Avoid to produce an ERROR during establishing of intra-multimaster psql-connection if it's not really needed. Caused by stress tests when I found dangerous places: some services can send dmq messages to channel, subscribed by another service.

danolivo · Mikhail Rutman · commit ba694083aafd · 2022-03-05T18:08:52.000+07:00
Tags: Multimaster
diff --git a/src/dmq.c b/src/dmq.c
@@ -1651,7 +1651,7 @@ dmq_push_buffer(DmqDestinationId dest_id, char *stream_name, const void *payload
 	res = shm_mq_send(dmq_local.mq_outh, buf.len, buf.data, false);
 	pfree(buf.data);
 	if (res != SHM_MQ_SUCCESS)
-		mtm_log(ERROR, "[DMQ] dmq_push: can't send to queue");
+		mtm_log(ERROR, "[DMQ] dmq_push: can't send to queue, status = %d", res);
 }
 
 /*
diff --git a/src/mtm_utils.c b/src/mtm_utils.c
@@ -33,23 +33,35 @@ disable_client_timeouts(PGconn *conn)
 
 	res = PQexec(conn, "SET statement_timeout = 0");
 	if (PQresultStatus(res) != PGRES_COMMAND_OK)
-		mtm_log(ERROR, "failed to set statement_timeout: %s",
+	{
+		mtm_log(WARNING, "failed to set statement_timeout: %s",
 				pchomp(PQerrorMessage(conn)));
+		return false;
+	}
 
 	res = PQexec(conn, "SET lock_timeout = 0");
 	if (PQresultStatus(res) != PGRES_COMMAND_OK)
-		mtm_log(ERROR, "failed to set lock_timeout: %s",
+	{
+		mtm_log(WARNING, "failed to set lock_timeout: %s",
 				pchomp(PQerrorMessage(conn)));
+		return false;
+	}
 
 	res = PQexec(conn, "SET idle_in_transaction_session_timeout = 0");
 	if (PQresultStatus(res) != PGRES_COMMAND_OK)
-		mtm_log(ERROR, "failed to set idle_in_transaction_session_timeout: %s",
+	{
+		mtm_log(WARNING, "failed to set idle_in_transaction_session_timeout: %s",
 				pchomp(PQerrorMessage(conn)));
+		return false;
+	}
 
 	res = PQexec(conn, "SET idle_session_timeout = 0");
 	if (PQresultStatus(res) != PGRES_COMMAND_OK)
-		mtm_log(ERROR, "failed to set idle_session_timeout: %s",
+	{
+		mtm_log(WARNING, "failed to set idle_session_timeout: %s",
 				pchomp(PQerrorMessage(conn)));
+		return false;
+	}
 
 	return true;
 }
@@ -90,7 +102,8 @@ MtmPQconnectPoll(PGconn *conn)
 	if (status != PGRES_POLLING_OK)
 		return status;
 
-	disable_client_timeouts(conn);
+	if (!disable_client_timeouts(conn))
+		status = PGRES_POLLING_FAILED;
 
 	return status;
 }
@@ -109,7 +122,11 @@ MtmPQconnectdb(const char *conninfo)
 	if (PQstatus(conn) != CONNECTION_OK)
 		return conn;
 
-	disable_client_timeouts(conn);
+	if (!disable_client_timeouts(conn))
+	{
+		PQfinish(conn);
+		return NULL;
+	}
 
 	return conn;
 }

Original file line number	Diff line number	Diff line change
`@@ -1651,7 +1651,7 @@ dmq_push_buffer(DmqDestinationId dest_id, char stream_name, const void payload`
`1651`	`1651`	`res = shm_mq_send(dmq_local.mq_outh, buf.len, buf.data, false);`
`1652`	`1652`	`pfree(buf.data);`
`1653`	`1653`	`if (res != SHM_MQ_SUCCESS)`
`1654`		`- mtm_log(ERROR, "[DMQ] dmq_push: can't send to queue");`
	`1654`	`+ mtm_log(ERROR, "[DMQ] dmq_push: can't send to queue, status = %d", res);`
`1655`	`1655`	`}`
`1656`	`1656`
`1657`	`1657`	`/*`