Structure of a Regular Dbspace

After disk-space initialization, you can add new dbspaces. When you create a dbspace, you assign at least one chunk (either raw or cooked disk space) to the dbspace. This chunk is referred to as the initial chunk of the dbspace. Figure 2 illustrates the structure of the initial chunk of a regular (nonroot) dbspace.

When the dbspace is first created, it contains the following structures:

• The first chunk free-list page in the chunk
• The tblspace tblspace for this dbspace
• Unused pages

Figure 2. Initial Chunk of Regular Dbspace

Structure of an Additional Dbspace Chunk

You can create a dbspace that contains more than one chunk. The initial chunk in a dbspace contains the tblspace tblspace for the dbspace. Additional chunks do not initially, but may in time if the tblspace tblspace is extended. When an additional chunk is first created, it contains the following structures:

• Two reserved pages (reserved for future use)
• The first chunk free-list page
• Unused pages

Figure 3 illustrates the structure of all additional chunks in a dbspace. (The structure also applies to additional chunks in the root dbspace.)

Figure 3. Additional Dbspace Chunk