Re: A 154 GB table swelled to 527 GB on the Slony slave. How to compact it? - Mailing list pgsql-general

From Aleksey Tsalolikhin
Subject Re: A 154 GB table swelled to 527 GB on the Slony slave. How to compact it?
Date
Msg-id CA+jMWoeqDsCbAnn-1G+eYCJHUD5UEh3hPcxFkZnOMOcDRrmfQA@mail.gmail.com
Whole thread Raw
In response to Re: A 154 GB table swelled to 527 GB on the Slony slave. How to compact it?  (Aleksey Tsalolikhin <atsaloli.tech@gmail.com>)
List pgsql-general
On Wed, Mar 14, 2012 at 8:06 PM, Aleksey Tsalolikhin
<atsaloli.tech@gmail.com> wrote:
> Executive summary:  Why would the TOAST table on the slave have 4x the
> page count of the master?

  Hypothesis:  the pages of the TOAST table on the slave have more
unused space in them than the pages of the TOAST table on the master.

  How do I test this hypothesis?  I need to examine the raw pages on disk.

  I'm looking at
http://momjian.us/main/writings/pgsql/internalpics.pdf   Slide 52
shows "internal page structure"  but I don't know how to actually look
at a page.
 Is it possible to do a raw dump of the pages of a table?  Do I just
look at the hexdump of the file corresponding to relfilenode?

Best,
Aleksey

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