Hi Bruce, Here is the db dump. In this db Parent contains only 10 childs of each type which produce a result set of 1000 rows (10 x 10 x 10). Here is the select statement executed...
SELECT Parent.name,ChildA.childID,ChildB.childID,ChildC.childID FROM Parent LEFT OUTER JOIN ChildA ON Parent.parentID=ChildA.parent LEFT OUTER JOIN ChildB ON Parent.parentID=ChildB.parent LEFT OUTER JOIN ChildC ON Parent.parentID=ChildC.parent WHERE Parent.parentID="192168000006101730570950300001" Best regards, Benjamin. -----Original Message----- From: Bruce Snyder [mailto:[EMAIL PROTECTED]] Sent: jeudi 28 mars 2002 7:00 To: Benjamin Voiturier Subject: Re: [castor-dev] Performance Issue JDO (repost sorta) This one time, at band camp, Benjamin Voiturier said: BV>If the database is populated as to have a parent with 100 childA, 100 BV>childB and 100 childC, a select clause like this one returns 1.000.000 BV>rows (100 x 100 x 100). Left outer joins are recursively executed BV>against the result set of the previous left outer join. I see that you're using MySQL. Please use mysqldump to dump the data from your database so that I can run it into one of my databases. Thanks, Bruce -- perl -e 'print unpack("u44", "\?0G)U8V4\@4VYY9&5R\"F)R=6-E0&)S;GED97(N;W)G\"\@\`\`");'
jdotest.sql
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