2017-10-11 13:06 GMT+02:00 johannes graën <johannes@xxxxxxxxxx>:
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
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