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Re: Known Bottlenecks - Mailing list pgsql-performance

From Grzegorz Jaśkiewicz
Subject Re: Known Bottlenecks
Date
Msg-id 2f4958ff0910190646n6dfc8d2fr4e851053a50a0a41@mail.gmail.com
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In response to Known Bottlenecks  (Vikul Khosla <vkhosla@gridsolv.com>)
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On Mon, Oct 19, 2009 at 2:43 PM, Vikul Khosla <vkhosla@gridsolv.com> wrote:
Jeff, Robert, I am still working on the "low cardinality" info you requested. Please bear with me.

In the meantime, have the following question:

Are there known "scenarios" where certain types of SQL queries perform worse in PG
than they do in ORacle ?

For example, I have observed some discussion where MAX (In Oracle) was replaced with ORDER/DESC/LIMIT
in PG.

I realize this is a loaded question, but it would be great if any of you would share some observed
generalities in this context.

other one would be SELECT .. WHERE foo IN (SELECT ...);   (use join instead, and in case of NOT IN , use left join).



--
GJ

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