VMS 6.2, Dec Rdb V6.1-13, Powerhouse 7.10E6

[Peter Bateman]

   Hi John:
 
      Unless you need the data retrieved in index order do not 
      use the VIAINDEX syntax as Bob mention if you do you
      will get an unnecessary ORDER BY.
 
      You can still CHOOSE on columns that are indexed in the database.
      Indeed you can mix indexed columns and non-indexed columns in the CHOOSE.
 
      The version of Oracle/RDB released about a year and a half ago
      had some performance enhancements embedded in it. I can't remember
      the version.
 
      PowerHouse 8 would let you write SQL that most likely be more efficient
      than accessing through QUIZ/QTP access statements.
      The big benefit is that multiple table joins can be done in the database engine
      with one open cursor execution rather than perhaps thousands of open 
      cursors ececutions with a large multi-table QUIZ/QTP.
 
      PowerHouse 7 programmers can sometimes get the DBA to create views 
      that use multiple table joins.
 
  Regards,
  Peter Bateman
  > To: resolutebay at yahoo.com> Subject: Re: VMS 6.2, Dec Rdb V6.1-13, Powerhouse 7.10E6> From: Bob.Deskin at ca.ibm.com> Date: Tue, 22 Apr 2008 11:01:04 -0400> CC: powerh-l-bounces+bob.deskin=ca.ibm.com at lists.sowder.com; powerh-l at lists.sowder.com> > This applies generally to relational support in PowerHouse.> > How much an index will help depends on what the database decides to do. We > do not explicitly use the index in PowerHouse, although we do use the > index to determine sequence (ORDER BY). We send the request to the > database and it decides whether using the index is more efficient. It's > going to depend on how many rows are retrieved, how many rows are in the > table, whether the index is unique or repeating and how long the chains > are, etc. So, as in all cases, I suggest some testing is in order.> > Bob> > > Bob Deskin> Senior Product Manager> Application Development Tools> COGNOS, an IBM company> +1 613-738-1338 ext 7268> bob.deskin at ca.ibm.com> http://powerhouse.cognos.com> > > > > "Penney, John" <resolutebay at yahoo.com> > Sent by: powerh-l-bounces+bob.deskin=ca.ibm.com at lists.sowder.com> 2008-04-22 10:04 am> > To> power-l <powerh-l at lists.sowder.com>> cc> > Subject> VMS 6.2, Dec Rdb V6.1-13, Powerhouse 7.10E6> > > > > > > Powerhouse Listers:> > Working on a system with the above parameters. Yes, not supported, but I > digress. I am analyzing some performance issues and need some advice > regarding CHOOSE on a non-keyed field (column) which one can do because > it's a relational database. Can one expect a significant improvement in > performance if said column was declared as an Index?> > In adhoc tests I have found about a 10% improvement in throughput using a > CHOOSE on a non-Indexed column versus a SELECT. What can I expect if it's > Indexed?> > Would somebody please share with me their experiences in these instances.> > Many thanks!> > JP in IL> Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it > now.-- > = = = = = = = = = = = = = = = = = = = = = = = = = = = => Mailing list: powerh-l at lists.sowder.com> Subscribe: &quot;subscribe&quot; in message body to > powerh-l-request at lists.sowder.com> Unsubscribe: &quot;unsubscribe &lt;password&gt;&quot; in message body to > powerh-l-request at lists.sowder.com> http://lists.sowder.com/mailman/listinfo/powerh-l> This list is closed, thus to post to the list you must be a subscriber.> Add 'site:lists.sowder.com powerh-l' to your search terms to search the > list archive at Google.> > -- > = = = = = = = = = = = = = = = = = = = = = = = = = = = => Mailing list: powerh-l at lists.sowder.com> Subscribe: &quot;subscribe&quot; in message body to powerh-l-request at lists.sowder.com> Unsubscribe: &quot;unsubscribe &lt;password&gt;&quot; in message body to powerh-l-request at lists.sowder.com> http://lists.sowder.com/mailman/listinfo/powerh-l> This list is closed, thus to post to the list you must be a subscriber.> Add 'site:lists.sowder.com powerh-l' to your search terms to search the list archive at Google.
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