RE: Setting parms in CL for PF - follow up

[CWilt@xxxxxxxxxxxx]

James,

Is the 32000 pulled out of the air?  You get the best performance when the
#records fits into a page/block.

I'd have to look up the pertinent info, as its not something I usually need
to be concerned about.

I suppose you'd usually be doing more updates than writes.  If you'd be
doing more writes, it might be good to skip the initial chain to the file to
see if the record is there.  Just try writing it and if you get an error
then you can do a chain and update ( i.e. exception only ).

How many records will usually require updates and how big are the records?
Since you are only looking at 5 fields, I'd consider a logical or an
index/view made up of only those 5 fields and the keys.  You'd be moving a
lot less data from the file to the program buffer then when you end up not
needing to update the record.  (Note SQL would call this index only access.)

I'd also consider getting rid of the chain an just doing READs sequentially
on each file letting my program keep the keys in sync.

Finally, if you can add indexes to the input file, I'd strongly be looking
at an SQL solution (particularly if the index only access mentioned above.)


HTH,
Charles





> -----Original Message-----
> From: James R. Newman, CDP [mailto:newman400@xxxxxxxxxxx]
> Sent: Friday, October 15, 2004 12:58 PM
> To: Midrange L
> Cc: vhamberg@xxxxxxxxxxx
> Subject: Setting parms in CL for PF - follow up
> 
> 
> Thanks for the great input on changing the CL for updating 
> this big file.  
> 
> Here's the changes I've made and plan to run over the 
> weekend.  Would someone tell me if this looks right?  FILE1 
> is the sequential input and FILE2 is the indexed output with 
> 1 logical:
> 
> 
> CHGLF   FILE(FILE2LF)  MAINT(*DLY)
> 
> OVRDBF  FILE(FILE1) NBRRCDS(32000)  SEQONLY(*YES)
> OVRDBF  FILE(FILE2) FRCRATIO(32000)
> CALL  PGM(BIGFREAKINUPDATE)
> 
> CHGLF   FILE(FILE2LF)  MAINT(*IMMED)
> 
> 
> TIA.
> 
> 
> James R. Newman, CDP
> --
> 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: http://lists.midrange.com/mailman/listinfo/midrange-l
> or email: MIDRANGE-L-request@xxxxxxxxxxxx
> Before posting, please take a moment to review the archives
> at http://archive.midrange.com/midrange-l.
>