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From Christian Haul <h...@dvs1.informatik.tu-darmstadt.de>
Subject Re: big ESQL performance problem - this one's weird
Date Tue, 04 Mar 2003 16:26:01 GMT
On 04.Mar.2003 -- 05:11 PM, Leszek Gawron wrote:
> On wto, mar 04, 2003 at 05:05:37 +0100, Torsten Curdt wrote:
> > >while trying to test the esql:get-object I have run just this:
> > ><esql:execute-query>
> > >	<esql:query>
> > >		SELECT * from kontrah</esql:query>
> > >		<esql:results>
> > >			<esql:row-results><a></a></esql:row-results>
> > >		</esql:results>
> > ></esql:execute-query>
> > >
> > >The execution time does not differ much from first case even though I do 
> > >not do any esql-getXXX.
> > 
> > Not weird at all!
> > You are still looping through the ResultSet (row-results)
> Yes but some people in this discussion blamed the amount of SAX events to
> handle for bad performance. So now it is clear that it's the rowset traversal
> that consumes so much CPU, but still why? I'm not skilled in JDBC. The only
> difference I can tell from Squirell SQL client is that it does not use prepared
> statements.

If you have a <esql:parameter .../> in your query, esql uses a
prepared statement. Otherwise it won't.

Another interesting point would be to restrict the data retrieved by
using "select some_column from kontrah" instead of "select * from kontrah" 
Might have a performance impact depending on how smart the driver is.

Other things that might apply are options to the jdbc driver on cache
/ transfer size, isolation modes etc. 

	Chris.
-- 
C h r i s t i a n       H a u l
haul@informatik.tu-darmstadt.de
    fingerprint: 99B0 1D9D 7919 644A 4837  7D73 FEF9 6856 335A 9E08

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