The SET CURRENT MDC ROLLOUT MODE statement assigns a value
to the CURRENT MDC ROLLOUT MODE special register. The value specifies
the type of rollout cleanup that is to be performed on qualifying
DELETE statements for multidimensional clustering (MDC) tables.
Invocation
This statement can be embedded
in an application program or issued through the use of dynamic SQL
statements. It is an executable statement that can be dynamically
prepared.
Authorization
None required.
Syntax
>>-SET--CURRENT--MDC ROLLOUT MODE--+-NONE----------+-----------><
+-IMMEDIATE-----+
+-DEFERRED------+
'-host-variable-'
Description
- NONE
- Specifies that MDC rollout optimization during delete operations
is not to be used. The DELETE statement is processed in the same way
as a DELETE statement that does not qualify for rollout.
- IMMEDIATE
- Specifies that MDC rollout optimization is to be used if the DELETE
statement qualifies. If the table has RID indexes, the indexes are
updated immediately during delete processing. The deleted blocks are
available for reuse after the transaction commits.
- DEFERRED
- Specifies that MDC rollout optimization is to be used if the DELETE
statement qualifies. If the table has RID indexes, index updates are
deferred until after the transactions commits. With this option, delete
processing is faster and uses less log space, but the deleted blocks
are not available for reuse until after the index updates are complete.
- host-variable
- A variable of type VARCHAR. The length of host-variable must
be less than or equal to 17 bytes (SQLSTATE 42815). The value
of the host variable must be a left-aligned string that is one
of 'NONE', 'IMMEDIATE', or 'DEFERRED' (case insensitive).
If host-variable has an associated indicator variable,
the value of that indicator variable must not indicate a null value
(SQLSTATE 42815).
Example
Specify deferred cleanup behavior
for the next DELETE statement that qualifies for rollout processing.
SET CURRENT MDC ROLLOUT MODE IMMEDIATE