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The Evolution of the Memory Model in IBM DB2 for Linux, UNIX and Windows
Memory Management in DB2 UDB V8
The Process Model
Before we continue and investigate the DB2 UDB V8 memory model it is helpful to have a short look at the
DB2 process model.
There is no need to discuss this figure in detail. The important aspect to remember here is that DB2
distributes its tasks to various processes, for example
• a listener process which is responsible for remote communication with the database,
• a number of db2agent and -subagent processes which carry out tasks on behalf of the applications,
• prefetchers and page cleaners which ensure efficient usage of the buffer pools,
• a log writer process which flushes log records from the log buffer to the log files on disk,
• a process that looks for possible deadlocks,
• a process called db2sysc (not shown in the figure above) which acts as the main DB2 system
controller and must be always present.
For some process types even a pool of these processes exists (e.g. for the db2agents).
The following is the beginning of a list of the DB2 processes in a typical SAP system running on AIX:
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