| From: | ITAGAKI Takahiro <itagaki(dot)takahiro(at)lab(dot)ntt(dot)co(dot)jp> |
|---|---|
| To: | Simon Riggs <simon(at)2ndquadrant(dot)com> |
| Cc: | pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: Notification when freespaces empty |
| Date: | 2005-05-24 08:23:26 |
| Message-ID: | 20050524165249.3AB4.ITAGAKI.TAKAHIRO@lab.ntt.co.jp |
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| Lists: | pgsql-hackers |
Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
> > Furthermore, this patch detaches empty fsmpages then.
> Does that do anything useful though?
> I thought we don't reallocate until VACUUM time, whereupon we identify
> any empty slots and reuse them. Who cares whether we deallocate earlier?
Yes, we cannot reuse them until next VACUUM.
But I think it is a problem that FSMs keep being scanned after they are almost empty.
In such a case, most stored pages are touched whenever new pages
are requested. I intended to cut FSMs earlier in order to omit the scans.
---
ITAGAKI Takahiro
NTT Cyber Space Laboratories
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