Reverted r113177 per CR
[lhc/web/wiklou.git] / includes / db / DatabasePostgres.php
index ce2fba8..6452f54 100644 (file)
@@ -16,8 +16,6 @@ class PostgresField implements Field {
         * @return null|PostgresField
         */
        static function fromText( $db, $table, $field ) {
-               global $wgDBmwschema;
-
                $q = <<<SQL
 SELECT
  attnotnull, attlen, COALESCE(conname, '') AS conname,
@@ -39,10 +37,10 @@ AND relname=%s
 AND attname=%s;
 SQL;
 
-               $table = $db->tableName( $table, false );
+               $table = $db->tableName( $table, 'raw' );
                $res = $db->query(
                        sprintf( $q,
-                               $db->addQuotes( $wgDBmwschema ),
+                               $db->addQuotes( $db->getCoreSchema() ),
                                $db->addQuotes( $table ),
                                $db->addQuotes( $field )
                        )
@@ -97,6 +95,84 @@ SQL;
 
 }
 
+/**
+ * Used to debug transaction processing
+ * Only used if $wgDebugDBTransactions is true
+ *
+ * @since 1.20
+ * @ingroup Database
+ */
+class PostgresTransactionState {
+
+       static $WATCHED = array(
+               array(
+                       "desc" => "Connection state changed from %s -> %s\n",  
+                       "states" => array(
+                               PGSQL_CONNECTION_OK       => "OK",
+                               PGSQL_CONNECTION_BAD      => "BAD"
+                       )
+               ),
+               array(
+                       "desc" => "Transaction state changed from %s -> %s\n",
+                       "states" => array(
+                               PGSQL_TRANSACTION_IDLE    => "IDLE",
+                               PGSQL_TRANSACTION_ACTIVE  => "ACTIVE",
+                               PGSQL_TRANSACTION_INTRANS => "TRANS",
+                               PGSQL_TRANSACTION_INERROR => "ERROR",
+                               PGSQL_TRANSACTION_UNKNOWN => "UNKNOWN"
+                       )
+               )
+       );
+
+       public function __construct( $conn ) {
+               $this->mConn = $conn;
+               $this->update();
+               $this->mCurrentState = $this->mNewState;
+       }
+
+       public function update() {
+               $this->mNewState = array( 
+                       pg_connection_status( $this->mConn ),
+                       pg_transaction_status( $this->mConn )
+               );
+       }
+
+       public function check() {
+               global $wgDebugDBTransactions;
+               $this->update();
+               if ( $wgDebugDBTransactions ) {
+                       if ( $this->mCurrentState !== $this->mNewState ) {
+                               $old = reset( $this->mCurrentState );
+                               $new = reset( $this->mNewState );
+                               foreach ( self::$WATCHED as $watched ) {
+                                       if ($old !== $new) {
+                                               $this->log_changed($old, $new, $watched);
+                                       }
+                                       $old = next( $this->mCurrentState );
+                                       $new = next( $this->mNewState );
+
+                               }
+                       }
+               }
+               $this->mCurrentState = $this->mNewState;
+       }
+
+       protected function describe_changed( $status, $desc_table ) {
+               if( isset( $desc_table[$status] ) ) {
+                       return $desc_table[$status];
+               } else {
+                       return "STATUS " . $status;
+               }
+       }
+
+       protected function log_changed( $old, $new, $watched ) {
+               wfDebug(sprintf($watched["desc"], 
+                       $this->describe_changed( $old, $watched["states"] ),
+                       $this->describe_changed( $new, $watched["states"] ))
+               );
+       }
+}
+
 /**
  * @ingroup Database
  */
@@ -136,15 +212,15 @@ class DatabasePostgres extends DatabaseBase {
        }
 
        function hasConstraint( $name ) {
-               global $wgDBmwschema;
                $SQL = "SELECT 1 FROM pg_catalog.pg_constraint c, pg_catalog.pg_namespace n WHERE c.connamespace = n.oid AND conname = '" .
-                               pg_escape_string( $this->mConn, $name ) . "' AND n.nspname = '" . pg_escape_string( $this->mConn, $wgDBmwschema ) ."'";
+                               pg_escape_string( $this->mConn, $name ) . "' AND n.nspname = '" . pg_escape_string( $this->mConn, $this->getCoreSchema() ) ."'";
                $res = $this->doQuery( $SQL );
                return $this->numRows( $res );
        }
 
        /**
         * Usually aborts on failure
+        * @return DatabaseBase|null
         */
        function open( $server, $user, $password, $dbName ) {
                # Test for Postgres support, to avoid suppressed fatal error
@@ -158,7 +234,6 @@ class DatabasePostgres extends DatabaseBase {
                        return;
                }
 
-               $this->close();
                $this->mServer = $server;
                $port = $wgDBport;
                $this->mUser = $user;
@@ -176,20 +251,21 @@ class DatabasePostgres extends DatabaseBase {
                if ( $port != false && $port != '' ) {
                        $connectVars['port'] = $port;
                }
-               $connectString = $this->makeConnectionString( $connectVars, PGSQL_CONNECT_FORCE_NEW );
-
+               $this->connectString = $this->makeConnectionString( $connectVars, PGSQL_CONNECT_FORCE_NEW );
+               $this->close();
                $this->installErrorHandler();
-               $this->mConn = pg_connect( $connectString );
+               $this->mConn = pg_connect( $this->connectString );
                $phpError = $this->restoreErrorHandler();
 
                if ( !$this->mConn ) {
                        wfDebug( "DB connection error\n" );
                        wfDebug( "Server: $server, Database: $dbName, User: $user, Password: " . substr( $password, 0, 3 ) . "...\n" );
                        wfDebug( $this->lastError() . "\n" );
-                       throw new DBConnectionError( $this, $phpError );
+                       throw new DBConnectionError( $this, str_replace( "\n", ' ', $phpError ) );
                }
 
                $this->mOpened = true;
+               $this->mTransactionState = new PostgresTransactionState( $this->mConn );
 
                global $wgCommandLineMode;
                # If called from the command-line (e.g. importDump), only show errors
@@ -200,14 +276,10 @@ class DatabasePostgres extends DatabaseBase {
                $this->query( "SET client_encoding='UTF8'", __METHOD__ );
                $this->query( "SET datestyle = 'ISO, YMD'", __METHOD__ );
                $this->query( "SET timezone = 'GMT'", __METHOD__ );
+               $this->query( "SET standard_conforming_strings = on", __METHOD__ );
 
                global $wgDBmwschema;
-               if ( $this->schemaExists( $wgDBmwschema ) ) {
-                       $safeschema = $this->addIdentifierQuotes( $wgDBmwschema );
-                       $this->doQuery( "SET search_path = $safeschema" );
-               } else {
-                       $this->doQuery( "SET search_path = public" );
-               }
+               $this->determineCoreSchema( $wgDBmwschema );
 
                return $this->mConn;
        }
@@ -218,7 +290,11 @@ class DatabasePostgres extends DatabaseBase {
         * @return
         */
        function selectDB( $db ) {
-               return (bool)$this->open( $this->mServer, $this->mUser, $this->mPassword, $db );
+               if ( $this->mDBname !== $db ) {
+                       return (bool)$this->open( $this->mServer, $this->mUser, $this->mPassword, $db );
+               } else {
+                       return true;
+               }
        }
 
        function makeConnectionString( $vars ) {
@@ -232,25 +308,31 @@ class DatabasePostgres extends DatabaseBase {
        /**
         * Closes a database connection, if it is open
         * Returns success, true if already closed
+        * @return bool
         */
-       function close() {
-               $this->mOpened = false;
-               if ( $this->mConn ) {
-                       return pg_close( $this->mConn );
-               } else {
-                       return true;
-               }
+       protected function closeConnection() {
+               return pg_close( $this->mConn );
        }
 
-       function doQuery( $sql ) {
+       protected function doQuery( $sql ) {
+               global $wgDebugDBTransactions;
                if ( function_exists( 'mb_convert_encoding' ) ) {
                        $sql = mb_convert_encoding( $sql, 'UTF-8' );
                }
+               $this->mTransactionState->check();
                $this->mLastResult = pg_query( $this->mConn, $sql );
-               $this->mAffectedRows = null; // use pg_affected_rows(mLastResult)
+               $this->mTransactionState->check();
+               $this->mAffectedRows = null;
                return $this->mLastResult;
        }
 
+       function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
+               /* Transaction stays in the ERROR state until rolledback */
+               $this->rollback( __METHOD__ );
+               parent::reportQueryError( $error, $errno, $sql, $fname, $tempIgnore );
+       }
+
+
        function queryIgnore( $sql, $fname = 'DatabasePostgres::queryIgnore' ) {
                return $this->query( $sql, $fname, true );
        }
@@ -259,7 +341,10 @@ class DatabasePostgres extends DatabaseBase {
                if ( $res instanceof ResultWrapper ) {
                        $res = $res->result;
                }
-               if ( !@pg_free_result( $res ) ) {
+               wfSuppressWarnings();
+               $ok = pg_free_result( $res );
+               wfRestoreWarnings();
+               if ( !$ok ) {
                        throw new DBUnexpectedError( $this, "Unable to free Postgres result\n" );
                }
        }
@@ -268,7 +353,9 @@ class DatabasePostgres extends DatabaseBase {
                if ( $res instanceof ResultWrapper ) {
                        $res = $res->result;
                }
-               @$row = pg_fetch_object( $res );
+               wfSuppressWarnings();
+               $row = pg_fetch_object( $res );
+               wfRestoreWarnings();
                # @todo FIXME: HACK HACK HACK HACK debug
 
                # @todo hashar: not sure if the following test really trigger if the object
@@ -283,7 +370,9 @@ class DatabasePostgres extends DatabaseBase {
                if ( $res instanceof ResultWrapper ) {
                        $res = $res->result;
                }
-               @$row = pg_fetch_array( $res );
+               wfSuppressWarnings();
+               $row = pg_fetch_array( $res );
+               wfRestoreWarnings();
                if( pg_last_error( $this->mConn ) ) {
                        throw new DBUnexpectedError( $this, 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) ) );
                }
@@ -294,7 +383,9 @@ class DatabasePostgres extends DatabaseBase {
                if ( $res instanceof ResultWrapper ) {
                        $res = $res->result;
                }
-               @$n = pg_num_rows( $res );
+               wfSuppressWarnings();
+               $n = pg_num_rows( $res );
+               wfRestoreWarnings();
                if( pg_last_error( $this->mConn ) ) {
                        throw new DBUnexpectedError( $this, 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) ) );
                }
@@ -317,6 +408,7 @@ class DatabasePostgres extends DatabaseBase {
 
        /**
         * This must be called after nextSequenceVal
+        * @return null
         */
        function insertId() {
                return $this->mInsertId;
@@ -357,6 +449,7 @@ class DatabasePostgres extends DatabaseBase {
         * This is not necessarily an accurate estimate, so use sparingly
         * Returns -1 if count cannot be found
         * Takes same arguments as Database::select()
+        * @return int
         */
        function estimateRowCount( $table, $vars = '*', $conds='', $fname = 'DatabasePostgres::estimateRowCount', $options = array() ) {
                $options['EXPLAIN'] = true;
@@ -375,6 +468,7 @@ class DatabasePostgres extends DatabaseBase {
        /**
         * Returns information about an index
         * If errors are explicitly ignored, returns NULL on failure
+        * @return bool|null
         */
        function indexInfo( $table, $index, $fname = 'DatabasePostgres::indexInfo' ) {
                $sql = "SELECT indexname FROM pg_indexes WHERE tablename='$table'";
@@ -447,7 +541,7 @@ class DatabasePostgres extends DatabaseBase {
                $didbegin = 0;
                if ( $ignore ) {
                        if ( !$this->mTrxLevel ) {
-                               $this->begin();
+                               $this->begin( __METHOD__ );
                                $didbegin = 1;
                        }
                        $olde = error_reporting( 0 );
@@ -478,7 +572,7 @@ class DatabasePostgres extends DatabaseBase {
                                        $tempsql .= '(' . $this->makeList( $row ) . ')';
 
                                        if ( $ignore ) {
-                                               pg_query( $this->mConn, "SAVEPOINT $ignore" );
+                                               $this->doQuery( "SAVEPOINT $ignore" );
                                        }
 
                                        $tempres = (bool)$this->query( $tempsql, $fname, $ignore );
@@ -486,9 +580,9 @@ class DatabasePostgres extends DatabaseBase {
                                        if ( $ignore ) {
                                                $bar = pg_last_error();
                                                if ( $bar != false ) {
-                                                       pg_query( $this->mConn, "ROLLBACK TO $ignore" );
+                                                       $this->doQuery( $this->mConn, "ROLLBACK TO $ignore" );
                                                } else {
-                                                       pg_query( $this->mConn, "RELEASE $ignore" );
+                                                       $this->doQuery( $this->mConn, "RELEASE $ignore" );
                                                        $numrowsinserted++;
                                                }
                                        }
@@ -503,7 +597,7 @@ class DatabasePostgres extends DatabaseBase {
                } else {
                        // Not multi, just a lone insert
                        if ( $ignore ) {
-                               pg_query($this->mConn, "SAVEPOINT $ignore");
+                               $this->doQuery( "SAVEPOINT $ignore" );
                        }
 
                        $sql .= '(' . $this->makeList( $args ) . ')';
@@ -511,9 +605,9 @@ class DatabasePostgres extends DatabaseBase {
                        if ( $ignore ) {
                                $bar = pg_last_error();
                                if ( $bar != false ) {
-                                       pg_query( $this->mConn, "ROLLBACK TO $ignore" );
+                                       $this->doQuery( "ROLLBACK TO $ignore" );
                                } else {
-                                       pg_query( $this->mConn, "RELEASE $ignore" );
+                                       $this->doQuery( "RELEASE $ignore" );
                                        $numrowsinserted++;
                                }
                        }
@@ -521,7 +615,7 @@ class DatabasePostgres extends DatabaseBase {
                if ( $ignore ) {
                        $olde = error_reporting( $olde );
                        if ( $didbegin ) {
-                               $this->commit();
+                               $this->commit( __METHOD__ );
                        }
 
                        // Set the affected row count for the whole operation
@@ -541,6 +635,7 @@ class DatabasePostgres extends DatabaseBase {
         * $conds may be "*" to copy the whole table
         * srcTable may be an array of tables.
         * @todo FIXME: Implement this a little better (seperate select/insert)?
+        * @return bool
         */
        function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = 'DatabasePostgres::insertSelect',
                $insertOptions = array(), $selectOptions = array() )
@@ -551,7 +646,7 @@ class DatabasePostgres extends DatabaseBase {
                $ignore = in_array( 'IGNORE', $insertOptions ) ? 'mw' : '';
 
                if( is_array( $insertOptions ) ) {
-                       $insertOptions = implode( ' ', $insertOptions );
+                       $insertOptions = implode( ' ', $insertOptions ); // FIXME: This is unused
                }
                if( !is_array( $selectOptions ) ) {
                        $selectOptions = array( $selectOptions );
@@ -567,12 +662,12 @@ class DatabasePostgres extends DatabaseBase {
                $didbegin = 0;
                if ( $ignore ) {
                        if( !$this->mTrxLevel ) {
-                               $this->begin();
+                               $this->begin( __METHOD__ );
                                $didbegin = 1;
                        }
                        $olde = error_reporting( 0 );
                        $numrowsinserted = 0;
-                       pg_query( $this->mConn, "SAVEPOINT $ignore");
+                       $this->doQuery( "SAVEPOINT $ignore" );
                }
 
                $sql = "INSERT INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
@@ -589,14 +684,14 @@ class DatabasePostgres extends DatabaseBase {
                if( $ignore ) {
                        $bar = pg_last_error();
                        if( $bar != false ) {
-                               pg_query( $this->mConn, "ROLLBACK TO $ignore" );
+                               $this->doQuery( "ROLLBACK TO $ignore" );
                        } else {
-                               pg_query( $this->mConn, "RELEASE $ignore" );
+                               $this->doQuery( "RELEASE $ignore" );
                                $numrowsinserted++;
                        }
                        $olde = error_reporting( $olde );
                        if( $didbegin ) {
-                               $this->commit();
+                               $this->commit( __METHOD__ );
                        }
 
                        // Set the affected row count for the whole operation
@@ -609,7 +704,7 @@ class DatabasePostgres extends DatabaseBase {
                return $res;
        }
 
-       function tableName( $name, $quoted = true ) {
+       function tableName( $name, $format = 'quoted' ) {
                # Replace reserved words with better ones
                switch( $name ) {
                        case 'user':
@@ -617,12 +712,13 @@ class DatabasePostgres extends DatabaseBase {
                        case 'text':
                                return 'pagecontent';
                        default:
-                               return parent::tableName( $name, $quoted );
+                               return parent::tableName( $name, $format );
                }
        }
 
        /**
         * Return the next in a sequence, save the value for retrieval via insertId()
+        * @return null
         */
        function nextSequenceValue( $seqName ) {
                $safeseq = str_replace( "'", "''", $seqName );
@@ -634,6 +730,7 @@ class DatabasePostgres extends DatabaseBase {
 
        /**
         * Return the current value of a sequence. Assumes it has been nextval'ed in this session.
+        * @return
         */
        function currentSequenceValue( $seqName ) {
                $safeseq = str_replace( "'", "''", $seqName );
@@ -643,83 +740,6 @@ class DatabasePostgres extends DatabaseBase {
                return $currval;
        }
 
-       /**
-        * REPLACE query wrapper
-        * Postgres simulates this with a DELETE followed by INSERT
-        * $row is the row to insert, an associative array
-        * $uniqueIndexes is an array of indexes. Each element may be either a
-        * field name or an array of field names
-        *
-        * It may be more efficient to leave off unique indexes which are unlikely to collide.
-        * However if you do this, you run the risk of encountering errors which wouldn't have
-        * occurred in MySQL
-        */
-       function replace( $table, $uniqueIndexes, $rows, $fname = 'DatabasePostgres::replace' ) {
-               $table = $this->tableName( $table );
-
-               if ( count( $rows ) == 0 ) {
-                       return;
-               }
-
-               # Single row case
-               if ( !is_array( reset( $rows ) ) ) {
-                       $rows = array( $rows );
-               }
-
-               foreach( $rows as $row ) {
-                       # Delete rows which collide
-                       if ( $uniqueIndexes ) {
-                               $sql = "DELETE FROM $table WHERE ";
-                               $first = true;
-                               foreach ( $uniqueIndexes as $index ) {
-                                       if ( $first ) {
-                                               $first = false;
-                                               $sql .= '(';
-                                       } else {
-                                               $sql .= ') OR (';
-                                       }
-                                       if ( is_array( $index ) ) {
-                                               $first2 = true;
-                                               foreach ( $index as $col ) {
-                                                       if ( $first2 ) {
-                                                               $first2 = false;
-                                                       } else {
-                                                               $sql .= ' AND ';
-                                                       }
-                                                       $sql .= $col.'=' . $this->addQuotes( $row[$col] );
-                                               }
-                                       } else {
-                                               $sql .= $index.'=' . $this->addQuotes( $row[$index] );
-                                       }
-                               }
-                               $sql .= ')';
-                               $this->query( $sql, $fname );
-                       }
-
-                       # Now insert the row
-                       $sql = "INSERT INTO $table (" . $this->makeList( array_keys( $row ), LIST_NAMES ) .') VALUES (' .
-                               $this->makeList( $row, LIST_COMMA ) . ')';
-                       $this->query( $sql, $fname );
-               }
-       }
-
-       # DELETE where the condition is a join
-       function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = 'DatabasePostgres::deleteJoin' ) {
-               if ( !$conds ) {
-                       throw new DBUnexpectedError( $this, 'DatabasePostgres::deleteJoin() called with empty $conds' );
-               }
-
-               $delTable = $this->tableName( $delTable );
-               $joinTable = $this->tableName( $joinTable );
-               $sql = "DELETE FROM $delTable WHERE $delVar IN (SELECT $joinVar FROM $joinTable ";
-               if ( $conds != '*' ) {
-                       $sql .= 'WHERE ' . $this->makeList( $conds, LIST_AND );
-               }
-               $sql .= ')';
-
-               $this->query( $sql, $fname );
-       }
-
        # Returns the size of a text field, or -1 for "unlimited"
        function textFieldSize( $table, $field ) {
                $table = $this->tableName( $table );
@@ -751,10 +771,70 @@ class DatabasePostgres extends DatabaseBase {
                return $this->query( 'CREATE ' . ( $temporary ? 'TEMPORARY ' : '' ) . " TABLE $newName (LIKE $oldName INCLUDING DEFAULTS)", $fname );
        }
 
+       function listTables( $prefix = null, $fname = 'DatabasePostgres::listTables' ) {
+               $eschema = $this->addQuotes( $this->getCoreSchema() );
+               $result = $this->query( "SELECT tablename FROM pg_tables WHERE schemaname = $eschema", $fname );
+               $endArray = array();
+
+               foreach( $result as $table ) {
+                       $vars = get_object_vars($table);
+                       $table = array_pop( $vars );
+                       if( !$prefix || strpos( $table, $prefix ) === 0 ) {
+                               $endArray[] = $table;
+                       }
+               }
+
+               return $endArray;
+       }
+
        function timestamp( $ts = 0 ) {
                return wfTimestamp( TS_POSTGRES, $ts );
        }
 
+       /* 
+        * Posted by cc[plus]php[at]c2se[dot]com on 25-Mar-2009 09:12
+        * to http://www.php.net/manual/en/ref.pgsql.php
+        *
+        * Parsing a postgres array can be a tricky problem, he's my
+        * take on this, it handles multi-dimensional arrays plus
+        * escaping using a nasty regexp to determine the limits of each
+        * data-item.
+        *
+        * This should really be handled by PHP PostgreSQL module
+        *
+        * @since 1.20
+        * @param $text   string: postgreql array returned in a text form like {a,b}
+        * @param $output string
+        * @param $limit  int
+        * @param $offset int
+        * @return string
+        */
+       function pg_array_parse( $text, &$output, $limit = false, $offset = 1 ) {
+               if( false === $limit ) {
+                       $limit = strlen( $text )-1;
+                       $output = array();
+               }
+               if( '{}' == $text ) {
+                       return $output;
+               }
+               do {
+                       if ( '{' != $text{$offset} ) {
+                               preg_match( "/(\\{?\"([^\"\\\\]|\\\\.)*\"|[^,{}]+)+([,}]+)/",
+                                       $text, $match, 0, $offset );
+                               $offset += strlen( $match[0] );
+                               $output[] = ( '"' != $match[1]{0} 
+                                               ? $match[1] 
+                                               : stripcslashes( substr( $match[1], 1, -1 ) ) );
+                               if ( '},' == $match[3] ) {
+                                       return $output;
+                               }
+                       } else {
+                               $offset = $this->pg_array_parse( $text, $output, $limit, $offset+1 );
+                       }
+               } while ( $limit > $offset );
+               return $output;
+       }
+
        /**
         * Return aggregated value function call
         */
@@ -762,28 +842,120 @@ class DatabasePostgres extends DatabaseBase {
                return $valuedata;
        }
 
-       function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
-               // Ignore errors during error handling to avoid infinite recursion
-               $ignore = $this->ignoreErrors( true );
-               $this->mErrorCount++;
+       /**
+        * @return string wikitext of a link to the server software's web site
+        */
+       public static function getSoftwareLink() {
+               return '[http://www.postgresql.org/ PostgreSQL]';
+       }
+
+
+       /**
+        * Return current schema (executes SELECT current_schema())
+        * Needs transaction
+        *
+        * @since 1.20
+        * @return string return default schema for the current session
+        */
+       function getCurrentSchema() {
+               $res = $this->query( "SELECT current_schema()", __METHOD__);
+               $row = $this->fetchRow( $res );
+               return $row[0];
+       }
+
+       /**
+        * Return list of schemas which are accessible without schema name
+        * This is list does not contain magic keywords like "$user"
+        * Needs transaction
+        *
+        * @seealso getSearchPath()
+        * @seealso setSearchPath()
+        * @since 1.20
+        * @return array list of actual schemas for the current sesson
+        */
+       function getSchemas() {
+               $res = $this->query( "SELECT current_schemas(false)", __METHOD__);
+               $row = $this->fetchRow( $res );
+               $schemas = array();
+               /* PHP pgsql support does not support array type, "{a,b}" string is returned */
+               return $this->pg_array_parse($row[0], $schemas);
+       }
+
+       /**
+        * Return search patch for schemas
+        * This is different from getSchemas() since it contain magic keywords
+        * (like "$user").
+        * Needs transaction
+        *
+        * @since 1.20
+        * @return array how to search for table names schemas for the current user
+        */
+       function getSearchPath() {
+               $res = $this->query( "SHOW search_path", __METHOD__);
+               $row = $this->fetchRow( $res );
+               /* PostgreSQL returns SHOW values as strings */
+               return explode(",", $row[0]);
+       }
+
+       /**
+        * Update search_path, values should already be sanitized
+        * Values may contain magic keywords like "$user"
+        * @since 1.20
+        *
+        * @param $search_path array list of schemas to be searched by default
+        */
+       function setSearchPath( $search_path ) {
+               $this->query( "SET search_path = " . implode(", ", $search_path) );
+       }
 
-               if ( $ignore || $tempIgnore ) {
-                       wfDebug( "SQL ERROR (ignored): $error\n" );
-                       $this->ignoreErrors( $ignore );
+       /**
+        * Determine default schema for MediaWiki core
+        * Adjust this session schema search path if desired schema exists
+        * and is not alread there.
+        *
+        * We need to have name of the core schema stored to be able
+        * to query database metadata.
+        *
+        * This will be also called by the installer after the schema is created
+        *
+        * @since 1.20
+        * @param desired_schema string 
+        */
+       function determineCoreSchema( $desired_schema ) {
+               $this->begin( __METHOD__ );
+               if ( $this->schemaExists( $desired_schema ) ) {
+                       if ( in_array( $desired_schema, $this->getSchemas() ) ) {
+                               $this->mCoreSchema = $desired_schema;
+                               wfDebug("Schema \"" . $desired_schema . "\" already in the search path\n");
+                       } else {
+                               /**
+                                * Append our schema (e.g. 'mediawiki') in front
+                                * of the search path
+                                * Fixes bug 15816 
+                                */
+                               $search_path = $this->getSearchPath();
+                               array_unshift( $search_path, 
+                                       $this->addIdentifierQuotes( $desired_schema ));
+                               $this->setSearchPath( $search_path );   
+                               $this->mCoreSchema = $desired_schema;
+                               wfDebug("Schema \"" . $desired_schema . "\" added to the search path\n");
+                       }
                } else {
-                       $message = "A database error has occurred.  Did you forget to run maintenance/update.php after upgrading?  See: http://www.mediawiki.org/wiki/Manual:Upgrading#Run_the_update_script\n" .
-                               "Query: $sql\n" .
-                               "Function: $fname\n" .
-                               "Error: $errno $error\n";
-                       throw new DBUnexpectedError( $this, $message );
+                       $this->mCoreSchema = $this->getCurrentSchema();
+                       wfDebug("Schema \"" . $desired_schema . "\" not found, using current \"". $this->mCoreSchema ."\"\n");
                }
+               /* Commit SET otherwise it will be rollbacked on error or IGNORE SELECT */
+               $this->commit( __METHOD__ );
        }
 
        /**
-        * @return string wikitext of a link to the server software's web site
+        * Return schema name fore core MediaWiki tables
+        *
+        * @since 1.20
+        * @return string core schema name
         */
-       public static function getSoftwareLink() {
-               return '[http://www.postgresql.org/ PostgreSQL]';
+       function getCoreSchema() {
+               return $this->mCoreSchema;
        }
 
        /**
@@ -809,16 +981,16 @@ class DatabasePostgres extends DatabaseBase {
        /**
         * Query whether a given relation exists (in the given schema, or the
         * default mw one if not given)
+        * @return bool
         */
        function relationExists( $table, $types, $schema = false ) {
-               global $wgDBmwschema;
                if ( !is_array( $types ) ) {
                        $types = array( $types );
                }
                if ( !$schema ) {
-                       $schema = $wgDBmwschema;
+                       $schema = $this->getCoreSchema();
                }
-               $table = $this->tableName( $table, false );
+               $table = $this->tableName( $table, 'raw' );
                $etable = $this->addQuotes( $table );
                $eschema = $this->addQuotes( $schema );
                $SQL = "SELECT 1 FROM pg_catalog.pg_class c, pg_catalog.pg_namespace n "
@@ -832,8 +1004,9 @@ class DatabasePostgres extends DatabaseBase {
        /**
         * For backward compatibility, this function checks both tables and
         * views.
+        * @return bool
         */
-       function tableExists( $table, $schema = false ) {
+       function tableExists( $table, $fname = __METHOD__, $schema = false ) {
                return $this->relationExists( $table, array( 'r', 'v' ), $schema );
        }
 
@@ -842,18 +1015,16 @@ class DatabasePostgres extends DatabaseBase {
        }
 
        function triggerExists( $table, $trigger ) {
-               global $wgDBmwschema;
-
                $q = <<<SQL
        SELECT 1 FROM pg_class, pg_namespace, pg_trigger
                WHERE relnamespace=pg_namespace.oid AND relkind='r'
-                     AND tgrelid=pg_class.oid
-                     AND nspname=%s AND relname=%s AND tgname=%s
+                         AND tgrelid=pg_class.oid
+                         AND nspname=%s AND relname=%s AND tgname=%s
 SQL;
                $res = $this->query(
                        sprintf(
                                $q,
-                               $this->addQuotes( $wgDBmwschema ),
+                               $this->addQuotes( $this->getCoreSchema() ),
                                $this->addQuotes( $table ),
                                $this->addQuotes( $trigger )
                        )
@@ -866,22 +1037,20 @@ SQL;
        }
 
        function ruleExists( $table, $rule ) {
-               global $wgDBmwschema;
                $exists = $this->selectField( 'pg_rules', 'rulename',
                        array(
                                'rulename' => $rule,
                                'tablename' => $table,
-                               'schemaname' => $wgDBmwschema
+                               'schemaname' => $this->getCoreSchema()
                        )
                );
                return $exists === $rule;
        }
 
        function constraintExists( $table, $constraint ) {
-               global $wgDBmwschema;
                $SQL = sprintf( "SELECT 1 FROM information_schema.table_constraints ".
                           "WHERE constraint_schema = %s AND table_name = %s AND constraint_name = %s",
-                       $this->addQuotes( $wgDBmwschema ),
+                       $this->addQuotes( $this->getCoreSchema() ),
                        $this->addQuotes( $table ),
                        $this->addQuotes( $constraint )
                );
@@ -894,20 +1063,23 @@ SQL;
        }
 
        /**
-        * Query whether a given schema exists. Returns the name of the owner
+        * Query whether a given schema exists. Returns true if it does, false if it doesn't.
+        * @return bool
         */
        function schemaExists( $schema ) {
-               $eschema = str_replace( "'", "''", $schema );
-               $SQL = "SELECT rolname FROM pg_catalog.pg_namespace n, pg_catalog.pg_roles r "
-                               ."WHERE n.nspowner=r.oid AND n.nspname = '$eschema'";
-               $res = $this->query( $SQL );
-               if ( $res && $res->numRows() ) {
-                       $row = $res->fetchObject();
-                       $owner = $row->rolname;
-               } else {
-                       $owner = false;
-               }
-               return $owner;
+               $exists = $this->selectField( '"pg_catalog"."pg_namespace"', 1,
+                       array( 'nspname' => $schema ), __METHOD__ );
+               return (bool)$exists;
+       }
+
+       /**
+        * Returns true if a given role (i.e. user) exists, false otherwise.
+        * @return bool
+        */
+       function roleExists( $roleName ) {
+               $exists = $this->selectField( '"pg_catalog"."pg_roles"', 1,
+                       array( 'rolname' => $roleName ), __METHOD__ );
+               return (bool)$exists;
        }
 
        function fieldInfo( $table, $field ) {
@@ -916,6 +1088,7 @@ SQL;
 
        /**
         * pg_field_type() wrapper
+        * @return string
         */
        function fieldType( $res, $index ) {
                if ( $res instanceof ResultWrapper ) {
@@ -929,6 +1102,10 @@ SQL;
                return $sql;
        }
 
+       /**
+        * @param $b
+        * @return Blob
+        */
        function encodeBlob( $b ) {
                return new Blob( pg_escape_bytea( $this->mConn, $b ) );
        }
@@ -944,6 +1121,10 @@ SQL;
                return pg_escape_string( $this->mConn, $s );
        }
 
+       /**
+        * @param $s null|bool|Blob
+        * @return int|string
+        */
        function addQuotes( $s ) {
                if ( is_null( $s ) ) {
                        return 'NULL';
@@ -1054,4 +1235,17 @@ SQL;
        public function getSearchEngine() {
                return 'SearchPostgres';
        }
+
+       public function streamStatementEnd( &$sql, &$newLine ) {
+               # Allow dollar quoting for function declarations
+               if ( substr( $newLine, 0, 4 ) == '$mw$' ) {
+                       if ( $this->delimiter ) {
+                               $this->delimiter = false;
+                       }
+                       else {
+                               $this->delimiter = ';';
+                       }
+               }
+               return parent::streamStatementEnd( $sql, $newLine );
+       }
 } // end DatabasePostgres class