Re: pgsql: autovacuum: handle analyze for partitioned tables

On 4/9/21 11:45 PM, Justin Pryzby wrote:
> On Fri, Apr 09, 2021 at 05:31:55PM -0400, Alvaro Herrera wrote:
>> On 2021-Apr-09, Robert Haas wrote:
>>
>>> Does this need to worry about new partitions getting attached to a
>>> partitioned table, or old ones getting detached? (Maybe it does
>>> already, not sure.)
>>
>> Good question. It does not.
>
> I think there's probably cases where this is desirable, and cases where it's
> undesirable, so I don't think it's necessarily a problem.
>
> One data point: we do DETACH/ATTACH tables during normal operation, before
> type-promoting ALTERs, to avoid worst-case disk use, and to avoid locking the
> table for a long time. It'd be undesirable (but maybe of no great consequence)
> to trigger an ALTER when we DETACH them, since we'll re-ATTACH it shortly
> afterwards.
>
> However, I think DROP should be handled ?
>

IMHO we should prefer the default behavior which favors having updated
statistics, and maybe have a way to override it for individual commands.
So ATTACH would update changes_since_analyze by default, but it would be
possible to disable that.

regards

--
Tomas Vondra
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