On Sat, Jan 14, 2006 at 04:13:56PM -0500, Qingqing Zhou wrote:
>
> "Qingqing Zhou" <[EMAIL PROTECTED]> wrote
> >
> > I wonder if we should really implement file-system-cache-warmup strategy
> > which we have discussed before. There are two natural good places to do
> > this:
> >
> > (1) sequentail
"Qingqing Zhou" <[EMAIL PROTECTED]> wrote
>
> I wonder if we should really implement file-system-cache-warmup strategy
> which we have discussed before. There are two natural good places to do
> this:
>
> (1) sequentail scan
> (2) bitmap index scan
>
For the sake of memory, there is a third place
"Greg Stark" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
>
> Hm. Personally I have a hunch you're right. But there we have no actual
> evidence. The first thing that needs to happen is changes to use O_DIRECT
> for
> everything and then benchmarking one of those big TPC tests wit
Qingqing Zhou <[EMAIL PROTECTED]> writes:
> > In other words, the difference between being in Postgres's buffer cache and
> > being in the filesystem cache, while not insignificant, isn't really
> > relevant
> > to the planner since it affects sequential scans and index scans equally.
>
> The b
On Sat, 7 Jan 2006, Greg Stark wrote:
>
> "Qingqing Zhou" <[EMAIL PROTECTED]> writes:
>
> > For b1, it actually doesn't matter much though. With bitmap we definitely
> > can give a better EXPLAIN numbers for seqscan only, but without the bitmap,
> > we seldom make wrong choice of choosing/not ch
"Qingqing Zhou" <[EMAIL PROTECTED]> writes:
> For b1, it actually doesn't matter much though. With bitmap we definitely
> can give a better EXPLAIN numbers for seqscan only, but without the bitmap,
> we seldom make wrong choice of choosing/not choosing sequential scan.
I think you have a more
"Qingqing Zhou" <[EMAIL PROTECTED]> wrote
>
>> Feasibility: Our bufmgr lock rewrite already makes this possible. But to
>> enable it, we may need more work: (w1) make bufferpool relation-wise,
>> which makes our estimation of data page residence more easy and reliable.
>> (w2) add aggresive pre-re
On Thu, 5 Jan 2006, Qingqing Zhou wrote:
>
> Feasibility: Our bufmgr lock rewrite already makes this possible. But to
> enable it, we may need more work: (w1) make bufferpool relation-wise,
> which makes our estimation of data page residence more easy and reliable.
> (w2) add aggresive pre-read o
On Thu, 5 Jan 2006, Tom Lane wrote:
>
> The difference between the cached and non-cached states is that the
> kernel has seen fit to remove those pages from its cache. It is
> reasonable to suppose that it did so because there was a more immediate
> use for the memory. Trying to override that b
Qingqing Zhou <[EMAIL PROTECTED]> writes:
> Hinted by this thread:
> http://archives.postgresql.org/pgsql-performance/2006-01/msg00016.php
> I wonder if we should really implement file-system-cache-warmup strategy
> which we have discussed before.
The difference between the cached and non-ca
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