On Thu, Apr 28, 2011 at 10:59 PM, Simon Riggs <simon@xxxxxxxxxxxxxxx> wrote: > On Wed, Apr 27, 2011 at 5:24 PM, Phoenix Kiula <phoenix.kiula@xxxxxxxxx> 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. Thanks Simon. (And others for good advice, but that was not my question. I already know using boolean as TRUE/FALSE is sensible. But I have a peculiar reason for asking what I am.) Simon, if I understand you correctly -- more than one column in a row should have NULL for NULL to be useful in saving space? What if in a row there are many columns but only one will be NULL? Thanks -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
