Getting Started with DB2 Express-C

6
Chapter 6 – DB2 Architecture
In this chapter we briefly discuss the DB2 architecture. You will learn about:
Note:
• The DB2 process model
• The DB2 memory model
• The DB2 storage model
For more information about the DB2 architecture, watch this video:
http://www.channeldb2.com/video/video/show?id=807741:Video:4482
6.1 DB2 process model
Figure 6.1 depicts the DB2 Process Model. In this figure, rectangles represent processes
while ellipses represent threads. The main DB2 process is called db2sysc. Under this
process there are several threads, the main one is also called the db2sysc. This is the
main thread that spawns other threads. When a remote application tries to connect to the
server using an SQL CONNECT statement, the remote listeners for the communication
protocol will receive this request and contact a DB2 coordinator agent (db2agent). A DB2
agent is like a little worker that performs operations on behalf of DB2. When the application
is local, that is, running on the same server as DB2, the steps are very similar, only that a
db2ipccm agent handles the request instead of the db2tcpcm thread. In some cases, such
as when parallelism is enabled, a db2agent may spawn other agents which appear as
db2agntp threads. Other agents shown in the figure such as db2pfchr, db2loggr, db2dlock
may also be used for different purposes. Most common processes are described in Table
6.1, and most common threads are described in Table 6.2.