sql-keeper-service

The keeper uses a simple 'first to insert' a row wins methodology for deciding winner and looser. This is quite primitive and decides that any exception from the insert operation is a duplicate key exception and therefore a looser.

A org.oddjob.scheduling.LoosingOutcome will continue to Poll the database (for as long as it has listeners) until the work is complete. The default polling schedule polls every 5 seconds indefinitely. The pollSchedule property can be used to poll for a limited time, after which it flags an exception state. This could be used by loosing servers to flag the winner is taking too long and has possibly crashed.

This is an example of the SQL that would create a suitable table.

 CREATE TABLE oddjob_grabbable(
   key VARCHAR(32),
   instance VARCHAR(32),
   winner VARCHAR(32),
   complete boolean,
  CONSTRAINT oddjob_pk PRIMARY KEY (key, instance))
 

This service does not tidy up the database so rows will grow indefinitely. A separate tidy job should be implemented.

Property Summary

Example Summary

Property Detail

The connection to use.

The name.

The schedule to provide the polling interval.

The number of outstanding loosing outcome's polling of the database that are still in progress.

The scheduling service for polling.

The database table name.

Examples

See the User Guide.