Re: performance degredation after upgrade from 9.6 to 12

Hey Jeff,
First of all thank you again for the quick response. I really appreciate
your comments.
Unfortunately I installed pg from rpms so I cant compile my current env but
I can install it from source code and migrate the data via pg_dump. Can you
explain how can I compile the sources without this commit ?
I understand that my test such a good test but I thought that using
something simple can show my issue. I was sure that I added the results of
the same tests after disabling the param but it seems that I didnt do it.
I'll send it tomorrow because right now im not inforont of my pc. The
bottom line, after disabling this param the same query took less time in
pg12(significly).
From this email chain and other peoples comments it seems that I'm not the
only one who was facing this issue. One thing that might worth mentitoning,
in all my tests I didnt use a big env, my db was at max 30GB and the max
duration of a query was about 10s. It seems that this happens when we use
queries with short duration (in your test you mentioned u used the same
test but with 100 times more rows, maybe that is the reason it took more
time ?) - maybe on "short" queries it creates degredation ? It is just an
assumption...

I'll try to do most tests tomorrow and update with results.

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