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Hi John:<BR>
<BR>
Unless you need the data retrieved in index order do not <BR>
use the VIAINDEX syntax as Bob mention if you do you<BR>
will get an unnecessary ORDER BY.<BR>
<BR>
You can still CHOOSE on columns that are indexed in the database.<BR>
Indeed you can mix indexed columns and non-indexed columns in the CHOOSE.<BR>
<BR>
The version of Oracle/RDB released about a year and a half ago<BR>
had some performance enhancements embedded in it. I can't remember<BR>
the version.<BR>
<BR>
PowerHouse 8 would let you write SQL that most likely be more efficient<BR>
than accessing through QUIZ/QTP access statements.<BR>
The big benefit is that multiple table joins can be done in the database engine<BR>
with one open cursor execution rather than perhaps thousands of open <BR>
cursors ececutions with a large multi-table QUIZ/QTP.<BR>
<BR>
PowerHouse 7 programmers can sometimes get the DBA to create views <BR>
that use multiple table joins.<BR>
<BR>
Regards,<BR>
Peter Bateman<BR>
<BR><BR>> To: resolutebay@yahoo.com<BR>> Subject: Re: VMS 6.2, Dec Rdb V6.1-13, Powerhouse 7.10E6<BR>> From: Bob.Deskin@ca.ibm.com<BR>> Date: Tue, 22 Apr 2008 11:01:04 -0400<BR>> CC: powerh-l-bounces+bob.deskin=ca.ibm.com@lists.sowder.com; powerh-l@lists.sowder.com<BR>> <BR>> This applies generally to relational support in PowerHouse.<BR>> <BR>> How much an index will help depends on what the database decides to do. We <BR>> do not explicitly use the index in PowerHouse, although we do use the <BR>> index to determine sequence (ORDER BY). We send the request to the <BR>> database and it decides whether using the index is more efficient. It's <BR>> going to depend on how many rows are retrieved, how many rows are in the <BR>> table, whether the index is unique or repeating and how long the chains <BR>> are, etc. So, as in all cases, I suggest some testing is in order.<BR>> <BR>> Bob<BR>> <BR>> <BR>> Bob Deskin<BR>> Senior Product Manager<BR>> Application Development Tools<BR>> COGNOS, an IBM company<BR>> +1 613-738-1338 ext 7268<BR>> bob.deskin@ca.ibm.com<BR>> http://powerhouse.cognos.com<BR>> <BR>> <BR>> <BR>> <BR>> "Penney, John" <resolutebay@yahoo.com> <BR>> Sent by: powerh-l-bounces+bob.deskin=ca.ibm.com@lists.sowder.com<BR>> 2008-04-22 10:04 am<BR>> <BR>> To<BR>> power-l <powerh-l@lists.sowder.com><BR>> cc<BR>> <BR>> Subject<BR>> VMS 6.2, Dec Rdb V6.1-13, Powerhouse 7.10E6<BR>> <BR>> <BR>> <BR>> <BR>> <BR>> <BR>> Powerhouse Listers:<BR>> <BR>> Working on a system with the above parameters. Yes, not supported, but I <BR>> digress. I am analyzing some performance issues and need some advice <BR>> regarding CHOOSE on a non-keyed field (column) which one can do because <BR>> it's a relational database. Can one expect a significant improvement in <BR>> performance if said column was declared as an Index?<BR>> <BR>> In adhoc tests I have found about a 10% improvement in throughput using a <BR>> CHOOSE on a non-Indexed column versus a SELECT. What can I expect if it's <BR>> Indexed?<BR>> <BR>> Would somebody please share with me their experiences in these instances.<BR>> <BR>> Many thanks!<BR>> <BR>> JP in IL<BR>> Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it <BR>> now.-- <BR>> = = = = = = = = = = = = = = = = = = = = = = = = = = = =<BR>> Mailing list: powerh-l@lists.sowder.com<BR>> Subscribe: &quot;subscribe&quot; in message body to <BR>> powerh-l-request@lists.sowder.com<BR>> Unsubscribe: &quot;unsubscribe &lt;password&gt;&quot; in message body to <BR>> powerh-l-request@lists.sowder.com<BR>> http://lists.sowder.com/mailman/listinfo/powerh-l<BR>> This list is closed, thus to post to the list you must be a subscriber.<BR>> Add 'site:lists.sowder.com powerh-l' to your search terms to search the <BR>> list archive at Google.<BR>> <BR>> -- <BR>> = = = = = = = = = = = = = = = = = = = = = = = = = = = =<BR>> Mailing list: powerh-l@lists.sowder.com<BR>> Subscribe: &quot;subscribe&quot; in message body to powerh-l-request@lists.sowder.com<BR>> Unsubscribe: &quot;unsubscribe &lt;password&gt;&quot; in message body to powerh-l-request@lists.sowder.com<BR>> http://lists.sowder.com/mailman/listinfo/powerh-l<BR>> This list is closed, thus to post to the list you must be a subscriber.<BR>> Add 'site:lists.sowder.com powerh-l' to your search terms to search the list archive at Google.<BR><BR><br /><hr />You could win $1000 a day, now until May 12th, just for signing in to Windows Live Messenger. <a href='http://g.msn.ca/ca55/211' target='_new'>Check out SignInAndWIN.ca to learn more!</a></body>
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