IBM 000-8697 Bedienungsanleitung Seite 199

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System Architecture 2-105
tblspace Tblspace
tblspace Tblspace Entries
Eachdata page inthetblspacetblspacedescribes one tblspaceinthedbspace
and is considered one entry. Entries in the tblspace tblspace are added when
anewtable is created.Thefirstpage in every tblspacetblspaceisabitmap of
the pages inthe tblspacetblspace. The secondpage isthe first tblspaceentry,
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:
Tblspace Number
Each tblspace that is described in the tblspace receives a tblspace number.
This tblspacenumber is the same value thatis stored asthe 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
anddisplaysitalongwiththetablenameandthehexadecimalrepresentation
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
an8-byteentry.(Aspecialcolumnisdefinedasa
VARCHAR, BYTE, or TEXT data type.)
Index information Each indexon the table is tracked with a16-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.
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