| From: | "Jonah H(dot) Harris" <jonah(dot)harris(at)gmail(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: Optimization rules for semi and anti joins |
| Date: | 2009-02-11 01:12:56 |
| Message-ID: | 36e682920902101712w3bc22c18t703f5b2d84e21f94@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Tue, Feb 10, 2009 at 8:09 PM, Jonah H. Harris <jonah(dot)harris(at)gmail(dot)com>wrote:
> On Tue, Feb 10, 2009 at 3:10 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>
>> I wrote (in response to Kevin Grittner's recent issues):
>> > Reflecting on this further, I suspect there are also some bugs in the
>> > planner's rules about when semi/antijoins can commute with other joins;
>>
>> After doing some math I've concluded this is in fact the case. Anyone
>> want to check my work?
>
>
> FWIW, the logic looks correct to me.
Cripes! I just had an idea and it looks like the buggers beat me to it :(
http://www.google.com/patents?id=4bqBAAAAEBAJ&dq=null+aware+anti-join
--
Jonah H. Harris, Senior DBA
myYearbook.com
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