pgpool2.git / summary / log / commit / refs

commit    7f529685e0db856bd8b67d3e614ef478ecce90b3
Author:   Yugo Nagata <nagata@sraoss.co.jp>
Date:     Wed Jun 06 02:41:14 2012 +0000

    Fix hangup when query conflict occurs in Hot-Standby mode.
    - Query example to reproduce:
      (S1) BEGIN;
      (S1) SELECT * FROM t;
      (S2) DELETE FROM t;
      (S2) VACUUM t;
    
    Fix SmpleQuery() to handle errors by calling check_errors().
    - Previously, check_errors() was called only in Execute().


 pool_process_query.c | 14 ++++++++++++--
 pool_proto_modules.c | 39 ++++++++++++++++++++++++++++++++-------
 pool_proto_modules.h |  2 +-
 3 files changed, 45 insertions(+), 10 deletions(-)

diff --git a/pool_process_query.c b/pool_process_query.c
index 281c118c2..d8d2b6141 100644
--- a/pool_process_query.c
+++ b/pool_process_query.c
@@ -4171,9 +4171,9 @@ int detect_deadlock_error(POOL_CONNECTION *backend, int major)
 	return r;
 }
 
-int detect_serialization_error(POOL_CONNECTION *backend, int major)
+int detect_serialization_error(POOL_CONNECTION *backend, int major, bool unread)
 {
-	int r =  detect_error(backend, SERIALIZATION_FAIL_ERROR_CODE, major, 'E', true);
+	int r =  detect_error(backend, SERIALIZATION_FAIL_ERROR_CODE, major, 'E', unread);
 	if (r == SPECIFIED_ERROR)
 		pool_debug("detect_serialization_error: received serialization failure message from backend");
 	return r;
@@ -4628,6 +4628,16 @@ SELECT_RETRY:
 			if (FD_ISSET(CONNECTION(backend, i)->fd, &readmask))
 			{
 				int r;
+				/*
+				 * connection was terminated due to confilct with recovery
+				 */
+				r = detect_serialization_error(CONNECTION(backend, i), MAJOR(backend), false);
+				if (r == SPECIFIED_ERROR)
+				{
+					pool_log("connection on node %d was terminated due to conflict with recovery", i);
+					return POOL_ERROR;
+				}
+
 				/*
 				 * admin shutdown postmaster or postmaster goes down
 				 */
diff --git a/pool_proto_modules.c b/pool_proto_modules.c
index 488bdde1f..261f18fb2 100644
--- a/pool_proto_modules.c
+++ b/pool_proto_modules.c
@@ -116,6 +116,7 @@ POOL_STATUS SimpleQuery(POOL_CONNECTION *frontend,
 	char *string;
 	int lock_kind;
 	bool is_likely_select = false;
+	int specific_error = 0;
 
 	POOL_SESSION_CONTEXT *session_context;
 	POOL_QUERY_CONTEXT *query_context;
@@ -582,15 +583,39 @@ POOL_STATUS SimpleQuery(POOL_CONNECTION *frontend,
 				pool_query_context_destroy(query_context);
 				return POOL_END;
 			}
+
+			/* Check specific errors */
+			specific_error = check_errors(backend, MASTER_NODE_ID);
+			if (specific_error)
+			{
+				/* log error message */
+				generate_error_message("SimpleQuery: ", specific_error, contents);
+			}
 		}
 
-		/*
-		 * Send the query to other than master node.
-		 */
-		if (pool_send_and_wait(query_context, -1, MASTER_NODE_ID) != POOL_CONTINUE)
+		if (specific_error)
 		{
-			pool_query_context_destroy(query_context);
-			return POOL_END;
+			char msg[1024] = POOL_ERROR_QUERY; /* large enough */
+			int len = strlen(msg);
+
+			memset(msg + len, 0, sizeof(int));
+
+			/* send query to other nodes */
+			query_context->rewritten_query = msg;
+			query_context->rewritten_length = len;
+			if (pool_send_and_wait(query_context, -1, MASTER_NODE_ID) != POOL_CONTINUE)
+				return POOL_END;
+		}
+		else
+		{
+			/*
+			 * Send the query to other than master node.
+			 */
+			if (pool_send_and_wait(query_context, -1, MASTER_NODE_ID) != POOL_CONTINUE)
+			{
+				pool_query_context_destroy(query_context);
+				return POOL_END;
+			}
 		}
 
 		/* Send "COMMIT" or "ROLLBACK" to only master node if query is "COMMIT" or "ROLLBACK" */
@@ -3080,7 +3105,7 @@ static int check_errors(POOL_CONNECTION_POOL *backend, int backend_id)
 	 * M:S2:ERROR:  could not serialize access due to concurrent update
 	 * S:S2:UPDATE t1 SET i = i + 1; <-- success in UPDATE and data becomes inconsistent!
 	 */
-	if (detect_serialization_error(CONNECTION(backend, backend_id), MAJOR(backend)) == SPECIFIED_ERROR)
+	if (detect_serialization_error(CONNECTION(backend, backend_id), MAJOR(backend), true) == SPECIFIED_ERROR)
 		return 2;
 
 	/*
diff --git a/pool_proto_modules.h b/pool_proto_modules.h
index 68053b9c8..533a86bea 100644
--- a/pool_proto_modules.h
+++ b/pool_proto_modules.h
@@ -163,7 +163,7 @@ extern void query_ps_status(char *query, POOL_CONNECTION_POOL *backend);		/* sho
 extern POOL_STATUS start_internal_transaction(POOL_CONNECTION *frontend, POOL_CONNECTION_POOL *backend, Node *node);
 extern POOL_STATUS end_internal_transaction(POOL_CONNECTION *frontend, POOL_CONNECTION_POOL *backend);
 extern int detect_deadlock_error(POOL_CONNECTION *master, int major);
-extern int detect_serialization_error(POOL_CONNECTION *master, int major);
+extern int detect_serialization_error(POOL_CONNECTION *master, int major, bool unread);
 extern int detect_active_sql_transaction_error(POOL_CONNECTION *backend, int major);
 extern int detect_query_cancel_error(POOL_CONNECTION *backend, int major);
 extern bool is_partition_table(POOL_CONNECTION_POOL *backend, Node *node);


[parent: da11bcdfa9c6]