198 DB2 UDB ESE V8 Performance Guide for High Performance OLTP and BI
deadlocks can be minimized. However, lock waits and timeouts may still
11.Tune the database configuration parameters LOCKLIST, MAXLOCKS and
DLCHKTIME to minimize lock escalations and optimize deadlock detection
cycles as described in 3.4.6, “Locking considerations” on page 260.
12.OLTP environments are high throughput and transactional in nature, and
should therefore use row level locking with CS isolation level unless there is a
specific reason for a more restrictive lock. They should also commit more
frequently to reduce the duration a lock is held.
13.BI environments are low throughput and predominantly read only in nature,
and either table level locks or row locks with CS or UR isolation level would be
3.4 System environment considerations
While application design is critical, there are a number of system considerations
that can significantly impact overall system performance. System tuning is
typically performed by DBAs in conjunction with operating system administrators.
The following system performance-related considerations are discussed here:
I/O placement considerations
Monitor switch settings
Buffer pool considerations
Package cache considerations
Catalog cache considerations
Other memory considerations
3.4.1 I/O placement considerations
Proper disk subsystem placement of critical DB2 objects is essential to reducing
I/O times and ensuring high availability of these objects.
Figure 3-17 on page 199 describes the default directory structure for a database.
Figure 3-18 on page 200 highlights the main DB2 objects.