Re: Optional skipping of unchanged relations during ANALYZE?

> I can't help but think that this SMART option is not as smart as it
> should be to actually
> be valuable.
>
> I agree that we should never skip a table that has never been
> analyzed. My concern
> is that n_mod_since_analyze == 0 is not very useful.
>
> IMO, for the purpose of ensuring that we never skip relations that have never been analyzed,
> checking last_analyze / last_autoanalyze being NULL seems sufficient and reliable.

edba754f052 introduced --missing-stats-only for vacuumdb. Although
this was intended
for pg_upgrade, it does note in the commit message that "it might be
useful in other situations"
Perhaps, this is one of the situations.

So, instead of a smart mode, maybe we should be thinking about an
ANALYZE (missing_stats_only) option that follows what is done in
vacuumdb; and will skip tables that don't need to be analyzed.
Ultimately vacuumdb can just use this option.

The criteria for tables missing stats is more comprehensive than a simple
last_analyze / last_autoanalyze being NULL.

A followup commit 984d7165dd also mentions:

"
For v19, perhaps we could introduce a simple, inexpensive way to
discover which relations are missing statistics, such as a system
function or view with similar privilege requirements to ANALYZE.
Unfortunately, it is far too late for anything like that in v18.
"

What do you think?

--
Sami Imseih
Amazon Web Services (AWS)