So, does it mean that VACUUM will never clean dead rows if you have a
non-stop transactional activity in your PG database???... (24/7 OLTP
for ex.)
Rgds,
-Dimitri
On 8/19/10, Kevin Grittner <Kevin.Grittner@wicourts.gov> wrote:
> Alexandre de Arruda Paes <adaldeia@gmail.com> wrote:
>> 2010/8/18 Tom Lane <tgl@sss.pgh.pa.us>
>
>>> There's an open transaction somewhere that VACUUM is preserving
>>> the tuples for. This transaction need not ever have touched the
>>> table, or ever intend to touch the table --- but VACUUM cannot
>>> know that, so it saves any tuples that the transaction might be
>>> entitled to see if it looked.
>>>
>>> > carmen=# select * from vlocks where relname='tp93t'; select *
>>> > from pg_stat_activity where usename='webpa';
>>>
>>> You keep on showing us only subsets of pg_stat_activity :-(
>
>> select * from pg_stat_activity where usename='webpa';
>
> You keep on showing us only subsets of pg_stat_activity :-(
>
> *ANY* open transaction, including "idle in transaction" including
> transactions by other users in other databases will prevent vacuum
> from cleaning up rows, for the reasons Tom already gave you.
>
> What do you get from?:
>
> select * from pg_stat_activity where current_query <> '<IDLE>'
> order by xact_start limit 10;
>
> -Kevin
>
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