Hi! I wanted to try the new join algorithm you mentioned and tried "diagnose new join on" with the new 7.4.3 Build 25 on W2K, but I just get an error. Is there something wrong with the statement or is it only available from CVS Builds? Thanks! (Gerald)
----- Original Message ----- From: Becker, Holger To: '[EMAIL PROTECTED]' ; Knappke, Christian Cc: [EMAIL PROTECTED] Sent: Wednesday, June 18, 2003 9:59 AM Subject: RE: Is performance really this bad?! Experiences, PLEASE! [EMAIL PROTECTED] wrote: > > The ORDER BY is senseless with unique Forms.Title and > Kiosks.Name. But it > tells the database to perform it anyway, thus the "RESULT IS > COPIED" and a > lot of temp space usage and sort activity is necessary. > > I didn't realise that a join will automatically order it too! > I guess that > makes sense. Unfortunately, I need the ordering done by > Upper case - for > next version I will add UpperTitle and UpperName columns that are > automatically updated, but I'm stuck without them at the moment. > I guess as this is a select query, there is no way to get rid of the > "result is copied" ie keep it all in memory? One remark to the "result is copied" and the join in SAP DB. Until now the join algorithm always results in a physically build result table. So the explain of the join will also shows "result is copied" without the order by clause. Additionally every single join step creates an intermediate result set which exists until the next join step. With version 7.4.4 SAP DB will introduce a additionally new join implementation without those temporary intermediate result. We hope that this will reduce i/o and temp page consumption of the join. The new algorithm is still in beta and test phase and have to be manually activated with the command "diagnose new join on". Kind regards, Holger SAP Labs Berlin _______________________________________________ sapdb.general mailing list [EMAIL PROTECTED] http://listserv.sap.com/mailman/listinfo/sapdb.general _______________________________________________ sapdb.general mailing list [EMAIL PROTECTED] http://listserv.sap.com/mailman/listinfo/sapdb.general
