Re: Re: patch submission: truncate trailing nulls from heap rows to reduce the size of the null bitmap

From: Gokulakannan Somasundaram <gokul007(at)gmail(dot)com>
To: Simon Riggs <simon(at)2ndquadrant(dot)com>
Cc: Robert Haas <robertmhaas(at)gmail(dot)com>, Greg Stark <stark(at)mit(dot)edu>, Josh Berkus <josh(at)agliodbs(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Re: patch submission: truncate trailing nulls from heap rows to reduce the size of the null bitmap
Date: 2012-04-29 11:50:49
Message-ID: CAHMh4-aGz-_dENoG-OvA-228AzfoeH1dRWr6b2LgejcsGdQmBA@mail.gmail.com
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There might be a patch available for this already. In the worst case
articulated above (less than 64 columns), if all the nulls are trailing
nulls, the bitmap need not be saved. Actually it is not 64(actually 72), as
postgres heaptupleheader is only 23 bytes and one byte is left for the
start of the bitmap.

The same principle can be considered for Index Tuple as an extension

Thanks,
Gokul.

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