On Fri, Apr 11, 2008 at 04:02:36PM -0400, Chris Hoover wrote: > I'm doing some testing on how to decrease our database size as I work on a > partitioning scheme. > > I have found that if I have the database store all empty strings as nulls, I > get a significant savings over saving them as blank strings (i.e. ''). > Below is an example of savings I am seeing for the same table: > > In my test case, storing empty strings give me a table size of 20,635,648 > Storing empty strings as nulls gives me a table size of: 5,742,592. > > As you can see, storing empty strings as nulls is saving me approximately > 72% on this table. So, I am wanting to understand what Postgres is doing > differently with the nulls. Would someone kindly enlighten me on this. > > (P.S. I am using a nullif(trim(column),'') in my partition and view rules to > store the nulls, and coalesce(column,'') to give my application the data > back without nulls.) > > Thanks, > > Chris > > PG 8.1 >
PostgreSQL stores NULLs differently. This accounts for your space difference. If you application can work with NULLs instead of '' (not the same thing), go for it. Cheers, Ken -- Sent via pgsql-admin mailing list (pgsql-admin@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-admin
