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Posible planner improvement?

From: Albert Cervera Areny <albert(at)sedifa(dot)com>
To: pgsql-performance(at)postgresql(dot)org
Subject: Posible planner improvement?
Date: 2008-05-21 10:28:47
Message-ID: 200805211228.48248.albert@sedifa.com (view raw or flat)
Thread:
Lists: pgsql-performance
I've got a query similar to this:

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:

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

The change is pretty simple and it seems (note I don't have a clue on how the 
planner works) it'd be possible for the planner to make this assumption 
itself. Do you think it is really feasible/appropiate?

 

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Next:From: Frank DekervelDate: 2008-05-21 10:37:22
Subject: Re: "append" takes a lot of time in a query
Previous:From: Craig RingerDate: 2008-05-21 08:00:46
Subject: Re: Varchar pkey instead of integer

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