On Fri, Mar 29, 2024 at 1:38 AM Euler Taveira <euler@eulerto.com> wrote: > On Thu, Mar 28, 2024, at 9:39 AM, Alexander Korotkov wrote: > > Fixed along with other issues spotted by Alexander Lakhin. > > > [I didn't read the whole thread. I'm sorry if I missed something ...] > > You renamed the function in a previous version but let me suggest another one: > pg_wal_replay_wait. It uses the same pattern as the other recovery control > functions [1]. I think "for" doesn't add much for the function name and "lsn" is > used in functions that return an LSN (that's not the case here). > > postgres=# \df pg_wal_replay* > List of functions > -[ RECORD 1 ]-------+--------------------- > Schema | pg_catalog > Name | pg_wal_replay_pause > Result data type | void > Argument data types | > Type | func > -[ RECORD 2 ]-------+--------------------- > Schema | pg_catalog > Name | pg_wal_replay_resume > Result data type | void > Argument data types | > Type | func
Makes sense to me. I tried to make a new procedure name consistent with functions acquiring various WAL positions. But you're right, it's better to be consistent with other functions controlling wal replay.
> Regarding the arguments, I think the timeout should be bigint. There is at least > another function that implements a timeout that uses bigint. > > postgres=# \df pg_terminate_backend > List of functions > -[ RECORD 1 ]-------+-------------------------------------- > Schema | pg_catalog > Name | pg_terminate_backend > Result data type | boolean > Argument data types | pid integer, timeout bigint DEFAULT 0 > Type | func > > I also suggests that the timeout unit should be milliseconds, hence, using > bigint is perfectly fine for the timeout argument. > > + <para> > + Throws an ERROR if the target <acronym>lsn</acronym> was not replayed > + on standby within given timeout. Parameter <parameter>timeout</parameter> > + is the time in seconds to wait for the <parameter>target_lsn</parameter> > + replay. When <parameter>timeout</parameter> value equals to zero no > + timeout is applied. > + </para></entry>
This generally makes sense, but I'm not sure about this. The milliseconds timeout was used initially but received critics in [1].
I see in Postgres we already have different units for timeouts:
e.g in guc's:
wal_receiver_status_interval in seconds
tcp_keepalives_idle in seconds
commit_delay in microseconds
deadlock_timeout in milliseconds max_standby_archive_delay in milliseconds vacuum_cost_delay in milliseconds autovacuum_vacuum_cost_delay in milliseconds etc..
I haven't counted precisely, but I feel that milliseconds are the most often used in both guc's and functions. So I'd propose using milliseconds for the patch as it was proposed originally.