MediaWiki  master
SqlBlobStore.php
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1 <?php
28 namespace MediaWiki\Storage;
29 
30 use AppendIterator;
33 use IDBAccessObject;
34 use IExpiringStore;
35 use InvalidArgumentException;
36 use MWException;
37 use StatusValue;
38 use WANObjectCache;
39 use Wikimedia\Assert\Assert;
40 use Wikimedia\AtEase\AtEase;
44 
54 
55  // Note: the name has been taken unchanged from the old Revision class.
56  public const TEXT_CACHE_GROUP = 'revisiontext:10';
57 
61  private $dbLoadBalancer;
62 
66  private $extStoreAccess;
67 
71  private $cache;
72 
76  private $dbDomain;
77 
81  private $cacheExpiry = 604800; // 7 days
82 
86  private $compressBlobs = false;
87 
91  private $legacyEncoding = false;
92 
96  private $useExternalStore = false;
97 
109  public function __construct(
113  $dbDomain = false
114  ) {
115  $this->dbLoadBalancer = $dbLoadBalancer;
116  $this->extStoreAccess = $extStoreAccess;
117  $this->cache = $cache;
118  $this->dbDomain = $dbDomain;
119  }
120 
124  public function getCacheExpiry() {
125  return $this->cacheExpiry;
126  }
127 
131  public function setCacheExpiry( int $cacheExpiry ) {
132  $this->cacheExpiry = $cacheExpiry;
133  }
134 
138  public function getCompressBlobs() {
139  return $this->compressBlobs;
140  }
141 
145  public function setCompressBlobs( $compressBlobs ) {
146  $this->compressBlobs = $compressBlobs;
147  }
148 
153  public function getLegacyEncoding() {
154  return $this->legacyEncoding;
155  }
156 
162  wfDeprecated( __METHOD__ );
163  return null;
164  }
165 
174  public function setLegacyEncoding( string $legacyEncoding ) {
175  $this->legacyEncoding = $legacyEncoding;
176  }
177 
181  public function getUseExternalStore() {
183  }
184 
188  public function setUseExternalStore( bool $useExternalStore ) {
189  $this->useExternalStore = $useExternalStore;
190  }
191 
195  private function getDBLoadBalancer() {
196  return $this->dbLoadBalancer;
197  }
198 
204  private function getDBConnection( $index ) {
205  $lb = $this->getDBLoadBalancer();
206  return $lb->getConnectionRef( $index, [], $this->dbDomain );
207  }
208 
219  public function storeBlob( $data, $hints = [] ) {
220  try {
221  $flags = $this->compressData( $data );
222 
223  # Write to external storage if required
224  if ( $this->useExternalStore ) {
225  // Store and get the URL
226  $data = $this->extStoreAccess->insert( $data, [ 'domain' => $this->dbDomain ] );
227  if ( !$data ) {
228  throw new BlobAccessException( "Failed to store text to external storage" );
229  }
230  if ( $flags ) {
231  $flags .= ',';
232  }
233  $flags .= 'external';
234 
235  // TODO: we could also return an address for the external store directly here.
236  // That would mean bypassing the text table entirely when the external store is
237  // used. We'll need to assess expected fallout before doing that.
238  }
239 
240  $dbw = $this->getDBConnection( DB_PRIMARY );
241 
242  $old_id = $dbw->nextSequenceValue( 'text_old_id_seq' );
243  $dbw->insert(
244  'text',
245  [
246  'old_id' => $old_id,
247  'old_text' => $data,
248  'old_flags' => $flags,
249  ],
250  __METHOD__
251  );
252 
253  $textId = $dbw->insertId();
254 
255  return self::makeAddressFromTextId( $textId );
256  } catch ( MWException $e ) {
257  throw new BlobAccessException( $e->getMessage(), 0, $e );
258  }
259  }
260 
273  public function getBlob( $blobAddress, $queryFlags = 0 ) {
274  Assert::parameterType( 'string', $blobAddress, '$blobAddress' );
275 
276  $error = null;
277  $blob = $this->cache->getWithSetCallback(
278  $this->getCacheKey( $blobAddress ),
279  $this->getCacheTTL(),
280  function ( $unused, &$ttl, &$setOpts ) use ( $blobAddress, $queryFlags, &$error ) {
281  // Ignore $setOpts; blobs are immutable and negatives are not cached
282  list( $result, $errors ) = $this->fetchBlobs( [ $blobAddress ], $queryFlags );
283  // No negative caching; negative hits on text rows may be due to corrupted replica DBs
284  $error = $errors[$blobAddress] ?? null;
285  return $result[$blobAddress];
286  },
287  [ 'pcGroup' => self::TEXT_CACHE_GROUP, 'pcTTL' => IExpiringStore::TTL_PROC_LONG ]
288  );
289 
290  if ( $error ) {
291  throw new BlobAccessException( $error );
292  }
293 
294  Assert::postcondition( is_string( $blob ), 'Blob must not be null' );
295  return $blob;
296  }
297 
309  public function getBlobBatch( $blobAddresses, $queryFlags = 0 ) {
310  // FIXME: All caching has temporarily been removed in I94c6f9ba7b9caeeb due to T235188.
311  // Caching behavior should be restored by reverting I94c6f9ba7b9caeeb as soon as
312  // the root cause of T235188 has been resolved.
313 
314  list( $blobsByAddress, $errors ) = $this->fetchBlobs( $blobAddresses, $queryFlags );
315 
316  $blobsByAddress = array_map( static function ( $blob ) {
317  return $blob === false ? null : $blob;
318  }, $blobsByAddress );
319 
320  $result = StatusValue::newGood( $blobsByAddress );
321  if ( $errors ) {
322  foreach ( $errors as $error ) {
323  $result->warning( 'internalerror', $error );
324  }
325  }
326  return $result;
327  }
328 
339  private function fetchBlobs( $blobAddresses, $queryFlags ) {
340  $textIdToBlobAddress = [];
341  $result = [];
342  $errors = [];
343  foreach ( $blobAddresses as $blobAddress ) {
344  try {
345  list( $schema, $id ) = self::splitBlobAddress( $blobAddress );
346  } catch ( InvalidArgumentException $ex ) {
347  throw new BlobAccessException(
348  $ex->getMessage() . '. Use findBadBlobs.php to remedy.',
349  0,
350  $ex
351  );
352  }
353 
354  // TODO: MCR: also support 'ex' schema with ExternalStore URLs, plus flags encoded in the URL!
355  if ( $schema === 'bad' ) {
356  // Database row was marked as "known bad", no need to trigger an error.
357  wfDebug(
358  __METHOD__
359  . ": loading known-bad content ($blobAddress), returning empty string"
360  );
361  $result[$blobAddress] = '';
362  continue;
363  } elseif ( $schema === 'tt' ) {
364  $textId = intval( $id );
365 
366  if ( $textId < 1 || $id !== (string)$textId ) {
367  $errors[$blobAddress] = "Bad blob address: $blobAddress."
368  . ' Use findBadBlobs.php to remedy.';
369  $result[$blobAddress] = false;
370  }
371 
372  $textIdToBlobAddress[$textId] = $blobAddress;
373  } else {
374  $errors[$blobAddress] = "Unknown blob address schema: $schema."
375  . ' Use findBadBlobs.php to remedy.';
376  $result[$blobAddress] = false;
377  }
378  }
379 
380  $textIds = array_keys( $textIdToBlobAddress );
381  if ( !$textIds ) {
382  return [ $result, $errors ];
383  }
384  // Callers doing updates will pass in READ_LATEST as usual. Since the text/blob tables
385  // do not normally get rows changed around, set READ_LATEST_IMMUTABLE in those cases.
386  $queryFlags |= DBAccessObjectUtils::hasFlags( $queryFlags, self::READ_LATEST )
387  ? self::READ_LATEST_IMMUTABLE
388  : 0;
389  list( $index, $options, $fallbackIndex, $fallbackOptions ) =
390  DBAccessObjectUtils::getDBOptions( $queryFlags );
391  // Text data is immutable; check replica DBs first.
392  $dbConnection = $this->getDBConnection( $index );
393  $rows = $dbConnection->select(
394  'text',
395  [ 'old_id', 'old_text', 'old_flags' ],
396  [ 'old_id' => $textIds ],
397  __METHOD__,
398  $options
399  );
400  $numRows = 0;
401  if ( $rows instanceof IResultWrapper ) {
402  $numRows = $rows->numRows();
403  }
404 
405  // Fallback to DB_PRIMARY in some cases if not all the rows were found, using the appropriate
406  // options, such as FOR UPDATE to avoid missing rows due to REPEATABLE-READ.
407  if ( $numRows !== count( $textIds ) && $fallbackIndex !== null ) {
408  $fetchedTextIds = [];
409  foreach ( $rows as $row ) {
410  $fetchedTextIds[] = $row->old_id;
411  }
412  $missingTextIds = array_diff( $textIds, $fetchedTextIds );
413  $dbConnection = $this->getDBConnection( $fallbackIndex );
414  $rowsFromFallback = $dbConnection->select(
415  'text',
416  [ 'old_id', 'old_text', 'old_flags' ],
417  [ 'old_id' => $missingTextIds ],
418  __METHOD__,
419  $fallbackOptions
420  );
421  $appendIterator = new AppendIterator();
422  $appendIterator->append( $rows );
423  $appendIterator->append( $rowsFromFallback );
424  $rows = $appendIterator;
425  }
426 
427  foreach ( $rows as $row ) {
428  $blobAddress = $textIdToBlobAddress[$row->old_id];
429  $blob = false;
430  if ( $row->old_text !== null ) {
431  $blob = $this->expandBlob( $row->old_text, $row->old_flags, $blobAddress );
432  }
433  if ( $blob === false ) {
434  $errors[$blobAddress] = "Bad data in text row {$row->old_id}."
435  . ' Use findBadBlobs.php to remedy.';
436  }
437  $result[$blobAddress] = $blob;
438  }
439 
440  // If we're still missing some of the rows, set errors for missing blobs.
441  if ( count( $result ) !== count( $blobAddresses ) ) {
442  foreach ( $blobAddresses as $blobAddress ) {
443  if ( !isset( $result[$blobAddress ] ) ) {
444  $errors[$blobAddress] = "Unable to fetch blob at $blobAddress."
445  . ' Use findBadBlobs.php to remedy.';
446  $result[$blobAddress] = false;
447  }
448  }
449  }
450  return [ $result, $errors ];
451  }
452 
463  private function getCacheKey( $blobAddress ) {
464  return $this->cache->makeGlobalKey(
465  'SqlBlobStore-blob',
466  $this->dbLoadBalancer->resolveDomainID( $this->dbDomain ),
467  $blobAddress
468  );
469  }
470 
490  public function expandBlob( $raw, $flags, $cacheKey = null ) {
491  if ( is_string( $flags ) ) {
492  $flags = explode( ',', $flags );
493  }
494 
495  // Use external methods for external objects, text in table is URL-only then
496  if ( in_array( 'external', $flags ) ) {
497  $url = $raw;
498  $parts = explode( '://', $url, 2 );
499  if ( count( $parts ) == 1 || $parts[1] == '' ) {
500  return false;
501  }
502 
503  if ( $cacheKey ) {
504  // The cached value should be decompressed, so handle that and return here.
505  return $this->cache->getWithSetCallback(
506  $this->getCacheKey( $cacheKey ),
507  $this->getCacheTTL(),
508  function () use ( $url, $flags ) {
509  // Ignore $setOpts; blobs are immutable and negatives are not cached
510  $blob = $this->extStoreAccess
511  ->fetchFromURL( $url, [ 'domain' => $this->dbDomain ] );
512 
513  return $blob === false ? false : $this->decompressData( $blob, $flags );
514  },
515  [ 'pcGroup' => self::TEXT_CACHE_GROUP, 'pcTTL' => WANObjectCache::TTL_PROC_LONG ]
516  );
517  } else {
518  $blob = $this->extStoreAccess->fetchFromURL( $url, [ 'domain' => $this->dbDomain ] );
519  return $blob === false ? false : $this->decompressData( $blob, $flags );
520  }
521  } else {
522  return $this->decompressData( $raw, $flags );
523  }
524  }
525 
542  public function compressData( &$blob ) {
543  $blobFlags = [];
544 
545  // Revisions not marked as UTF-8 will have legacy decoding applied by decompressData().
546  // XXX: if $this->legacyEncoding is not set, we could skip this. That would however be
547  // risky, since $this->legacyEncoding being set in the future would lead to data corruption.
548  $blobFlags[] = 'utf-8';
549 
550  if ( $this->compressBlobs ) {
551  if ( function_exists( 'gzdeflate' ) ) {
552  $deflated = gzdeflate( $blob );
553 
554  if ( $deflated === false ) {
555  wfLogWarning( __METHOD__ . ': gzdeflate() failed' );
556  } else {
557  $blob = $deflated;
558  $blobFlags[] = 'gzip';
559  }
560  } else {
561  wfDebug( __METHOD__ . " -- no zlib support, not compressing" );
562  }
563  }
564  return implode( ',', $blobFlags );
565  }
566 
582  public function decompressData( string $blob, array $blobFlags ) {
583  if ( in_array( 'error', $blobFlags ) ) {
584  // Error row, return false
585  return false;
586  }
587 
588  if ( in_array( 'gzip', $blobFlags ) ) {
589  # Deal with optional compression of archived pages.
590  # This can be done periodically via maintenance/compressOld.php, and
591  # as pages are saved if $wgCompressRevisions is set.
592  $blob = gzinflate( $blob );
593 
594  if ( $blob === false ) {
595  wfWarn( __METHOD__ . ': gzinflate() failed' );
596  return false;
597  }
598  }
599 
600  if ( in_array( 'object', $blobFlags ) ) {
601  # Generic compressed storage
602  $obj = unserialize( $blob );
603  if ( !is_object( $obj ) ) {
604  // Invalid object
605  return false;
606  }
607  $blob = $obj->getText();
608  }
609 
610  // Needed to support old revisions left over from the 1.4 / 1.5 migration.
611  if ( $blob !== false && $this->legacyEncoding
612  && !in_array( 'utf-8', $blobFlags ) && !in_array( 'utf8', $blobFlags )
613  ) {
614  # Old revisions kept around in a legacy encoding?
615  # Upconvert on demand.
616  # ("utf8" checked for compatibility with some broken
617  # conversion scripts 2008-12-30)
618  # Even with //IGNORE iconv can whine about illegal characters in
619  # *input* string. We just ignore those too.
620  # REF: https://bugs.php.net/bug.php?id=37166
621  # REF: https://phabricator.wikimedia.org/T18885
622  AtEase::suppressWarnings();
623  $blob = iconv( $this->legacyEncoding, 'UTF-8//IGNORE', $blob );
624  AtEase::restoreWarnings();
625  }
626 
627  return $blob;
628  }
629 
637  private function getCacheTTL() {
639 
640  if ( $cache->getQoS( $cache::ATTR_DURABILITY ) >= $cache::QOS_DURABILITY_RDBMS ) {
641  // Do not cache RDBMs blobs in...the RDBMs store
642  $ttl = $cache::TTL_UNCACHEABLE;
643  } else {
644  $ttl = $this->cacheExpiry ?: $cache::TTL_UNCACHEABLE;
645  }
646 
647  return $ttl;
648  }
649 
670  public function getTextIdFromAddress( $address ) {
671  list( $schema, $id, ) = self::splitBlobAddress( $address );
672 
673  if ( $schema !== 'tt' ) {
674  return null;
675  }
676 
677  $textId = intval( $id );
678 
679  if ( !$textId || $id !== (string)$textId ) {
680  throw new InvalidArgumentException( "Malformed text_id: $id" );
681  }
682 
683  return $textId;
684  }
685 
699  public static function makeAddressFromTextId( $id ) {
700  return 'tt:' . $id;
701  }
702 
713  public static function splitBlobAddress( $address ) {
714  if ( !preg_match( '/^([-+.\w]+):([^\s?]+)(\?([^\s]*))?$/', $address, $m ) ) {
715  throw new InvalidArgumentException( "Bad blob address: $address" );
716  }
717 
718  $schema = strtolower( $m[1] );
719  $id = $m[2];
720  $parameters = wfCgiToArray( $m[4] ?? '' );
721 
722  return [ $schema, $id, $parameters ];
723  }
724 
725  public function isReadOnly() {
726  if ( $this->useExternalStore && $this->extStoreAccess->isReadOnly() ) {
727  return true;
728  }
729 
730  return ( $this->getDBLoadBalancer()->getReadOnlyReason() !== false );
731  }
732 }
MediaWiki\Storage\SqlBlobStore\getBlob
getBlob( $blobAddress, $queryFlags=0)
Retrieve a blob, given an address.
Definition: SqlBlobStore.php:273
WANObjectCache\getQoS
getQoS( $flag)
Definition: WANObjectCache.php:2530
MediaWiki\Storage\SqlBlobStore\getDBLoadBalancer
getDBLoadBalancer()
Definition: SqlBlobStore.php:195
MediaWiki\Storage\BlobAccessException
Exception representing a failure to access a data blob.
Definition: BlobAccessException.php:33
StatusValue
Generic operation result class Has warning/error list, boolean status and arbitrary value.
Definition: StatusValue.php:43
MediaWiki\Storage\SqlBlobStore\getCacheKey
getCacheKey( $blobAddress)
Get a cache key for a given Blob address.
Definition: SqlBlobStore.php:463
MediaWiki\Storage\SqlBlobStore\TEXT_CACHE_GROUP
const TEXT_CACHE_GROUP
Definition: SqlBlobStore.php:56
MediaWiki\Storage\SqlBlobStore\$useExternalStore
bool $useExternalStore
Definition: SqlBlobStore.php:96
MediaWiki\Storage\SqlBlobStore\getDBConnection
getDBConnection( $index)
Definition: SqlBlobStore.php:204
MediaWiki\Storage\SqlBlobStore
Service for storing and loading Content objects.
Definition: SqlBlobStore.php:53
MediaWiki\Storage\SqlBlobStore\__construct
__construct(ILoadBalancer $dbLoadBalancer, ExternalStoreAccess $extStoreAccess, WANObjectCache $cache, $dbDomain=false)
Definition: SqlBlobStore.php:109
MediaWiki\Storage\SqlBlobStore\$compressBlobs
bool $compressBlobs
Definition: SqlBlobStore.php:86
MediaWiki\Storage\SqlBlobStore\$dbDomain
string bool $dbDomain
DB domain ID of a wiki or false for the local one.
Definition: SqlBlobStore.php:76
MediaWiki\Storage\SqlBlobStore\getTextIdFromAddress
getTextIdFromAddress( $address)
Returns an ID corresponding to the old_id field in the text table, corresponding to the given $addres...
Definition: SqlBlobStore.php:670
MediaWiki\Storage\SqlBlobStore\splitBlobAddress
static splitBlobAddress( $address)
Splits a blob address into three parts: the schema, the ID, and parameters/flags.
Definition: SqlBlobStore.php:713
MediaWiki\Storage\SqlBlobStore\expandBlob
expandBlob( $raw, $flags, $cacheKey=null)
Expand a raw data blob according to the flags given.
Definition: SqlBlobStore.php:490
MediaWiki\Storage\SqlBlobStore\$dbLoadBalancer
ILoadBalancer $dbLoadBalancer
Definition: SqlBlobStore.php:61
wfLogWarning
wfLogWarning( $msg, $callerOffset=1, $level=E_USER_WARNING)
Send a warning as a PHP error and the debug log.
Definition: GlobalFunctions.php:1056
DBAccessObjectUtils\getDBOptions
static getDBOptions( $bitfield)
Get an appropriate DB index, options, and fallback DB index for a query.
Definition: DBAccessObjectUtils.php:52
IDBAccessObject
Interface for database access objects.
Definition: IDBAccessObject.php:57
MediaWiki\Storage\SqlBlobStore\getBlobBatch
getBlobBatch( $blobAddresses, $queryFlags=0)
A batched version of BlobStore::getBlob.
Definition: SqlBlobStore.php:309
ExternalStoreAccess
This is the main interface for fetching or inserting objects with ExternalStore.
Definition: ExternalStoreAccess.php:42
Wikimedia\Rdbms\IDatabase
Basic database interface for live and lazy-loaded relation database handles.
Definition: IDatabase.php:38
MediaWiki\Storage\SqlBlobStore\setLegacyEncoding
setLegacyEncoding(string $legacyEncoding)
Set the legacy encoding to assume for blobs that do not have the utf-8 flag set.
Definition: SqlBlobStore.php:174
MediaWiki\Storage\SqlBlobStore\getCompressBlobs
getCompressBlobs()
Definition: SqlBlobStore.php:138
MediaWiki\Storage\SqlBlobStore\getLegacyEncoding
getLegacyEncoding()
Definition: SqlBlobStore.php:153
IExpiringStore
Generic interface providing TTL constants for lightweight expiring object stores.
Definition: IExpiringStore.php:13
MWException
MediaWiki exception.
Definition: MWException.php:29
wfDeprecated
wfDeprecated( $function, $version=false, $component=false, $callerOffset=2)
Logs a warning that a deprecated feature was used.
Definition: GlobalFunctions.php:997
MediaWiki\Storage\SqlBlobStore\getLegacyEncodingConversionLang
getLegacyEncodingConversionLang()
Definition: SqlBlobStore.php:161
MediaWiki\Storage\SqlBlobStore\setCacheExpiry
setCacheExpiry(int $cacheExpiry)
Definition: SqlBlobStore.php:131
MediaWiki\Storage\SqlBlobStore\getCacheTTL
getCacheTTL()
Get the text cache TTL.
Definition: SqlBlobStore.php:637
Wikimedia\Rdbms\IResultWrapper
Result wrapper for grabbing data queried from an IDatabase object.
Definition: IResultWrapper.php:26
MediaWiki\Storage\SqlBlobStore\$extStoreAccess
ExternalStoreAccess $extStoreAccess
Definition: SqlBlobStore.php:66
MediaWiki\Storage\SqlBlobStore\isReadOnly
isReadOnly()
Check if the blob metadata or backing blob data store is read-only.
Definition: SqlBlobStore.php:725
$blob
$blob
Definition: testCompression.php:70
MediaWiki\Storage\SqlBlobStore\decompressData
decompressData(string $blob, array $blobFlags)
Re-converts revision text according to its flags.
Definition: SqlBlobStore.php:582
MediaWiki\Storage\SqlBlobStore\makeAddressFromTextId
static makeAddressFromTextId( $id)
Returns an address referring to content stored in the text table row with the given ID.
Definition: SqlBlobStore.php:699
wfCgiToArray
wfCgiToArray( $query)
This is the logical opposite of wfArrayToCgi(): it accepts a query string as its argument and returns...
Definition: GlobalFunctions.php:375
wfDebug
wfDebug( $text, $dest='all', array $context=[])
Sends a line to the debug log if enabled or, optionally, to a comment in output.
Definition: GlobalFunctions.php:894
DBAccessObjectUtils
Helper class for DAO classes.
Definition: DBAccessObjectUtils.php:29
DBAccessObjectUtils\hasFlags
static hasFlags( $bitfield, $flags)
Definition: DBAccessObjectUtils.php:35
MediaWiki\Storage\SqlBlobStore\storeBlob
storeBlob( $data, $hints=[])
Stores an arbitrary blob of data and returns an address that can be used with getBlob() to retrieve t...
Definition: SqlBlobStore.php:219
StatusValue\newGood
static newGood( $value=null)
Factory function for good results.
Definition: StatusValue.php:82
DB_PRIMARY
const DB_PRIMARY
Definition: defines.php:27
WANObjectCache
Multi-datacenter aware caching interface.
Definition: WANObjectCache.php:131
MediaWiki\Storage\SqlBlobStore\fetchBlobs
fetchBlobs( $blobAddresses, $queryFlags)
MCR migration note: this corresponded to Revision::fetchText.
Definition: SqlBlobStore.php:339
MediaWiki\Storage\SqlBlobStore\getUseExternalStore
getUseExternalStore()
Definition: SqlBlobStore.php:181
MediaWiki\Storage
Definition: BlobAccessException.php:23
MediaWiki\Storage\SqlBlobStore\getCacheExpiry
getCacheExpiry()
Definition: SqlBlobStore.php:124
MediaWiki\Storage\SqlBlobStore\$cacheExpiry
int $cacheExpiry
Definition: SqlBlobStore.php:81
MediaWiki\Storage\BlobStore
Service for loading and storing data blobs.
Definition: BlobStore.php:35
unserialize
unserialize( $serialized)
Definition: ApiMessageTrait.php:146
MediaWiki\Storage\SqlBlobStore\setCompressBlobs
setCompressBlobs( $compressBlobs)
Definition: SqlBlobStore.php:145
wfWarn
wfWarn( $msg, $callerOffset=1, $level=E_USER_NOTICE)
Send a warning either to the debug log or in a PHP error depending on $wgDevelopmentWarnings.
Definition: GlobalFunctions.php:1043
MediaWiki\Storage\SqlBlobStore\$cache
WANObjectCache $cache
Definition: SqlBlobStore.php:71
MediaWiki\Storage\SqlBlobStore\setUseExternalStore
setUseExternalStore(bool $useExternalStore)
Definition: SqlBlobStore.php:188
MediaWiki\Storage\SqlBlobStore\compressData
compressData(&$blob)
If $wgCompressRevisions is enabled, we will compress data.
Definition: SqlBlobStore.php:542
MediaWiki\Storage\SqlBlobStore\$legacyEncoding
bool string $legacyEncoding
Definition: SqlBlobStore.php:91
Wikimedia\Rdbms\ILoadBalancer
Database cluster connection, tracking, load balancing, and transaction manager interface.
Definition: ILoadBalancer.php:81