Am Freitag, 3. März 2006 11:03 schrieb Paul Mackay: > I've created a table like this : > CREATE TABLE tmp_A ( > c "char", > i int4 > ); > > And another one > CREATE TABLE tmp_B ( > i int4, > ii int4 > );
> The end result is that the physical size on disk used by table tmp_A is > exactly the same as table tmp_B (as revealed by the pg_relation_size > function) ! An int4 field is required to be aligned at a 4-byte boundary internally, so there are 3 bytes wasted between tmp_A.c and tmp_A.i. If you switch the order of the fields you should see space savings. (Note, however, that the per-row overhead is about 32 bytes, so you'll probably only save about 10% overall, rather than the 37.5% that one might expect.) -- Peter Eisentraut http://developer.postgresql.org/~petere/ ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
