From 734771d4d39f8cb2ed70fb4e6e6972b681003685 Mon Sep 17 00:00:00 2001 From: Tatsuo Ishii Date: Sun, 11 Aug 2024 15:36:37 +0900 Subject: [PATCH] Fix another bug in replication mode and snapshot isolation mode. This is a follow up commit for 181d300de6337fe9a10b60ddbd782aa886b563e9. If previous query produces parameter status message, subsequent parse() needs to read and process it because it wants to read Ready for query message which is supposed to follow the parameter status message. However when ParameterStatus() gets called, the query in progress flag was set and it was possible that only one of parameter status message from backend was processed if the query processed in this parse() call is load balanced. It is likely that the parameter status message comes from all live backend because they are generated by SET command, and SET command are sent to all live backend in replication mode and snapshot isolation mode. So unset the query in progress flag before calling ParameterStatus(). Here is the test case written in pgproto data format. 'P' "" "SET application_name TO foo" 'B' "" "" 0 0 0 'E' "" 0 'P' "" "SELECT 1" 'B' "" "" 0 0 0 'E' "" 0 'P' "" "SET application_name TO bar" 'B' "" "" 0 0 0 'E' "" 0 'S' 'Y' 'X' Backpatch-through: v4.1. --- src/protocol/pool_proto_modules.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/src/protocol/pool_proto_modules.c b/src/protocol/pool_proto_modules.c index e62a3e0bf..71bad97d2 100644 --- a/src/protocol/pool_proto_modules.c +++ b/src/protocol/pool_proto_modules.c @@ -1469,6 +1469,12 @@ Parse(POOL_CONNECTION * frontend, POOL_CONNECTION_POOL * backend, { int i; + /* + * Temporarily unset query in progress so that all live backend + * are processed. + */ + pool_unset_query_in_progress(); + /* synchronize transaction state */ for (i = 0; i < NUM_BACKENDS; i++) {