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Updates generated columns in tables that are in check pending mode and
have limited log space. This tool is used to prepare for a SET INTEGRITY statement
on a table that has columns which are generated by expressions.
Authorization
One of the following
Command Syntax
>>-db2gncol----d--database----s--schema_name----t--table_name--->
>-----c--commit_count----+---------------------------+---------->
'--u--userid---p--password--'
>-----+-----+--------------------------------------------------><
'--h--'
Command Parameters
- -d database
- Specifies an alias name for the database in which the table is located.
- -s schema_name
- Specifies the schema name for the table. The schema name is case sensitive.
- -t table_name
- Specifies the table for which new column values generated by expressions
are to be computed. The table name is case sensitive.
- -c commit_count
- Specifies the number of rows updated between commits. This parameter
influences the size of the log space required to generate the column values.
- -u userid
- Specifies a user ID with system administrator or database administrator
privileges. If this option is omitted, the current user is assumed.
- -p password
- Specifies the password for the specified user ID.
- -h
- Displays help information. When this option is specified, all other
options are ignored, and only the help information is displayed.
Usage Notes
Using this tool instead of the FORCE GENERATED option on the SET INTEGRITY
statement may be necessary if a table is large and the following conditions
exist:
- All column values must be regenerated after altering the generation expression
of a generated column.
- An external UDF used in a generated column was changed, causing many column
values to change.
- A generated column was added to the table.
- A large load or load append was performed that did not provide values
for the generated columns.
- The log space is too small due to long-running concurrent transactions
or the size of the table.
This tool will regenerate all column values that were created based on
expressions. While the table is being updated, intermittent commits are performed
to avoid using up all of the log space. Once db2gncol has been run, the table can be taken out of check pending mode using
the SET INTEGRITY statement.
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