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