Re: [HACKERS] selectivity calculation for or_clause is wrong ?

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: "Hiroshi Inoue" <Inoue(at)tpf(dot)co(dot)jp>
Cc: "pgsql-hackers" <pgsql-hackers(at)postgreSQL(dot)org>
Subject: Re: [HACKERS] selectivity calculation for or_clause is wrong ?
Date: 1999-07-31 18:26:10
Message-ID: 17571.933445570@sss.pgh.pa.us
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"Hiroshi Inoue" <Inoue(at)tpf(dot)co(dot)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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