org.apache.ode.scheduler.simple

Interface DatabaseDelegate

All Known Implementing Classes:

JdbcDelegate

public interface DatabaseDelegate

Database abstraction; provides all database access for the simple scheduler.

Author:

Maciej Szefler ( m s z e f l e r @ g m a i l . c o m )

Method Summary

Modifier and Type	Method and Description
void	acquireTransactionLocks()
void	deleteAllJobs()
boolean	deleteJob(java.lang.String jobid, java.lang.String nodeId) Delete a job from the database.
java.util.List<org.apache.ode.scheduler.simple.Job>	dequeueImmediate(java.lang.String nodeId, long maxtime, int maxjobs) "Dequeue" jobs from the database that are ready for immediate execution; this basically is a select/delete operation with constraints on the nodeId and scheduled time.
java.util.List<java.lang.String>	getNodeIds() Return a list of unique nodes identifiers found in the database.
boolean	insertJob(org.apache.ode.scheduler.simple.Job job, java.lang.String nodeId, boolean loaded) Save the job in the database.
boolean	insertNode(java.lang.String nodeId, long heartbeat, java.lang.String leaderNodeId)
boolean	removeNode(java.lang.String nodeId)
java.util.List<Node>	retrieveClusterNodes(java.lang.String leaderNode)
int	updateAssignToNode(java.lang.String nodeId, int x, int y, long maxtime) Assign a particular node identifier to a fraction of jobs in the database that do not have one, and are up for execution within a certain time.
boolean	updateJob(org.apache.ode.scheduler.simple.Job job) Update the job in the database (only updates timestamp and retryCount)
boolean	updateNodeHeartbeat(java.lang.String nodeId, long heartbeat, java.lang.String leaderNodeId)
int	updateReassign(java.lang.String oldnode, java.lang.String newnode) Reassign jobs from one node to another.

Method Detail

insertJob

boolean insertJob(org.apache.ode.scheduler.simple.Job job,
                  java.lang.String nodeId,
                  boolean loaded)
           throws DatabaseException

Save the job in the database.

Parameters:

job - the job

nodeId - node assigned to the job (or null if no node has been asssigned)

loaded - whether the job has been loaded into memory (i.e. in preperation for execution)

Throws:

DatabaseException - in case of error

updateJob

boolean updateJob(org.apache.ode.scheduler.simple.Job job)
           throws DatabaseException

Update the job in the database (only updates timestamp and retryCount)

Parameters:

job - the job

Throws:

DatabaseException - in case of error

deleteJob

boolean deleteJob(java.lang.String jobid,
                  java.lang.String nodeId)
           throws DatabaseException

Delete a job from the database.

Parameters:

jobid - job identifier

nodeId - node identifier

Throws:

DatabaseException - in case of error

getNodeIds

java.util.List<java.lang.String> getNodeIds()
                                     throws DatabaseException

Return a list of unique nodes identifiers found in the database. This is used to initialize the list of known nodes when a new node starts up.

Returns:

list of unique node identfiers found in the databaseuniqu

Throws:

DatabaseException

dequeueImmediate

java.util.List<org.apache.ode.scheduler.simple.Job> dequeueImmediate(java.lang.String nodeId,
                                                                     long maxtime,
                                                                     int maxjobs)
                                                              throws DatabaseException

"Dequeue" jobs from the database that are ready for immediate execution; this basically is a select/delete operation with constraints on the nodeId and scheduled time.

Parameters:

nodeId - node identifier of the jobs

maxtime - only jobs with scheduled time earlier than this will be dequeued

maxjobs - maximum number of jobs to deqeue

Returns:

list of jobs that met the criteria and were deleted from the database

Throws:

DatabaseException - in case of error

updateAssignToNode

int updateAssignToNode(java.lang.String nodeId,
                       int x,
                       int y,
                       long maxtime)
                throws DatabaseException

Assign a particular node identifier to a fraction of jobs in the database that do not have one, and are up for execution within a certain time. Only a fraction of the jobs found are assigned the node identifier. This fraction is determined by the "y" parameter, while membership in the group (of jobs that get the nodeId) is determined by the "x" parameter. Essentially the logic is: UPDATE jobs AS job WHERE job.scheduledTime before :maxtime AND job.nodeId is null AND job.scheduledTime MOD :y == :x SET job.nodeId = :nodeId

Parameters:

nodeId - node identifier to assign to jobs

x - the result of the mod-division

y - the dividend of the mod-division

maxtime - only jobs with scheduled time earlier than this will be updated

Returns:

number of jobs updated

Throws:

DatabaseException - in case of error

updateReassign

int updateReassign(java.lang.String oldnode,
                   java.lang.String newnode)
            throws DatabaseException

Reassign jobs from one node to another.

Parameters:

oldnode - node assigning from

newnode - new node asssigning to

Returns:

number of rows changed

Throws:

DatabaseException

acquireTransactionLocks

void acquireTransactionLocks()

deleteAllJobs

void deleteAllJobs()

insertNode

boolean insertNode(java.lang.String nodeId,
                   long heartbeat,
                   java.lang.String leaderNodeId)
            throws DatabaseException

Throws:

DatabaseException

removeNode

boolean removeNode(java.lang.String nodeId)
            throws DatabaseException

Throws:

DatabaseException

updateNodeHeartbeat

boolean updateNodeHeartbeat(java.lang.String nodeId,
                            long heartbeat,
                            java.lang.String leaderNodeId)
                     throws DatabaseException

Throws:

DatabaseException

retrieveClusterNodes

java.util.List<Node> retrieveClusterNodes(java.lang.String leaderNode)
                                   throws DatabaseException

Throws:

DatabaseException