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Re: [HACKERS] selectivity calculation for or_clause is wrong ? - Mailing list pgsql-hackers

From Tom Lane
Subject Re: [HACKERS] selectivity calculation for or_clause is wrong ?
Date
Msg-id 17571.933445570@sss.pgh.pa.us
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In response to RE: [HACKERS] selectivity calculation for or_clause is wrong ?  ("Hiroshi Inoue" <Inoue@tpf.co.jp>)
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"Hiroshi Inoue" <Inoue@tpf.co.jp> writes:
>>>> Why is valid_or_clause(clausenode) necessary ?
>> 
>> Looks like a waste of cycles to me too.
>
> It's not only a waste of cycles.
> [ snip ]
> rows of each plan  261 : 773 : 1274  not =  1 : 2 : 3.
> It's nearly = 1 :3 :5.
> elements of or_clause except its first element are evaluated 
> twice and the results are accumlated.

BTW, I fixed this...
        regards, tom lane

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