Portal | Manuals | References | Downloads | Info | Programs | JCLs | Mainframe wiki | Quick Ref
IBM Mainframe Computers Forums Index
 
Register
 
IBM Mainframe Computers Forums Index Mainframe: Search IBM Mainframe Forum: FAQ Memberlist Profile Log in to check your private messages Log in
 
Performance issue of VSAM when compared to Table

 
Post new topic   Reply to topic    IBMMAINFRAMES.com Support Forums -> COBOL Programming
View previous topic :: :: View next topic  
Author Message
harry143

New User


Joined: 05 Nov 2007
Posts: 21
Location: hyd

PostPosted: Thu Mar 13, 2008 5:58 pm    Post subject: Performance issue of VSAM when compared to Table
Reply with quote

Hi,

Please see the below two points:

1) Random search in a VSAM File
2) Storing the VSAM file in an occurs table and Searching in it with the matching fields using perform statement.

Can any body suggest which one is the best when coming to performance issue??
I have a large amount of records to be searched.
Back to top
View user's profile Send private message

Craq Giegerich

Senior Member


Joined: 19 May 2007
Posts: 1512
Location: Virginia, USA

PostPosted: Thu Mar 13, 2008 6:02 pm    Post subject:
Reply with quote

It would depend. How many times are you going to be searching the table, how big would the table be, does the vsam file have a key to use for the search?
Back to top
View user's profile Send private message
harry143

New User


Joined: 05 Nov 2007
Posts: 21
Location: hyd

PostPosted: Thu Mar 13, 2008 6:08 pm    Post subject:
Reply with quote

Craq Giegerich wrote:
It would depend. How many times are you going to be searching the table, how big would the table be, does the vsam file have a key to use for the search?


The table would be an occurs of 3000.
Yes the VSAm file has the key to search.
for each record nearly two to three times i have to serach.
Back to top
View user's profile Send private message
Bill O'Boyle

CICS Moderator


Joined: 14 Jan 2008
Posts: 2504
Location: Atlanta, Georgia, USA

PostPosted: Thu Mar 13, 2008 6:22 pm    Post subject: Performance issue of VSAM when compared to Table
Reply with quote

If there's someone in your shop that writes Assembler, you could call an Assembler sub-program (which issues a SHOWCB Macro) and it can return the number of records and (if needed) the LRECL of the target VSAM file which you want to load into memory.

Then, you can define your table in LINKAGE, with an OCCURS DEPENDING ON and acquire dynamic storage via the LE Callable Service routine "CEEGTST" or an Assembler sub-program which issues an MVS "GETMAIN".

By doing it this way, you won't have to worry about defining an OCCURS table in WS, which could spill over at 3:00am, causing someone to increase the OCCURS, re-compile the program and cross their fingers.

However, if it spills over once, it will spill over again.

Murphy is alive and well ya know. icon_wink.gif

HTH....

Regards,

Bill
Back to top
View user's profile Send private message
View previous topic :: :: View next topic  
Post new topic   Reply to topic    IBMMAINFRAMES.com Support Forums -> COBOL Programming All times are GMT + 6 Hours
Page 1 of 1

 

Search our Forum:

Similar Topics
Topic Author Forum Replies Posted
No new posts ISSUE IN copying Sequential file reco... thesumitk JCL & VSAM 2 Wed Dec 13, 2017 3:07 pm
No new posts Compare VSAM files using DFSORT pshongal DFSORT/ICETOOL 5 Thu Nov 23, 2017 10:24 am
No new posts SIGNAL ON HALT issue packerm CLIST & REXX 1 Fri Oct 20, 2017 6:56 pm
No new posts Update table without cursor Ron Klop DB2 3 Wed Oct 11, 2017 1:06 pm
No new posts Table(Unicode(Graphic) table) loading... muralikrishnan_new DB2 0 Thu Oct 05, 2017 5:10 pm

Facebook
Back to Top
 
Job Vacancies | Forum Rules | Bookmarks | Subscriptions | FAQ | Polls | Contact Us