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Overview
| Comment: | Make sure the queueMutex is held prior to writing the pQueueLast field of the write queue in the async demonstration code. Ticket #3405. (CVS 5744) |
|---|---|
| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
5622a1e285fc4d5720f7180a0eb55195 |
| User & Date: | drh 2008-09-26 20:02:50.000 |
Context
|
2008-09-26
| ||
| 21:08 | Add the "truncate" journal mode which commits transactions by truncating the rollback journal file to zero length and not calling fsync(). (CVS 5745) (check-in: 7c561f2e92 user: drh tags: trunk) | |
| 20:02 | Make sure the queueMutex is held prior to writing the pQueueLast field of the write queue in the async demonstration code. Ticket #3405. (CVS 5744) (check-in: 5622a1e285 user: drh tags: trunk) | |
| 17:31 | Performance enhancement: avoid calling reparentChildPages() from balance_nonroot(). (CVS 5743) (check-in: 28fd0a50ca user: danielk1977 tags: trunk) | |
Changes
Changes to src/test_async.c.
1 2 3 4 5 6 7 8 9 10 11 12 | /* ** 2005 December 14 ** ** The author disclaims copyright to this source code. In place of ** a legal notice, here is a blessing: ** ** May you do good and not evil. ** May you find forgiveness for yourself and forgive others. ** May you share freely, never taking more than you give. ** ************************************************************************* ** | | | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | /* ** 2005 December 14 ** ** The author disclaims copyright to this source code. In place of ** a legal notice, here is a blessing: ** ** May you do good and not evil. ** May you find forgiveness for yourself and forgive others. ** May you share freely, never taking more than you give. ** ************************************************************************* ** ** $Id: test_async.c,v 1.48 2008/09/26 20:02:50 drh Exp $ ** ** This file contains an example implementation of an asynchronous IO ** backend for SQLite. ** ** WHAT IS ASYNCHRONOUS I/O? ** ** With asynchronous I/O, write requests are handled by a separate thread |
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aHolder[iIdx] = 0;
rc = pthread_cond_wait(pCond, pMutex);
if( rc==0 ){
aHolder[iIdx] = pthread_self();
}
return rc;
}
/* Call our async_XX wrappers instead of selected pthread_XX functions */
#define pthread_mutex_lock async_mutex_lock
#define pthread_mutex_unlock async_mutex_unlock
#define pthread_mutex_trylock async_mutex_trylock
#define pthread_cond_wait async_cond_wait
#endif /* !defined(NDEBUG) */
/*
** Add an entry to the end of the global write-op list. pWrite should point
** to an AsyncWrite structure allocated using sqlite3_malloc(). The writer
** thread will call sqlite3_free() to free the structure after the specified
** operation has been completed.
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aHolder[iIdx] = 0;
rc = pthread_cond_wait(pCond, pMutex);
if( rc==0 ){
aHolder[iIdx] = pthread_self();
}
return rc;
}
/*
** Assert that the mutex is held by the current thread.
*/
static void assert_mutex_is_held(pthread_mutex_t *pMutex){
int iIdx;
pthread_mutex_t *aMutex = (pthread_mutex_t *)(&async);
pthread_t *aHolder = (pthread_t *)(&asyncdebug);
for(iIdx=0; iIdx<3; iIdx++){
if( pMutex==&aMutex[iIdx] ) break;
}
assert(iIdx<3);
assert( aHolder[iIdx]==pthread_self() );
}
/* Call our async_XX wrappers instead of selected pthread_XX functions */
#define pthread_mutex_lock async_mutex_lock
#define pthread_mutex_unlock async_mutex_unlock
#define pthread_mutex_trylock async_mutex_trylock
#define pthread_cond_wait async_cond_wait
#else /* if defined(NDEBUG) */
#define assert_mutex_is_held(X) /* A no-op when not debugging */
#endif /* !defined(NDEBUG) */
/*
** Add an entry to the end of the global write-op list. pWrite should point
** to an AsyncWrite structure allocated using sqlite3_malloc(). The writer
** thread will call sqlite3_free() to free the structure after the specified
** operation has been completed.
|
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** structures for this file. Obtain the async.lockMutex mutex
** before doing so.
*/
pthread_mutex_lock(&async.lockMutex);
rc = unlinkAsyncFile(pData);
pthread_mutex_unlock(&async.lockMutex);
async.pQueueFirst = p->pNext;
sqlite3_free(pData);
doNotFree = 1;
break;
}
case ASYNC_UNLOCK: {
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** structures for this file. Obtain the async.lockMutex mutex
** before doing so.
*/
pthread_mutex_lock(&async.lockMutex);
rc = unlinkAsyncFile(pData);
pthread_mutex_unlock(&async.lockMutex);
if( !holdingMutex ){
pthread_mutex_lock(&async.queueMutex);
holdingMutex = 1;
}
assert_mutex_is_held(&async.queueMutex);
async.pQueueFirst = p->pNext;
sqlite3_free(pData);
doNotFree = 1;
break;
}
case ASYNC_UNLOCK: {
|
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holdingMutex = 1;
}
/* ASYNC_TRACE(("UNLINK %p\n", p)); */
if( p==async.pQueueLast ){
async.pQueueLast = 0;
}
if( !doNotFree ){
async.pQueueFirst = p->pNext;
sqlite3_free(p);
}
assert( holdingMutex );
/* An IO error has occured. We cannot report the error back to the
** connection that requested the I/O since the error happened
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holdingMutex = 1;
}
/* ASYNC_TRACE(("UNLINK %p\n", p)); */
if( p==async.pQueueLast ){
async.pQueueLast = 0;
}
if( !doNotFree ){
assert_mutex_is_held(&async.queueMutex);
async.pQueueFirst = p->pNext;
sqlite3_free(p);
}
assert( holdingMutex );
/* An IO error has occured. We cannot report the error back to the
** connection that requested the I/O since the error happened
|
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