2018-06-01 17:53 GMT+02:00 Tom Lane <t...@sss.pgh.pa.us>: > Ashutosh Bapat <ashutosh.ba...@enterprisedb.com> writes: > > I think the patch is right if we were to handle only SQLValueFunction, > > but the bigger picture here is that we aren't evaluating stable > > functions before run-time partition pruning happens. I was under the > > impression that the stable functions/expressions get evaluated and > > folded into a constant just before the execution begins since a stable > > function produces the same output for same input during one execution > > invocation. But I am not able to find where we do that and probably we > > don't do that at all. > > We don't; there was a patch floating around to make that happen, but > it hasn't been updated lately. > > 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. >
The result is correct - but it was unpleasant surprise. I searched the most simple demo for this feature, and it doesn't work. Filtering based on CURRENT_DATE is often. Regards Pavel > regards, tom lane >
