On Fri, Dec 23, 2005 at 11:04:50AM -0500, Tom Lane wrote: > It's not that easy --- in the MVCC world there simply isn't a unique > count that is the right answer for every observer. But the idea of > packaging a count(*) mechanism as an index type seems like it might be > a good one. I don't think the planner objection need be taken too > seriously: we already have a good big wart in there for recognizing > MIN/MAX indexability, and this sort of transformation would fit pretty > naturally with what's already done in planagg.c.
AFAICS two big problems with using an index type: 1. The index isn't told when the tuple is deleted. 2. The server expects to be able to lookup an index. Other than that... -- Martijn van Oosterhout <kleptog@svana.org> 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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