Re: Autovacuum versus rolled-back transactions - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Autovacuum versus rolled-back transactions
Date
Msg-id 15412.1180660768@sss.pgh.pa.us
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In response to Re: Autovacuum versus rolled-back transactions  (Alvaro Herrera <alvherre@commandprompt.com>)
Responses Re: Autovacuum versus rolled-back transactions  (Alvaro Herrera <alvherre@commandprompt.com>)
List pgsql-hackers
Alvaro Herrera <alvherre@commandprompt.com> writes:
> If we apply Heikki's idea of advancing OldestXmin, I think what we
> should do is grab the value from pgstats when vacuum starts, and each
> time we're going to advance OldestXmin, grab the value from pgstats
> again; accumulate the differences from the various pgstat grabs.  At the
> end we send the accumulated differences as the new dead tuple count.

Considering that each of those values will be up to half a second old,
I can hardly think that this will accomplish anything except to
introduce a great deal of noise ...
        regards, tom lane


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