× The internal search function is temporarily non-functional. The current search engine is no longer viable and we are researching alternatives.
As a stop gap measure, we are using Google's custom search engine service.
If you know of an easy to use, open source, search engine ... please contact support@midrange.com.



You might want to check whether the pool where this job runs is using expert cache - has to be a shared pool for this - can be *BASE. You check this in WRKSYSSTS, the column that says *FIXED or *CALC. Expert cache is *CALC. Your mileage may vary, since the action EC takes is based on overall I/O patterns - completely sequential will result in larger transfers from disk to main memory - up to a max of 128K instead of the 4K used for DDS-created files. Since you will be using keyed access for FILE2, there might be random access. This could be made mostly sequential in terms of physical I/O, I think, by having FILE1 sorted according to the order of FILE2. There is a concept called "locality" involved here. Nonetheless, expert cache will choose the best I/O request size for you.

If you have enough main memory, then bringing an entire file into a pool using SETOBJACC can be very beneficial - the actual reading and updates will use minimal true I/O. But I doubt this is feasible with this large a pair of files. If you do have room for one file, make it FILE2, I think.

NBRRCDS and SEQONLY affect different aspects of the process. NBRRCDS is related to physical disk I/O. It might be that, since the largest single block size that the I/O can do at a time is 128K, there might be no advantage to more records than will fit in 128K. But this is worth trying with different values. Remember, this is getting data from auxiliary storage (physical disk) to the database buffers, not the program buffers.

SEQONLY manages the movement of data between the database buffers and the program buffers. Once records are in the program buffers, processing is very fast. So maximizing the amount of data in these buffers is beneficial, IIRC. The limit is like 32K. You need to be sure your pool has enough room for the internal program buffers, which will be the number of records specified on SEQONLY * storage length per record.

Because you have not specified a record count on the SEQONLY parameter, the system will use the number of records that fit in 4096 bytes - this is not very much, and I think you'd do well to figure out a value to put there.

At 11:04 PM 10/15/2004, you wrote:
1.  None of the 5 fields tested are part of the key in the LF.

2. I got the 32000 size on NBRRCDS and FRCRATIO because the actual upper limit was something like 32676 and I was too lazy to go back to help to find the exact number. I picked the large number thinking "pull more records into memory = faster processing", right?

3. Month-to-month, there's probably an equal number of adds and updates to the master file - about 40,000 of each.


I'll post the run times when completed.



----- Original Message ----- From: "James R. Newman, CDP" <newman400@xxxxxxxxxxx>
To: "Midrange L" <MIDRANGE-L@xxxxxxxxxxxx>
Cc: <vhamberg@xxxxxxxxxxx>
Sent: Friday, October 15, 2004 11:58 AM
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.



--
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.


As an Amazon Associate we earn from qualifying purchases.

This thread ...

Replies:

Follow On AppleNews
Return to Archive home page | Return to MIDRANGE.COM home page

This mailing list archive is Copyright 1997-2024 by midrange.com and David Gibbs as a compilation work. Use of the archive is restricted to research of a business or technical nature. Any other uses are prohibited. Full details are available on our policy page. If you have questions about this, please contact [javascript protected email address].

Operating expenses for this site are earned using the Amazon Associate program and Google Adsense.