Re: Assert failure on 'list_member_ptr(rel->joininfo, restrictinfo)'

On Fri, Dec 8, 2023 at 3:13 PM Alexander Pyhalov <a(dot)pyhalov(at)postgrespro(dot)ru>
wrote:

> Andrei Lepikhov писал(а) 2023-12-08 07:37:
> > I'd already clashed with Tom on copying the required_relids field and
> > voluntarily made unnecessary copies in the project [1].
> > And ... stuck into huge memory consumption. The reason was in
> > Bitmapsets:
> > When we have 1E3-1E4 partitions and try to reparameterize a join, one
> > bitmapset field can have a size of about 1kB. Having bitmapset
> > referencing Relation with a large index value, we had a lot of (for
> > example, 1E4 * 1kB) copies on each reparametrization of such a field.
> > Alexander Pyhalov should remember that case.
>
> Yes. If it matters, this happened during reparametrization when 2
> partitioned tables with 1000 partitions each were joined. Then
> asymmetric pw join managed to eat lots of memory for bitmapsets (by
> lots of memory I mean all available on the test VM).

By reparametrization did you mean the work done in
reparameterize_path_by_child()? If so maybe you'd be interested in the
patch [1] which postpones reparameterization of paths until createplan.c
and thus can help avoid unnecessary reparametrization work.

[1]
https://www.postgresql.org/message-id/CAMbWs48PBwe1YadzgKGW_ES%3DV9BZhq00BaZTOTM6Oye8n_cDNg%40mail.gmail.com

Thanks
Richard