pgpool2.git / summary / log / commit / refs

commit    4d91196df63ab34ac6567cfd793134e160680c9d
Author:   Tatsuo Ishii <ishii@postgresql.org>
Date:     Thu Jun 21 23:42:08 2012 +0000

    Fix segfault in the case on memory query cache is enabled and PHP PDO
    used. Actually this is not specific for PDO: PDO sends Sync message
    right after Parse. Pgpool is confused because
    pool_handle_query_cache() is called within ReadyForQuery() in this
    case. Solution is, checking query_context->query_w_hex.  If it is
    NULL, then Bind message has not been sent yet.
    
    Here is the small PDO script to reproduce the problem just F.Y.I.
    <?php
      function db() {
        $db = new PDO("pgsql:host=localhost;port=11002;dbname=test");
    	return $db;
      }
    
      $n = 1;
      for($i=0;$i < $n;$i++)
      {
        $db[$i] = db();
        $stmt = $db[$i]->prepare("SELECT :num::int");
        $stmt->execute(array(':num' => $i));
        print_r($stmt->fetch());
        //sleep(1);
        $db[$i] = NULL;
        echo date(DATE_RFC822);
      }
    //  sleep(300);
    ?>


 pool_proto_modules.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/pool_proto_modules.c b/pool_proto_modules.c
index 7817ae99e..cf208addf 100644
--- a/pool_proto_modules.c
+++ b/pool_proto_modules.c
@@ -1725,10 +1725,21 @@ POOL_STATUS ReadyForQuery(POOL_CONNECTION *frontend,
 			/* Memory cache enabled? */
 			if (cache_commit && pool_config->memory_cache_enabled)
 			{
+				/* If we are doing extended query and the state is after EXECUTE,
+				 * then we can commit cache.
+				 * We check latter condition by looking at query_context->query_w_hex.
+				 * This check is neccessary for certain flame work such as PHP PDO.
+				 * It sends Sync message right after PARSE and it produces
+				 * "Ready for query" message from backend.
+				 */
 				if (pool_is_doing_extended_query_message())
 				{
-					pool_handle_query_cache(backend, session_context->query_context->query_w_hex, node, state);
-					free(session_context->query_context->query_w_hex); // malloced in Execute().
+					if (session_context->query_context->query_w_hex)
+					{
+						pool_handle_query_cache(backend, session_context->query_context->query_w_hex, node, state);
+						free(session_context->query_context->query_w_hex);
+						session_context->query_context->query_w_hex = NULL;
+					}
 				}
 				else
 				{


[parent: 50a10bfc45db]