RE: DB/2 index updates

midrange-l-request@xxxxxxxxxxxx wrote:

>   1. Re: DB/2 index updates (John Ross)
>
> From the help on V5R2
>
>*IMMED

For anyone interested, the whole confusion came from a temporary insanity 
involving an unrelated problem. I was looking at access path updates to figure 
a way to solve something I know I have to do in the future, and this seemed a 
way to get my mind off the other mess for a while.

Here's the deal on *IMMED, etc.:

There's an element of counterintuitiveness in this. If you don't think 
correctly at the start, you get far off-track. Where I went wrong was in 
mistakenly thinking about what *DLY maint meant -- i.e., when could it ever be 
in effect if access path maintenance was in fact immediate? How could updates 
to key values occur if no program was running against the file?

>From the help text: "*DLY: The maintenance of the access path is delayed until 
>the member is opened for use." That wording allows (kind of incorrect) 
>inference that keys can somehow be modified while the member is _NOT_ open for 
>use. If no program has the member open, how can any updates ever occur?

The wording _could_ have been more like "The maintenance of the access path is 
delayed until the _access path_ is opened for use."

By specifying 'K'eyed access in my test program, the keyed access path is 
opened for use, thereby causing immediate maintenance. When the program 
specifies non-keyed access, an arrival-sequence access path is used an 
*DLY/*REBLD works as expected. Alternatively, if there are multiple keyed 
access paths, the program could open keyed access path #1 and update the key 
field for keyed access path #2; *DLY/*REBLD would then be effective for access 
path #2.

A new day, clarity and sanity have returned. Amazing how far a mistaken thought 
can take you.

Tom Liotta

-- 
Tom Liotta
The PowerTech Group, Inc.
19426 68th Avenue South
Kent, WA 98032
Phone  253-872-7788 x313
Fax    253-872-7904
http://www.powertech.com


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