updateCollation.php

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<?php
require_once __DIR__ . '/Maintenance.php';

class UpdateCollation extends Maintenance {
    const BATCH_SIZE = 100; // Number of rows to process in one batch
    const SYNC_INTERVAL = 5; // Wait for replica DBs after this many batches

    public $sizeHistogram = [];

    public function __construct() {
        parent::__construct();

        global $wgCategoryCollation;
        $this->addDescription( <<<TEXT
This script will find all rows in the categorylinks table whose collation is
out-of-date (cl_collation != '$wgCategoryCollation') and repopulate cl_sortkey
using the page title and cl_sortkey_prefix.  If all collations are
up-to-date, it will do nothing.
TEXT
        );

        $this->addOption( 'force', 'Run on all rows, even if the collation is ' .
            'supposed to be up-to-date.', false, false, 'f' );
        $this->addOption( 'previous-collation', 'Set the previous value of ' .
            '$wgCategoryCollation here to speed up this script, especially if your ' .
            'categorylinks table is large. This will only update rows with that ' .
            'collation, though, so it may miss out-of-date rows with a different, ' .
            'even older collation.', false, true );
        $this->addOption( 'target-collation', 'Set this to the new collation type to ' .
            'use instead of $wgCategoryCollation. Usually you should not use this, ' .
            'you should just update $wgCategoryCollation in LocalSettings.php.',
            false, true );
        $this->addOption( 'dry-run', 'Don\'t actually change the collations, just ' .
            'compile statistics.' );
        $this->addOption( 'verbose-stats', 'Show more statistics.' );
    }

    public function execute() {
        global $wgCategoryCollation;

        $dbw = $this->getDB( DB_MASTER );
        $dbr = $this->getDB( DB_REPLICA );
        $force = $this->getOption( 'force' );
        $dryRun = $this->getOption( 'dry-run' );
        $verboseStats = $this->getOption( 'verbose-stats' );
        if ( $this->hasOption( 'target-collation' ) ) {
            $collationName = $this->getOption( 'target-collation' );
            $collation = Collation::factory( $collationName );
        } else {
            $collationName = $wgCategoryCollation;
            $collation = Collation::singleton();
        }

        // Collation sanity check: in some cases the constructor will work,
        // but this will raise an exception, breaking all category pages
        $collation->getFirstLetter( 'MediaWiki' );

        // Locally at least, (my local is a rather old version of mysql)
        // mysql seems to filesort if there is both an equality
        // (but not for an inequality) condition on cl_collation in the
        // WHERE and it is also the first item in the ORDER BY.
        if ( $this->hasOption( 'previous-collation' ) ) {
            $orderBy = 'cl_to, cl_type, cl_from';
        } else {
            $orderBy = 'cl_collation, cl_to, cl_type, cl_from';
        }
        $options = [
            'LIMIT' => self::BATCH_SIZE,
            'ORDER BY' => $orderBy,
            'STRAIGHT_JOIN' // per T58041
        ];

        if ( $force ) {
            $collationConds = [];
        } else {
            if ( $this->hasOption( 'previous-collation' ) ) {
                $collationConds['cl_collation'] = $this->getOption( 'previous-collation' );
            } else {
                $collationConds = [ 0 =>
                    'cl_collation != ' . $dbw->addQuotes( $collationName )
                ];
            }

            $count = $dbr->estimateRowCount(
                'categorylinks',
                '*',
                $collationConds,
                __METHOD__
            );
            // Improve estimate if feasible
            if ( $count < 1000000 ) {
                $count = $dbr->selectField(
                    'categorylinks',
                    'COUNT(*)',
                    $collationConds,
                    __METHOD__
                );
            }
            if ( $count == 0 ) {
                $this->output( "Collations up-to-date.\n" );

                return;
            }
            if ( $dryRun ) {
                $this->output( "$count rows would be updated.\n" );
            } else {
                $this->output( "Fixing collation for $count rows.\n" );
            }
            wfWaitForSlaves();
        }
        $count = 0;
        $batchCount = 0;
        $batchConds = [];
        do {
            $this->output( "Selecting next " . self::BATCH_SIZE . " rows..." );

            // cl_type must be selected as a number for proper paging because
            // enums suck.
            if ( $dbw->getType() === 'mysql' ) {
                $clType = 'cl_type+0 AS "cl_type_numeric"';
            } else {
                $clType = 'cl_type';
            }
            $res = $dbw->select(
                [ 'categorylinks', 'page' ],
                [ 'cl_from', 'cl_to', 'cl_sortkey_prefix', 'cl_collation',
                    'cl_sortkey', $clType,
                    'page_namespace', 'page_title'
                ],
                array_merge( $collationConds, $batchConds, [ 'cl_from = page_id' ] ),
                __METHOD__,
                $options
            );
            $this->output( " processing..." );

            if ( !$dryRun ) {
                $this->beginTransaction( $dbw, __METHOD__ );
            }
            foreach ( $res as $row ) {
                $title = Title::newFromRow( $row );
                if ( !$row->cl_collation ) {
                    # This is an old-style row, so the sortkey needs to be
                    # converted.
                    if ( $row->cl_sortkey == $title->getText()
                        || $row->cl_sortkey == $title->getPrefixedText()
                    ) {
                        $prefix = '';
                    } else {
                        # Custom sortkey, use it as a prefix
                        $prefix = $row->cl_sortkey;
                    }
                } else {
                    $prefix = $row->cl_sortkey_prefix;
                }
                # cl_type will be wrong for lots of pages if cl_collation is 0,
                # so let's update it while we're here.
                if ( $title->getNamespace() == NS_CATEGORY ) {
                    $type = 'subcat';
                } elseif ( $title->getNamespace() == NS_FILE ) {
                    $type = 'file';
                } else {
                    $type = 'page';
                }
                $newSortKey = $collation->getSortKey(
                    $title->getCategorySortkey( $prefix ) );
                if ( $verboseStats ) {
                    $this->updateSortKeySizeHistogram( $newSortKey );
                }

                if ( !$dryRun ) {
                    $dbw->update(
                        'categorylinks',
                        [
                            'cl_sortkey' => $newSortKey,
                            'cl_sortkey_prefix' => $prefix,
                            'cl_collation' => $collationName,
                            'cl_type' => $type,
                            'cl_timestamp = cl_timestamp',
                        ],
                        [ 'cl_from' => $row->cl_from, 'cl_to' => $row->cl_to ],
                        __METHOD__
                    );
                }
                if ( $row ) {
                    $batchConds = [ $this->getBatchCondition( $row, $dbw ) ];
                }
            }
            if ( !$dryRun ) {
                $this->commitTransaction( $dbw, __METHOD__ );
            }

            $count += $res->numRows();
            $this->output( "$count done.\n" );

            if ( !$dryRun && ++$batchCount % self::SYNC_INTERVAL == 0 ) {
                $this->output( "Waiting for replica DBs ... " );
                wfWaitForSlaves();
                $this->output( "done\n" );
            }
        } while ( $res->numRows() == self::BATCH_SIZE );

        $this->output( "$count rows processed\n" );

        if ( $verboseStats ) {
            $this->output( "\n" );
            $this->showSortKeySizeHistogram();
        }
    }

    function getBatchCondition( $row, $dbw ) {
        if ( $this->hasOption( 'previous-collation' ) ) {
            $fields = [ 'cl_to', 'cl_type', 'cl_from' ];
        } else {
            $fields = [ 'cl_collation', 'cl_to', 'cl_type', 'cl_from' ];
        }
        $first = true;
        $cond = false;
        $prefix = false;
        foreach ( $fields as $field ) {
            if ( $dbw->getType() === 'mysql' && $field === 'cl_type' ) {
                // Range conditions with enums are weird in mysql
                // This must be a numeric literal, or it won't work.
                $encValue = intval( $row->cl_type_numeric );
            } else {
                $encValue = $dbw->addQuotes( $row->$field );
            }
            $inequality = "$field > $encValue";
            $equality = "$field = $encValue";
            if ( $first ) {
                $cond = $inequality;
                $prefix = $equality;
                $first = false;
            } else {
                $cond .= " OR ($prefix AND $inequality)";
                $prefix .= " AND $equality";
            }
        }

        return $cond;
    }

    function updateSortKeySizeHistogram( $key ) {
        $length = strlen( $key );
        if ( !isset( $this->sizeHistogram[$length] ) ) {
            $this->sizeHistogram[$length] = 0;
        }
        $this->sizeHistogram[$length]++;
    }

    function showSortKeySizeHistogram() {
        $maxLength = max( array_keys( $this->sizeHistogram ) );
        if ( $maxLength == 0 ) {
            return;
        }
        $numBins = 20;
        $coarseHistogram = array_fill( 0, $numBins, 0 );
        $coarseBoundaries = [];
        $boundary = 0;
        for ( $i = 0; $i < $numBins - 1; $i++ ) {
            $boundary += $maxLength / $numBins;
            $coarseBoundaries[$i] = round( $boundary );
        }
        $coarseBoundaries[$numBins - 1] = $maxLength + 1;
        $raw = '';
        for ( $i = 0; $i <= $maxLength; $i++ ) {
            if ( $raw !== '' ) {
                $raw .= ', ';
            }
            if ( !isset( $this->sizeHistogram[$i] ) ) {
                $val = 0;
            } else {
                $val = $this->sizeHistogram[$i];
            }
            for ( $coarseIndex = 0; $coarseIndex < $numBins - 1; $coarseIndex++ ) {
                if ( $coarseBoundaries[$coarseIndex] > $i ) {
                    $coarseHistogram[$coarseIndex] += $val;
                    break;
                }
            }
            if ( $coarseIndex == $numBins - 1 ) {
                $coarseHistogram[$coarseIndex] += $val;
            }
            $raw .= $val;
        }

        $this->output( "Sort key size histogram\nRaw data: $raw\n\n" );

        $maxBinVal = max( $coarseHistogram );
        $scale = 60 / $maxBinVal;
        $prevBoundary = 0;
        for ( $coarseIndex = 0; $coarseIndex < $numBins; $coarseIndex++ ) {
            if ( !isset( $coarseHistogram[$coarseIndex] ) ) {
                $val = 0;
            } else {
                $val = $coarseHistogram[$coarseIndex];
            }
            $boundary = $coarseBoundaries[$coarseIndex];
            $this->output( sprintf( "%-10s %-10d |%s\n",
                $prevBoundary . '-' . ( $boundary - 1 ) . ': ',
                $val,
                str_repeat( '*', $scale * $val ) ) );
            $prevBoundary = $boundary;
        }
    }
}

$maintClass = "UpdateCollation";
require_once RUN_MAINTENANCE_IF_MAIN;