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List:       postgresql-general
Subject:    Re: [HACKERS] crash on 8.2 and cvshead - failed to add item to the
From:       Heikki Linnakangas <heikki () enterprisedb ! com>
Date:       2007-01-31 10:46:37
Message-ID: 45C0738D.10204 () enterprisedb ! com
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Tom Lane wrote:
> Are you still concerned about the PageGetFreeSpace issue?

Not anymore.

The failure case I had in mind was not being able to find any valid 
split points when a page is full of max-sized index tuples. On a closer 
look, that doesn't seem to be a problem. Even though checksplitloc would 
incorrectly consider the split (HIKEY+item)-(HIKEY+item+item) as 
invalid, the split (HIKEY+item+item)-(HIKEY+item) is just as good. 
Similarly on the rightmost page, even if (HIKEY+item)-(item+item+item) 
is incorrectly considered as invalid, (HIKEY+item+item)-(item+item) is fine.

There also seems to always be some slack space because of alignments.

-- 
   Heikki Linnakangas
   EnterpriseDB   http://www.enterprisedb.com

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