Db2- Tablespace

The DB2 database uses tablespaces. From a logical point of view, a tablespace

holds database objects, such as tables and indexes. On disk, a tablespace consists

of one or more data files, known as containers. The capacity of a tablespace can

be increased by adding containers to it.

With <SAPSID> being PRD, the SAP naming convention for tablespace names is

PRD#<tablespace_name><extension>.

The abbreviations in the tablespace name are part of the container name.

Containers are numbered starting with 000. A full path specification for a DB2

container for SAP system PRD would be:

• /db2/PRD/sapdata1/NODE0000/PRD#BTABD.container000 (UNIX)

• h:\db2\PRD\sapdata1\NODE0000\PRD#BTABD.container000 (Windows)

Hint: Note: The SAP system and SAP tools (such as SAP Storage

Management in ST04) suggest that the naming conventions be observed.

Following the SAP naming convention ensures fast and efficient support

from SAP.

2005/Q4

Figure 30: SQL Statement Processing (2)

This example shows the processing when an SQL statement is executed that

changes data:

1. Statements that will alter data – such as UPDATE/INSERT/DELETE SQL

statements – are sent from the SAP application to the associated DB2 agent.

2. The DB2 page holding the data is altered in the buffer pool. Much later, it

will be transferred to disk. At the same time, the DB2 agent process writes

information about the changes to the data to the log buffer. DB2 uses the

log records for this write operation.

3. The db2loggw process is responsible for writing the contents of the log

buffer to the current active log file. This is done when an application ends

the transaction by issuing a COMMIT SQL statement, every second, and

when the log buffer is full.

4. I/O cleaners or page cleaners copy updated pages to disk when triggered. I/O

cleaners get triggered

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