IBM 000-8697 Manual Do Utilizador

System Architecture

Each data page in the tblspace tblspace describes one tblspace in the dbspace
and is considered one entry. Entries in the tblspace tblspace are added when
a new table is created. The first page in every tblspace tblspace is a bit map of
the pages in the tblspace tblspace. The second page is the first tblspace entry,
and it describes itself. The third page describes the first user-created table in
this dbspace. Each tblspace tblspace entry (page) includes the following
components:

Each tblspace that is described in the tblspace receives a tblspace number.
This tblspace number is the same value that is stored as the partnum field in
the systables system catalog table. It also appears in a tbstat -t listing.

The tblspace number (partnum) is stored as an integer (4 bytes). The
following

SQL

 query retrieves the partnum for every table in the database

and displays it along with the table name and the hexadecimal representation
of partnum:

SELECT tabname, partnum, HEX(partnum) hex_tblspace_name FROM systables

Page header

24 bytes, standard page header information

Page-ending timestamp

4 bytes

Tblspace header

56 bytes, general tblspace information available
from a tbcheck -pt display

Column information

Each special column in the table is tracked with
an 8-byte entry. (A special column is defined as a

VARCHAR

,

BYTE

, or

TEXT

 data type.)

Index information

Each index on the table is tracked with a 16-byte
entry.

Index column information Each column component in each index key is

tracked with a 4-byte entry.

Extent information

Each extent allocated to this tblspace is tracked
with an 8-byte entry.