diff --git a/pg4wp/driver_pgsql.php b/pg4wp/driver_pgsql.php
index 46275bb..65ae3e0 100644
--- a/pg4wp/driver_pgsql.php
+++ b/pg4wp/driver_pgsql.php
@@ -255,6 +255,13 @@
 			// LIMIT is not allowed in DELETE queries
 			$sql = str_replace( 'LIMIT 1', '', $sql);
 			$sql = str_replace( ' REGEXP ', ' ~ ', $sql);
+			
+			// This handles removal of duplicate entries in table options
+			if( false !== strpos( $sql, 'DELETE o1 FROM '))
+				$sql = "DELETE FROM ${table_prefix}options WHERE option_id IN " .
+					"(SELECT o1.option_id FROM ${table_prefix}options AS o1, ${table_prefix}options AS o2 " .
+					"WHERE o1.option_name = o2.option_name " .
+					"AND o1.option_id < o2.option_id)";
 		}
 		// Fix tables listing
 		elseif( 0 === strpos($sql, 'SHOW TABLES'))
@@ -321,6 +328,19 @@ WHERE bc.oid = i.indrelid
 				$index = $table.'_'.$index;
 				$sql = "CREATE {$unique}INDEX $index ON $table ($columns)";
 			}
+			$pattern = '/ALTER TABLE\s+(\w+)\s+DROP INDEX\s+([^\s]+)/';
+			if( 1 === preg_match( $pattern, $sql, $matches))
+			{
+				$table = $matches[1];
+				$index = $matches[2];
+				$sql = "DROP INDEX ${table}_${index}";
+			}
+			$pattern = '/ALTER TABLE\s+(\w+)\s+DROP PRIMARY KEY/';
+			if( 1 === preg_match( $pattern, $sql, $matches))
+			{
+				$table = $matches[1];
+				$sql = "ALTER TABLE ${table} DROP CONSTRAINT ${table}_pkey";
+			}
 		}
 		// Table description
 		elseif( 0 === strpos( $sql, 'DESCRIBE'))
diff --git a/readme.txt b/readme.txt
index a6f88c6..0c382f6 100644
--- a/readme.txt
+++ b/readme.txt
@@ -50,7 +50,9 @@ There is no screenshot for this plugin
 
 == Changelog ==
 
-* Upgrading from WP 2.8.6 to WP 2.9.1 works with errors
+
+* Upgrading from WP 2.8.6 to WP 2.9.1 works with a minor error
+	Upgrading should remove an index on table "wp_options" that may not exist, throwing an error
 * Installing WP 2.9.1 works smoothly
 * Generic hack to avoid duplicate index names
 * REGEXP gets replaced with '~'