This
parameter specifies the default value for the CURRENT REFRESH AGE
special register. The value represents the maximum duration since
a particular time-stamped event occurred to a cached data object.
The cached data object can be used during this period to help optimize
the processing of a query. An
example of a time-stamped event is processing a REFRESH TABLE statement
on a system-maintained REFRESH DEFERRED materialized query table.
- Configuration type
- Database
- Parameter type
- Configurable
- Default [range]
- 0 [0 - 99999999999999 (ANY)]
- Unit of measure
- None
This
parameter specifies a time stamp value with a data type of DECIMAL(20,6).
The value must be 0 - 99999999999999 or a valid time stamp within
that range. The valid format for the range is
yyyymmddhhmmss.
nnnnnn,
where:
- yyyy is the number of years and can have a
value of 0 - 9999.
- mm is the number of months and can have a value
of 0 - 11.
- dd is the number of days and can have a value
of 0 - 30.
- hh is the number of hours and can have a value
of 0 - 23.
- mm is the number of minutes and can have a
value of 0 - 59.
- ss is the number of seconds and can have a
value of 0 - 59.
- nnnnnn is the number of fractional seconds.
The fractional seconds portion of the value is ignored and therefore
can be any value.
You do not have to include the leading zeros for the entire value
or the trailing fractional seconds. However, individual elements that
have another element to the left must include the zeros. For example,
to represent 1 hour, 7 minutes, and 5 seconds, use 10705.
To
set the dft_refresh_age configuration parameter
to a value other than 0 or 99999999999999 (ANY), you must set the dft_mttb_types database
configuration parameter to REPLICATION or NONE.
If
the CURRENT REFRESH AGE has a value of 99999999999999 (ANY), and the
QUERY OPTIMIZATION class has a value of two, five or more, REFRESH
DEFERRED materialized query tables are considered to optimize the
processing of a dynamic query.
DB2 10.5 for Linux, UNIX, and Windows