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* Optimizer question with equivalent joins
@ 2002-06-21 14:26 Dirk Lutzebaeck <lutzeb@aeccom.com>
0 siblings, 1 reply; 2+ messages in thread
From: Dirk Lutzebaeck @ 2002-06-21 14:26 UTC (permalink / raw)
To: pgsql-sql
Hello,
say I have a join which says
t.a = t.b and t.b = t.c
do I need to give the optimizer a hint by saying it more redundantly
t.a = t.b and t.b = t.c and t.c = t.a
or is this just counter productive because there is one more join?
In the real world I have 10-20 equivalent joins which would really
blow up if I have to choose the second option.
Dirk
^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: Optimizer question with equivalent joins
@ 2002-06-21 15:18 Tom Lane <tgl@sss.pgh.pa.us>
parent: Dirk Lutzebaeck <lutzeb@aeccom.com>
0 siblings, 0 replies; 2+ messages in thread
From: Tom Lane @ 2002-06-21 15:18 UTC (permalink / raw)
To: Dirk Lutzebaeck <lutzeb@aeccom.com>; +Cc: pgsql-sql
Dirk Lutzebaeck <lutzeb@aeccom.com> writes:
> say I have a join which says
> t.a = t.b and t.b = t.c
> do I need to give the optimizer a hint by saying it more redundantly
> t.a = t.b and t.b = t.c and t.c = t.a
Not since about 7.0.3 ...
regards, tom lane
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2002-06-21 14:26 Optimizer question with equivalent joins Dirk Lutzebaeck <lutzeb@aeccom.com>
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