Clean up postgres connection handling
authorAaron Schulz <aschulz@wikimedia.org>
Tue, 18 Oct 2016 01:21:46 +0000 (18:21 -0700)
committerAaron Schulz <aschulz@wikimedia.org>
Wed, 19 Oct 2016 01:08:49 +0000 (01:08 +0000)
* Remove non-connection magic case when no DB $user
  is given. This was removed from the base class.
* Use PGSQL_CONNECT_FORCE_NEW to let LoadBalancer
  handle connection reuse. This makes it work like
  the mysql classes.
* Make postgres connection error messages actually
  be useful by using the PHP error when possible.
  This makes it clear if the problem is authentication
  or something else and so on.

Change-Id: I3fd76c1e2db8d6008074f5347b201554579b549a

includes/libs/rdbms/database/Database.php
includes/libs/rdbms/database/DatabasePostgres.php
includes/libs/rdbms/loadbalancer/LoadBalancer.php

index f33e244..4266912 100644 (file)
@@ -651,14 +651,22 @@ abstract class Database implements IDatabase, IMaintainableDatabase, LoggerAware
                if ( $this->htmlErrors !== false ) {
                        ini_set( 'html_errors', $this->htmlErrors );
                }
+
+               return $this->getLastPHPError();
+       }
+
+       /**
+        * @return string|bool Last PHP error for this DB (typically connection errors)
+        */
+       protected function getLastPHPError() {
                if ( $this->mPHPError ) {
                        $error = preg_replace( '!\[<a.*</a>\]!', '', $this->mPHPError );
                        $error = preg_replace( '!^.*?:\s?(.*)$!', '$1', $error );
 
                        return $error;
-               } else {
-                       return false;
                }
+
+               return false;
        }
 
        /**
index 84021a0..016b9cd 100644 (file)
@@ -92,10 +92,6 @@ class DatabasePostgres extends Database {
                        );
                }
 
-               if ( !strlen( $user ) ) { # e.g. the class is being loaded
-                       return null;
-               }
-
                $this->mServer = $server;
                $this->mUser = $user;
                $this->mPassword = $password;
@@ -121,7 +117,8 @@ class DatabasePostgres extends Database {
                $this->installErrorHandler();
 
                try {
-                       $this->mConn = pg_connect( $this->connectString );
+                       // Use new connections to let LoadBalancer/LBFactory handle reuse
+                       $this->mConn = pg_connect( $this->connectString, PGSQL_CONNECT_FORCE_NEW );
                } catch ( Exception $ex ) {
                        $this->restoreErrorHandler();
                        throw $ex;
@@ -130,10 +127,11 @@ class DatabasePostgres extends Database {
                $phpError = $this->restoreErrorHandler();
 
                if ( !$this->mConn ) {
-                       $this->queryLogger->debug( "DB connection error\n" );
                        $this->queryLogger->debug(
+                               "DB connection error\n" .
                                "Server: $server, Database: $dbName, User: $user, Password: " .
-                               substr( $password, 0, 3 ) . "...\n" );
+                               substr( $password, 0, 3 ) . "...\n"
+                       );
                        $this->queryLogger->debug( $this->lastError() . "\n" );
                        throw new DBConnectionError( $this, str_replace( "\n", ' ', $phpError ) );
                }
@@ -380,9 +378,9 @@ class DatabasePostgres extends Database {
                        } else {
                                return pg_last_error();
                        }
-               } else {
-                       return 'No database connection';
                }
+
+               return $this->getLastPHPError() ?: 'No database connection';
        }
 
        function lastErrno() {
index 682698d..8a51fe2 100644 (file)
@@ -552,7 +552,7 @@ class LoadBalancer implements ILoadBalancer {
                if ( $i == self::DB_REPLICA ) {
                        $this->mLastError = 'Unknown error'; // reset error string
                        # Try the general server pool if $groups are unavailable.
-                       $i = in_array( false, $groups, true )
+                       $i = ( $groups === [ false ] )
                                ? false // don't bother with this if that is what was tried above
                                : $this->getReaderIndex( false, $domain );
                        # Couldn't find a working server in getReaderIndex()?
@@ -886,7 +886,7 @@ class LoadBalancer implements ILoadBalancer {
                        // If all servers were busy, mLastError will contain something sensible
                        throw new DBConnectionError( null, $this->mLastError );
                } else {
-                       $context['db_server'] = $conn->getProperty( 'mServer' );
+                       $context['db_server'] = $conn->getServer();
                        $this->connLogger->warning(
                                "Connection error: {last_error} ({db_server})",
                                $context