6.5.5 Database update log acquisition methods

Organization of this subsection
(1) Database update log acquisition methods
(2) Specification of the database update log acquisition method

(1) Database update log acquisition methods

There are three database update log acquisition methods:

  1. Log acquisition mode
    This mode acquires a database update log required for rollback and rollforward. It is used to create additional data or to reorganize data when there are not many data items.
  2. Pre-update log acquisition mode
    This method acquires only the database update log required for rollback. It is used to create, add, or reorganize data when there are many data items.
  3. No-log mode
    This mode does not acquire a database update log. It is used to create or reorganize data when there is only one table per RDAREA (if the table is partitioned, only one row-partitioned table per RDAREA) and any related index is also placed in one RDAREA.

(2) Specification of the database update log acquisition method

There are two ways to specify the database update log acquisition method:

#1: This way is used to specify the database update log acquisition method for a UAP that updates user RDAREAs.
#2: This way is used to specify the database update log acquisition method for a UAP that updates user LOB RDAREAs.
Note
The database update log acquisition method for user LOB RDAREAs (RECOVERY operand of CREATE TABLE) may depend on a specification in the client environment definition, as explained in the following table.

Table 6-7 Database update log acquisition method for user LOB RDAREAs depending on a specification in the client environment definition

Client environment definition PDDBLOGRECOVERY operand value in CREATE TABLE
ALLPARTIALNO
ALLALLPARTIALNO
NONONONO
ALL: Log acquisition mode
PARTIAL: Pre-update log acquisition mode
NO: No-log mode

For example, if PARTIAL is specified in the RECOVERY operand of CREATE TABLE and the log acquisition method is set to NO in the client environment definition, then NO (no-log mode) is set for the user LOB RDAREAs.