Re: Freeze avoidance of very large table.

On Wed, Apr 22, 2015 at 06:36:23PM -0500, Jim Nasby wrote:
> On 4/22/15 6:12 PM, Bruce Momjian wrote:
> >My point is that for the life of 200M transactions, you would have the
> >overhead of an additional file per table in the file system, and updates
> >of that.  I just don't know if the overhead over the long time period
> >would be smaller than the VACUUM FREEZE.  It might be fine --- I don't
> >know.  People seem to focus on the big activities, while many small
> >activities can lead to larger slowdowns.
> 
> Ahh. This wouldn't be for the life of 200M transactions; it would be
> a permanent fork, just like the VM is.

Right.  My point is that either you do X 2M times to maintain that fork
and the overhead of the file existance, or you do one VACUUM FREEZE.  I
am saying that 2M is a large number and adding all those X's might
exceed the cost of a VACUUM FREEZE.

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
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