Re: FSM, now without WAL-logging

On Mon, 2008-09-22 at 20:43 +0300, Heikki Linnakangas wrote:

> Attached is a revamped version of the FSM rewrite. WAL-logging is now
> gone. Any inconsistencies between levels of the FSM is fixed during
> vacuum, and by searchers when they run into a dead end because of a
> discrepancy. Corruption within FSM pages is likewise fixed by vacuum and
> searchers.
>
> The FSM in a warm standby gets updated by replay of heap CLEAN WAL
> records. That means that the FSM will reflect the situation after the
> last vacuum, which is better than what we have now, but not quite
> up-to-date. I'm worried that this might not be enough...

I hadn't realised you would remove it completely. Did you identify WAL
as the bottleneck?

Is there some mid-way point between every time and almost never
(VACUUM!)?

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Simon Riggs www.2ndQuadrant.com
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