On Wed, 2007-11-14 at 17:46 -0500, Tom Lane wrote:
> Russell Smith <[EMAIL PROTECTED]> writes:
> > It is possible that analyze is not getting the number of dead rows right?
> 
> Hah, I think you are on to something.  ANALYZE is telling the truth
> about how many "dead" rows it saw, but its notion of "dead" is "not good
> according to SnapshotNow".  Thus, rows inserted by a not-yet-committed
> transaction would be counted as dead.  So if these are background
> auto-analyzes being done in parallel with inserting transactions that
> run for awhile, seeing a few not-yet-committed rows would be
> unsurprising.
> 
> I wonder if that is worth fixing?  I'm not especially concerned about
> the cosmetic aspect of it, but if we mistakenly launch an autovacuum
> on the strength of an inflated estimate of dead rows, that could be
> costly.

Sounds to me like that could result in autovacuum kicking off while
doing large data loads.  This sounds suspiciously like problem someone
on -novice was having - tripping over a windows autovac bug while doing
a data load

http://archives.postgresql.org/pgsql-novice/2007-11/msg00025.php

-- 
Brad Nicholson  416-673-4106
Database Administrator, Afilias Canada Corp.



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