Re: pg_stat_get_backend_subxact() and backend IDs?

On Wed, Aug 23, 2023 at 07:32:06PM -0700, Nathan Bossart wrote:
> On Thu, Aug 24, 2023 at 10:22:49AM +0900, Ian Lawrence Barwick wrote:
>> Looking at the code, this is happening because
>> "pgstat_fetch_stat_local_beentry()"
>> expects to be passed the backend ID as an integer representing a 1-based index
>> referring to "localBackendStatusTable", but "pg_stat_get_backend_subxact()"
>> is presumably intended to take the actual BackendId , as per other
>> "pg_stat_get_XXX()"
>> functions.
>
> Yes, this was changed in d7e39d7, but 10ea0f9 seems to have missed the
> memo.

BTW I'd argue that this is a bug in v16 that we should try to fix before
GA, so I've added an open item [0]. I assigned it to Robert (CC'd) since
he was the committer, but I'm happy to pick it up.

[0] https://wiki.postgresql.org/wiki/PostgreSQL_16_Open_Items#Open_Issues

--
Nathan Bossart
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