Compaq AA-Q88CE-TE manual Binding Server Channels to Named Partitions, Explicit Partition Creation

Partition Management

3.3 Life Cycle of a Partition

3.3.1 Implicit Partition Creation

Partitions are created implicitly when an application program calls

rtr_open_channel( ) to create a server channel, specifying the key segments and value ranges for the segments with the pkeyseg argument. Other partition attributes are established with the flags argument. Before RTR V3.2, this was the only way in which partitions could be created. Partitions created in this way are automatically deleted when the last server channel to the partition is closed.

3.3.2 Explicit Partition Creation

Partitions can also be created by the system operator before server application program start up using system management commands. This gives the operator more control over partition characteristics. Partitions created in this way remain in the system until either explicitly deleted by the operator, or RTR is stopped.

3.3.3 Persistence of Partition Definitions

RTR stores partition definitions in the journal, and records for each transaction the partition in which it was processed. This is convenient when viewing or editing the contents of the journal, where the partition name can be used to select a subset of the transactions in the journal. RTR will not permit a change in the partition name or definition as long as transactions remain in the journal that were processed under the current name or definition for the partition. If transactions remain in the journal and you need to change the partition name or definition, you can take the following actions:

•Start appropriate servers to complete processing of the transactions.

•Remove the transactions from the journal with the SET TRANSACTION command.

•Replace the RTR journal with the CREATE JOURNAL/SUPERSEDE command. Note that this will destroy any transactions remaining in the journal and should be done with caution.

3.4Binding Server Channels to Named Partitions

For a server application to be able to open a channel to an explicitly created partition, the application passes the name of the partition through the pkeyseg argument of rtr_open_channel( ) call. It is not necessary to pass key segment descriptors, but if the application does so, they must be compatible with the existing partition definition. You may pass partition characteristics through the flags argument, but these will be superseded by those of the existing partition.

Example:

RTR> create partition/KEY1=(type. . .) par_one

. . .

rtr_keyseg_t partition_name;

partition_name.ks_type = rtr_keyseg_partition; partition_name.ks_lo_bound = "par_one";

status - rtr_open_channel( . . ., RTR_F_OPE_SERVER, . . ., 1, &partition_name);

Summarizing, to fully de-couple server applications from the definition of the partitions to be processed, write applications that open server channels where only the required partition name is passed. Leave the management of the partition characteristics to the system managers and operators.

Partition Management 3–3