Re: Slow queries on simple index

"Lillian Berry" <lillian@star-ark.net> writes:
> Logs on our PostgreSQL cluster show frequent slow reads on a simple query by unique index.
> This issue has been present for some years, and survived multiple server moves as well as PostgreSQL version
upgrades.
> Vacuuming or reindexing the table does not seem to help.

What else is going on in that database?  The fact that you show
several different sessions suffering similar delays at almost the
same time seems suspicious to me.  I'm wondering if something is
taking an exclusive lock on that table and then sitting on it
for a second or two.

            regards, tom lane