If the unit containing the front-end server terminates abnormally due to an error, the transaction that was being executed from that front-end server may be placed in uncompleted status. Because uncompleted transactions lock the database, some database referencing or updating may be limited. To resolve an uncompleted transaction, normally the front-end server must be recovered from the error and then restarted. If the abnormally terminated front-end server is a recovery-unnecessary front-end server, HiRDB automatically resolves the uncompleted transaction. This enables you to use another front-end or back-end server to restart database update processing. A unit that contains a recovery-unnecessary front-end server is called a recovery-unnecessary front-end server unit. The following figure shows operations based on whether a recovery-unnecessary front-end server is used.
Figure 9-3 Operation based on whether a recovery-unnecessary front-end server is used
Note that HiRDB Non Recover FES is required in order to use recovery-unnecessary front-end servers.
Figure 9-4 Example of a system configuration using a recovery-unnecessary front-end server
To use a recovery-unnecessary front-end server, specify stls in the -k option of the pdstart operand.
Operating status of recovery-unnecessary front-end server unit (pdls -d command execution result) | Corrective action |
---|---|
STOP (stopped) | Execute the pdstart -q command, and then restart the recovery-unnecessary front-end server unit. |
PAUSE (restart of the process server process is paused) |
|
STARTING |
|
ONLINE (operating) | |
STOPPING |