Re: Should we add GUCs to allow partition pruning to be disabled?

On Sun, Mar 10, 2019 at 10:53:02PM +1300, David Rowley wrote:
> On Fri, 11 May 2018 at 17:37, Amit Langote <Langote_Amit_f8(at)lab(dot)ntt(dot)co(dot)jp> wrote:
> > 5. The last sentence in caveats, that is,
> >
> > "Partitioning using these techniques will work well with up to perhaps a
> > hundred partitions; don't try to use many thousands of partitions."
> >
> > should perhaps be reworded as:
> >
> > "So the legacy inheritance based partitioning will work well with up to
> > perhaps a hundred partitions; don't try to use many thousands of partitions."

> In the -general post, I was just about to point them at the part in
> the documents that warn against these large partition hierarchies, but
> it looks like the warning was removed in bebc46931a1, or at least
> modified to say that constraint exclusion with heritance tables is
> slow. I really wonder if we shouldn't put something back in there to
> warn against this sort of thing.

+1

I believe I was of the same mind when I wrote:
https://www.postgresql.org/message-id/flat/20180525215002.GD14378%40telsasoft.com#c9de33b17fe63cecad4ac30fb1662531

Justin

PS. Sorry to dredge up another 10 month old thread..