2017-10-11 13:06 GMT+02:00 johannes graën <johan...@selfnet.de>: > Hi, > > I wrote a query that joins several tables usually returning less than > 1000 rows, groups them and generates a JSON object of the result. In > 9.6 is was a question of milliseconds for that query to return the > requested data. Now, after upgrading to 10, the query never returns - > at least it hasn't returned in the last hour. > > To see what happens, I requested the query plan [1]. It looks complex > and shows a lot of parallelization. I don't have the query plan from > 9.6, but I remember it being considerably simpler. > > Can anyone have a guess what altered the performance here so > dramatically? Is there a way to disable new parallelization features > just for this query to see if it makes any difference? > >
have you fresh statistics? After upgrade is necessary to run ANALYZE command Regards Pavel Best > Johannes > > > [1] https://explain.depesz.com/s/xsPP > > > -- > Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-performance >
