On Thu, May 18, 2023 at 04:03:36PM -0400, Tom Lane wrote: > Yeah. I see the problem: when starting up an EPQ recheck, we stuff > the tuple-to-test into the epqstate->relsubs_slot[] entry for the > relation it came from, but we do nothing to the EPQ state for the > other target relations, which allows the EPQ plan to fetch rows > from those relations as usual. If it finds a (non-updated) row > passing the qual, kaboom! We decide the EPQ check passed.
Ah, so the EPQ check only fails for the last tuple because we won't fetch rows from the other relations. I think that explains the behavior I'm seeing. > What we need to do, I think, is set epqstate->relsubs_done[] for > all target relations except the one we are stuffing a tuple into. This seems generally reasonable to me. > While nodeModifyTable can certainly be made to do that, things are > complicated by the fact that currently ExecScanReScan thinks it ought > to clear all the relsubs_done flags, which would break things again. > I wonder if we can simply delete that code. Dropping the > FDW/Custom-specific code there is a bit scary, but on the whole that > looks like code that got cargo-culted in rather than anything we > actually need. I see that part was added in 385f337 [0]. I haven't had a chance to evaluate whether it seems necessary. [0] https://postgr.es/m/9A28C8860F777E439AA12E8AEA7694F80117370C%40BPXM15GP.gisp.nec.co.jp -- Nathan Bossart Amazon Web Services: https://aws.amazon.com
