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DB2 Storage Objects 15
database name, and the table space name in Figure 2 on page 14 must match
the definitions on Figure 3 on page 15.
Figure 3. User Defined Table Space: Step 2— Define the Table Space
3.4 DB2 System Table Spaces
DB2 uses four internally defined databases to control and manage itself and the
application data. The databases are:
• The Catalog database
• The Directory database
• The Work database
• The Default database
This section provides a general description of these databases.
Two tables, SYSIBM.SYSCOPY, belonging to the DB2 catalog, and
SYSIBM.SYSLGRNX, belonging to the DB2 directory, are directly used by DB2 to
manage backup and recovery; they are also described in this section.
3.4.1 The DB2 Catalog and Directory
The Catalog database is named DSNDB06. The Directory database is named
DSNDB01. Both databases contain DB2 system tables. DB2 system tables store
data definitions, security information, data statistics and recovery information for
the DB2 system. The DB2 system tables reside in DB2 system table spaces.
The DB2 system table spaces are allocated when a DB2 system is first created,
that is, during the installation process. DB2 provides the IDCAMS statements
required to allocate these data sets as VSAM LDSs. The size of these LDSs is
calculated from user parameters specified on DB2 installation panels. Figure 4 on
page 16 shows panel DSNTIPD with default values for sizing DB2 system table
spaces. In this figure, parameters numbered 1 to 12 are used to size DB2 catalog
and directory table spaces.
3.4.2 The Work Database
In a non-data sharing environment, the Work database is called DSNDB07. In a
data sharing environment, the name is chosen by the user. The Work database is
used by DB2 to resolve SQL queries that require temporary work space. For
example, SQL statements containing JOIN, ORDER BY, GROUP BY, may require
space in the Work database, but this depends on available storage for the DB2
internal sort and the access path chosen by the DB2 optimizer.
Multiple table spaces can be created for the Work database. These table spaces
follow the normal rules for creating a table space. At least two table spaces
should be created, one with a 4K page size, and the other one with a 32K page
size. DB2 V6 supports page sizes of 8K and 16K for table spaces, but not for the
CREATE TABLESPACE PAOLOR1 IN DSN8D61A
BUFFERPOOL BP0
CLOSE NO
USING VCAT DB2V610Z;