Re: Clock sweep not caching enough B-Tree leaf pages?

On 2014-04-16 07:55:44 -0500, Merlin Moncure wrote:
> > 1. Bgwriter needs to be improved so that it can help in reducing
> > usage count and finding next victim buffer (run the clock sweep
> > and add buffers to the free list).
> > 2. SetLatch for bgwriter (wakeup bgwriter) when elements in freelist
> > are less.
> > 3. Split the workdone globallock (Buffreelist) in StrategyGetBuffer
> > (a spinlock for the freelist, and an lwlock for the clock sweep).
> > Here we can try to make it lock free based on atomic ops as
> > well.
> > 4. Bgwriter needs to be more aggressive, logic based on which it
> > calculates how many buffers it needs to process needs to be
> > improved.
> > 5. Contention around buffer mapping locks.
> > 6. Cacheline bouncing around the buffer header spinlocks, is there
> > anything we can do to reduce this?
> > 7. Choose Optimistically used buffer in StrategyGetBuffer().
> > 8. Don't bump the usage count every time buffer is pinned.
>
> What about: 9. Don't wait on locked buffer in the clock sweep.

I don't think we do that? Or are you referring to locked buffer headers?

Greetings,

Andres Freund

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Andres Freund http://www.2ndQuadrant.com/
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