Re: pg_plan_advice

On 26/03/26 10:55, Robert Haas wrote:
>> I realize not having query texts reduces its effectiveness (since you
>> don't see which parameters produced which plan advice), but it still
>> helps surface which different advice strings where seen for which
>> query IDs, letting you identify if you're getting a mix of bad and
>> good plans. And I'm just really worried people will enable this on
>> production in shared collection mode and take down their system.
>
> I fully admit that pg_collect_advice is crude, but I don't think
> ripping out some portion of the limited functionality that it has is
> going to get us where we want to be. If it hadn't collected the query
> strings, it would have been useless for the purpose for which I
> originally wrote it. We could add a GUC for a length limit, perhaps,
> but I think the real feature that this needs to be used in the way
> that you seem to want to use it is deduplication, and as I said
> earlier, I think we should consider adding the advice collection logic
> to pg_stat_statements rather than building an alternative version of
> that module with overlapping functionality.
>

I also think that we should consider adding the advice string on
pg_stat_statements. It seems to make more sense to me IMHO.

Adding support for auto_explain to explain(plan_advice, ...) (or any
other custom explain option from loadable modules) would help or make
sense here? I have been thinking about this for a while.

--
Matheus Alcantara
EDB: https://www.enterprisedb.com