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Partition Management
3.6 Managing Partitions
3.6.2 Controlling Transaction Presentation
Transaction presentation is the process of passing transactions to idle server
channels for processing. While transaction presentation is active, new
transactions are started on the first free server channel for the appropriate
partition.
Use the
/SUSPEND
qualifier to the
SET PARTITION
command to halt the
presentation of new transactions to servers on the backend where the command
is entered. The command completes when the processing of all currently active
transactions is complete. The optional
/TIMEOUT
qualifier specifies, as a number
of seconds, the time that the command waits for completion. If the command
times out, presentation of new transactions are suspended, but there still exist
transactions for which servers have yet to complete processing. The operator
must decide either to reenter the command and wait a further period of time,
or resume the partition. Note that use of this command does not affect any
transaction timeout value specified by RTR clients, so such transactions may
encounter a timeout condition if the partition remains suspended.
/RESUME
qualifier restarts presentation of transactions to the server application
channels.
3.6.2.1 Command Line Example
Example usage of the qualifiers:
RTR> SET PARTITION/FACILITY=Facility1/SUSPEND/TIMEOUT=5 Facility1:Partition1
RTR>
RTR> SET PARTITION/FACILITY=Facility1/RESUME Facility1:Partition1
For a more complete description see the SET PARTITION command in Chapter
6.
3.6.2.2 Programming Information
To suspend transaction presentation on a partition with a timeout of 30 seconds,
program the
set_qualifier
argument of the
rtr_set_info( )
call as follows:
rtr_qualifier_value_t set_qualifiers[ 3 ];
rtr_partition_state_t newState = rtr_partition_state_suspend;
rtr_uns_32_t ulTimeoutSecs = 30;
set_qualifiers[ 0 ].qv_qualifier = rtr_partition_state;
set_qualifiers[ 0 ].qv_value = &newState;
set_qualifiers[ 1 ].qv_qualifier = rtr_partition_cmd_timeout_secs;
set_qualifiers[ 1 ].qv_value = &ulTimeoutSecs;
set_qualifiers[ 2 ].qv_qualifier = rtr_qualifiers_end;
set_qualifiers[ 2 ].qv_value = NULL;
Note that the timeout is an optional element. To resume transaction presentation,
specify
newState
as
rtr_partition_state_resume
.
3.6.3 Controlling Recovery
The purpose of RTR automated recovery is to ensure the best possible consistency
of application databases across a distributed computing environment. To achieve
this RTR relies in part on information stored in the journals of the participating
systems. Should one or more of these systems be unavailable at recovery time,
automated recovery may stall or fail awaiting availability of these systems and
their journals. This is good from the point of view of data consistency, but bad
when viewed from an application availability perspective.
3–6 Partition Management