On Fri, Mar 03, 2006 at 11:03:24AM +0100, Paul Mackay wrote: > 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) ! Given that a "char" field is supposed to be 1 byte in size and a > int4 4 bytes, shouldn't the tmp_A use a smaller disk space ? Or is it that > any value, whatever the type, requires at least 4 bytes to be stored ? Alignment. An int4 value must start on a multiple of 4 offset, so you get three bytes of padding. If you put the int4, then the char it should work better. Although whole rows have alignment requirements too... Have a nice day, -- Martijn van Oosterhout <kleptog@xxxxxxxxx> http://svana.org/kleptog/ > Patent. n. Genius is 5% inspiration and 95% perspiration. A patent is a > tool for doing 5% of the work and then sitting around waiting for someone > else to do the other 95% so you can sue them.
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