202 Performance Tuning for Content Manager
Figure 8-1 shows an example of a simple IBM Lotus 1-2-3® spreadsheet using
the snapshot elements to compute the buffer pool ratios.
Figure 8-1 Lotus 1-2-3 spreadsheet
If your server exceeds 1 GB RAM, consider increasing the default database
buffer pool sizes. This can improve performance for heavy loads. To see whether
increasing the buffer pool sizes could help, monitor buffer pool logical and
physical reads for both data and indexes as mentioned earlier; also monitor
committed memory and buffer pool hit ratios. In general, keep the total of all
buffer pools below 50% of total physical memory, and even less if a Resource
Manager or middle-tier server shares the same machine.
8.6 Parameter tuning
There are two types of DB2 configuration parameters that are typically the
subject of tuning: database manager (instance) and database. This section
provides a discussion of some of the more important of these configuration
parameters that you can tune to improve Content Manager performance. Each
parameter is discussed in detail, along with its default value and our
recommendation as to what the value should be set to based on our
experiences. Keep in mind that these are only recommendations and that your
specific system environment might require different values based on your tuning.
For each parameter, the type of parameter (dbm or db) as well as the relative
performance impact is provided:
High Can have a significant impact on performance.
Medium Can have some impact on performance.
Low Has a less general or less significant impact on performance.
Table 8-1 on page 203 lists in order the configuration parameters discussed in
this section.
Chapter 8. Tuning DB2 for Content Manager 203
Table 8-1 Configuration parameter table
Long name Short name Impact
Intra-partition parallelism INTRA_PARALLEL DBM - High
Maximum number of concurrently
active databases
Maximum number of active applications MAXAPPLS DB - Medium
Average number of active applications AVG_APPLS DB - Low
Maximum number of database
manager agents
Maximum number of client connections MAX_CONNECTIONS DBM - Medium
Maximum number of coordinating
Initial number of agents in pool NUM_INITAGENTS DBM - Medium
Agent pool size NUM_POOLAGENTS DBM - High
Maximum number of fenced processes FENCED_POOL DBM - Medium
Keep fenced process KEEPFENCED DBM - Medium
Initial number of fenced processes NUM_INITFENCED DBM - Medium
Maximum database files open per
Maximum total files open MAXTOTFILOP DBM - Medium
Database heap DBHEAP DB - Medium
Catalog cache size CATALOGCACHE_SZ DB - High
Package cache size PCKCACHESZ DB - High
Log buffer size LOGBUFSZ DB - High
Maximum storage for lock list LOCKLIST DB - High
Application control heap size APP_CTL_HEAP_SZ DB - Medium
Application heap size APPLHEAPSZ DB - Medium
Sort heap size SORTHEAP DB - High
Sort heap threshold SHEAPTHRES DBM - High
Statement heap size STMTHEAP DB - Medium
204 Performance Tuning for Content Manager
You can tune some or all of the following parameters during the initial installation
of your Content Manager system. We also recommend maintenance tuning on a
regular basis to ensure that performance does not degrade over time. Many of
the parameters can be tuned without having to turn off your system. Remember
the general performance tuning guideline: change one parameter at a time.
Changing database manager configuration parameters
Use this generic procedure to retrieve and update database manager (DBM)
configuration parameters. The specific update command appears in the
respective parameters subsection.
Query heap size QUERY_HEAP_SZ DBM - Medium
Java interpreter heap size JAVA_HEAP_SZ DBM - High
Private memory threshold PRIV_MEM_THRESH DBM - Medium
Client I/O block size RQRIOBLK DBM - Medium
Application support layer heap size ASLHEAPSZ DBM - High
Changed pages threshold CHNGPGS_THRESH DB - High
Number of asynchronous page
Number of I/O servers NUM_IOSERVERS DB - High
Maximum percent of lock list before
Lock timeout LOCKTIMEOUT DB - Medium
Size of the log files LOGFILSIZ DB - Medium
Number of primary logs LOGPRIMARY DB - Medium
Number of secondary log files LOGSECOND DB - Medium
Minimum commits before write logs to
Connection concentrator MAX_CONNECTIONS
Long name Short name Impact

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