Michael Fuhr <mike@xxxxxxxx> writes: > On Mon, Jun 25, 2007 at 09:51:30AM +0900, ssoo@xxxxxxxxxxxxxxx wrote: >> 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. Even with no other columns involved, if you're on a machine with MAXALIGN = 8 (which includes all 64-bit platforms as well as some that aren't), the row width won't shrink. As for that pg_dump measurement, the text form isn't going to get smaller ... "1.2" is the same length as "1.2". regards, tom lane
