Re: Proposal for Null Bitmap Optimization(for TrailingNULLs)

Hi,
I have currently completed the following
a) If there are only trailing nulls in the heap, no null-bitmap gets stored
b) If there are trailing nulls in addition to nulls inbetween values in the
heap, then the trailing nulls are not added to the null-bitmap. I wouldn't
have done it, but it came almost free of cost
c) If there are only trailing nulls in the index, no null-bitmap gets stored

The index part gave some issues and i hope i have fixed it. i am still
testing it(feeling sleepy :)). So i will post the patch, as soon as i
complete testing.

Thanks,
Gokul.

On Dec 18, 2007 12:05 AM, Gokulakannan Somasundaram <gokul007(at)gmail(dot)com>
wrote:

> Hi,
> I made the fix and tested it today. It involved some 10-15 lines of
> code change. I will mail it tomorrow. Feel free to give suggestions on
> making the fix more maintainable.
> I have followed Gregory's advice in the fix - Instead of changing the
> slot_deform_tuple, i have reduced the number of attributes field of the
> HeapTupleHeader(during insertion), so that the trailing nulls are treated
> the same as newly added columns. Thanks Gregory.
> Regarding arrangement of the columns, my take is to leave it to the
> user on the arrangement of the columns. May be we can put some kind of
> tuning hint somewhere in our document on the suggestions. I have made the
> above statement, without thinking about other advantages, if any.
>
>
>
> --
> Thanks,
> Gokul.
> CertoSQL Project,
> Allied Solution Group.
> (www.alliedgroups.com)
>

--
Thanks,
Gokul.
CertoSQL Project,
Allied Solution Group.
(www.alliedgroups.com)