29use \MediaWiki\MediaWikiServices;
30use \Wikimedia\WaitConditionLoop;
31use \Wikimedia\Rdbms\TransactionProfiler;
105 parent::__construct(
$params );
110 if ( isset(
$params[
'servers'] ) ) {
111 $this->serverInfos = [];
112 $this->serverTags = [];
113 $this->numServers = count(
$params[
'servers'] );
115 foreach (
$params[
'servers'] as $tag => $info ) {
116 $this->serverInfos[$index] = $info;
117 if ( is_string( $tag ) ) {
118 $this->serverTags[$index] = $tag;
120 $this->serverTags[$index] = isset( $info[
'host'] ) ? $info[
'host'] :
"#$index";
124 } elseif ( isset(
$params[
'server'] ) ) {
125 $this->serverInfos = [
$params[
'server'] ];
126 $this->numServers = count( $this->serverInfos );
129 $this->serverInfos =
false;
130 $this->numServers = 1;
133 if ( isset(
$params[
'purgePeriod'] ) ) {
134 $this->purgePeriod = intval(
$params[
'purgePeriod'] );
136 if ( isset(
$params[
'tableName'] ) ) {
139 if ( isset(
$params[
'shards'] ) ) {
140 $this->shards = intval(
$params[
'shards'] );
142 if ( isset(
$params[
'syncTimeout'] ) ) {
143 $this->syncTimeout =
$params[
'syncTimeout'];
145 $this->replicaOnly = !empty(
$params[
'slaveOnly'] );
155 protected function getDB( $serverIndex ) {
156 if ( !isset( $this->conns[$serverIndex] ) ) {
157 if ( $serverIndex >= $this->numServers ) {
158 throw new MWException( __METHOD__ .
": Invalid server index \"$serverIndex\"" );
161 # Don't keep timing out trying to connect for each call if the DB is down
162 if ( isset( $this->connFailureErrors[$serverIndex] )
163 && ( time() - $this->connFailureTimes[$serverIndex] ) < 60
165 throw $this->connFailureErrors[$serverIndex];
168 if ( $this->serverInfos ) {
170 $info = $this->serverInfos[$serverIndex];
171 $type = isset( $info[
'type'] ) ? $info[
'type'] :
'mysql';
172 $host = isset( $info[
'host'] ) ? $info[
'host'] :
'[unknown]';
173 $this->logger->debug( __CLASS__ .
": connecting to $host" );
176 $db = Database::factory(
$type, $info );
180 $lb = MediaWikiServices::getInstance()->getDBLoadBalancer();
182 if ( $lb->getServerType( $lb->getWriterIndex() ) !==
'sqlite' ) {
184 $db = $lb->getConnection( $index, [],
false, $lb::CONN_TRX_AUTO );
189 $db = $lb->getConnection( $index );
193 $this->logger->debug( sprintf(
"Connection %s will be used for SqlBagOStuff", $db ) );
194 $this->conns[$serverIndex] = $db;
197 return $this->conns[$serverIndex];
206 if ( $this->shards > 1 ) {
207 $hash = hexdec( substr( md5( $key ), 0, 8 ) ) & 0x7fffffff;
212 if ( $this->numServers > 1 ) {
214 ArrayUtils::consistentHashSort( $sortedServers, $key );
215 reset( $sortedServers );
216 $serverIndex =
key( $sortedServers );
229 if ( $this->shards > 1 ) {
230 $decimals = strlen( $this->shards - 1 );
232 sprintf(
"%0{$decimals}d", $index );
245 $values = $this->
getMulti( [ $key ] );
246 if ( array_key_exists( $key, $values ) ) {
247 $casToken = $values[$key];
248 return $values[$key];
257 foreach (
$keys as $key ) {
259 $keysByTable[$serverIndex][
$tableName][] = $key;
265 foreach ( $keysByTable as $serverIndex => $serverKeys ) {
267 $db = $this->
getDB( $serverIndex );
268 foreach ( $serverKeys as
$tableName => $tableKeys ) {
270 [
'keyname',
'value',
'exptime' ],
271 [
'keyname' => $tableKeys ],
276 $db->trxLevel() ? [
'LOCK IN SHARE MODE' ] : []
278 if (
$res ===
false ) {
281 foreach (
$res as $row ) {
282 $row->serverIndex = $serverIndex;
284 $dataRows[$row->keyname] = $row;
292 foreach (
$keys as $key ) {
293 if ( isset( $dataRows[$key] ) ) {
294 $row = $dataRows[$key];
295 $this->
debug(
"get: retrieved data; expiry time is " . $row->exptime );
298 $db = $this->
getDB( $row->serverIndex );
299 if ( $this->
isExpired( $db, $row->exptime ) ) {
300 $this->
debug(
"get: key has expired" );
302 $values[$key] = $this->
unserialize( $db->decodeBlob( $row->value ) );
308 $this->
debug(
'get: no matching rows' );
315 public function setMulti( array $data, $expiry = 0 ) {
317 foreach ( $data as $key =>
$value ) {
319 $keysByTable[$serverIndex][
$tableName][] = $key;
325 $exptime = (int)$expiry;
326 foreach ( $keysByTable as $serverIndex => $serverKeys ) {
329 $db = $this->
getDB( $serverIndex );
336 if ( $exptime < 0 ) {
340 if ( $exptime == 0 ) {
344 $encExpiry = $db->timestamp( $exptime );
346 foreach ( $serverKeys as
$tableName => $tableKeys ) {
348 foreach ( $tableKeys as $key ) {
351 'value' => $db->encodeBlob( $this->
serialize( $data[$key] ) ),
352 'exptime' => $encExpiry,
377 if ( (
$flags & self::WRITE_SYNC ) == self::WRITE_SYNC ) {
384 protected function cas( $casToken, $key,
$value, $exptime = 0 ) {
388 $db = $this->
getDB( $serverIndex );
389 $exptime = intval( $exptime );
391 if ( $exptime < 0 ) {
395 if ( $exptime == 0 ) {
399 $encExpiry = $db->timestamp( $exptime );
407 'value' => $db->encodeBlob( $this->serialize(
$value ) ),
408 'exptime' => $encExpiry
412 'value' => $db->encodeBlob( $this->serialize( $casToken ) )
422 return (
bool)$db->affectedRows();
425 public function delete( $key ) {
429 $db = $this->
getDB( $serverIndex );
432 [
'keyname' => $key ],
442 public function incr( $key, $step = 1 ) {
446 $db = $this->
getDB( $serverIndex );
447 $step = intval( $step );
448 $row = $db->selectRow(
450 [
'value',
'exptime' ],
451 [
'keyname' => $key ],
454 if ( $row ===
false ) {
459 $db->delete(
$tableName, [
'keyname' => $key ], __METHOD__ );
460 if ( $this->
isExpired( $db, $row->exptime ) ) {
466 $oldValue = intval( $this->
unserialize( $db->decodeBlob( $row->value ) ) );
467 $newValue = $oldValue + $step;
471 'value' => $db->encodeBlob( $this->serialize( $newValue ) ),
472 'exptime' => $row->exptime
473 ], __METHOD__,
'IGNORE' );
475 if ( $db->affectedRows() == 0 ) {
487 public function merge( $key, callable $callback, $exptime = 0, $attempts = 10,
$flags = 0 ) {
488 $ok = $this->
mergeViaCas( $key, $callback, $exptime, $attempts );
489 if ( (
$flags & self::WRITE_SYNC ) == self::WRITE_SYNC ) {
500 $db = $this->
getDB( $serverIndex );
503 [
'exptime' => $db->timestamp( $this->convertExpiry( $expiry ) ) ],
504 [
'keyname' => $key,
'exptime > ' . $db->addQuotes( $db->timestamp( time() ) ) ],
507 if ( $db->affectedRows() == 0 ) {
532 if ( time() > 0x7fffffff ) {
533 return $db->timestamp( 1 << 62 );
535 return $db->timestamp( 0x7fffffff );
540 if ( !$this->purgePeriod || $this->replicaOnly ) {
545 if ( $this->purgePeriod !== 1 && mt_rand( 0, $this->purgePeriod - 1 ) ) {
550 if ( $now > ( $this->lastExpireAll + 1 ) ) {
551 $this->lastExpireAll = $now;
570 $db = $this->
getDB( $serverIndex );
571 $dbTimestamp = $db->timestamp( $timestamp );
572 $totalSeconds =
false;
573 $baseConds = [
'exptime < ' . $db->addQuotes( $dbTimestamp ) ];
578 if ( $maxExpTime !==
false ) {
579 $conds[] =
'exptime >= ' . $db->addQuotes( $maxExpTime );
583 [
'keyname',
'exptime' ],
586 [
'LIMIT' => 100,
'ORDER BY' =>
'exptime' ] );
591 $row =
$rows->current();
592 $minExpTime = $row->exptime;
593 if ( $totalSeconds ===
false ) {
597 foreach (
$rows as $row ) {
598 $keys[] = $row->keyname;
599 $maxExpTime = $row->exptime;
605 'exptime >= ' . $db->addQuotes( $minExpTime ),
606 'exptime < ' . $db->addQuotes( $dbTimestamp ),
611 if ( $progressCallback ) {
612 if ( intval( $totalSeconds ) === 0 ) {
615 $remainingSeconds =
wfTimestamp( TS_UNIX, $timestamp )
617 if ( $remainingSeconds > $totalSeconds ) {
618 $totalSeconds = $remainingSeconds;
620 $processedSeconds = $totalSeconds - $remainingSeconds;
621 $percent = ( $i + $processedSeconds / $totalSeconds )
622 / $this->shards * 100;
625 + ( $serverIndex / $this->numServers * 100 );
626 call_user_func( $progressCallback, $percent );
647 $db = $this->
getDB( $serverIndex );
670 if ( function_exists(
'gzdeflate' ) ) {
671 return gzdeflate( $serial );
683 if ( function_exists(
'gzinflate' ) ) {
684 MediaWiki\suppressWarnings();
685 $decomp = gzinflate( $serial );
686 MediaWiki\restoreWarnings();
688 if (
false !== $decomp ) {
708 $this->logger->error(
"DBError: {$exception->getMessage()}" );
711 $this->logger->debug( __METHOD__ .
": ignoring connection error" );
714 $this->logger->debug( __METHOD__ .
": ignoring query error" );
729 } elseif ( $db->wasReadOnlyError() ) {
730 if ( $db->trxLevel() && $this->usesMainDB() ) {
738 $this->logger->error(
"DBError: {$exception->getMessage()}" );
741 $this->logger->debug( __METHOD__ .
": ignoring connection error" );
744 $this->logger->debug( __METHOD__ .
": ignoring query error" );
755 unset( $this->conns[$serverIndex] );
757 if ( isset( $this->connFailureTimes[$serverIndex] ) ) {
758 if ( time() - $this->connFailureTimes[$serverIndex] >= 60 ) {
759 unset( $this->connFailureTimes[$serverIndex] );
760 unset( $this->connFailureErrors[$serverIndex] );
762 $this->logger->debug( __METHOD__ .
": Server #$serverIndex already down" );
767 $this->logger->info( __METHOD__ .
": Server #$serverIndex down until " . ( $now + 60 ) );
768 $this->connFailureTimes[$serverIndex] = $now;
769 $this->connFailureErrors[$serverIndex] = $exception;
777 $db = $this->
getDB( $serverIndex );
778 if ( $db->getType() !==
'mysql' ) {
779 throw new MWException( __METHOD__ .
' is not supported on this DB server' );
784 'CREATE TABLE ' . $db->tableName( $this->getTableNameByShard( $i ) ) .
785 ' LIKE ' . $db->tableName(
'objectcache' ),
804 $lb = MediaWikiServices::getInstance()->getDBLoadBalancer();
805 if ( $lb->getServerCount() <= 1 ) {
810 $masterPos = $lb->getMasterPos();
812 $loop =
new WaitConditionLoop(
813 function () use ( $lb, $masterPos ) {
814 return $lb->waitForAll( $masterPos, 1 );
820 return ( $loop->invoke() === $loop::CONDITION_REACHED );
wfTimestampNow()
Convenience function; returns MediaWiki timestamp for the present time.
wfTimestamp( $outputtype=TS_UNIX, $ts=0)
Get a timestamp string in one of various formats.
interface is intended to be more or less compatible with the PHP memcached client.
convertExpiry( $exptime)
Convert an optionally relative time to an absolute time.
callable[] $busyCallbacks
setLastError( $err)
Set the "last error" registry.
mergeViaCas( $key, $callback, $exptime=0, $attempts=10)
Class to store objects in the database.
getDB( $serverIndex)
Get a connection to the specified database.
string[] $serverTags
(server index => tag/host name)
LoadBalancer null $separateMainLB
createTables()
Create shard tables.
getTableByKey( $key)
Get the server index and table name for a given key.
getMulti(array $keys, $flags=0)
Get an associative array containing the item for each of the keys that have items.
array[] $serverInfos
(server index => server config)
deleteAll()
Delete content of shard tables in every server.
__construct( $params)
Constructor.
getWithToken( $key, &$casToken, $flags=0)
isExpired( $db, $exptime)
changeTTL( $key, $expiry=0)
Reset the TTL on a key if it exists.
handleWriteError(DBError $exception, IDatabase $db=null, $serverIndex)
Handle a DBQueryError which occurred during a write operation.
array $connFailureTimes
UNIX timestamps.
array $connFailureErrors
Exceptions.
deleteObjectsExpiringBefore( $timestamp, $progressCallback=false)
Delete objects from the database which expire before a certain date.
cas( $casToken, $key, $value, $exptime=0)
Check and set an item.
merge( $key, callable $callback, $exptime=0, $attempts=10, $flags=0)
Merge changes into the existing cache value (possibly creating a new one)
serialize(&$data)
Serialize an object and, if possible, compress the representation.
markServerDown(DBError $exception, $serverIndex)
Mark a server down due to a DBConnectionError exception.
unserialize( $serial)
Unserialize and, if necessary, decompress an object.
getTableNameByShard( $index)
Get the table name for a given shard index.
incr( $key, $step=1)
Increase stored value of $key by $value while preserving its TTL.
handleReadError(DBError $exception, $serverIndex)
Handle a DBError which occurred during a read operation.
setMulti(array $data, $expiry=0)
Batch insertion.
We use the convention $dbr for read and $dbw for write to help you keep track of whether the database object is a the world will explode Or to be a subsequent write query which succeeded on the master may fail when replicated to the slave due to a unique key collision Replication on the slave will stop and it may take hours to repair the database and get it back online Setting read_only in my cnf on the slave will avoid this but given the dire we prefer to have as many checks as possible We provide a but the wrapper functions like please read the documentation for tableName() and addQuotes(). You will need both of them. ------------------------------------------------------------------------ Basic query optimisation ------------------------------------------------------------------------ MediaWiki developers who need to write DB queries should have some understanding of databases and the performance issues associated with them. Patches containing unacceptably slow features will not be accepted. Unindexed queries are generally not welcome in MediaWiki
deferred txt A few of the database updates required by various functions here can be deferred until after the result page is displayed to the user For updating the view updating the linked to tables after a etc PHP does not yet have any way to tell the server to actually return and disconnect while still running these but it might have such a feature in the future We handle these by creating a deferred update object and putting those objects on a global list
design txt This is a brief overview of the new design More thorough and up to date information is available on the documentation wiki at etc Handles the details of getting and saving to the user table of the and dealing with sessions and cookies OutputPage Encapsulates the entire HTML page that will be sent in response to any server request It is used by calling its functions to add in any and then calling but I prefer the flexibility This should also do the output encoding The system allocates a global one in $wgOut Title Represents the title of an and does all the work of translating among various forms such as plain database key
namespace being checked & $result
do that in ParserLimitReportFormat instead use this to modify the parameters of the image all existing parser cache entries will be invalid To avoid you ll need to handle that somehow(e.g. with the RejectParserCacheValue hook) because MediaWiki won 't do it for you. & $defaults also a ContextSource after deleting those rows but within the same transaction $rows
it s the revision text itself In either if gzip is the revision text is gzipped $flags
null means default in associative array with keys and values unescaped Should be merged with default with a value of false meaning to suppress the attribute in associative array with keys and values unescaped noclasses & $ret
returning false will NOT prevent logging $e
const QOS_SYNCWRITES_NONE