The DB2 directory is used to store information about the operation and
housekeeping of the DB2 environment. This directory, unlike the DB2 catalog,
cannot be accessed by using SQL.
The DB2 directory contains information required to start DB2; activities and utilities in the DB2 environment do the updating and deleting of table entries in the DB2 directory.
The DB2 directory contains information required to start DB2; activities and utilities in the DB2 environment do the updating and deleting of table entries in the DB2 directory.
Directory Table
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Information Contents
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SPT01
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Referred to
as the skeleton package table (SKPT), this table contains information about
the access paths and the internal form of the SQL for a package at bind time.
Entries are made into this table during bind time (BIND PACKAGE), and entries
are deleted when a package is freed (FREE PACKAGE). This table is loaded into
memory at execution time, along with the SCT02 table described next.
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SCT02
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Referred to as the skeleton cursor
table (SKCT), this table contains information about access paths and the internal
form of the SQL for an application plan. Entries in this table are made when
a plan is bound (BIND PLAN) and deleted when a plan is freed (FREE PLAN).
This table is also loaded into memory at execution time.
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DBD01
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Information
about DBDs (database descriptors), which are internal control blocks, is kept
in this table. Each DB2 database has one DBD for its objects: table spaces,
indexes, tables, referential integrity constraints, and check constraints.
Updates to this table are made when a database is created or updated. This
information is accessed by DB2 in place of continually using the DB2 catalog,
permitting faster, more efficient access to this information. The information
in the DBD01 directory table is also contained in the DB2 catalog.
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SYSLGRNX
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Referred to as the log range
table, this table contains information from the DB2 logs about the RBA
(relative byte address) range for updates. This allows DB2 to efficiently
find the RBAs needed from the DB2 logs for recovery purposes. A row is
inserted every time a table space or a partition is opened or updated and is
updated when the object is closed.
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SYSUTILX
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This system
utilities table stores information about the execution of DB2 utilities,
including the status and the steps during execution. This information is used
when a utility needs to be restarted. Information in this table is added when
a utility is started, and the entry is removed when the execution has ended.
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