Large update in Sybase - sybase

Question

I need your help to solve a problem that I have with a large update. Hi we want to create a server for developers/testers and we want that have a copy from production, so we want to obfuscate the NSS with a random NSS generated at the moment that I execute the update, so I create a function that do this process. This its the update:
UPDATE CUSTOMERS SET
NAME = 'John',
LAST NAME ='Doe',
NSS = RandomNSS
plan '(i_scan PK_CUSTOMERS CUSTOMERS)'
The update works fine except that the table its 9 million long so I got the log suspended or the message that you are out of locks so the process never finish so I tried to implement the following:
SET ROWCOUNT 10000
WHILE (1 = 1)
BEGIN
BEGIN TRANSACTION
UPDATE CUSTOMERS SET
NAME = 'John',
LAST NAME ='Doe',
NSS = RandomNSS
plan '(i_scan PK_CUSTOMERS CUSTOMERS)'
IF ##ROWCOUNT = 0
BEGIN
COMMIT TRANSACTION
BREAK
END
COMMIT TRANSACTION
END
SET ROWCOUNT 0
But it doesn't solve the problem because I don't have a where clause so the update never finish even that all the customers name are John Doe, so can you help me to create a query that help me to finish this process?

Answer 1

First, on the DEV system, I would change the setting for the databse so that it will truncate the transaction log when it checkpoints. That will keep the log from filling up while you accomplish the update. Because the DEV database is restored from PROD database, it's not important to dump the transaction logs for recoverability.
sp_dboption DEV_DB, 'trunc log on chkpt', true
If you must do the update, try changing the while loop to continue until all the names are changed to "John", like the following.
SET ROWCOUNT 10000
while ( select count(*) from CUSTOMERS where name != "John" and LAST_NAME != 'Doe' ) > 0
BEGIN
BEGIN TRANSACTION
UPDATE CUSTOMERS SET
NAME = 'John',
LAST NAME ='Doe',
NSS = RandomNSS
WHERE name != "John" AND LAST_NAME != "DOE"
plan '(i_scan PK_CUSTOMERS CUSTOMERS)'
COMMIT TRANSACTION
END
SET ROWCOUNT 0
Alternatively, you can create a view on the database, grabbing the Production data you want, while obscuring the fields you don't want the devs to see. This view can then be used to select into the DevelopementDB, or exported/imported with bcp
create view DEV_VIEW (NAME, LAST_NAME, NSS, colA, colB) as
select "John", "Doe", RandomNSS, other_colA, other_colB
from CUSTOMERS