Re: Piggybacking vacuum I/O

Pavan Deolasee wrote:
> Another simpler solution for VACUUM would be to read the entire CLOG file
> in local memory. Most of the transaction status queries can be satisfied
> from
> this local copy and the normal CLOG is consulted only when the status is
> unknown (TRANSACTION_STATUS_IN_PROGRESS)

The clog is only for finished (committed/aborted/crashed) transactions.
If a transaction is in progress, the clog is never consulted. Anyway,
that'd only be reasonable for vacuums, and I'm actually more worried if
we had normal backends thrashing the clog buffers.

--   Heikki Linnakangas  EnterpriseDB   http://www.enterprisedb.com