-C Do\snot\suse\sthe\sTryEnterCriticalSection\sAPI\son\swindows\ssince\sit\sis\nunavailable\son\ssome\splatforms.\s(CVS\s4399)
-D 2007-09-04T22:31:37
+C Fix\sa\sproblem\sin\sthe\stest\sscripts\sfor\sthe\sasynchronous\sbackend.\s(CVS\s4400)
+D 2007-09-05T11:34:54
F Makefile.in cbfb898945536a8f9ea8b897e1586dd1fdbcc5db
F Makefile.linux-gcc 65241babba6faf1152bf86574477baab19190499
F README 9c4e2d6706bdcc3efdd773ce752a8cdab4f90028
F src/test7.c a9d509d0e9ad214b4772696f49f6e61be26213d1
F src/test8.c f113aa3723a52113d0fa7c28155ecd37e7e04077
F src/test9.c b46c8fe02ac7cca1a7316436d8d38d50c66f4b2f
-F src/test_async.c e221db3e87b472733a8015be7d70bae0edb848b1
+F src/test_async.c 5d30feff6238f083eb32a55f5c18b036a1a5e40c
F src/test_autoext.c 855157d97aa28cf84233847548bfacda21807436
F src/test_btree.c c1308ba0b88ab577fa56c9e493a09829dfcded9c
F src/test_config.c 6fb459214b27952b143f45e35200d94096d54cc6
F test/alter3.test a6eec8f454be9b6ce73d8d7dc711453675a10ce7
F test/altermalloc.test 1f4d2d66750bea1a78cd9f0b7dba5bfb155dd6cf
F test/analyze.test 2f55535aa335785db1a2f97d3f3831c16c09f8b0
-F test/async.test 18e7dc66535f3d86c05e0f954384472e2ed52490
-F test/async2.test a8ef7abfda880b171b2f0a8476300816e33a808a
+F test/async.test c52216f8bdebff26900a338b75ea6079944bf141
+F test/async2.test 75f2d15f4c27189ec3296cf2565ec91834bbed76
F test/attach.test b849e1baae863c3a6132ff8b9b1baf356ab6c178
F test/attach2.test 78bc1a25ea8785c7571b44f5947ada2bd5d78127
F test/attach3.test eafcafb107585aecc2ed1569a77914138eef46a9
F www/vdbe.tcl 87a31ace769f20d3627a64fa1fade7fed47b90d0
F www/version3.tcl 890248cf7b70e60c383b0e84d77d5132b3ead42b
F www/whentouse.tcl fc46eae081251c3c181bd79c5faef8195d7991a5
-P 3794dcd31a74e90b181b336bf6a4c917bda526b8
-R f8c85691f2efa8fda77b1b74d5099eab
-U drh
-Z 971dbe3f56f98d850a595d781e5442d1
+P bf3d67d1bd1c48fff45dc24818b8358f79c9fdef
+R 25fb668c32b81804b4ade4316a54624b
+U danielk1977
+Z 8a09ee32bd86264ddd0da49c7bb5aaae
** Asynchronous I/O appears to give better responsiveness, but at a price.
** You lose the Durable property. With the default I/O backend of SQLite,
** once a write completes, you know that the information you wrote is
-** safely on disk. With the asynchronous I/O, this is no the case. If
-** your program crashes or if you take a power lose after the database
+** safely on disk. With the asynchronous I/O, this is not the case. If
+** your program crashes or if a power lose occurs after the database
** write but before the asynchronous write thread has completed, then the
** database change might never make it to disk and the next user of the
** database might not see your change.
**
** HOW IT WORKS
**
-** Asynchronous I/O works by overloading the OS-layer disk I/O routines
-** with modified versions that store the data to be written in queue of
-** pending write operations. Look at the asyncEnable() subroutine to see
-** how overloading works. Six os-layer routines are overloaded:
+** Asynchronous I/O works by creating a special SQLite "vfs" structure
+** and registering it with sqlite3_vfs_register(). When files opened via
+** this vfs are written to (using sqlite3OsWrite()), the data is not
+** written directly to disk, but is placed in the "write-queue" to be
+** handled by the background thread.
**
-** sqlite3OsOpenReadWrite;
-** sqlite3OsOpenReadOnly;
-** sqlite3OsOpenExclusive;
-** sqlite3OsDelete;
-** sqlite3OsFileExists;
-** sqlite3OsSyncDirectory;
-**
-** The original implementations of these routines are saved and are
-** used by the writer thread to do the real I/O. The substitute
-** implementations typically put the I/O operation on a queue
-** to be handled later by the writer thread, though read operations
-** must be handled right away, obviously.
-**
-** Asynchronous I/O is disabled by setting the os-layer interface routines
-** back to their original values.
+** The special vfs is registered (and unregistered) by calls to
+** function asyncEnable() (see below).
**
** LIMITATIONS
**
/*
** If this symbol is defined, then file-system locks are obtained as
** required. This slows things down, but allows multiple processes
-** to access the database concurrently.
+** to access the database concurrently. If this symbol is not defined,
+** then connections from within a single process will respect each
+** others database locks, but external connections will not - leading
+** to database corruption.
*/
#define ENABLE_FILE_LOCKING
** Basic rules:
**
** * Both read and write access to the global write-op queue must be
-** protected by the async.queueMutex.
+** protected by the async.queueMutex. As are the async.ioError and
+** async.nFile variables.
+**
+** * The async.aLock hash-table and all AsyncLock and AsyncFileLock
+** structures must be protected by teh async.lockMutex mutex.
**
** * The file handles from the underlying system are assumed not to
** be thread safe.
AsyncWrite *pNext; /* Next write operation (to any file) */
};
+/*
+** An instance of this structure is created for each distinct open file
+** (i.e. if two handles are opened on the one file, only one of these
+** structures is allocated) and stored in the async.aLock hash table. The
+** keys for async.aLock are the full pathnames of the opened files.
+**
+** AsyncLock.pList points to the head of a linked list of AsyncFileLock
+** structures, one for each handle currently open on the file.
+**
+** If the opened file is not a main-database (the SQLITE_OPEN_MAIN_DB is
+** not passed to the sqlite3OsOpen() call), or if ENABLE_FILE_LOCKING is
+** not defined at compile time, variables AsyncLock.pFile and
+** AsyncLock.eLock are never used. Otherwise, pFile is a file handle
+** opened on the file in question and used to obtain the file-system
+** locks required by database connections within this process.
+**
+** See comments above the asyncLock() function for more details on
+** the implementation of database locking used by this backend.
+*/
+struct AsyncLock {
+ sqlite3_file *pFile;
+ int eLock;
+ AsyncFileLock *pList;
+};
+
/*
** An instance of the following structure is allocated along with each
** AsyncFileData structure (see AsyncFileData.lock), but is only used if the
** file was opened with the SQLITE_OPEN_MAIN_DB.
-**
-** The global async.aLock[] hash table maps from database file-name to a
-** linked-list of AsyncFileLock structures corresponding to handles opened on
-** the file. The AsyncFileLock structures are linked into the list when the
-** file is opened and removed when it is closed. Mutex async.lockMutex must be
-** held before accessing any AsyncFileLock structure or the async.aLock[]
-** table.
*/
struct AsyncFileLock {
int eLock; /* Internally visible lock state (sqlite pov) */
AsyncFileLock *pNext;
};
-struct AsyncLock {
- sqlite3_file *pFile;
- int eLock;
- AsyncFileLock *pList;
-};
-
/*
** The AsyncFile structure is a subclass of sqlite3_file used for
** asynchronous IO.
assert(pIter->eAsyncLock>=pIter->eLock);
if( pIter->eAsyncLock>eRequired ){
eRequired = pIter->eAsyncLock;
+ assert(eRequired>=0 && eRequired<=SQLITE_LOCK_EXCLUSIVE);
}
}
if( eRequired>pLock->eLock ){
}
/*
-** No disk locking is performed. We keep track of locks locally in
-** the async.aLock hash table. Locking should appear to work the same
-** as with standard (unmodified) SQLite as long as all connections
-** come from this one process. Connections from external processes
-** cannot see our internal hash table (obviously) and will thus not
-** honor our locks.
+** The following two methods - asyncLock() and asyncUnlock() - are used
+** to obtain and release locks on database files opened with the
+** asynchronous backend.
*/
static int asyncLock(sqlite3_file *pFile, int eLock){
int rc = SQLITE_OK;
}
if( rc==SQLITE_OK ){
p->lock.eLock = eLock;
- if( eLock>p->lock.eAsyncLock ){
- p->lock.eAsyncLock = eLock;
- }
+ p->lock.eAsyncLock = MAX(p->lock.eAsyncLock, eLock);
}
assert(p->lock.eAsyncLock>=p->lock.eLock);
if( rc==SQLITE_OK ){
AsyncFileData *p = ((AsyncFile *)pFile)->pData;
AsyncFileLock *pLock = &p->lock;
pthread_mutex_lock(&async.lockMutex);
- if( pLock->eLock>eLock ){
- pLock->eLock = eLock;
- }
+ pLock->eLock = MIN(pLock->eLock, eLock);
pthread_mutex_unlock(&async.lockMutex);
return addNewAsyncWrite(p, ASYNC_UNLOCK, 0, eLock, 0);
}
static void asyncEnable(int enable){
if( enable ){
if( !async_vfs.pAppData ){
+ static int hashTableInit = 0;
async_vfs.pAppData = (void *)sqlite3_vfs_find(0);
async_vfs.mxPathname = ((sqlite3_vfs *)async_vfs.pAppData)->mxPathname;
sqlite3_vfs_register(&async_vfs, 1);
- sqlite3HashInit(&async.aLock, SQLITE_HASH_BINARY, 1);
+ if( !hashTableInit ){
+ sqlite3HashInit(&async.aLock, SQLITE_HASH_BINARY, 1);
+ hashTableInit = 1;
+ }
}
}else{
if( async_vfs.pAppData ){
sqlite3_vfs_unregister(&async_vfs);
async_vfs.pAppData = 0;
- sqlite3HashClear(&async.aLock);
}
}
}
pLock = sqlite3HashFind(&async.aLock, pData->zName, pData->nName);
for(ppIter=&pLock->pList; *ppIter; ppIter=&((*ppIter)->pNext)){
if( (*ppIter)==&pData->lock ){
- *ppIter = (*ppIter)->pNext;
+ *ppIter = pData->lock.pNext;
break;
}
}
if( !pLock->pList ){
- if( pLock->pFile ) sqlite3OsClose(pLock->pFile);
+ if( pLock->pFile ){
+ sqlite3OsClose(pLock->pFile);
+ }
sqlite3_free(pLock);
sqlite3HashInsert(&async.aLock, pData->zName, pData->nName, 0);
+ if( !sqliteHashFirst(&async.aLock) ){
+ sqlite3HashClear(&async.aLock);
+ }
}else{
rc = getFileLock(pLock);
}
AsyncFileData *pData = p->pFileData;
int eLock = p->nByte;
pthread_mutex_lock(&async.lockMutex);
- if( pData->lock.eAsyncLock>eLock ){
- if( pData->lock.eLock>eLock ){
- pData->lock.eAsyncLock = pData->lock.eLock;
- }else{
- pData->lock.eAsyncLock = eLock;
- }
- }
+ pData->lock.eAsyncLock = MIN(
+ pData->lock.eAsyncLock, MAX(pData->lock.eLock, eLock)
+ );
assert(pData->lock.eAsyncLock>=pData->lock.eLock);
pLock = sqlite3HashFind(&async.aLock, pData->zName, pData->nName);
rc = getFileLock(pLock);
projects / thirdparty / sqlite.git / commitdiff
