Re: [PERFORM] Posible planner improvement? - Mailing list pgsql-hackers

From Stephen R. van den Berg
Subject Re: [PERFORM] Posible planner improvement?
Date
Msg-id 20080525082133.GB27965@cuci.nl
Whole thread Raw
In response to Re: [PERFORM] Posible planner improvement?  (Decibel! <decibel@decibel.org>)
List pgsql-hackers
Decibel! wrote:
>For reference, the original query as posted to -performance:

>select * from t1, t2 where t1.id > 158507 and t1.id = t2.id;

>That took > 84 minutes (the query was a bit longer but this is the  
>part that made the difference) after a little change the query took  
>~1 second:

Just out of curiosity, would predefining the order of join have solved
the issue, as in:

a. select * from t1 join t2 using(id) where t1.id > 158507;
vs.
b. select * from t2 join t1 using(id) where t1.id > 158507;

I'd expect a to be faster than b, is it?
-- 
Sincerely,                                                          srb@cuci.nl          Stephen R. van den Berg.
"Technology is stuff that doesn't work yet."   --  Bran Ferren
"We no longer think of chairs as technology."  --  Douglas Adams


pgsql-hackers by date:

Previous
From: Hans-Juergen Schoenig
Date:
Subject: DROP ROLE dependency tracking ...
Next
From: Hans-Juergen Schoenig
Date:
Subject: Re: [PATCHES] WITH RECURSIVE patch V0.1