Re: CQE, SQE and QAQQINI

[Charles Wilt <charles.wilt@xxxxxxxxx>]

Elvis,

Have you any hands on experience in a BPCS shop?

It would seem to me, that some combination of additional EVI and
regular indexes should allow the SQE to perform as fast as the CQE
would have using S/O logicals.

In other words, while a "quick fix" for a BPCS shop would be to set
IGNORE_DERIVED_INDEX= *NO, with a little work a BPCS shop could take
advantage of SQE.

Do you agree/disagree?

Charles

On Fri, Aug 28, 2009 at 10:43 AM, Elvis
Budimlic<ebudimlic@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
> This is the only known detractor I have seen to making the switch. CQE can
> use keyed S/O LFs and since in BPCS keys queries were written with these S/O
> LFs in mind, they're tightly integrated and perform well. SQE cannot use S/O
> LFs and even if an equivalent full sql index exists, it won't perform as
> well (it'll come close). If you don't build full sql indexes (or non-S/O
> keyed LFS) though, CQE will beat the pants off of SQE, since SQE will have
> to default to table scans in that case.
>
> That said, IGNORE_DERIVED_INDEX is a default on V6R1 and I have seen many
> fantastic results on customers machines. One guy even got a promotion after
> he made the switch (no kidding; system performance went up dramatically and
> CPU usage dropped dramatically).
>
> Elvis
>
> Celebrating 11-Years of SQL Performance Excellence on IBM i, i5/OS and
> OS/400
> www.centerfieldtechnology.com
>
>
> -----Original Message-----
> Subject: Re: CQE, SQE and QAQQINI
>
> Would it concern you that a major software house sides with your boss?
> http://www-912.ibm.com/n_dir/nas4apar.nsf/c79815e083182fec862564c00079d117/2
> ed784e875e77a4586257490003c6d39?OpenDocument
>
> ********************************************************
>  SQL Performance
> ********************************************************
> --------------------------------------------------------
> Affected BPCS versions:  V6.x, V8.x
> --------------------------------------------------------
> Infor recommends the following QAQQINI file setting to
> be activated for support with R610:
> QAQQINI IGNORE_DERIVED_INDEX  *NO
>
> The BPCS and ERPLX database contains large numbers of
> Select/Omit logical files and if this option is not set,
> these logical files will be ignored when the SQL Optimzer
> selects logical files to run a given query. This can cause
> poor performance.
>
> The following command shows how to setup this option...
>
>
> Rob Berendt
>
>
>
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