Merge "add IGNORE INDEX option to mysql database handler"

[lhc/web/wiklou.git] / includes / db / Database.php

diff --git a/includes/db/Database.php b/includes/db/Database.php
index eca80d8..0a1774d 100644 (file)
--- a/includes/db/Database.php
+++ b/includes/db/Database.php
@@ -1344,8 +1344,13 @@ abstract class DatabaseBase implements IDatabase {
                } else {
                        $useIndex = '';
                }
+               if ( isset( $options['IGNORE INDEX'] ) && is_string( $options['IGNORE INDEX'] ) ) {
+                       $ignoreIndex = $this->ignoreIndexClause( $options['IGNORE INDEX'] );
+               } else {
+                       $ignoreIndex = '';
+               }
 
-               return [ $startOpts, $useIndex, $preLimitTail, $postLimitTail ];
+               return [ $startOpts, $useIndex, $preLimitTail, $postLimitTail, $ignoreIndex ];
        }
 
        /**
@@ -1413,31 +1418,34 @@ abstract class DatabaseBase implements IDatabase {
                $useIndexes = ( isset( $options['USE INDEX'] ) && is_array( $options['USE INDEX'] ) )
                        ? $options['USE INDEX']
                        : [];
+               $ignoreIndexes = ( isset( $options['IGNORE INDEX'] ) && is_array( $options['IGNORE INDEX'] ) )
+                       ? $options['IGNORE INDEX']
+                       : [];
 
                if ( is_array( $table ) ) {
                        $from = ' FROM ' .
-                               $this->tableNamesWithUseIndexOrJOIN( $table, $useIndexes, $join_conds );
+                               $this->tableNamesWithIndexClauseOrJOIN( $table, $useIndexes, $ignoreIndexes, $join_conds );
                } elseif ( $table != '' ) {
                        if ( $table[0] == ' ' ) {
                                $from = ' FROM ' . $table;
                        } else {
                                $from = ' FROM ' .
-                                       $this->tableNamesWithUseIndexOrJOIN( [ $table ], $useIndexes, [] );
+                                       $this->tableNamesWithIndexClauseOrJOIN( [ $table ], $useIndexes, $ignoreIndexes, [] );
                        }
                } else {
                        $from = '';
                }
 
-               list( $startOpts, $useIndex, $preLimitTail, $postLimitTail ) =
+               list( $startOpts, $useIndex, $preLimitTail, $postLimitTail, $ignoreIndex ) =
                        $this->makeSelectOptions( $options );
 
                if ( !empty( $conds ) ) {
                        if ( is_array( $conds ) ) {
                                $conds = $this->makeList( $conds, LIST_AND );
                        }
-                       $sql = "SELECT $startOpts $vars $from $useIndex WHERE $conds $preLimitTail";
+                       $sql = "SELECT $startOpts $vars $from $useIndex $ignoreIndex WHERE $conds $preLimitTail";
                } else {
-                       $sql = "SELECT $startOpts $vars $from $useIndex $preLimitTail";
+                       $sql = "SELECT $startOpts $vars $from $useIndex $ignoreIndex $preLimitTail";
                }
 
                if ( isset( $options['LIMIT'] ) ) {
@@ -2048,19 +2056,21 @@ abstract class DatabaseBase implements IDatabase {
 
        /**
         * Get the aliased table name clause for a FROM clause
-        * which might have a JOIN and/or USE INDEX clause
+        * which might have a JOIN and/or USE INDEX or IGNORE INDEX clause
         *
         * @param array $tables ( [alias] => table )
         * @param array $use_index Same as for select()
+        * @param array $ignore_index Same as for select()
         * @param array $join_conds Same as for select()
         * @return string
         */
-       protected function tableNamesWithUseIndexOrJOIN(
-               $tables, $use_index = [], $join_conds = []
+       protected function tableNamesWithIndexClauseOrJOIN(
+               $tables, $use_index = [], $ignore_index = [], $join_conds = []
        ) {
                $ret = [];
                $retJOIN = [];
                $use_index = (array)$use_index;
+               $ignore_index = (array)$ignore_index;
                $join_conds = (array)$join_conds;
 
                foreach ( $tables as $alias => $table ) {
@@ -2079,6 +2089,12 @@ abstract class DatabaseBase implements IDatabase {
                                                $tableClause .= ' ' . $use;
                                        }
                                }
+                               if ( isset( $ignore_index[$alias] ) ) { // has IGNORE INDEX?
+                                       $ignore = $this->ignoreIndexClause( implode( ',', (array)$ignore_index[$alias] ) );
+                                       if ( $ignore != '' ) {
+                                               $tableClause .= ' ' . $ignore;
+                                       }
+                               }
                                $on = $this->makeList( (array)$conds, LIST_AND );
                                if ( $on != '' ) {
                                        $tableClause .= ' ON (' . $on . ')';
@@ -2092,6 +2108,14 @@ abstract class DatabaseBase implements IDatabase {
                                        implode( ',', (array)$use_index[$alias] )
                                );
 
+                               $ret[] = $tableClause;
+                       } elseif ( isset( $ignore_index[$alias] ) ) {
+                               // Is there an INDEX clause for this table?
+                               $tableClause = $this->tableNameWithAlias( $table, $alias );
+                               $tableClause .= ' ' . $this->ignoreIndexClause(
+                                       implode( ',', (array)$ignore_index[$alias] )
+                               );
+
                                $ret[] = $tableClause;
                        } else {
                                $tableClause = $this->tableNameWithAlias( $table, $alias );
@@ -2224,6 +2248,20 @@ abstract class DatabaseBase implements IDatabase {
                return '';
        }
 
+       /**
+        * IGNORE INDEX clause. Unlikely to be useful for anything but MySQL. This
+        * is only needed because a) MySQL must be as efficient as possible due to
+        * its use on Wikipedia, and b) MySQL 4.0 is kind of dumb sometimes about
+        * which index to pick. Anyway, other databases might have different
+        * indexes on a given table. So don't bother overriding this unless you're
+        * MySQL.
+        * @param string $index
+        * @return string
+        */
+       public function ignoreIndexClause( $index ) {
+               return '';
+       }
+
        public function replace( $table, $uniqueIndexes, $rows, $fname = __METHOD__ ) {
                $quotedTable = $this->tableName( $table );
 
@@ -2488,7 +2526,8 @@ abstract class DatabaseBase implements IDatabase {
                        $selectOptions = [ $selectOptions ];
                }
 
-               list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
+               list( $startOpts, $useIndex, $tailOpts, $ignoreIndex ) = $this->makeSelectOptions(
+                       $selectOptions );
 
                if ( is_array( $srcTable ) ) {
                        $srcTable = implode( ',', array_map( [ &$this, 'tableName' ], $srcTable ) );
@@ -2498,7 +2537,7 @@ abstract class DatabaseBase implements IDatabase {
 
                $sql = "INSERT $insertOptions INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
                        " SELECT $startOpts " . implode( ',', $varMap ) .
-                       " FROM $srcTable $useIndex ";
+                       " FROM $srcTable $useIndex $ignoreIndex ";
 
                if ( $conds != '*' ) {
                        if ( is_array( $conds ) ) {