Re: Query optimizer 8.0.1 (and 8.0) - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Query optimizer 8.0.1 (and 8.0)
Date
Msg-id 27032.1107790330@sss.pgh.pa.us
Whole thread Raw
In response to Re: Query optimizer 8.0.1 (and 8.0)  (pgsql@mohawksoft.com)
Responses Re: Query optimizer 8.0.1 (and 8.0)  (pgsql@mohawksoft.com)
List pgsql-hackers
pgsql@mohawksoft.com writes:
> On a very basic level, why bother sampling the whole table at all? Why not
> check one block and infer all information from that? Because we know that
> isn't enough data. In a table of 4.6 million rows, can you say with any
> mathmatical certainty that a sample of 100 points can be, in any way,
> representative?

This is a statistical argument, not a rhetorical one, and I'm not going
to bother answering handwaving.  Show me some mathematical arguments for
a specific sampling rule and I'll listen.
        regards, tom lane


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