From 947cf9d587333219791a257389b95eae01d76237 Mon Sep 17 00:00:00 2001 From: Fujii Masao Date: Wed, 26 Nov 2025 23:35:44 +0900 Subject: [PATCH v4] Honor GUC settings specified in CREATE SUBSCRIPTION CONNECTION. Prior to v15, GUC settings supplied in the CONNECTION clause of CREATE SUBSCRIPTION were correctly passed through to the publisher's walsender. For example: CREATE SUBSCRIPTION mysub CONNECTION 'options=''-c wal_sender_timeout=1000''' PUBLICATION ... would cause wal_sender_timeout to take effect on the publisher's walsender. However, commit f3d4019da5d changed the way logical replication connections are established, forcing the publisher's relevant GUC settings (datestyle, intervalstyle, extra_float_digits) to override those provided in the CONNECTION string. As a result, from v15 through v18, GUC settings in the CONNECTION string were always ignored. This regression prevented per-connection tuning of logical replication. For example, using a shorter timeout for walsender connecting to a nearby subscriber and a longer one for walsender connecting to a remote subscriber. This commit restores the intended behavior by ensuring that GUC settings in the CONNECTION string are again passed through and applied by the walsender, allowing per-connection configuration. Backpatch to v15, where the regression was introduced. Author: Fujii Masao Reviewed-by: Chao Li Discussion: https://postgr.es/m/CAHGQGwGYV+-abbKwdrM2UHUe-JYOFWmsrs6=QicyJO-j+-Widw@mail.gmail.com Backpatch-through: 15 --- .../libpqwalreceiver/libpqwalreceiver.c | 43 ++++++++++++++----- 1 file changed, 32 insertions(+), 11 deletions(-) diff --git a/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c b/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c index 239641bfbb6..500632b462f 100644 --- a/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c +++ b/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c @@ -180,17 +180,6 @@ libpqrcv_connect(const char *conninfo, bool replication, bool logical, /* Tell the publisher to translate to our encoding */ keys[++i] = "client_encoding"; vals[i] = GetDatabaseEncodingName(); - - /* - * Force assorted GUC parameters to settings that ensure that the - * publisher will output data values in a form that is unambiguous - * to the subscriber. (We don't want to modify the subscriber's - * GUC settings, since that might surprise user-defined code - * running in the subscriber, such as triggers.) This should - * match what pg_dump does. - */ - keys[++i] = "options"; - vals[i] = "-c datestyle=ISO -c intervalstyle=postgres -c extra_float_digits=3"; } else { @@ -256,6 +245,38 @@ libpqrcv_connect(const char *conninfo, bool replication, bool logical, PQclear(res); } + /* + * Force assorted GUC parameters to settings that ensure that the + * publisher will output data values in a form that is unambiguous to the + * subscriber. (We don't want to modify the subscriber's GUC settings, + * since that might surprise user-defined code running in the subscriber, + * such as triggers.) This should match what pg_dump does. + */ + if (replication && logical) + { + const char *params[] = + {"datestyle", "intervalstyle", "extra_float_digits"}; + const char *values[] = {"ISO", "postgres", "3"}; + + for (int j = 0; j < lengthof(params); j++) + { + char sql[100]; + PGresult *res; + + sprintf(sql, "SET %s = %s", params[j], values[j]); + res = libpqsrv_exec(conn->streamConn, sql, + WAIT_EVENT_LIBPQWALRECEIVER_RECEIVE); + if (PQresultStatus(res) != PGRES_COMMAND_OK) + { + PQclear(res); + *err = psprintf(_("could not set %s: %s"), + params[j], pchomp(PQerrorMessage(conn->streamConn))); + goto bad_connection; + } + PQclear(res); + } + } + conn->logical = logical; return conn; -- 2.51.2