maintenance/convertLinks.inc

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