Structure of the Database Tblspace

The database tblspace appears only in the initial chunk of the root dbspace. The database tblspace contains one entry for each database managed by the database server. Figure 8 illustrates the location of the database tblspace.

Figure 8. Database Tblspace Location in Initial Chunk of Root Dbspace

Database Tblspace Number

The tblspace number of the database tblspace is always 0x100002. This tblspace number appears in an onstat -t listing if the database tblspace is active.

Database Tblspace Entries

Each database tblspace entry includes the following five components:

• Database name
• Database owner
• Date and time that the database was created
• The tblspace number of the systables system catalog table for this database
• Flags that indicate logging mode

The database tblspace includes a unique index on the database name to ensure that every database is uniquely named. For any database, the systables table describes each permanent table in the database. Therefore, the database tblspace only points to the detailed database information located elsewhere.

When the root dbspace is initialized, the database tblspace first extent is allocated. The initial-extent size and the next-extent size for the database tblspace are four pages. You cannot modify these values.