On Wed, Apr 12, 2023 at 12:44 PM Tom Lane <t...@sss.pgh.pa.us> wrote: > Pursuant to the discussion at [1], here's a patch that removes our > old restriction that a plan node having initPlans can't be marked > parallel-safe (dating to commit ab77a5a45). That was really a special > case of the fact that we couldn't transmit subplans to parallel > workers at all. We fixed that in commit 5e6d8d2bb and follow-ons, > but this case never got addressed.
Nice. > Along the way, this also takes care of some sloppiness about updating > path costs to match when we move initplans from one place to another > during createplan.c and setrefs.c. Since all the planning decisions are > already made by that point, this is just cosmetic; but it seems good > to keep EXPLAIN output consistent with where the initplans are. OK. It would be nicer if we had a more principled approach here, but that's a job for another day. > There's only one existing test case that visibly changes plan with > these changes. The new plan is clearly saner-looking than before, > and testing with some data loaded into the table confirms that it > is faster. I'm not sure if it's worth devising more test cases. It seems like it would be nice to see one or two additional scenarios where these changes bring a benefit, with different kinds of plan shapes. -- Robert Haas EDB: http://www.enterprisedb.com
