From: | ITAGAKI Takahiro <itagaki(dot)takahiro(at)oss(dot)ntt(dot)co(dot)jp> |
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To: | pgsql-patches(at)postgresql(dot)org |
Subject: | Dead Space Map patch |
Date: | 2006-12-28 06:14:56 |
Message-ID: | 20061228142827.5FBF.ITAGAKI.TAKAHIRO@oss.ntt.co.jp |
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Lists: | pgsql-patches |
This is a patch for TODO item:
| Create a bitmap of pages that need vacuuming
Dead Space Map allows VACUUM to scan only pages that need vacuuming.
I sent to HACKERS the description of this patch.
Comments, suggestions and evaluation reports are welcome.
Usage of the feature is below:
- VACUUM FREEZE is recommended.
Pages that need vacuuming and freezing are not separated in the patch.
If we do non-FREEZE VACUUM, next VACUUM will also read pages that we
cannot freeze all of tuples in it at the last VACUUM. It's a waste.
- [GUC] dsm_buffers (integer)
The used memory size in dead space map. Default is 16MB,
that can track maximum 1TB of heap tables.
- [GUC] dsm_vacuum (boolean)
This enables the dead space map in VACUUM. Default is on.
Even if it is off, DSM are always recorded and updated.
- contrib/pg_deadspacemap
This shows the contents of dead space map.
See also README.pg_deadspacemap.
Regards,
---
ITAGAKI Takahiro
NTT Open Source Software Center
Attachment | Content-Type | Size |
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deadspacemap.patch.gz | application/octet-stream | 25.3 KB |
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