Re: Dead Space Map - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Dead Space Map
Date
Msg-id 16849.1141150097@sss.pgh.pa.us
Whole thread Raw
In response to Re: Dead Space Map  (Greg Stark <gsstark@mit.edu>)
List pgsql-hackers
Greg Stark <gsstark@mit.edu> writes:
> I originally thought you meant if you are repeatedly updating the same record
> within the same transaction. In that case sure you could reuse the space but
> a) only if it's big enough for the new record and b) how often do you really
> do that?

Also, it's not that easy even within a single transaction: you could
have active snapshots inside your xact that can still see the obsoleted
tuple.
        regards, tom lane


pgsql-hackers by date:

Previous
From: Tom Lane
Date:
Subject: Re: [PERFORM] temporary indexes
Next
From: Bruce Momjian
Date:
Subject: Re: Dead Space Map