Heikki Linnakangas wrote: > I'd like to see still more evidence that it's a problem before we start > changing that piece of code. It has served us well for years.
So the TODO could be "investigate whether caching pg_clog and/or pg_subtrans in local memory can be useful for vacuum performance". > Bruce Momjian wrote: > >Is there a TODO here? > > > >--------------------------------------------------------------------------- > > > >Heikki Linnakangas wrote: > >>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. -- Alvaro Herrera http://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc. ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
