Add Database::conditional() function to build IF() or CASE statements

depending on the RDBMS used. Allowed NULL in some RC fields on PostgreSQL.

Fix for bug 407: rebuildrecentchanges.php fails on PostgreSQL
http://bugzilla.wikipedia.org/show_bug.cgi?id=407

diff --git a/includes/Database.php b/includes/Database.php
index c2d8730..d9ab045 100644 (file)
--- a/includes/Database.php
+++ b/includes/Database.php
@@ -1041,6 +1041,19 @@ class Database {
                return ' LIMIT '.(is_numeric($offset)?"{$offset},":"")."{$limit} ";
        }
 
+       /**
+        * Returns an SQL expression for a simple conditional.
+        * Uses IF on MySQL.
+        *
+        * @param string $cond SQL expression which will result in a boolean value
+        * @param string $trueVal SQL expression to return if true
+        * @param string $falseVal SQL expression to return if false
+        * @return string SQL fragment
+        */
+       function conditional( $cond, $trueVal, $falseVal ) {
+               return " IF($cond, $trueVal, $falseVal) ";
+       }
+
        /**
         * @todo document
         */

diff --git a/includes/DatabasePostgreSQL.php b/includes/DatabasePostgreSQL.php
index db4c7d8..75c7fe4 100644 (file)
--- a/includes/DatabasePostgreSQL.php
+++ b/includes/DatabasePostgreSQL.php
@@ -351,6 +351,19 @@ class DatabasePgsql extends Database {
        function limitResult($limit,$offset) {
                return " LIMIT $limit ".(is_numeric($offset)?" OFFSET {$offset} ":"");
        }
+       
+       /**
+        * Returns an SQL expression for a simple conditional.
+        * Uses CASE on PostgreSQL.
+        *
+        * @param string $cond SQL expression which will result in a boolean value
+        * @param string $trueVal SQL expression to return if true
+        * @param string $falseVal SQL expression to return if false
+        * @return string SQL fragment
+        */
+       function conditional( $cond, $trueVal, $falseVal ) {
+               return " (CASE WHEN $cond THEN $trueVal ELSE $falseVal END) ";
+       }
 
        # FIXME: actually detecting deadlocks might be nice
        function wasDeadlock() {

diff --git a/maintenance/postgresql/pg_tables.sql b/maintenance/postgresql/pg_tables.sql
index 41b979a..5e0324e 100644 (file)
--- a/maintenance/postgresql/pg_tables.sql
+++ b/maintenance/postgresql/pg_tables.sql
@@ -182,8 +182,8 @@ CREATE TABLE recentchanges (
     rc_this_oldid integer NOT NULL,
     rc_last_oldid integer NOT NULL,
     rc_type smallint NOT NULL,
-    rc_moved_to_ns smallint NOT NULL,
-    rc_moved_to_title varchar NOT NULL,
+    rc_moved_to_ns smallint,
+    rc_moved_to_title varchar,
     rc_ip inet,
     rc_patrolled smallint
 );

diff --git a/maintenance/rebuildrecentchanges.inc b/maintenance/rebuildrecentchanges.inc
index 2d9fc2f..13a8da0 100644 (file)
--- a/maintenance/rebuildrecentchanges.inc
+++ b/maintenance/rebuildrecentchanges.inc
@@ -17,7 +17,7 @@ function rebuildRecentChangesTablePass1()
        $dbw->delete( 'recentchanges', '*' );
 
        print( "Loading from CUR table...\n" );
-
+       
        $dbw->insertSelect( 'recentchanges', 'cur', 
                array(
                        'rc_timestamp' => 'cur_timestamp',
@@ -33,7 +33,7 @@ function rebuildRecentChangesTablePass1()
                        'rc_cur_id' => 'cur_id',
                        'rc_this_oldid' => 0,
                        'rc_last_oldid' => 0,
-                       'rc_type' => 'IF(cur_is_new,' . RC_NEW . ',' . RC_EDIT . ')'
+                       'rc_type' => $dbw->conditional( 'cur_is_new != 0', RC_NEW, RC_EDIT ),
                ), '*', $fname, array( 'ORDER BY' => 'inverse_timestamp', 'LIMIT' => 5000 )
        );
        
@@ -41,21 +41,23 @@ function rebuildRecentChangesTablePass1()
 
        $sql = "INSERT INTO $recentchanges (rc_timestamp,rc_cur_time,rc_user," .
       "rc_user_text,rc_namespace,rc_title,rc_comment,rc_minor,rc_bot,rc_new," .
-      "rc_cur_id,rc_this_oldid,rc_last_oldid) SELECT old_timestamp,cur_timestamp," .
+      "rc_cur_id,rc_this_oldid,rc_last_oldid,rc_type) SELECT old_timestamp,cur_timestamp," .
          "old_user,old_user_text,old_namespace,old_title,old_comment," .
-         "old_minor_edit,0,0,cur_id,old_id,0 FROM $old,$cur " .
+         "old_minor_edit,0,0,cur_id,old_id,0,0 FROM $old,$cur " .
          "WHERE old_namespace=cur_namespace AND old_title=cur_title ORDER BY $old.inverse_timestamp " .
          "LIMIT 5000";
        $dbw->query( $sql );
 
        $sql = "SELECT rc_timestamp FROM $recentchanges " .
-         "ORDER BY rc_timestamp DESC LIMIT 5000,1";
+         "ORDER BY rc_timestamp DESC" . $dbw->limitResult( 1, 5000 );
        $res = $dbw->query( $sql );
        $obj = $dbw->fetchObject( $res );
-       $ts = $obj->rc_timestamp;
-
-       $sql = "DELETE FROM $recentchanges WHERE rc_timestamp < '{$ts}'";
-       $dbw->query( $sql );
+       if( $obj ) {
+               $ts = $obj->rc_timestamp;
+       
+               $sql = "DELETE FROM $recentchanges WHERE rc_timestamp < '{$ts}'";
+               $dbw->query( $sql );
+       }
 }
 
 function rebuildRecentChangesTablePass2()