Re: page corruption on 8.3+ that makes it to standby

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Simon Riggs <simon@2ndquadrant.com>, Jeff Davis <pgsql@j-davis.com>, pgsql-hackers@postgresql.org
Date: 2010-07-29T14:35:02Z
Lists: pgsql-hackers
Robert Haas <robertmhaas@gmail.com> writes:
> On Thu, Jul 29, 2010 at 4:58 AM, Simon Riggs <simon@2ndquadrant.com> wrote:
>> Still don't understand why we would not initialize such pages. If we're
>> copying a relation we must know enough about it to init a page.

> Well, I don't see why we'd want to do that.  As Jeff Davis pointed
> out, if someone asks to move a table to a different tablespace,
> changing the contents as we go along seems a bit off-topic.  But the
> bigger problem is you haven't explained how you think we could
> determine what initialization ought to be performed.  There's no
> index-AM API that says "initialize this page".  I suppose we could
> invent one if there were some benefit, but we couldn't very well
> back-patch such a thing to 8.0.

Yeah.  And you really would have to get the AM involved.  Even if you
were willing to assume that you knew the special-space size for a
particular index type, it would not fly to assume that the special space
doesn't require initialization to some nonzero content.

			regards, tom lane