| From: | Mark Kirkwood <markir(at)paradise(dot)net(dot)nz> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Pavan Deolasee <pavan(at)enterprisedb(dot)com>, Gavin Sherry <swm(at)alcove(dot)com(dot)au>, Luke Lonergan <llonergan(at)greenplum(dot)com>, PGSQL Hackers <pgsql-hackers(at)postgresql(dot)org>, Doug Rady <drady(at)greenplum(dot)com>, Sherry Moore <sherry(dot)moore(at)sun(dot)com> |
| Subject: | Re: Bug: Buffer cache is not scan resistant |
| Date: | 2007-03-06 00:06:46 |
| Message-ID: | 45ECB096.2050709@paradise.net.nz |
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| Lists: | pgsql-hackers |
Tom Lane wrote:
>
> But what I wanted to see was the curve of
> elapsed time vs shared_buffers?
>
Of course! (lets just write that off to me being pre coffee...).
With the patch applied:
Shared Buffers Elapsed vmstat IO rate
-------------- ------- --------------
400MB 101 s 122 MB/s
2MB 101 s
1MB 97 s
768KB 94 s
512KB 84 s
256KB 79 s
128KB 75 s 166 MB/s
Looks *very* similar.
Cheers
Mark
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