Re: Limiting setting of hint bits by read-only queries; vacuum_delay

On 3/24/13 7:14 AM, Simon Riggs wrote:
> Patch to implement is a few hours work. The only complexity is
> deciding how to handle SQL in functions.... to which I would say, as
> simply as possible.

Like the Page replacement ideas, the throttle on how fast something like
this will get done depends not on development time, but on putting
together more performance regression tests. The idea I was thinking
about is refactoring the background writer's role in hint bit
maintenance. If backends could push "this looks dirty" page numbers
toward the BGW and keep going, it might stream those out to disk under
its control.

I also have a larger proposal for how to refactor I/O so that both
queries and CREATE INDEX have similar cost controls to the ones used to
limit vacuum. And two more based on collecting extra data for high cost
queries before they run.

But right now I keep biting my tongue about the design on all these, and
return to working on one of the patches already in the CF queue instead.

--
Greg Smith 2ndQuadrant US greg(at)2ndQuadrant(dot)com Baltimore, MD
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