Re: BUG #13426: table bloat - dead rows not removed after vacuum

Jamie Koceniak <jkoceniak@mediamath.com> wrote:
> David G. Johnston [mailto:david.g.johnston@gmail.com] wrote:

>> One possibility is that you have a long-running transaction
>> holding up cleanup.

> No long running queries are in pg_stat_activity.

It doesn't take a long-running *query* to cause a problem; it only
takes a long-running *transaction*.  Look for transactions which
are "idle in transaction" with an old xact_start value.  Also check
the pg_prepared_xacts view for rows with a "prepared" value that is
more than a few seconds old.  Either will prevent the cleanup of
dead rows.

--
Kevin Grittner
EDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company