Hello. At Thu, 7 Oct 2021 03:07:33 +0000, "kuroda.hay...@fujitsu.com" <kuroda.hay...@fujitsu.com> wrote in > Dear Hackers, > > While reading source codes about timeouts and GUC and I found that > strange behavior about client_connection_check_interval. > > Currently we did not an assign_hook about client_connection_check_interval, > that means a timeout will not turn on immediately if users change the GUC > from zero to arbitrary positive integer. > In my understanding the timeout will fire only when: > > * before starting transaction
You're misunderstanding here. Maybe you saw that start_xact_command() starts the timer but note that the function is called before every command execution. > * after firing the CLIENT_CONNECTION_CHECK_TIMEOUT timeout > > Hence I thought following inconvenient scenario: > > 1. set client_connection_check_interval = 0 in postgresql.conf > 2. start a tx > 3. SET LOCAL client_connection_check_interval to non-zero value > in order to checking clients until the end of the tx > 4. users expect to firing the timeout, but it does not work > because enable_timeout_after() will never execute in the tx So this is wrong. I should see the check performed as expected. That behavior would be clearly visualized if you inserted an elog() into pq_check_connection(). > Is this an expected behavior? If so, I think this spec should be documented. > If not, I think an assign_hook is needed for resolving the problem. > > How do you think? And it seems that the documentation describes the behavior correctly. https://www.postgresql.org/docs/14/runtime-config-connection.html > client_connection_check_interval (integer) > > Sets the time interval between optional checks that the client is > still connected, while running queries. regards. -- Kyotaro Horiguchi NTT Open Source Software Center
