Re: [PERFORM] performance drop after upgrade (9.6 > 10)

2017-10-26 Thread Justin Pryzby
On Tue, Oct 24, 2017 at 04:15:59PM +0200, johannes graën wrote: > Hi Pavel, *, > > you were right with ANALYZing the DB first. However, even after doing > so, I frequently see Seq Scans where an index was used before. This > usually cooccurs with parallelization and looked different before >

Re: [PERFORM] performance drop after upgrade (9.6 > 10)

2017-10-24 Thread Alvaro Herrera
johannes graën wrote: > Hi Pavel, *, > > you were right with ANALYZing the DB first. However, even after doing > so, I frequently see Seq Scans where an index was used before. This > usually cooccurs with parallelization and looked different before > upgrading to 10. I can provide an example for

Re: [PERFORM] performance drop after upgrade (9.6 > 10)

2017-10-24 Thread Johannes Graën
On 2017-10-24 17:18, Justin Pryzby wrote: > You could (re)install PG96 alongside PG10 and run a copy of the DB (even from > your homedir, or on a difference server) and pg_dump |pg_restore the relevant > tables (just be sure to specify the alternate host/port/user/etc as needed for > the restore

Re: [PERFORM] performance drop after upgrade (9.6 > 10)

2017-10-24 Thread Justin Pryzby
On Tue, Oct 24, 2017 at 04:15:59PM +0200, johannes graën wrote: > upgrading to 10. I can provide an example for 10 [1], but I cannot > generate a query plan for 9.6 anymore. You could (re)install PG96 alongside PG10 and run a copy of the DB (even from your homedir, or on a difference server) and

Re: [PERFORM] performance drop after upgrade (9.6 > 10)

2017-10-24 Thread johannes graën
Hi Pavel, *, you were right with ANALYZing the DB first. However, even after doing so, I frequently see Seq Scans where an index was used before. This usually cooccurs with parallelization and looked different before upgrading to 10. I can provide an example for 10 [1], but I cannot generate a

Re: [PERFORM] performance drop after upgrade (9.6 > 10)

2017-10-11 Thread johannes graën
On Wed, Oct 11, 2017 at 1:11 PM, Pavel Stehule wrote: > have you fresh statistics? After upgrade is necessary to run ANALYZE command Yes, that was missing indeed. I did ANALYZE but apparently on all databases but this one. I could have guessed that

Re: [PERFORM] performance drop after upgrade (9.6 > 10)

2017-10-11 Thread Pavel Stehule
2017-10-11 13:06 GMT+02:00 johannes graën : > 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

[PERFORM] performance drop after upgrade (9.6 > 10)

2017-10-11 Thread johannes graën
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