Re: Avoiding unnecessary reads in recovery

Heikki Linnakangas wrote:

> What we could have is the semantics of "Return a buffer, with either 
> correct contents or completely zeroed out". It would act just like 
> ReadBuffer if the buffer was already in memory, and zero out the page 
> otherwise. That's a bit strange semantics to have, but is simple to 
> implement and works for the use-cases we've been talking about.

Huh, why does that work in the case where the recovery code reads a
page, then evicts it because of memory pressure, and later needs to read
it again?

-- 
Alvaro Herrera                                http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.