Re: Indexes being ignored after upgrade to 9.5

On Wed, Jul 26, 2017 at 2:05 PM, Peter Geoghegan <pg(at)bowt(dot)ie> wrote:
> On Tue, Jul 25, 2017 at 10:34 PM, Nick Brennan <nbrennan02(at)gmail(dot)com> wrote:
>> We've added duplicate indexes and analyzing, however the new indexes are
>> still ignored unless we force using enable_seqscan=no or reduce
>> random_page_cost to 2. The query response times using the new indexes are
>> still as slow when we do this. Checking pg_stat_user_indexes the number of
>> tuples returned per idx_scan is far greater after the upgrade than before.
>> All indexes show valid in pg_indexes.

I assume that you mean that pg_stat_user_indexes.idx_tup_read is a lot
higher than before, in proportion to pg_stat_user_indexes.idx_scan.
What about the ratio between pg_stat_user_indexes.idx_tup_read and
pg_stat_user_indexes.idx_tup_fetch? How much has that changed by?

--
Peter Geoghegan