Try and be very specific what it is you are doing and why. For example - why are you using SQL? Are you doing SQL queries via the TCL prompt or using a client tool on Windows? What is the query? What do you mean by 'optimize the performance'...Etc., etc.
UV has two query languages and a single database engine. Meaning, there is should be no difference in respect to the utilisation of indices. Clearly, if you have having to do a SQL query that requires unnest or join operation - then indices may not be significant in improving performance. Try adding the EXPLAIN keyword to your query give some clue to what (if any) query optimisation is going on...including of indices. Being unfamiliar with SQL can also be part of the issue...it's extremely powerful and can be difficult to master. Hence not for the faint hearted - especially if the query is complex and/or your table/schema is also complex. You can perform queries which can have a profound impact on the system performance, if incorrectly structured. Indexes aren't the answer to every optimisation issue. There needs to be a balance between cost versus benefit. It depends on the nature and utilisation of the file in question. Therefore: one really needs to optimise one's own SQL skills...not an easy ask...then optimise your query in order maximise expected query performance. Or perhaps avoid SQL, if it is not really necessary to utilise it. Regards, David -----Original Message----- From: u2-users-boun...@listserver.u2ug.org [mailto:u2-users-boun...@listserver.u2ug.org] On Behalf Of Allen Egerton Sent: Saturday, 28 July 2012 1:35 AM To: .U2 List Subject: [U2] Universe; SQL; Indexes?? (10.3.7 on Windows) I'm using SQL to query Universe 10.3.7 data files, (ANSi-compliant and non-compliant formats) and indexing the files to try to optimize the performance seems in some cases to have little or no effect. I'm pretty clear on index behavior with Universe's native query language, but SQL is somewhat unfamiliar to me, and I'm wondering why I'm not getting the behavior I expect. Can anyone either point me to reference material on this, or offer thoughts based on experience? Thank you. -- Allen Egerton; aeger...@pobox.com ************** IMPORTANT MESSAGE ***************************** This e-mail message is intended only for the addressee(s) and contains information which may be confidential. If you are not the intended recipient please advise the sender by return email, do not use or disclose the contents, and delete the message and any attachments from your system. Unless specifically indicated, this email does not constitute formal advice or commitment by the sender or the Commonwealth Bank of Australia (ABN 48 123 123 124) or its subsidiaries. We can be contacted through our web site: commbank.com.au. If you no longer wish to receive commercial electronic messages from us, please reply to this e-mail by typing Unsubscribe in the subject line. ************************************************************** _______________________________________________ U2-Users mailing list U2-Users@listserver.u2ug.org http://listserver.u2ug.org/mailman/listinfo/u2-users
