org.objectweb.cjdbc.controller.loadbalancer.raidb2
Class RAIDb2_WRR

java.lang.Object
  javax.management.StandardMBean
      org.objectweb.cjdbc.controller.jmx.AbstractStandardMBean
          org.objectweb.cjdbc.controller.loadbalancer.AbstractLoadBalancer
              org.objectweb.cjdbc.controller.loadbalancer.raidb2.RAIDb2
                  org.objectweb.cjdbc.controller.loadbalancer.raidb2.RAIDb2_WRR

All Implemented Interfaces:

AbstractLoadBalancerMBean, javax.management.DynamicMBean, javax.management.NotificationBroadcaster, javax.management.NotificationEmitter, XmlComponent

public class RAIDb2_WRR

extends RAIDb2

RAIDb-2 Weighted Round Robin load balancer.

The read requests coming from the request manager are sent to the backend nodes using a weighted round robin. Write requests are broadcasted to all backends.

Version:

1.0

Author:

Emmanuel Cecchet , Julie Marguerite

Nested Class Summary

Nested classes inherited from class javax.management.StandardMBean

Field Summary

private java.util.HashMap

weights

Fields inherited from class org.objectweb.cjdbc.controller.loadbalancer.raidb2.RAIDb2

backendBlockingThreads, backendBlockingThreadsRWLock, backendNonBlockingThreads, backendNonBlockingThreadsRWLock, createTablePolicy, logger, waitForCompletionPolicy

Fields inherited from class org.objectweb.cjdbc.controller.loadbalancer.AbstractLoadBalancer

macroHandler, parsingGranularity, raidbLevel, totalOrderQueue, vdb

Fields inherited from class org.objectweb.cjdbc.controller.jmx.AbstractStandardMBean

Fields inherited from class javax.management.StandardMBean

Fields inherited from interface org.objectweb.cjdbc.common.xml.XmlComponent

DOCTYPE_CONTROLLER, DOCTYPE_DB, XML_VERSION

Constructor Summary

RAIDb2_WRR(VirtualDatabase vdb, WaitForCompletionPolicy waitForCompletionPolicy, CreateTablePolicy createTablePolicy)
Creates a new RAIDb-2 Weighted Round Robin request load balancer.

Method Summary

ControllerResultSet	execReadOnlyReadStoredProcedure(StoredProcedure proc, MetadataCache metadataCache) Chooses the node to execute the stored procedure using a round-robin algorithm.
ControllerResultSet	execReadRequest(SelectRequest request, MetadataCache metadataCache) Performs a read request.
java.lang.String	getInformation() Gets information about the request load balancer.
java.lang.String	getRaidb2Xml() return xml formatted information about this raidb2 load balancer
void	setWeight(java.lang.String name, int w) Associate a weight to a backend identified by its logical name.

Methods inherited from class org.objectweb.cjdbc.controller.loadbalancer.raidb2.RAIDb2

begin, commit, disableBackend, enableBackend, execReadStoredProcedure, executeRequestOnBackend, executeStoredProcedureOnBackend, execWriteRequest, execWriteRequestWithKeys, execWriteStoredProcedure, getNumberOfEnabledBackends, getXmlImpl, releaseSavepoint, rollback, rollback, setSavepoint, waitForAllWritesToComplete, waitForAllWritesToComplete, waitForAllWritesToComplete

Methods inherited from class org.objectweb.cjdbc.controller.loadbalancer.AbstractLoadBalancer

executeReadStoredProcedureOnBackend, executeSelectRequestOnBackend, executeUpdateRequestOnBackend, executeUpdateRequestOnBackendWithKeys, executeWriteStoredProcedureOnBackend, getAssociatedString, getConnectionAndBeginTransaction, getParsingGranularity, getRAIDbLevel, getXml, handleMacros, removeHeadFromAndNotifyTotalOrderQueue, setMacroHandler, setParsingGranularity, setRAIDbLevel, waitForTotalOrder

Methods inherited from class org.objectweb.cjdbc.controller.jmx.AbstractStandardMBean

addNotificationListener, getDescription, getDescription, getDescription, getDescription, getDescription, getDescription, getNotificationInfo, getParameterName, getParameterName, removeNotificationListener, removeNotificationListener, sendNotification

Methods inherited from class javax.management.StandardMBean

cacheMBeanInfo, getAttribute, getAttributes, getCachedMBeanInfo, getClassName, getConstructors, getDescription, getImpact, getImplementation, getImplementationClass, getMBeanInfo, getMBeanInterface, invoke, setAttribute, setAttributes, setImplementation

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

weights

private java.util.HashMap weights

Constructor Detail

RAIDb2_WRR

public RAIDb2_WRR(VirtualDatabase vdb,
                  WaitForCompletionPolicy waitForCompletionPolicy,
                  CreateTablePolicy createTablePolicy)
           throws java.lang.Exception

Creates a new RAIDb-2 Weighted Round Robin request load balancer.

Parameters:

vdb - The virtual database this load balancer belongs to.

waitForCompletionPolicy - How many backends must complete before returning the result?

createTablePolicy - The policy defining how 'create table' statements should be handled

Throws:

java.lang.Exception - if an error occurs

Method Detail

execReadRequest

public ControllerResultSet execReadRequest(SelectRequest request,
                                           MetadataCache metadataCache)
                                    throws java.sql.SQLException

Performs a read request. It is up to the implementation to choose to which backend node(s) this request should be sent.

Specified by:

execReadRequest in class RAIDb2

Parameters:

request - an SelectRequest

metadataCache - cached metadata to use to construct the result set

Returns:

the corresponding java.sql.ResultSet

Throws:

java.sql.SQLException - if an error occurs

See Also:

RAIDb2.execReadRequest(SelectRequest, MetadataCache)

execReadOnlyReadStoredProcedure

public ControllerResultSet execReadOnlyReadStoredProcedure(StoredProcedure proc,
                                                           MetadataCache metadataCache)
                                                    throws java.sql.SQLException

Chooses the node to execute the stored procedure using a round-robin algorithm. If the next node has not the needed stored procedure, we try the next one and so on until a suitable backend is found.

Specified by:

execReadOnlyReadStoredProcedure in class AbstractLoadBalancer

Parameters:

proc - the stored procedure call

metadataCache - MetadataCache (null if none)

Returns:

a ControllerResultSet value

Throws:

java.sql.SQLException - if an error occurs

See Also:

AbstractLoadBalancer.execReadOnlyReadStoredProcedure(StoredProcedure, MetadataCache)

setWeight

public void setWeight(java.lang.String name,
                      int w)
               throws java.sql.SQLException

Description copied from class: AbstractLoadBalancer

Associate a weight to a backend identified by its logical name.

Specified by:

setWeight in interface AbstractLoadBalancerMBean

Overrides:

setWeight in class AbstractLoadBalancer

Parameters:

name - the backend name

w - the weight

Throws:

java.sql.SQLException - if an error occurs

See Also:

AbstractLoadBalancer.setWeight(String, int)

getInformation

public java.lang.String getInformation()

Gets information about the request load balancer.

Specified by:

getInformation in interface AbstractLoadBalancerMBean

Specified by:

getInformation in class AbstractLoadBalancer

Returns:

String containing information

getRaidb2Xml

public java.lang.String getRaidb2Xml()

Description copied from class: RAIDb2

return xml formatted information about this raidb2 load balancer

Specified by:

getRaidb2Xml in class RAIDb2

Returns:

xml formatted string

See Also:

RAIDb2.getRaidb2Xml()