On Sat, Jun 2, 2018 at 5:16 PM, Jeff Janes <jeff.ja...@gmail.com> wrote: > On Fri, Jun 1, 2018 at 11:53 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: >> >> >> I agree though that it seems strange to special-case SQLValueFunction >> rather than any-stable-expression. As long as the evaluation happens >> at executor start (i.e. with the query's run-time snapshot) it should >> be reasonable to simplify any stable expression. >> >> It's worth questioning whether this is a bug fix or an improvement. >> If the latter, it probably ought to wait for v12. > > > If explaining the change requires reference to tokens from the source code, > rather than something an end user could understand, I'd argue it is a bug > fix rather than an improvement.
If we going to implement stable expression folding before the actual execution starts, that's a feature in itself. So, it's V12 material. Partition pruning will use that feature. I don't think we should make partition pruning work with stable expressions in some ad-hoc way in V11 and the some future release (mostly V12) implements it on top of stable expression folding feature. So my vote for making it work in V12. -- Best Wishes, Ashutosh Bapat EnterpriseDB Corporation The Postgres Database Company
