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Re: [pgsql-hackers] Group-count estimation statistics

This is a discussion on Re: [pgsql-hackers] Group-count estimation statistics within the pgsql Hackers forums, part of the PostgreSQL category; --> Josh Berkus <josh@agliodbs.com> writes: > Why 10? I'd think we could come up with a slightly less arbitrary number, ...


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Old 04-11-2008, 03:30 AM
Tom Lane
 
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Default Re: [pgsql-hackers] Group-count estimation statistics

Josh Berkus <josh@agliodbs.com> writes:
> Why 10? I'd think we could come up with a slightly less arbitrary number,


Well, it's probably within an order of magnitude of the right thing ;-).
We know we don't want 1, but 100 seems awfully optimistic.

If someone can come up with a more defensible number then I'm all for
it. Greg Stark's thought about a power correction seemed interesting
too, though again far too optimistic to trust without some good math
to back it up.

regards, tom lane

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