On Tue, 11 May 2021 at 11:34, Jonathan Chen <jonc@xxxxxxxxxxx> wrote: > PG13 LIMIT 1 : https://explain.depesz.com/s/GFki > PG13 no LIMIT: https://explain.depesz.com/s/U4vR > PG12 LIMIT 1 : https://explain.depesz.com/s/JAp4 The difference is coming from the fact that PostgreSQL 13 has incremental sort and can use the account_move_date_index to provide partially sorted input for the ORDER BY clause. PG12 didn't have this feature, so there was no index that could help getting pre-sorted input to the ORDER BY. You'd get along much better if you got rid of the account_move_date_index index and replaced it with: CREATE INDEX account_move_date_id_index ON account_move (date,id); Or instead or removing account_move_date_index, you could add an index such as: CREATE INDEX account_move_journal_id_date_index (journal_id, date, id); That should allow the query to run a bit more quickly. However, if the first of the two is fast enough then it might be better to not add too many extra indexes. David
