Re: BUG #15609: synchronous_commit=off insert performance regressionwith secondary indexes

On Tue, Jan 29, 2019 at 2:05 PM Saul, Jean Paolo
<paolo.saul@verizonconnect.com> wrote:
> Before each test run, I drop and recreate the table and indexes.

What happens if you don't create bool_idx, or replace it with another
index on some other column? I notice that you didn't show any case
that doesn't have this index, except for the PK-only case, which is
actually faster. I surmise that that's the common factor in all of the
test cases where you have observed a regression. It would be nice to
confirm or disprove this theory.

The nbtree code is known to deal poorly with low cardinality indexes
[1], something I'm currently working to address. Are you comparing
installations that are on the same hardware and operating system?

[1] https://postgr.es/m/CAH2-Wzmf0fvVhU+SSZpGW4Qe9t--j_DmXdX3it5JcdB8FF2EsA@mail.gmail.com
--
Peter Geoghegan