| From: | Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> |
|---|---|
| To: | grant <grant(at)amadensor(dot)com> |
| Cc: | Anthony Berglas <anthony(dot)berglas(at)lucida(dot)com>, pgsql-general(at)postgresql(dot)org |
| Subject: | Re: Multi-Versions and Vacuum |
| Date: | 2002-07-19 16:03:49 |
| Message-ID: | 200207191603.g6JG3nQ13908@candle.pha.pa.us |
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| Lists: | pgsql-general |
grant wrote:
> If Oracle uses multiple version concurrency, then why does it appear to do
> row locking (I use Oracle at work, but I do not admin it)
>
> The only downside I have seen to MVCS is the extra disk space, but with
> the performance improvements in a highly concurrent use environment, it is
> well worth it.
>
> Q: Does VACUUM FULL remove the rows that are too many for the FSM? Or,
> are they just stuck? I know that regular VACUUM will not allow reuse of
> overflowed rows. Also, how does one calculate the propper size for the
> FSM?
VACUUM full removes all unused rows from disk _including_ ones that
aren't in the free space map.
--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
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