On Wed, Mar 01, 2006 at 05:24:03PM +0100, denis@xxxxxxxxxxx wrote: > I made some tests with three different types: > > numeric, text and a specialized type written in c. > > The tests were made with 20 digit codes. <snip> > The results were not as expected. > > I was expecting these theoretical results: > mycode: 1.000.000 of records => 12.000.000 bytes > numeric: 1.000.000 of records => 18.000.000 bytes > text: 1.000.000 of records => 24.000.000 bytes > > That is the final size of the table with the text data type to be the > double of mycode type. > > The real results were: > mycode: 1.000.000 of records => 65.159.168 bytes > numeric: 1.000.000 of records => 74.895.702 bytes > text: 1.000.000 of records => 77.340.672 bytes > > The "text" table is only 16% larger than mycode one (I was expecting 100%!). You're missing the per-tuple overhead which is approximatly 28 bytes. Once you take alignment into account, it's not surprising the results are closer than you expected. 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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