RE: Limiting (but not stopping) interactive query by user

[Jim Damato <jdamato@xxxxxxxxxxxxxxxxx>]

I know about Extended Help.  From my last message the paragraph "The Change
Query Attributes (CHGQRYA) command specifies..."  was cut directly from the
Extended Help.

To me that's the source of the ambiguity.  I'm not saying you're wrong, but
the extended help suggests that there's a difference between a query and a
query.  I suppose I could find a nice clean WRKQRY query performing trivial
i/o on a monster table and see if CHGQRYA throttles it.  I don't know
whether the QRYTIMLMT parameter will affect only the opening of the view, as
the text suggests, or also affect the subsequent i/o.

If I find time for a test I'll let you know.

-Jim

-----Original Message-----
From: Mark S. Waterbury [mailto:mark.s.waterbury@xxxxxxx]
Sent: Friday, December 05, 2003 10:57 AM
To: Midrange Systems Technical Discussion
Subject: Re: Limiting (but not stopping) interactive query by user


Hi, Jim:

All query processing in OS/400 eventually invokes a query "engine",
the API *PGM in QSYS named QQQQRY. This is true for SQL,
whether running interactive SQL (STRSQL) or running a compiled
program that uses "embedded" SQL, and for Query Manager/400
queries, and Query/400 *QRYDFNs (RUNQRY), and when using
the OPNQRYF command in CL programs. Most third-party ISV
query tools (like ASC's SEQUEL) also invoke QQQQRY, either
directly, or indirectly (e.g. by using SQL/400 or QM/400, etc.).

QQQQRY is documented under OS/400 Programming, APIs in
the InfoCenter and in the API manuals.

Prompt the CHGQRYA command and press F1=Help, then press
F2=Extended Help to see help text for the entire command. This
text describes affecting the "query optimizer" and other "stuff" that
is all "below" (or "inside") the QQQQRY API.

So, as far as I can tell, values I set using CHGQRYA will apply
to ALL "queries".

Does that help?

Mark S. Waterbury

----- Original Message -----
> From: "Jim Damato" <jdamato@xxxxxxxxxxxxxxxxx>
> To: "'Midrange Systems Technical Discussion'" <midrange-l@xxxxxxxxxxxx>
> Sent: Friday, December 05, 2003 9:15 AM
> Subject: RE: Limiting (but not stopping) interactive query by user
>
> Is CHGQRYA really going to address the problem?
>
> The Change Query Attributes (CHGQRYA) command specifies attributes
> for database queries and database file keyed access path builds,
> rebuilds, and maintenance that are run in a job.  Database queries
> include the open of a SQL view and the running of SQL data
> manipulation statements.
>
> You're talking about AS/400 Query objects generated by WRKQRY, right?
Isn't
> there a potential difference between a query executed by RUNQRY
(regardless
> of interactive vs. batch) and the database queries and database file keyed
> access path builds covered by CHGQRYA?  You could potentially (and should
> ideally) be running queries using existing access paths and just
performing
> normal i/o.  I think this type of query execution is outside the scope of
> CHGQRYA.
>
> I think CHGQRYA will only cover certain RUNQRY scenarios.
>
> -Jim
>
> James P. Damato
> Manager - Technical Administration
> Dollar General Corporation
> <mailto:jdamato@xxxxxxxxxxxxxxxxx>