Re: Should a DB vacuum use up a lot of space ? - Mailing list pgsql-general

From John R Pierce
Subject Re: Should a DB vacuum use up a lot of space ?
Date
Msg-id 6d3ea2b9-d7f0-648e-8ceb-679b909c2442@hogranch.com
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In response to Re: Should a DB vacuum use up a lot of space ?  (Philippe Girolami <philippe.girolami@mosaik.com>)
List pgsql-general
On 8/7/2016 10:26 AM, Philippe Girolami wrote:
More weirdness this afternoon : the wraparound ERROR showed up again even though I have trouble believing I burned through so many transactions in under a day. But let’s assume I did, here is what I noticed

1) I vacuumed all other databases. For everyone of those, the age went down to 50M instead of zero. Is that normal ?
2) The only database that didn’t work on was template0 (the age did not change). It did work on template1

Should I suspect something fishy going on ?

do you have any long running 'idle in transaction' sessions?  these would show up in pg_stat_activity, you want to look at now()-xact_start to see the age of the oldest of these.    no tuples newer than the oldest xact_start can be vacuumed.

select * from pg_stat_activity where state='idle in transaction';

select count(*), max(now()-xact_start) from pg_stat_activity where state='idle in transaction';



-- 
john r pierce, recycling bits in santa cruz

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