PostgreSQL: Improve SQL error handling

After a query error, PostgreSQL transaction is aborted
until it's terminated or the query is closed.

All further queries result in:

  ERROR: current transaction is aborted, commands ignored
  until end of transaction block

Those subsequent errors are ignored by double fault handling in
DatabaseBase::reportQueryError but they cause all localization
of error messages to fail (unable to issue queries to message
tables) and errors lke

This resulted in a broken MediaWiki screen with

  <databaseerror>
  <dberrortext>

instead of localized error message.

We need to fully reset database connection because after
pg_connection_reset() various session parameters need to
be set again (like "search_path"), otherwise tables will not be
found.

   ERROR: relation "msg_resource" does not exist
   ERROR:  relation "l10n_cache" does not exist

diff --git a/includes/db/DatabasePostgres.php b/includes/db/DatabasePostgres.php
index 893b651..1f1d7ed 100644 (file)
--- a/includes/db/DatabasePostgres.php
+++ b/includes/db/DatabasePostgres.php
@@ -159,7 +159,6 @@ class DatabasePostgres extends DatabaseBase {
                        return;
                }
 
-               $this->close();
                $this->mServer = $server;
                $port = $wgDBport;
                $this->mUser = $user;
@@ -177,10 +176,14 @@ 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->reOpen();
+       }
 
+       function reOpen() {
+               $this->close();
                $this->installErrorHandler();
-               $this->mConn = pg_connect( $connectString );
+               $this->mConn = pg_connect( $this->connectString );
                $phpError = $this->restoreErrorHandler();
 
                if ( !$this->mConn ) {
@@ -253,6 +256,13 @@ class DatabasePostgres extends DatabaseBase {
                return $this->mLastResult;
        }
 
+       function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
+               $this->rollback( __METHOD__ );
+               $this->reOpen();
+               parent::reportQueryError( $error, $errno, $sql, $fname, $tempIgnore );
+       }
+
+
        function queryIgnore( $sql, $fname = 'DatabasePostgres::queryIgnore' ) {
                return $this->query( $sql, $fname, true );
        }