From: | Mark Kirkwood <markir(at)paradise(dot)net(dot)nz> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | pgsql-hackers(at)postgreSQL(dot)org |
Subject: | Re: ReadBuffer(P_NEW) versus valid buffers |
Date: | 2006-09-24 00:16:30 |
Message-ID: | 4515CE5E.1060309@paradise.net.nz |
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Lists: | pgsql-hackers |
Tom Lane wrote:
> So ReadBuffer without hesitation zeroes out the page of data we just
> filled, and returns it for re-filling. There went some tuples :-(
>
> Although this is clearly Not Our Bug, it's annoying that ReadBuffer
> falls into the trap so easily instead of complaining. I'm still
> disinclined to try to change the behavior of mdread(), but what I am
> considering doing is adding a check here to error out if not PageIsNew.
> AFAICS, if we do find a buffer for a page supposedly past EOF, it should
> be zero-filled because that's what mdread returns in this case. So this
> change would prevent Dan's silent-overwrite scenario without changing the
> behavior for any legitimate case.
>
> Thoughts, problems, better ideas?
>
The check looks good - are we chasing up the Linux kernel (or Suse) guys
to get the bug investigated?
Cheers
Mark
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