Re: CQE, SQE and QAQQINI

[Jim Essinger <dilbernator@xxxxxxxxx>]

Is it important to delete the logical file first?  Can you build the index,
then delete and recreate the logical?  Does the existence of the logical
impair the proper creation of the index?

This is a very informative thread!  Thanks all

Jim

On Fri, Aug 28, 2009 at 7:39 AM, Birgitta Hauser <Hauser@xxxxxxxxxxxxxxx>wrote:

> The main problem may be that there are access paths (for example in logical
> files with select/omit clauses) that are currently used by the CQE but
> ignored by the SQE.
> In this way SQL statement that perform well in the current environment will
> run very slowly.
>
> The best way is to search your logical files with keys and select omit
> clauses. Delete the logical files, create indexes for the key information
> and recreate your logical files. In this way SQL/SQE can use the new
> indexes
> and native I/O can use the DDS described logical files. Deleting and
> recreating the logical files is necessary, because a logical file can share
> access path with an SQL index, but a SQL index cannot share access path
> with
> a logical file (because of the larger default page size).
>
> Mit freundlichen Grüßen / Best regards
>
> Birgitta Hauser
>
> "Shoot for the moon, even if you miss, you'll land among the stars." (Les
> Brown)
> "If you think education is expensive, try ignorance." (Derek Bok)
> "What is worse than training your staff and losing them? Not training them
> and keeping them!"
>
> -----Ursprüngliche Nachricht-----
> Von: midrange-l-bounces@xxxxxxxxxxxx
> [mailto:midrange-l-bounces@xxxxxxxxxxxx] Im Auftrag von Jonathan Mason
> Gesendet: Friday, 28. August 2009 14:54
> An: midrange-l@xxxxxxxxxxxx
> Betreff: CQE, SQE and QAQQINI
>
> We have an SQL statement that uses the CQE and runs extremely slowly.  In
> test I have created an Encoded Vector Index and also changed a local
> version
> of the QAQQINI file so that the IGNORE_DERIVED_INDEXES is set to *YES.
>
> With these settings the SQL runs extremely fast, however the powers that be
> are nervous about changing a global setting that would potentially affect
> all SQL requests.
>
> I've spent the morning talking to my friend, Google, and searching through
> the Midrange.com archives, and everything I have seen indicates that using
> the SQE is better than using the CQE.
>
> With this in mind, are there any pitfalls in changing the
> IGNORE_DERIVED_INDEXES setting to *YES?  Should we expect all SQL to run at
> least as fast as does currently or is there a risk that some SQL processes
> could run slower?
>
> Thanks in advance
>
> Jonathan
>
>
>
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