maintenance/storage/trackBlobs.php

   1 <?php
   2
   3 require( dirname( __FILE__ ) .'/../commandLine.inc' );
   4
   5
   6 if ( count( $args ) < 1 ) {
   7         echo "Usage: php trackBlobs.php <cluster> [... <cluster>]\n";
   8         echo "Adds blobs from a given ES cluster to the blob_tracking table\n";
   9         echo "Automatically deletes the tracking table and starts from the start again when restarted.\n";
  10
  11         exit( 1 );
  12 }
  13 $tracker = new TrackBlobs( $args );
  14 $tracker->trackBlobs();
  15
  16 class TrackBlobs {
  17         var $clusters, $textClause;
  18         var $doBlobOrphans;
  19         var $trackedBlobs = array();
  20
  21         var $batchSize = 1000;
  22         var $reportingInterval = 10;
  23
  24         function __construct( $clusters ) {
  25                 $this->clusters = $clusters;
  26                 if ( extension_loaded( 'gmp' ) ) {
  27                         $this->doBlobOrphans = true;
  28                         foreach ( $clusters as $cluster ) {
  29                                 $this->trackedBlobs[$cluster] = gmp_init( 0 );
  30                         }
  31                 } else {
  32                         echo "Warning: the gmp extension is needed to find orphan blobs\n";
  33                 }
  34         }
  35
  36         function trackBlobs() {
  37                 $this->initTrackingTable();
  38                 $this->trackRevisions();
  39                 $this->trackOrphanText();
  40                 if ( $this->doBlobOrphans ) {
  41                         $this->findOrphanBlobs();
  42                 }
  43         }
  44
  45         function initTrackingTable() {
  46                 $dbw = wfGetDB( DB_MASTER );
  47                 if ( $dbw->tableExists( 'blob_tracking' ) ) {
  48                         $dbw->query( 'DROP TABLE ' . $dbw->tableName( 'blob_tracking' ) );
  49                         $dbw->query( 'DROP TABLE ' . $dbw->tableName( 'blob_orphans' ) );
  50                 }
  51                 $dbw->sourceFile( dirname( __FILE__ ) . '/blob_tracking.sql' );
  52         }
  53
  54         function getTextClause() {
  55                 if ( !$this->textClause ) {
  56                         $dbr = wfGetDB( DB_SLAVE );
  57                         $this->textClause = '';
  58                         foreach ( $this->clusters as $cluster ) {
  59                                 if ( $this->textClause != '' ) {
  60                                         $this->textClause .= ' OR ';
  61                                 }
  62                                 $this->textClause .= 'old_text LIKE ' . $dbr->addQuotes( $dbr->escapeLike( "DB://$cluster/" ) . '%' );
  63                         }
  64                 }
  65                 return $this->textClause;
  66         }
  67
  68         function interpretPointer( $text ) {
  69                 if ( !preg_match( '!^DB://(\w+)/(\d+)(?:/([0-9a-fA-F]+)|)$!', $text, $m ) ) {
  70                         return false;
  71                 }
  72                 return array(
  73                         'cluster' => $m[1],
  74                         'id' => intval( $m[2] ),
  75                         'hash' => isset( $m[3] ) ? $m[2] : null
  76                 );
  77         }
  78
  79         /**
  80          *  Scan the revision table for rows stored in the specified clusters
  81          */
  82         function trackRevisions() {
  83                 $dbw = wfGetDB( DB_MASTER );
  84                 $dbr = wfGetDB( DB_SLAVE );
  85
  86                 $textClause = $this->getTextClause();
  87                 $startId = 0;
  88                 $endId = $dbr->selectField( 'revision', 'MAX(rev_id)', false, __METHOD__ );
  89                 $batchesDone = 0;
  90                 $rowsInserted = 0;
  91
  92                 echo "Finding revisions...\n";
  93
  94                 while ( true ) {
  95                         $res = $dbr->select( array( 'revision', 'text' ),
  96                                 array( 'rev_id', 'rev_page', 'old_id', 'old_flags', 'old_text' ),
  97                                 array(
  98                                         'rev_id > ' . $dbr->addQuotes( $startId ),
  99                                         'rev_text_id=old_id',
 100                                         $textClause,
 101                                         "old_flags LIKE '%external%'",
 102                                 ),
 103                                 __METHOD__,
 104                                 array(
 105                                         'ORDER BY' => 'rev_id',
 106                                         'LIMIT' => $this->batchSize
 107                                 )
 108                         );
 109                         if ( !$res->numRows() ) {
 110                                 break;
 111                         }
 112
 113                         $insertBatch = array();
 114                         foreach ( $res as $row ) {
 115                                 $startId = $row->rev_id;
 116                                 $info = $this->interpretPointer( $row->old_text );
 117                                 if ( !$info ) {
 118                                         echo "Invalid DB:// URL in rev_id {$row->rev_id}\n";
 119                                         continue;
 120                                 }
 121                                 if ( !in_array( $info['cluster'], $this->clusters ) ) {
 122                                         echo "Invalid cluster returned in SQL query: {$info['cluster']}\n";
 123                                         continue;
 124                                 }
 125                                 $insertBatch[] = array(
 126                                         'bt_page' => $row->rev_page,
 127                                         'bt_rev_id' => $row->rev_id,
 128                                         'bt_text_id' => $row->old_id,
 129                                         'bt_cluster' => $info['cluster'],
 130                                         'bt_blob_id' => $info['id'],
 131                                         'bt_cgz_hash' => $info['hash']
 132                                 );
 133                                 if ( $this->doBlobOrphans ) {
 134                                         gmp_setbit( $this->trackedBlobs[$info['cluster']], $info['id'] );
 135                                 }
 136                         }
 137                         $dbw->insert( 'blob_tracking', $insertBatch, __METHOD__ );
 138                         $rowsInserted += count( $insertBatch );
 139
 140                         ++$batchesDone;
 141                         if ( $batchesDone >= $this->reportingInterval ) {
 142                                 $batchesDone = 0;
 143                                 echo "$startId / $endId\n";
 144                                 wfWaitForSlaves( 5 );
 145                         }
 146                 }
 147                 echo "Found $rowsInserted revisions\n";
 148         }
 149
 150         /**
 151          * Scan the text table for orphan text
 152          * Orphan text here does not imply DB corruption -- deleted text tracked by the
 153          * archive table counts as orphan for our purposes.
 154          */
 155         function trackOrphanText() {
 156                 # Wait until the blob_tracking table is available in the slave
 157                 $dbw = wfGetDB( DB_MASTER );
 158                 $dbr = wfGetDB( DB_SLAVE );
 159                 $pos = $dbw->getMasterPos();
 160                 $dbr->masterPosWait( $pos, 100000 );
 161
 162                 $textClause = $this->getTextClause( $this->clusters );
 163                 $startId = 0;
 164                 $endId = $dbr->selectField( 'text', 'MAX(old_id)', false, __METHOD__ );
 165                 $rowsInserted = 0;
 166                 $batchesDone = 0;
 167
 168                 echo "Finding orphan text...\n";
 169
 170                 # Scan the text table for orphan text
 171                 while ( true ) {
 172                         $res = $dbr->select( array( 'text', 'blob_tracking' ),
 173                                 array( 'old_id', 'old_flags', 'old_text' ),
 174                                 array(
 175                                         'old_id>' . $dbr->addQuotes( $startId ),
 176                                         $textClause,
 177                                         "old_flags LIKE '%external%'",
 178                                         'bt_text_id IS NULL'
 179                                 ),
 180                                 __METHOD__,
 181                                 array(
 182                                         'ORDER BY' => 'old_id',
 183                                         'LIMIT' => $this->batchSize
 184                                 ),
 185                                 array( 'blob_tracking' => array( 'LEFT JOIN', 'bt_text_id=old_id' ) )
 186                         );
 187                         $ids = array();
 188                         foreach ( $res as $row ) {
 189                                 $ids[] = $row->old_id;
 190                         }
 191
 192                         if ( !$res->numRows() ) {
 193                                 break;
 194                         }
 195
 196                         $insertBatch = array();
 197                         foreach ( $res as $row ) {
 198                                 $startId = $row->old_id;
 199                                 $info = $this->interpretPointer( $row->old_text );
 200                                 if ( !$info ) {
 201                                         echo "Invalid DB:// URL in old_id {$row->old_id}\n";
 202                                         continue;
 203                                 }
 204                                 if ( !in_array( $info['cluster'], $this->clusters ) ) {
 205                                         echo "Invalid cluster returned in SQL query\n";
 206                                         continue;
 207                                 }
 208
 209                                 $insertBatch[] = array(
 210                                         'bt_page' => 0,
 211                                         'bt_rev_id' => 0,
 212                                         'bt_text_id' => $row->old_id,
 213                                         'bt_cluster' => $info['cluster'],
 214                                         'bt_blob_id' => $info['id'],
 215                                         'bt_cgz_hash' => $info['hash']
 216                                 );
 217                                 if ( $this->doBlobOrphans ) {
 218                                         gmp_setbit( $this->trackedBlobs[$info['cluster']], $info['id'] );
 219                                 }
 220                         }
 221                         $dbw->insert( 'blob_tracking', $insertBatch, __METHOD__ );
 222
 223                         $rowsInserted += count( $insertBatch );
 224                         ++$batchesDone;
 225                         if ( $batchesDone >= $this->reportingInterval ) {
 226                                 $batchesDone = 0;
 227                                 echo "$startId / $endId\n";
 228                                 wfWaitForSlaves( 5 );
 229                         }
 230                 }
 231                 echo "Found $rowsInserted orphan text rows\n";
 232         }
 233
 234         /**
 235          * Scan the blobs table for rows not registered in blob_tracking (and thus not
 236          * registered in the text table).
 237          *
 238          * Orphan blobs are indicative of DB corruption. They are inaccessible and
 239          * should probably be deleted.
 240          */
 241         function findOrphanBlobs() {
 242                 if ( !extension_loaded( 'gmp' ) ) {
 243                         echo "Can't find orphan blobs, need bitfield support provided by GMP.\n";
 244                         return;
 245                 }
 246
 247                 $dbw = wfGetDB( DB_MASTER );
 248
 249                 foreach ( $this->clusters as $cluster ) {
 250                         echo "Searching for orphan blobs in $cluster...\n";
 251                         $lb = wfGetLBFactory()->getExternalLB( $cluster );
 252                         try {
 253                                 $extDB = $lb->getConnection( DB_SLAVE );
 254                         } catch ( DBConnectionError $e ) {
 255                                 if ( strpos( $e->error, 'Unknown database' ) !== false ) {
 256                                         echo "No database on $cluster\n";
 257                                 } else {
 258                                         echo "Error on $cluster: " . $e->getMessage() . "\n";
 259                                 }
 260                                 continue;
 261                         }
 262                         $startId = 0;
 263                         $batchesDone = 0;
 264                         $actualBlobs = gmp_init( 0 );
 265                         $endId = $extDB->selectField( 'blobs', 'MAX(blob_id)', false, __METHOD__ );
 266
 267                         // Build a bitmap of actual blob rows
 268                         while ( true ) {
 269                                 $res = $extDB->select( 'blobs',
 270                                         array( 'blob_id' ),
 271                                         array( 'blob_id > ' . $extDB->addQuotes( $startId ) ),
 272                                         __METHOD__,
 273                                         array( 'LIMIT' => $this->batchSize, 'ORDER BY' => 'blob_id' )
 274                                 );
 275
 276                                 if ( !$res->numRows() ) {
 277                                         break;
 278                                 }
 279
 280                                 foreach ( $res as $row ) {
 281                                         gmp_setbit( $actualBlobs, $row->blob_id );
 282                                 }
 283                                 $startId = $row->blob_id;
 284
 285                                 ++$batchesDone;
 286                                 if ( $batchesDone >= $this->reportingInterval ) {
 287                                         $batchesDone = 0;
 288                                         echo "$startId / $endId\n";
 289                                 }
 290                         }
 291
 292                         // Find actual blobs that weren't tracked by the previous passes
 293                         // This is a set-theoretic difference A \ B, or in bitwise terms, A & ~B
 294                         $orphans = gmp_and( $actualBlobs, gmp_com( $this->trackedBlobs[$cluster] ) );
 295
 296                         // Traverse the orphan list
 297                         $insertBatch = array();
 298                         $id = 0;
 299                         while ( true ) {
 300                                 $id = gmp_scan1( $orphans, $id );
 301                                 if ( $id == -1 ) {
 302                                         break;
 303                                 }
 304                                 $insertBatch[] = array(
 305                                         'bo_cluster' => $cluster,
 306                                         'bo_blob_id' => $id
 307                                 );
 308                                 ++$id;
 309                         }
 310
 311                         // Insert the batch
 312                         echo "Found " . count( $insertBatch ) . " orphan(s) in $cluster\n";
 313                         $dbw->insert( 'blob_orphans', $insertBatch, __METHOD__ );
 314                 }
 315         }
 316 }