
return ((rc==SQLITE_NOMEM||rc==SQLITE_IOERR_NOMEM)?rc:SQLITE_BUSY);
}
pPager->journalOpen = 1;
pPager->journalStarted = 0;
@@ -3513,9 +3588,6 @@ static int pagerAcquire(
*/
assert( pPager!=0 );
*ppPage = 0;
if( pPager->errCode && pPager->errCode!=SQLITE_FULL ){
return pPager->errCode;
}
/* If this is the first page accessed, then get a SHARED lock
** on the database file. pagerSharedLock() is a no-op if
@@ -3562,8 +3634,8 @@ static int pagerAcquire(
}
nMax = sqlite3PagerPagecount(pPager);
if( pPager->errCode ){
sqlite3PagerUnref(pPg);
rc = pPager->errCode;
sqlite3PagerUnref(pPg);
return rc;
}
@@ -3668,6 +3740,7 @@ DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno){
** removed.
*/
int sqlite3PagerUnref(DbPage *pPg){
Pager *pPager = pPg->pPager;
/* Decrement the reference count for this page
*/
@@ -3682,7 +3755,6 @@ int sqlite3PagerUnref(DbPage *pPg){
** destructor and add the page to the freelist.
*/
if( pPg->nRef==0 ){
Pager *pPager = pPg->pPager;
lruListAdd(pPg);
if( pPager->xDestructor ){
@@ -3698,7 +3770,7 @@ int sqlite3PagerUnref(DbPage *pPg){
pagerUnlockAndRollback(pPager);
}
}
pagerLeave(pPg->pPager);
pagerLeave(pPager);
return SQLITE_OK;
}
@@ -3766,7 +3838,7 @@ static int pager_open_journal(Pager *pPager){
if( pPager->stmtAutoopen && rc==SQLITE_OK ){
rc = sqlite3PagerStmtBegin(pPager);
}
if( rc!=SQLITE_OK && rc!=SQLITE_NOMEM ){
if( rc!=SQLITE_OK && rc!=SQLITE_NOMEM && rc!=SQLITE_IOERR_NOMEM ){
rc = pager_end_transaction(pPager);
if( rc==SQLITE_OK ){
rc = SQLITE_FULL;
@@ -4331,7 +4403,10 @@ static int pager_incr_changecounter(Pager *pPager, int isDirect){
if( !isDirect ){
rc = sqlite3PagerWrite(pPgHdr);
if( rc!=SQLITE_OK ) return rc;
if( rc!=SQLITE_OK ){
sqlite3PagerUnref(pPgHdr);
return rc;
}
}
/* Increment the value just read and write it back to byte 24. */
@@ -4411,13 +4486,14 @@ int sqlite3PagerCommitPhaseOne(Pager *pPager, const char *zMaster, Pgno nTrunc){
** file. Because of the atomic-write property of the host file-system,
** this is safe.
*/
rc = pager_incr_changecounter(pPager, 1);
if( rc==SQLITE_OK ){
rc = pager_incr_changecounter(pPager, 1);
}
}else{
rc = sqlite3JournalCreate(pPager->jfd);
if( rc!=SQLITE_OK ) goto sync_exit;
}
if( !useAtomicWrite )
if( !useAtomicWrite && rc==SQLITE_OK )
#endif
/* If a master journal file name has already been written to the