maintenance/convertLinks.inc

   1 <?php
   2 /**
   3  * @file
   4  * @todo document
   5  * @ingroup Maintenance
   6  */
   7
   8 /** */
   9 function convertLinks() {
  10         global $wgDBtype;
  11         if( $wgDBtype == 'postgres' ) {
  12                 wfOut( "Links table already ok on Postgres.\n" );
  13                 return;
  14         }
  15
  16         wfOut( "Converting links table to ID-ID...\n" );
  17
  18         global $wgLang, $wgDBserver, $wgDBadminuser, $wgDBadminpassword, $wgDBname;
  19         global $noKeys, $logPerformance, $fh;
  20
  21         $tuplesAdded = $numBadLinks = $curRowsRead = 0; #counters etc
  22         $totalTuplesInserted = 0; # total tuples INSERTed into links_temp
  23
  24         $reportCurReadProgress = true; #whether or not to give progress reports while reading IDs from cur table
  25         $curReadReportInterval = 1000; #number of rows between progress reports
  26
  27         $reportLinksConvProgress = true; #whether or not to give progress reports during conversion
  28         $linksConvInsertInterval = 1000; #number of rows per INSERT
  29
  30         $initialRowOffset = 0;
  31         #$finalRowOffset = 0; # not used yet; highest row number from links table to process
  32
  33         # Overwrite the old links table with the new one.  If this is set to false,
  34         # the new table will be left at links_temp.
  35         $overwriteLinksTable = true;
  36
  37         # Don't create keys, and so allow duplicates in the new links table.
  38         # This gives a huge speed improvement for very large links tables which are MyISAM. (What about InnoDB?)
  39         $noKeys = false;
  40
  41
  42         $logPerformance = false; # output performance data to a file
  43         $perfLogFilename = "convLinksPerf.txt";
  44         #--------------------------------------------------------------------
  45
  46         $dbw = wfGetDB( DB_MASTER );
  47         list ($cur, $links, $links_temp, $links_backup) = $dbw->tableNamesN( 'cur', 'links', 'links_temp', 'links_backup' );
  48
  49         $res = $dbw->query( "SELECT l_from FROM $links LIMIT 1" );
  50         if ( $dbw->fieldType( $res, 0 ) == "int" ) {
  51                 wfOut( "Schema already converted\n" );
  52                 return;
  53         }
  54
  55         $res = $dbw->query( "SELECT COUNT(*) AS count FROM $links" );
  56         $row = $dbw->fetchObject($res);
  57         $numRows = $row->count;
  58         $dbw->freeResult( $res );
  59
  60         if ( $numRows == 0 ) {
  61                 wfOut( "Updating schema (no rows to convert)...\n" );
  62                 createTempTable();
  63         } else {
  64                 if ( $logPerformance ) { $fh = fopen ( $perfLogFilename, "w" ); }
  65                 $baseTime = $startTime = getMicroTime();
  66                 # Create a title -> cur_id map
  67                 wfOut( "Loading IDs from $cur table...\n" );
  68                 performanceLog ( "Reading $numRows rows from cur table...\n" );
  69                 performanceLog ( "rows read vs seconds elapsed:\n" );
  70
  71                 $dbw->bufferResults( false );
  72                 $res = $dbw->query( "SELECT cur_namespace,cur_title,cur_id FROM $cur" );
  73                 $ids = array();
  74
  75                 while ( $row = $dbw->fetchObject( $res ) ) {
  76                         $title = $row->cur_title;
  77                         if ( $row->cur_namespace ) {
  78                                 $title = $wgLang->getNsText( $row->cur_namespace ) . ":$title";
  79                         }
  80                         $ids[$title] = $row->cur_id;
  81                         $curRowsRead++;
  82                         if ($reportCurReadProgress) {
  83                                 if (($curRowsRead % $curReadReportInterval) == 0) {
  84                                         performanceLog( $curRowsRead . " " . (getMicroTime() - $baseTime) . "\n" );
  85                                         wfOut( "\t$curRowsRead rows of $cur table read.\n" );
  86                                 }
  87                         }
  88                 }
  89                 $dbw->freeResult( $res );
  90                 $dbw->bufferResults( true );
  91                 wfOut( "Finished loading IDs.\n\n" );
  92                 performanceLog( "Took " . (getMicroTime() - $baseTime) . " seconds to load IDs.\n\n" );
  93         #--------------------------------------------------------------------
  94
  95                 # Now, step through the links table (in chunks of $linksConvInsertInterval rows),
  96                 # convert, and write to the new table.
  97                 createTempTable();
  98                 performanceLog( "Resetting timer.\n\n" );
  99                 $baseTime = getMicroTime();
 100                 wfOut( "Processing $numRows rows from $links table...\n" );
 101                 performanceLog( "Processing $numRows rows from $links table...\n" );
 102                 performanceLog( "rows inserted vs seconds elapsed:\n" );
 103
 104                 for ($rowOffset = $initialRowOffset; $rowOffset < $numRows; $rowOffset += $linksConvInsertInterval) {
 105                         $sqlRead = "SELECT * FROM $links ";
 106                         $sqlRead = $dbw->limitResult($sqlRead, $linksConvInsertInterval,$rowOffset);
 107                         $res = $dbw->query($sqlRead);
 108                         if ( $noKeys ) {
 109                                 $sqlWrite = array("INSERT INTO $links_temp (l_from,l_to) VALUES ");
 110                         } else {
 111                                 $sqlWrite = array("INSERT IGNORE INTO $links_temp (l_from,l_to) VALUES ");
 112                         }
 113
 114                         $tuplesAdded = 0; # no tuples added to INSERT yet
 115                         while ( $row = $dbw->fetchObject($res) ) {
 116                                 $fromTitle = $row->l_from;
 117                                 if ( array_key_exists( $fromTitle, $ids ) ) { # valid title
 118                                         $from = $ids[$fromTitle];
 119                                         $to = $row->l_to;
 120                                         if ( $tuplesAdded != 0 ) {
 121                                                 $sqlWrite[] = ",";
 122                                         }
 123                                         $sqlWrite[] = "($from,$to)";
 124                                         $tuplesAdded++;
 125                                 } else { # invalid title
 126                                         $numBadLinks++;
 127                                 }
 128                         }
 129                         $dbw->freeResult($res);
 130                         #wfOut( "rowOffset: $rowOffset\ttuplesAdded: $tuplesAdded\tnumBadLinks: $numBadLinks\n" );
 131                         if ( $tuplesAdded != 0  ) {
 132                                 if ($reportLinksConvProgress) {
 133                                         wfOut( "Inserting $tuplesAdded tuples into $links_temp..." );
 134                                 }
 135                                 $dbw->query( implode("",$sqlWrite) );
 136                                 $totalTuplesInserted += $tuplesAdded;
 137                                 if ($reportLinksConvProgress)
 138                                         wfOut( " done. Total $totalTuplesInserted tuples inserted.\n" );
 139                                         performanceLog( $totalTuplesInserted . " " . (getMicroTime() - $baseTime) . "\n"  );
 140                         }
 141                 }
 142                 wfOut( "$totalTuplesInserted valid titles and $numBadLinks invalid titles were processed.\n\n" );
 143                 performanceLog( "$totalTuplesInserted valid titles and $numBadLinks invalid titles were processed.\n" );
 144                 performanceLog( "Total execution time: " . (getMicroTime() - $startTime) . " seconds.\n" );
 145                 if ( $logPerformance ) { fclose ( $fh ); }
 146         }
 147         #--------------------------------------------------------------------
 148
 149         if ( $overwriteLinksTable ) {
 150                 $dbConn = Database::newFromParams( $wgDBserver, $wgDBadminuser, $wgDBadminpassword, $wgDBname );
 151                 if (!($dbConn->isOpen())) {
 152                         wfOut( "Opening connection to database failed.\n" );
 153                         return;
 154                 }
 155                 # Check for existing links_backup, and delete it if it exists.
 156                 wfOut( "Dropping backup links table if it exists..." );
 157                 $dbConn->query( "DROP TABLE IF EXISTS $links_backup", DB_MASTER);
 158                 wfOut( " done.\n" );
 159
 160                 # Swap in the new table, and move old links table to links_backup
 161                 wfOut( "Swapping tables '$links' to '$links_backup'; '$links_temp' to '$links'..." );
 162                 $dbConn->query( "RENAME TABLE links TO $links_backup, $links_temp TO $links", DB_MASTER );
 163                 wfOut( " done.\n\n" );
 164
 165                 $dbConn->close();
 166                 wfOut( "Conversion complete. The old table remains at $links_backup;\n" );
 167                 wfOut( "delete at your leisure.\n" );
 168         } else {
 169                 wfOut( "Conversion complete.  The converted table is at $links_temp;\n" );
 170                 wfOut( "the original links table is unchanged.\n" );
 171         }
 172 }
 173
 174 #--------------------------------------------------------------------
 175
 176 function createTempTable() {
 177         global $wgDBserver, $wgDBadminuser, $wgDBadminpassword, $wgDBname;
 178         global $noKeys;
 179         $dbConn = Database::newFromParams( $wgDBserver, $wgDBadminuser, $wgDBadminpassword, $wgDBname );
 180
 181         if (!($dbConn->isOpen())) {
 182                 wfOut( "Opening connection to database failed.\n" );
 183                 return;
 184         }
 185         $links_temp = $dbConn->tableName( 'links_temp' );
 186
 187         wfOut( "Dropping temporary links table if it exists..." );
 188         $dbConn->query( "DROP TABLE IF EXISTS $links_temp");
 189         wfOut( " done.\n" );
 190
 191         wfOut( "Creating temporary links table..." );
 192         if ( $noKeys ) {
 193                 $dbConn->query( "CREATE TABLE $links_temp ( " .
 194                 "l_from int(8) unsigned NOT NULL default '0', " .
 195                 "l_to int(8) unsigned NOT NULL default '0')");
 196         } else {
 197                 $dbConn->query( "CREATE TABLE $links_temp ( " .
 198                 "l_from int(8) unsigned NOT NULL default '0', " .
 199                 "l_to int(8) unsigned NOT NULL default '0', " .
 200                 "UNIQUE KEY l_from(l_from,l_to), " .
 201                 "KEY (l_to))");
 202         }
 203         wfOut( " done.\n\n" );
 204 }
 205
 206 function performanceLog( $text ) {
 207         global $logPerformance, $fh;
 208         if ( $logPerformance ) {
 209                 fwrite( $fh, $text );
 210         }
 211 }
 212
 213 function getMicroTime() { # return time in seconds, with microsecond accuracy
 214         list($usec, $sec) = explode(" ", microtime());
 215         return ((float)$usec + (float)$sec);
 216 }