Re: Reduce the size of PageFreeSpaceInfo on 64bit platform - Mailing list pgsql-patches

From ITAGAKI Takahiro
Subject Re: Reduce the size of PageFreeSpaceInfo on 64bit platform
Date
Msg-id 20070813102754.6A35.ITAGAKI.TAKAHIRO@oss.ntt.co.jp
Whole thread Raw
In response to Re: Reduce the size of PageFreeSpaceInfo on 64bit platform  (Decibel! <decibel@decibel.org>)
Responses Re: Reduce the size of PageFreeSpaceInfo on 64bit platform  (ITAGAKI Takahiro <itagaki.takahiro@oss.ntt.co.jp>)
List pgsql-patches
Decibel! <decibel@decibel.org> wrote:

> > The sizeof(PageFreeSpaceInfo) is 16 bytes

> So... does that mean that the comment in the config file about 6 bytes
> per page is incorrect?

There are no comments the usage of maintenance_work_mem in the config file
nor the documentation. Memory consumed by max_fsm_pages is only mentioned.

#maintenance_work_mem = 16MB # min 1MB
#max_fsm_pages = 204800      # min max_fsm_relations*16, 6 bytes each


But surely the difference of memory usage between maintenance_work_mem
and max_fsm_pages might confuse users. I'll rewrite my patch to use
FSMPageData in both places so that users can always estimate the memory
to 6 bytes per page.

Regards,
---
ITAGAKI Takahiro
NTT Open Source Software Center



pgsql-patches by date:

Previous
From: Michael Glaesemann
Date:
Subject: Re: final CSVlog patch
Next
From: ITAGAKI Takahiro
Date:
Subject: Re: Reduce the size of PageFreeSpaceInfo on 64bit platform