Performance Tuning for Content Manager

244 Performance Tuning for Content Manager

In these equations, 4,096 is the number of bytes per page, 100 is the largest

percentage value allowed for MAXLOCKS, 36 is the number of bytes per lock

on a 32-bit system, and 56 is the number of bytes per lock on a 64-bit system.

 If you know that one of your applications requires 1,000 locks, and you do not

want lock escalation to occur, then you should choose values for MAXLOCKS

and LOCKLIST in this formula so that the result is greater than 1,000. (For

example, use 10 for MAXLOCKS and 100 for LOCKLIST.)

 If MAXLOCKS is set too low, lock escalation happens when there is still

enough lock space for other concurrent applications. If MAXLOCKS is set too

high, a few applications can consume most of the lock space, and other

applications will have to perform lock escalation. The need for lock escalation

in this case results in poor concurrency.

Use the database system monitor to help you track and tune this configuration

parameter.

8.6.34 Lock timeout (LOCKTIMEOUT)

Impact

DB - Medium

Description

This parameter specifies the number of seconds that an application will wait to

obtain a lock. This helps avoid global deadlocks for applications.

If you set this parameter to zero, locks are not waited for. In this situation, if no

lock is available at the time of the request, the application immediately receives a

-911.

If you set this parameter to -1, lock timeout detection will be turned off. In this

situation, if no lock is available at the time of the request, the application will wait

for a lock until:

 The lock is granted.

 A deadlock occurs.

Default values (range)

-1 (-1; 0 - 30,000) seconds

To update

Run the following DB2 command:

db2 update db cfg for <database name> using LOCKTIMEOUT <parameter

value>