Re: Simple IN vs IN values performace

Thanks for suggestion

with tmp tables there are another issue - there are already 5-6 tables and
2-3 IN filters. If i will replace them with tmp tables it may hit query
planner limits and it will become to produce terrible query plans, for
example when genetic query optimizer starts

On Tue, Feb 23, 2021 at 1:45 AM Ron <ronljohnsonjr(at)gmail(dot)com> wrote:

> On 2/22/21 9:00 AM, Oleksandr Voytsekhovskyy wrote:
>
> Greetings,
>
> We have queries with IN filters with long list of INT values
>
> Sometimes, they running extremely slow, and I have found suggestion to use
> syntax
>
> Field IN (VALUES(1465), (1478), ...
>
> Instead of
>
> Field IN (1465, 1478, ...
>
> On some cases it helps, but on other it makes query running 1000+ times
> slower
>
>
> Insert the values into a TEMPORARY TABLE, then join that to your main
> table?
>
>
> So the issue is:
> - some queries much faster with simple IN
> - some queries much faster with IN + VALUES
>
> Here is explain on case when it’s extremely slow:
>
> -> HashAggregate (cost=5.78..9.62 rows=385 width=4)
> Group Key: ""*VALUES*"".column1"
> -> Values Scan on ""*VALUES*"" (cost=0.00..4.81 rows=385 width=4)"
>
> What is the right way to pass long INT values list to IN filter?
>
> I am using PostgreSQL 13.1 on Ubuntu
>
>
> --
> Angular momentum makes the world go 'round.
>