On 2025/03/06 21:55, Robins Tharakan wrote:
Hi, Thanks for taking a look at the patch, and for your feedback. On Wed, 5 Mar 2025 at 03:22, Fujii Masao <masao.fu...@oss.nttdata.com <mailto:masao.fu...@oss.nttdata.com>> wrote: On 2025/02/16 16:05, Robins Tharakan wrote: > This patch introduces a new function pg_accept_connections_start_time(). Shouldn't this function also handle the time when the postmaster starts accepting read-only connections? With the patch, it doesn’t seem to cover that case, and it looks like an unexpected timestamp is returned when run on a standby server. Maybe the function should return a record with two columns — one for when the postmaster starts accepting read-only connections and another for normal connections? I am not sure if I understand the question. For a given (re)start, a database user would either be looking for a read-only or a read-write start time (based on whether the server is a standby or not). Are you saying that for a given instance of start, a database user would be interested in two timestamps (once when the database became ready to accept read-only connections, and then quickly thereafter also began accepting read-writes?) Even if possible, that feels unnecessary - but I may be misunderstanding here.
With the v1 patch, running pg_accept_connections_start_time() on a standby returned an unexpected timestamp: =# select * from pg_accept_connections_start_time(); pg_accept_connections_start_time ---------------------------------- 2000-01-01 09:00:00+09 So my comment meant that this seems odd and should be fixed. Since I've not fully understood how this function is used, I'm not sure what timestamp should be returned in the standby. But I just thought it seems intuitive to return the timestamp when the standby started accepting read-only connections, in that case.
But you bring up a good point around standbys. Attached is v2 of the patch that returns a more accurate time on a standby (ie. it captures the time just after emitting a message that it's ready for read-only connections).
Thanks for updating the patch! With v2 patch. when the standby is promoted to primary, the result of pg_postmaster_open_time() appears to switch to the time when the primary began accepting normal connections. If this is intentional, it's better to clarify this behavior in the documentation. Regards, -- Fujii Masao Advanced Computing Technology Center Research and Development Headquarters NTT DATA CORPORATION
