Re: NULL saves disk space?

On Wed, Apr 27, 2011 at 5:24 PM, Phoenix Kiula <phoenix(dot)kiula(at)gmail(dot)com> wrote:
> Possibly a dumb question but there isn't much about this.
> http://www.google.com/search?sourceid=chrome&ie=UTF-8&q=postgresql+null+value+disk+space
> I have some BOOLEAN columns. 90% of the cases of the columns is FALSE. Do I
> save disk space by having them as NULL instead of FALSE? So my application
> would have conditional code for NULL and TRUE, instead of FALSE and TRUE.
> Thanks...

Yes, NULL values take no additional space, but the row needs a null
bitmap so it is possible that if this was the only NULL then it could
occupy more space.

If you have multiple columns, then you should use NULLs.

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 Simon Riggs                   http://www.2ndQuadrant.com/
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