/**
* Attempt a series of file operations.
* Callers are responsible for handling file locking.
*
* $opts is an array of options, including:
* 'force' : Errors that would normally cause a rollback do not.
* The remaining operations are still attempted if any fail.
* 'allowStale' : Don't require the latest available data.
* This can increase performance for non-critical writes.
* This has no effect unless the 'force' flag is set.
*
* The resulting Status will be "OK" unless:
* a) unexpected operation errors occurred (network partitions, disk full...)
* b) significant operation errors occured and 'force' was not set
*
* @param $performOps Array List of FileOp operations
* @param $opts Array Batch operation options
* @return Status
*/
public static final function attemptBatch(array $performOps, array $opts)
{
$status = Status::newGood();
$allowStale = !empty($opts['allowStale']);
$ignoreErrors = !empty($opts['force']);
$n = count($performOps);
if ($n > self::MAX_BATCH_SIZE) {
$status->fatal('backend-fail-batchsize', $n, self::MAX_BATCH_SIZE);
return $status;
}
$predicates = FileOp::newPredicates();
// account for previous op in prechecks
// Do pre-checks for each operation; abort on failure...
foreach ($performOps as $index => $fileOp) {
if ($allowStale) {
$fileOp->allowStaleReads();
// allow potentially stale reads
}
$subStatus = $fileOp->precheck($predicates);
$status->merge($subStatus);
if (!$subStatus->isOK()) {
// operation failed?
$status->success[$index] = false;
++$status->failCount;
if (!$ignoreErrors) {
return $status;
// abort
}
}
}
if ($ignoreErrors) {
# Treat all precheck() fatals as merely warnings
$status->setResult(true, $status->value);
}
// Restart PHP's execution timer and set the timeout to safe amount.
// This handles cases where the operations take a long time or where we are
// already running low on time left. The old timeout is restored afterwards.
# @TODO: re-enable this for when the number of batches is high.
#$scopedTimeLimit = new FileOpScopedPHPTimeout( self::TIME_LIMIT_SEC );
// Attempt each operation...
foreach ($performOps as $index => $fileOp) {
if ($fileOp->failed()) {
continue;
// nothing to do
}
$subStatus = $fileOp->attempt();
$status->merge($subStatus);
if ($subStatus->isOK()) {
$status->success[$index] = true;
++$status->successCount;
} else {
$status->success[$index] = false;
++$status->failCount;
// We can't continue (even with $ignoreErrors) as $predicates is wrong.
// Log the remaining ops as failed for recovery...
for ($i = $index + 1; $i < count($performOps); $i++) {
$performOps[$i]->logFailure('attempt_aborted');
}
return $status;
// bail out
}
}
return $status;
}
/**
* Attempt to perform a series of file operations.
* Callers are responsible for handling file locking.
*
* $opts is an array of options, including:
* - force : Errors that would normally cause a rollback do not.
* The remaining operations are still attempted if any fail.
* - nonJournaled : Don't log this operation batch in the file journal.
* - concurrency : Try to do this many operations in parallel when possible.
*
* The resulting Status will be "OK" unless:
* - a) unexpected operation errors occurred (network partitions, disk full...)
* - b) significant operation errors occurred and 'force' was not set
*
* @param array $performOps List of FileOp operations
* @param array $opts Batch operation options
* @param FileJournal $journal Journal to log operations to
* @return Status
*/
public static function attempt( array $performOps, array $opts, FileJournal $journal ) {
wfProfileIn( __METHOD__ );
$status = Status::newGood();
$n = count( $performOps );
if ( $n > self::MAX_BATCH_SIZE ) {
$status->fatal( 'backend-fail-batchsize', $n, self::MAX_BATCH_SIZE );
wfProfileOut( __METHOD__ );
return $status;
}
$batchId = $journal->getTimestampedUUID();
$ignoreErrors = !empty( $opts['force'] );
$journaled = empty( $opts['nonJournaled'] );
$maxConcurrency = isset( $opts['concurrency'] ) ? $opts['concurrency'] : 1;
$entries = array(); // file journal entry list
$predicates = FileOp::newPredicates(); // account for previous ops in prechecks
$curBatch = array(); // concurrent FileOp sub-batch accumulation
$curBatchDeps = FileOp::newDependencies(); // paths used in FileOp sub-batch
$pPerformOps = array(); // ordered list of concurrent FileOp sub-batches
$lastBackend = null; // last op backend name
// Do pre-checks for each operation; abort on failure...
foreach ( $performOps as $index => $fileOp ) {
$backendName = $fileOp->getBackend()->getName();
$fileOp->setBatchId( $batchId ); // transaction ID
// Decide if this op can be done concurrently within this sub-batch
// or if a new concurrent sub-batch must be started after this one...
if ( $fileOp->dependsOn( $curBatchDeps )
|| count( $curBatch ) >= $maxConcurrency
|| ( $backendName !== $lastBackend && count( $curBatch ) )
) {
$pPerformOps[] = $curBatch; // push this batch
$curBatch = array(); // start a new sub-batch
$curBatchDeps = FileOp::newDependencies();
}
$lastBackend = $backendName;
$curBatch[$index] = $fileOp; // keep index
// Update list of affected paths in this batch
$curBatchDeps = $fileOp->applyDependencies( $curBatchDeps );
// Simulate performing the operation...
$oldPredicates = $predicates;
$subStatus = $fileOp->precheck( $predicates ); // updates $predicates
$status->merge( $subStatus );
if ( $subStatus->isOK() ) {
if ( $journaled ) { // journal log entries
$entries = array_merge( $entries,
$fileOp->getJournalEntries( $oldPredicates, $predicates ) );
}
} else { // operation failed?
$status->success[$index] = false;
++$status->failCount;
if ( !$ignoreErrors ) {
wfProfileOut( __METHOD__ );
return $status; // abort
}
}
}
// Push the last sub-batch
if ( count( $curBatch ) ) {
$pPerformOps[] = $curBatch;
}
// Log the operations in the file journal...
if ( count( $entries ) ) {
$subStatus = $journal->logChangeBatch( $entries, $batchId );
if ( !$subStatus->isOK() ) {
wfProfileOut( __METHOD__ );
return $subStatus; // abort
}
}
if ( $ignoreErrors ) { // treat precheck() fatals as mere warnings
$status->setResult( true, $status->value );
}
// Attempt each operation (in parallel if allowed and possible)...
self::runParallelBatches( $pPerformOps, $status );
wfProfileOut( __METHOD__ );
return $status;
}
