Re: Vacuum not removing dead tuples

Thanks Laurenz,

A replication slot was my issue. Much appreciated for the insight.

Thanks,
Rui

> On Nov 15, 2017, at 5:06 AM, Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at> wrote:
>
> Rui DeSousa wrote:
>> Is there a reason vacuum will not remove dead tuples other than the usual suspects?
>> There are no two phase transactions and even after a restoring the database
>> from binary backup with nothing connect to the restored instance;
>> vacuum still does not remove the dead tuples.
>
> There are three possibilities:
>
> 1) Active transactions:
>
> SELECT backend_xmin, xact_start, datname, pid, query
> FROM pg_stat_activity
> WHERE state <> 'idle'
> ORDER BY xact_start;
>
> 2) Prepared transactions:
>
> SELECT xid, prepared
> FROM pg_prepared_xacts;
>
> 3) Lagging replication slots:
>
> SELECT xmin, slot_name, active, active_pid
> FROM pg_replication_slots;
>
> The "xid" columns will tell you which tuples VACUUM can
> remove: Any tuple with "xmax" less than this are fair game.
>
> Yours,
> Laurenz Albe