Re: Some thoughts about i/o priorities and throttling vacuum

On Fri, 2003-10-17 at 10:25, Shridhar Daithankar wrote:
> OK. So here is what I understand. I have a table which contains 100 rows which
> appeated there due to some insert operation. Then I vacuum it. And sit there for
> internity for rest of the database to approach the singularity(the xid
> wraparound..:-) Nice term, isn't it?).
>
> So this static table is vulnerable to xid wraparound? I doubt.

No that table would probably be ok, because you did a vacuum on it after
the inserts. The problem is that pg_autovacuum may choose not to do a
vacuum if you didn't cross a threshold, or someone outside of
pg_autovacuum may have done the vacuum and autovac doesn't know about
it, so it can't guarantee that all tables in the database are safe from
xid wraparound.

One additional thing, some of this might be possible if pg_autovacuum
saved its data between restarts. Right now it restarts with no memory
of what happened before.