IBM Mainframe Forum Index
 
Log In
 
IBM Mainframe Forum Index Mainframe: Search IBM Mainframe Forum: FAQ Register
 

Generating test Data by Recursive SQL


IBM Mainframe Forums -> DB2
Post new topic   Reply to topic
View previous topic :: View next topic  
Author Message
Jimy Carol

New User


Joined: 31 Aug 2012
Posts: 25
Location: Australia

PostPosted: Thu Dec 26, 2013 3:00 pm
Reply with quote

Hello ,

I need to create massive test data for a DB2 table (more than 1 billion) with 5 columns . Is using a recursive SQL is good idea . I heard that it should not used for generating huge data. Could someone guide me as the pros and cons of using recursive SQL to genrate test data , here is the sql i am trying to use :

WITH NUMBERS (LEVEL, NEXTONE) AS
(
SELECT 1, 1
FROM SYSIBM.SYSDUMMY1
UNION ALL
SELECT LEVEL +1, LEVEL +1
FROM NUMBERS
WHERE LEVEL < 1000000
)
SELECT NEXTONE
FROM NUMBERS
ORDER BY NEXTONE


Regards
carol
Back to top
View user's profile Send private message
Bill Woodger

Moderator Emeritus


Joined: 09 Mar 2011
Posts: 7310
Location: Inside the Matrix

PostPosted: Thu Dec 26, 2013 3:41 pm
Reply with quote

You've been posting long enough to know to use the Code tags.

Doing anything billions of times requires doing it cpu-efficiently, not source-code-efficiently. Create your data outside DB2 (SORT, IEBDG, a program) and stuff it in (not a technical expression) en masse.

Might cost you an hour of your time doing it, but will save many hours babysitting the process itself.
Back to top
View user's profile Send private message
GuyC

Senior Member


Joined: 11 Aug 2009
Posts: 1281
Location: Belgium

PostPosted: Thu Dec 26, 2013 5:30 pm
Reply with quote

Problem with recursive SQL or any SQL generating huge temp data is that it consumes memory or DSNDB07 space. not to mention CPU-cycles.

IEBDG + LOAD like Bill suggested

or ...
Its been a while since I tried this, but I believe you can get the same result with an sensitive dynamic cursor :
*UNTESTED*
poulate the table with a 1000 rows.
Code:

alter tablespace mytablespace not logged
open mycursor sensitive dynamic cursor for select keycolumn, datacolumn from mytable
fetch into :mykey, :mydata
perform until sqlcode <> 0 or :mykey > 100000
    insert into mytable :mykey + 1000, :mydata
    fetch into :mykey, :mydata
end-perform
close cursor
alter tablespace mytablespace logged
Back to top
View user's profile Send private message
View previous topic :: :: View next topic  
Post new topic   Reply to topic View Bookmarks
All times are GMT + 6 Hours
Forum Index -> DB2

 


Similar Topics
Topic Forum Replies
No new posts View GDG data which is copied from a ... JCL & VSAM 2
No new posts JCL (SET) variables in input stream data JCL & VSAM 0
No new posts Assembler test under mask question PL/I & Assembler 5
No new posts Issues with outrec overlay while extr... SYNCSORT 7
No new posts compare two file to find position/dat... SYNCSORT 2
Search our Forums:

Back to Top