Re: BUG #17330: EXPLAIN hangs and very long query plans

On Fri, Dec 10, 2021 at 2:36 AM Peter Geoghegan <pg(at)bowt(dot)ie> wrote:

> Sounds like a problem with get_actual_variable_range(), which can scan
> indexes at plan time to determine minimum or maximum values.
>
> This actually has been improved quite a bit since Postgres 10. So as
> Jeff said, seems like you might benefit from upgrading to a newer
> major version. v11 has improved things in this exact area.
>

On my Docker instance when I execute EXPLAIN it starts reading a lot of
data. The indexes of the biggest table the query reads are 50GB, so my
guess is that it reads those indexes.

I allowed EXPLAIN in Docker to finish and it took almost 500 seconds and it
was reading data all the time. After I reindexed the biggest table, EXPLAIN
finished instantly. Can the index corruption cause this?

Note that this started happening in production after we deleted a few
million rows from the biggest table.

Regards,
Strahinja