On Dec 21, 2003, at 11:47 PM, Tom Lane wrote:
> "Steven D.Arnold" <stevena@neosynapse.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
