On Jun 26, 2026, at 10:14 AM, Adrian Klaver <[email protected]> wrote: > > > > On 6/26/26 10:58 AM, Israel Brewster wrote: >> In postgreSQL 15, I had the below query that worked quickly. Now, I make no >> claims that the query is the best possible, or even a good query, but it DID >> work, and it did so quickly enough to be un-noticable when running. >> Then I upgrade to PostgreSQL 18 - and now the query never completes (as in, >> I get a command timeout after at least half an hour before I get a result). >> Looking at the EXPLAIN (https://explain.depesz.com/s/llAQ >> <https://explain.depesz.com/s/llAQ>) makes it pretty obvious why: we have a >> sequence scan on a large table inside a nested loop - and that sequence scan >> is apparently not short circuiting. > > The link provided shows no times or rows, did you pick the correct one? >> I tried the obvious: REINDEX database and VACUUM ANALYZE, but neither >> helped. I have my default_statistics_target set to 500 at the moment. >> Then I tried SET enable_seqscan = off; Lo and behold, the query ran in only >> 123.888 ms (fun number :-D ) - https://explain.depesz.com/s/K2K9 >> <https://explain.depesz.com/s/K2K9> > > This one does not show the actual query.
Right, sorry. It’s the same query as in the first one though. Only difference is sequence scan off. --- Israel Brewster Software Engineer Alaska Volcano Observatory Geophysical Institute - UAF 2156 Koyukuk Drive Fairbanks AK 99775-7320 Work: 907-474-5172 cell: 907-328-9145 > > >> --- >> Israel Brewster >> Software Engineer >> Alaska Volcano Observatory >> Geophysical Institute - UAF >> 2156 Koyukuk Drive >> Fairbanks AK 99775-7320 >> Work: 907-474-5172 >> cell: 907-328-9145 >
