Re: Optional skipping of unchanged relations during ANALYZE?

Hi everyone,


On 20.01.2026 13:24, VASUKI M wrote:
> I’m planning to work on a small improvement around ANALYZE behavior and
> wanted to ask the community for guidance before proceeding.

Thanks for working on this — it indeed looks like it could reduce the 
time spent executing ANALYZE.


>
> Currently, when ANALYZE is run over many relations, it analyzes all
> eligible tables even if some of them have not changed since their last
> ANALYZE. In environments with many mostly-static tables, this can lead
> to repeated work with little benefit.
>
> I’m considering working on an optional mode where ANALYZE would skip
> relations that have not been modified since their last analyze, based
> on existing pg_stat counters (for example, mod_since_analyze = 0).

We should consider n_mod_since_analyze as well.


>
> Before moving forward, I’d like to understand:
>
> --whether this aligns with PostgreSQL’s statistics and planner design,
>
> --if there are reasons ANALYZE should always re-run even for unchanged
> relations,
>
> --and whether such behavior would be acceptable if it were strictly
> opt-in.
>
> Any feedback, concerns, or pointers would be very helpful.

One concern that comes to mind is changes in statistics targets. For 
example, statistics may have been collected with 
default_statistics_target = 100, and later either 
default_statistics_target or a per-column statistics target is increased 
(e.g., to 200).

As far as I know, we currently do not track which statistics target was 
used when the existing statistics were collected. If someone knows a 
reliable way to determine this, please correct me.

If we cannot determine that, we would need to decide whether such 
relations should still be skipped

-- 
Best regards,
Ilia Evdokimov,
Tantor Labs LLC,
https://tantorlabs.com/