Re: Bgwriter LRU cleaning: we've been going at this all wrong

[Jim Nasby <decibel(at)decibel(dot)org>]

On Jun 26, 2007, at 11:57 PM, Greg Smith wrote:
> On Wed, 27 Jun 2007, ITAGAKI Takahiro wrote:
>
> > It might be good to use statistics information about buffer usage  
> > to modify X runtime.
>
> I have a complete set of working code that tracks buffer usage  
> statistics as the background writer scans, so that it has an idea  
> what % of the buffer cache is dirty, how many pages have each of  
> the various usage counts, that sort of thing.  The problem was that  
> the existing BGW mechanisms were so clumsy and inefficient that  
> giving them more information didn't make them usefully smarter.   
> I'll revive that code again if it looks like it may help here.

Even if it's not used by bgwriter for self-tuning, having that  
information available would be very useful for anyone trying to hand- 
tune the system.
--
Jim Nasby                                            jim(at)nasby(dot)net
EnterpriseDB      http://enterprisedb.com      512.569.9461 (cell)