On Mon, Jun 25, 2007 at 09:51:30AM +0900, ssoo@xxxxxxxxxxxxxxx wrote: > Real type takes 4 byte storage sizes and double precision takes 8 bytes. > I altered a data type from double precision to real and vacuumed DB. Altering a column's type rewrites the table so vacuuming afterward shouldn't be necessary. > But PostgreSQL's data disk usage did not shrinked. > And pg_dump size remained same. > It seems that real takes 8 byte storage sizes. Real is 4 bytes but other columns' alignment requirements might result in no space being saved. -- Michael Fuhr
