| From: | Steven D(dot)Arnold <stevena(at)neosynapse(dot)net> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | pgsql-general <pgsql-general(at)postgresql(dot)org> |
| Subject: | Re: bug in query planning? |
| Date: | 2003-12-22 17:36:09 |
| Message-ID: | 547BEBA6-34A5-11D8-96F2-000A95BA4396@neosynapse.net |
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| Thread: | |
| Lists: | pgsql-general |
On Dec 21, 2003, at 11:47 PM, Tom Lane wrote:
> "Steven D.Arnold" <stevena(at)neosynapse(dot)net> writes:
>> Query (2) below is the same query, but we reverse the order of the
>> tables. It's obviously not quite the same query semantically, even
>> though in my case it should always produce the same result.
>
> Since it is in fact not the same query, I'm unclear on why you expect
> it to produce the same plan.
What I expect is for both queries to use the index on the messages
table! Why is it not doing that?
> FWIW, I believe that 7.4 will recognize that (1) and (3) are
> semantically equivalent.
I will try 7.4 and report back.
steve
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