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> Ian Turner <vectro@pipeline.com> writes:
> > Don't variable-length records incur a performance overhead?
>
> Only to the extent that the system can't cache offset information for
> later columns in that table. While someone evidently once thought that
> was worthwhile, I've never seen the column-access code show up as a
> particularly hot spot in any profile I've run. I doubt you could
> actually measure any difference, let alone show it to be important
> enough to be worth worrying about.
It clearly is a hot-spot. That monster macro, fastgetattr(), in
heapam.h is in there for a reason. It accounts for about 5% for straight
sequential scan case, last I heard from someone who ran a test.
--
Bruce Momjian | http://candle.pha.pa.us
pgman@candle.pha.pa.us | (610) 853-3000
+ If your life is a hard drive, | 830 Blythe Avenue
+ Christ can be your backup. | Drexel Hill, Pennsylvania 19026
