| From: | ITAGAKI Takahiro <itagaki(dot)takahiro(at)oss(dot)ntt(dot)co(dot)jp> |
|---|---|
| To: | "Gokulakannan Somasundaram" <gokul007(at)gmail(dot)com> |
| Cc: | "pgsql-hackers list" <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Hash Join Optimization |
| Date: | 2008-03-28 08:34:20 |
| Message-ID: | 20080328172434.6A07.52131E4D@oss.ntt.co.jp |
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| Lists: | pgsql-hackers |
"Gokulakannan Somasundaram" <gokul007(at)gmail(dot)com> wrote:
> I think the creation of minimal_tuple in the middle is a overhead which can
> be avoided by creating a mem-map and directly creating the minimal_tuple in
> the mem-map.
Many implementations of mem-map disallow to extend the sizes.
Do you have any solution about extending the mmap-ed region?
> Since Hash join is used mainly to join huge tables, this might
> benefit those warehouse customers of postgres.
If we use mmap, we will be restricted by virtual memory size.
It means we need to drop huge tempspace supports in 32bit platform, no?
Regards,
---
ITAGAKI Takahiro
NTT Open Source Software Center
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