pgpool2.git / summary / log / commit / refs

commit    7355ebb4d9288e7b08517618d96ec02f64a5d5e0
Author:   Tatsuo Ishii <ishii@postgresql.org>
Date:     Fri Mar 31 03:49:59 2017 +0000

    Consider SHOW command as kind of a read query.
    
    In streaming replication mode, if SHOW is issued then subsequent
    SELECTs are sent to the primary node in an explicit transaction. This
    is not a reasonable and unnecessary limitation.
    
    Also fix hang when parse command returns error.


 src/context/pool_query_context.c  |  7 +++++++
 src/protocol/CommandComplete.c    |  9 +++++++++
 src/protocol/pool_process_query.c |  4 ++++
 src/protocol/pool_proto_modules.c | 28 ++++++++++++++++++++++++----
 4 files changed, 44 insertions(+), 4 deletions(-)

diff --git a/src/context/pool_query_context.c b/src/context/pool_query_context.c
index 365429a3f..7b6d7da74 100644
--- a/src/context/pool_query_context.c
+++ b/src/context/pool_query_context.c
@@ -1387,6 +1387,13 @@ static POOL_DEST send_to_where(Node *node, char *query)
 			 */
 			return POOL_PRIMARY; 
 		}
+		/*
+		 * SHOW
+		 */
+		else if (IsA(node, VariableShowStmt))
+		{
+			return POOL_EITHER;
+		}
 
 		/*
 		 * Other statements are sent to primary
diff --git a/src/protocol/CommandComplete.c b/src/protocol/CommandComplete.c
index 8974c9e83..ac80ce199 100644
--- a/src/protocol/CommandComplete.c
+++ b/src/protocol/CommandComplete.c
@@ -68,6 +68,7 @@ POOL_STATUS CommandComplete(POOL_CONNECTION *frontend, POOL_CONNECTION_POOL *bac
 	/*
 	 * If operated in streaming replication mode and doing an extended query,
 	 * read backend message according to the query context.
+	 * Also we set the transaction state at this point.
 	 */
 	if (STREAM && pool_is_doing_extended_query_message())
 	{
@@ -89,6 +90,14 @@ POOL_STATUS CommandComplete(POOL_CONNECTION *frontend, POOL_CONNECTION_POOL *bac
 					return POOL_END;
 				p1 = palloc(len);
 				memcpy(p1, p, len);
+
+				if (session_context->query_context->parse_tree &&
+					is_start_transaction_query(session_context->query_context->parse_tree))
+					TSTATE(backend, i) ='T';		/* we are inside a transaction */
+
+					ereport(DEBUG1,
+							(errmsg("processing command complete"),
+							 errdetail("set transaction state to T")));
 			}
 		}
 	}
diff --git a/src/protocol/pool_process_query.c b/src/protocol/pool_process_query.c
index 93356ebae..567ff0651 100644
--- a/src/protocol/pool_process_query.c
+++ b/src/protocol/pool_process_query.c
@@ -1080,6 +1080,7 @@ static int
  * - COPY TO STDOUT
  * - EXPLAIN
  * - EXPLAIN ANALYZE and query is SELECT not including writing functions
+ * - SHOW
  *
  * Note that for SELECT this function returns false.
  */
@@ -1200,6 +1201,9 @@ bool is_select_query(Node *node, char *sql)
 				return true;
 		}
 	}
+	else if (IsA(node, VariableShowStmt))		/* SHOW command */
+		return true;
+
 	return false;
 }
 
diff --git a/src/protocol/pool_proto_modules.c b/src/protocol/pool_proto_modules.c
index 8c541b26d..00350dfe2 100644
--- a/src/protocol/pool_proto_modules.c
+++ b/src/protocol/pool_proto_modules.c
@@ -2639,10 +2639,30 @@ POOL_STATUS ProcessBackendResponse(POOL_CONNECTION *frontend,
 					pool_set_ignore_till_sync();
 					pool_unset_query_in_progress();
 
-					/* Remove all pending messages */
-					while (pool_pending_message_pull_out())
-						;
-					pool_pending_message_reset_previous_message();
+					if (STREAM)
+					{
+						POOL_PENDING_MESSAGE *pmsg;
+						int i;
+
+						/* Remove all pending messages */
+						do
+						{
+							pmsg = pool_pending_message_pull_out();
+							pool_pending_message_free_pending_message(pmsg);
+						}
+						while (pmsg);
+
+						pool_pending_message_reset_previous_message();
+
+						/* Discard read buffer */
+						for (i=0;i<NUM_BACKENDS;i++)
+						{
+							if (VALID_BACKEND(i))
+							{
+								pool_discard_read_buffer(CONNECTION(backend, i));
+							}
+						}
+					}
 				}
 				break;
 


[parent: 36a34cfe5bb8]