There are two system jobs that build the IDX in the background, two at time, one per job.
QSYSARB4
QSYSARB5
Many other variables come into play.
Type of DASD - SSH or HDD
CPU
Memory
In our environment, most LF are always in use, thus we could never run a CL like this.
Another reason we run Reorg while active.
Paul
-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of D*B
Sent: Friday, October 20, 2017 3:39 PM
To: Midrange Systems Technical Discussion
Subject: Re: Questionable practice in file handling in CL
<Duane>
I'm looking at a CL that:
1. deletes the 6 logicals on a single physical file 2. deletes the physical file 3. recreates the physical from the DDS 4. runs an RPG program that writes (20k to 30k) records to the physical 5. recreates the 6 logicals
The only explanation I can come up with is that it once was thought that the system would be faster if the logicals were built one at a time after the physical was built rather than during the running of the RPG program.
Does anybody have stats to back this up.
</Duane>
... it all depends and so you would have to benchmark your own stats - if runtime would be long enough.
We've had the situation that deleting 30 millions of records of a file with
900 million recordsm having multiple logicals (all SQL DDL defined, but this doesn't make much diffrence) was terrible slow (taking hours). Best was:
changing all lfs to mainte deferred, making the delete and afterwards changing all lfs back to maint *immed in parallel jobs - this was cutting down hours to minutes, but for tables with only a few millions of records, the diffrence would be neglectable or zero +/- some small number.
For very small tables (20 k to 30 k - lol) it would be hard to measure some diffrence at all. Make it simple or leave it as it is, if you wouldnT have to touch it anyway.
D*B
--
This is the Midrange Systems Technical Discussion (MIDRANGE-L) mailing list To post a message email: MIDRANGE-L@xxxxxxxxxxxx To subscribe, unsubscribe, or change list options,
visit:
https://lists.midrange.com/mailman/listinfo/midrange-l
or email: MIDRANGE-L-request@xxxxxxxxxxxx Before posting, please take a moment to review the archives at
https://archive.midrange.com/midrange-l.
Please contact support@xxxxxxxxxxxx for any subscription related questions.
Help support midrange.com by shopping at amazon.com with our affiliate link:
http://amzn.to/2dEadiD
midrange.com
