On Thu, Oct 8, 2020 at 2:58 PM Amit Langote <amitlangot...@gmail.com> wrote: > On Wed, Oct 7, 2020 at 12:51 AM Tom Lane <t...@sss.pgh.pa.us> wrote: > > Ashutosh Bapat <ashutosh.bapat....@gmail.com> writes: > > > On Mon, Oct 5, 2020 at 11:59 PM Tom Lane <t...@sss.pgh.pa.us> wrote: > > >> ... we could avoid the growth in eclass members for large partition sets > > >> if we simply didn't store child eclass members, instead translating > > >> on-the-fly when we need to deal with child rels. I have a patch > > >> about half done, but it won't be possible to determine the true > > >> performance implications of that idea until it's all done. More > > >> later. > > +1 to this idea. We've seen mainly get_eclass_for_sort_expr() become > a bottleneck with large partition sets and getting rid of it would be > really great. > > [1] > https://www.postgresql.org/message-id/CAApHDvrEXcadNYAAdq6RO0eKZUG6rRHXJGAbpzj8y432gCD9bA%40mail.gmail.com
Oops, I linked this thread but forgot to write why. Well, I had meant to say that I had unsuccessfully tried to implement this idea as a PoC back when David had started the linked discussion to address the same problem. -- Amit Langote EDB: http://www.enterprisedb.com
