Re: Invalid page header - Mailing list pgsql-admin

From Tom Lane
Subject Re: Invalid page header
Date
Msg-id 1688.1283377013@sss.pgh.pa.us
Whole thread Raw
In response to Invalid page header  (Ireneusz Pluta <ipluta@wp.pl>)
List pgsql-admin
Ireneusz Pluta <ipluta@wp.pl> writes:
> - when playing with pg_filedump I noticed that last pages of the table
> are always initially reported as damaged, as they come, then, as newer
> pages get allocated and filled, these initially bad pages "become
> valid", as in the following example repeating the same pg_filedump.

This doesn't seem terribly surprising.  A newly-added page on disk will
be initially filled with zeroes, which I think pg_filedump will complain
about.  It won't get overwritten with "valid" data until the page is
next written, either because of a checkpoint or because the buffer space
is needed for another page.  pg_filedump can't see the state of the page
within the server's buffers, which is what counts here.

            regards, tom lane

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