Configuring Counter Caches


Overview

Tasks

Included with

Tivoli Problem Management

Overview

Counters and counter caches

Counters are the values that Tivoli Problem Management uses to determine unique record IDs for many of the tables in the Tivoli Problem Management database. Caching is the process by which a batch of counter numbers is stored in memory, or cached, on a client workstation. When the database server returns a batch of counter numbers, as requested by a client workstation, this is called a counter cache. (A list of the available counter caches is displayed in the Counters tab of the Application dialog box.)

How Tivoli Problem Management uses counter caches

You can configure Tivoli Problem Management to retrieve a batch of counter numbers and store them in memory. When a user creates a new record, the next number in the counter cache is used as the record ID, then the number is removed from the counter cache. When the cache is empty, Tivoli Problem Management retrieves a new batch of counters from the database server.

Because Tivoli Problem Management does not need to access the database server each time the user creates a new record, counter caching significantly decreases the time spent communicating with the database server, and increases overall performance.

Records created using counter caches may have record IDs that are not based on the time they are assigned. These record IDs do not represent the system-wide order in which the records were created. For example, assume you have two users who are both creating new problem records. The first client workstation issues a GetNextNumber command to the database server. The database server returns counters with a problem ID of 1 through 50 to the first client. When the second client calls the server, it gets counters 51 through 100. If these two users are working simultaneously, the first would use counter 1 while the second is using counter 51, and so on.

Edit Counter dialog box

Change the size of a counter cache at the Edit Counter dialog box so that client workstations do not need to request counter caches too often. Counter caching significantly decreases the time spent communicating with the database server, and increases overall performance. For more information, see Editing a counter cache size.

To access the Edit Counter dialog box:

  1. In the Application dialog box, choose the Counters tab.
  2. From the Counter List, select a counter cache name, then choose Edit.
    Result: The Edit Counter dialog box appears.

View Counter dialog box

View the current size of any counter cache in the View Counter dialog box. For more information, see Viewing a counter cache size.

To access the View Counter dialog box:

  1. In the Application dialog box, choose the Counters tab.
  2. From the Counter List, select a counter cache name, then choose View.
    Result: The View Counter dialog box appears.

Tasks

Determining optimal cache values

The cache values for counters vary in size. You should pick a cache value large enough so that your users do not need to request counter caches very often. To determine the cache value, you need to know how many new records of each type are created over a period of time. The following procedure describes one method for getting this information.

To determine the optimal cache value:

  1. Execute the following SQL statement at the beginning of the week and save the results:
    SELECT COUNTER_NAME, NEXT_NUMBER FROM COUNTERS
  2. One week later, execute the same command, then compare the results for changes in various counters.
  3. Estimate the best cache size for each counter.
    Tip: Tivoli's recommended setting is the average number of counters used in one hour by one analyst. For example, if each help desk analyst creates an average of 80 call records per day (10 calls per hour), set the caching value to at least 10. You can set cache sizes larger than this recommended average. The larger the caching size, the less often the client workstation requests a new batch of counters. However, when an analyst quits Tivoli Problem Management, unused IDs in the counter caches are discarded. Large cache sizes can lead to large gaps in the numbering sequences of record IDs.
Here is a table of some of the actions most often used in Tivoli Problem Management, the counters used during the action, and the number of times the counter is used during the action.
Action Counters Used Times Used
Register a Call CALL 1
PROBLEM 1
PROBLEM HISTORY 1
Freeze a Problem PROBLEM HISTORY 1
ESCALATION LOG 1
Resume a Problem PROBLEM HISTORY 1
Transfer Call ALARM 1
ESCALATION LOG 1
DISPATCH 1
PROBLEM HISTORY 1
Transfer Problem PROBLEM HISTORY 1
WORK HISTORY 1
ESCALATION LOG 1
ALARM 1
Pickup Call PROBLEM HISTORY 1
Pickup Problem PROBLEM HISTORY 1

Editing a counter cache size

Any change made to counter cache sizes affects all Tivoli Problem Management users the next time they start Tivoli Problem Management. You do not need to set counter cache sizes at each workstation for each user.

To edit a counter cache size:

  1. In the Edit Counter dialog box, in the Cache Size box, type a new counter cache size.
  2. Choose OK.
    Result: The new value appears in the Cache Size column in the Counters tab of the Application dialog box.

Viewing a counter cache size

Check the settings for a counter cache at either the View Counter dialog box.
  1. In the View Counter dialog box, view the settings for this counter cache. For details on the displayed information, see Editing a counter cache size.
  2. Choose Close.