Обсуждение: Is there a way to know write statistics on an individual index
Hi,
I know there's a pg_stats_user_indexes that gives statistics about the index scans/fetches, but I don't find any information about how many writes(insert/update/delete) happen on this individual index.
Is there some tool that could achieve this?
Thanks,
Alun
On Thu, 8 Dec 2022 at 19:59, higherone <higherone@gmail.com> wrote: > I know there's a pg_stats_user_indexes that gives statistics about the index scans/fetches, but I don't find any informationabout how many writes(insert/update/delete) happen on this individual index. > Is there some tool that could achieve this? Is this a partial index? If not, those should just increase at the same rate that's mentioned in pg_stat_user_tables for the table that the index belongs to. David
On Thu, Dec 8, 2022 at 2:53 AM David Rowley <dgrowleyml@gmail.com> wrote: > > On Thu, 8 Dec 2022 at 19:59, higherone <higherone@gmail.com> wrote: > > I know there's a pg_stats_user_indexes that gives statistics about the index scans/fetches, but I don't find any informationabout how many writes(insert/update/delete) happen on this individual index. > > Is there some tool that could achieve this? > > Is this a partial index? If not, those should just increase at the > same rate that's mentioned in pg_stat_user_tables for the table that > the index belongs to. Well, not deletes, right? And HOT updates won't affect indexes either, so they should be subtracted from n_tup_upd.
It's not a partial index, but I believe the pg_stat_user_tables contains all the writes on the table, which not necessarily updates the individual index I'm interested in (e.g. when the updated column is not part of the index columns) .
On Fri, Dec 9, 2022 at 2:06 PM Maciek Sakrejda <m.sakrejda@gmail.com> wrote:
On Thu, Dec 8, 2022 at 2:53 AM David Rowley <dgrowleyml@gmail.com> wrote:
>
> On Thu, 8 Dec 2022 at 19:59, higherone <higherone@gmail.com> wrote:
> > I know there's a pg_stats_user_indexes that gives statistics about the index scans/fetches, but I don't find any information about how many writes(insert/update/delete) happen on this individual index.
> > Is there some tool that could achieve this?
>
> Is this a partial index? If not, those should just increase at the
> same rate that's mentioned in pg_stat_user_tables for the table that
> the index belongs to.
Well, not deletes, right? And HOT updates won't affect indexes either,
so they should be subtracted from n_tup_upd.