[ci skip] Fix #4808
diff --git a/system/database/drivers/postgre/postgre_driver.php b/system/database/drivers/postgre/postgre_driver.php
index 58d4451..dfd87f9 100644
--- a/system/database/drivers/postgre/postgre_driver.php
+++ b/system/database/drivers/postgre/postgre_driver.php
@@ -288,7 +288,7 @@
 	 */
 	public function is_write_type($sql)
 	{
-		if (preg_match('#^(INSERT|UPDATE).*RETURNING\s.+(\,\s?.+)*$#i', $sql))
+		if (preg_match('#^(INSERT|UPDATE).*RETURNING\s.+(\,\s?.+)*$#is', $sql))
 		{
 			return FALSE;
 		}