org.objectweb.cjdbc.controller.loadbalancer.paralleldb
Class ParallelDB

java.lang.Object
  javax.management.StandardMBean
      org.objectweb.cjdbc.controller.jmx.AbstractStandardMBean
          org.objectweb.cjdbc.controller.loadbalancer.AbstractLoadBalancer
              org.objectweb.cjdbc.controller.loadbalancer.paralleldb.ParallelDB

All Implemented Interfaces:

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

Direct Known Subclasses:

ParallelDB_LPRF, ParallelDB_RR

public abstract class ParallelDB

extends AbstractLoadBalancer

These are generic functions for all ParallelDB load balancers.

Read and write queries are load balanced on the backends without any replication (assuming that the underlying parallel database takes care of data replication). The load balancers provide failover for reads and writes.

Version:

1.0

Author:

Emmanuel Cecchet , Jaco Swart

Nested Class Summary

Nested classes inherited from class javax.management.StandardMBean

Field Summary

private java.util.Hashtable	backendPerTransactionId
private int	numberOfEnabledBackends

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

logger, 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

ParallelDB(VirtualDatabase vdb)
Creates a new ParallelDB load balancer with NO_PARSING and a SingleDB RAIDb level.

Method Summary

void	begin(TransactionMarkerMetaData tm) Begin a new transaction.
abstract DatabaseBackend	chooseBackendForReadRequest(AbstractRequest request) Choose a backend using the implementation specific load balancing algorithm for read request execution.
abstract DatabaseBackend	chooseBackendForWriteRequest(AbstractWriteRequest request) Choose a backend using the implementation specific load balancing algorithm for write request execution.
void	commit(TransactionMarkerMetaData tm) Commit a transaction.
void	disableBackend(DatabaseBackend db) Disables a backend that was previously enabled.
void	enableBackend(DatabaseBackend db, boolean writeEnabled) Enables a backend that was previously disabled.
ControllerResultSet	execReadOnlyReadStoredProcedure(StoredProcedure proc, MetadataCache metadataCache) Call a read-only stored procedure that returns a ResultSet.
ControllerResultSet	execReadRequest(SelectRequest request, MetadataCache metadataCache) Perform a read request.
ControllerResultSet	execReadStoredProcedure(StoredProcedure proc, MetadataCache metadataCache) Call a stored procedure that returns a ResultSet.
private ControllerResultSet	executeReadRequestOnBackend(SelectRequest request, DatabaseBackend backend, MetadataCache metadataCache) Execute a read request on the selected backend.
private ControllerResultSet	executeReadStoredProcedureOnBackend(StoredProcedure proc, DatabaseBackend backend, MetadataCache metadataCache) Execute a stored procedure on the selected backend.
private int	executeWriteRequestOnBackend(AbstractWriteRequest request, DatabaseBackend backend) Execute a write request on the selected backend.
private ControllerResultSet	executeWriteRequestWithKeysOnBackend(AbstractWriteRequest request, DatabaseBackend backend, MetadataCache metadataCache) Execute a write request on the selected backend and return the autogenerated keys.
private int	executeWriteStoredProcedureOnBackend(StoredProcedure proc, DatabaseBackend backend) Execute a stored procedure on the selected backend.
int	execWriteRequest(AbstractWriteRequest request) Perform a write request.
ControllerResultSet	execWriteRequestWithKeys(AbstractWriteRequest request, MetadataCache metadataCache) Perform a write request and return a ResultSet containing the auto generated keys.
int	execWriteStoredProcedure(StoredProcedure proc) Call a stored procedure that performs an update.
int	getNumberOfEnabledBackends() Get the number of currently enabled backends. 0 means that no backend is available.
abstract java.lang.String	getParallelDBXml() Return the XML tags of the ParallelDB load balancer implementation.
java.lang.String	getXmlImpl() Get information about the Request Load Balancer in xml
void	releaseSavepoint(TransactionMarkerMetaData tm, java.lang.String name) Release a savepoint from a transaction
void	rollback(TransactionMarkerMetaData tm) Rollback a transaction.
void	rollback(TransactionMarkerMetaData tm, java.lang.String savepointName) Rollback a transaction to a savepoint
void	setSavepoint(TransactionMarkerMetaData tm, java.lang.String name) Set a savepoint to a transaction.

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

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

backendPerTransactionId

private java.util.Hashtable backendPerTransactionId

numberOfEnabledBackends

private int numberOfEnabledBackends

Constructor Detail

ParallelDB

public ParallelDB(VirtualDatabase vdb)
           throws java.sql.SQLException,
                  javax.management.NotCompliantMBeanException

Creates a new ParallelDB load balancer with NO_PARSING and a SingleDB RAIDb level.

Parameters:

vdb - the virtual database this load balancer belongs to.

Throws:

java.sql.SQLException - if an error occurs

javax.management.NotCompliantMBeanException - if the MBean is not JMX compliant

Method Detail

chooseBackendForReadRequest

public abstract DatabaseBackend chooseBackendForReadRequest(AbstractRequest request)
                                                     throws java.sql.SQLException

Choose a backend using the implementation specific load balancing algorithm for read request execution.

Parameters:

request - request to execute

Returns:

the chosen backend

Throws:

java.sql.SQLException - if an error occurs

chooseBackendForWriteRequest

public abstract DatabaseBackend chooseBackendForWriteRequest(AbstractWriteRequest request)
                                                      throws java.sql.SQLException

Choose a backend using the implementation specific load balancing algorithm for write request execution.

Parameters:

request - request to execute

Returns:

the chosen backend

Throws:

java.sql.SQLException - if an error occurs

execReadRequest

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

Description copied from class: AbstractLoadBalancer

Perform 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 AbstractLoadBalancer

Parameters:

request - an SelectRequest

metadataCache - MetadataCache (null if none)

Returns:

the corresponding ControllerResultSet

Throws:

java.sql.SQLException - if an error occurs

See Also:

AbstractLoadBalancer.execReadRequest(SelectRequest, MetadataCache)

execReadOnlyReadStoredProcedure

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

Description copied from class: AbstractLoadBalancer

Call a read-only stored procedure that returns a ResultSet. The stored procedure will be executed by one node only.

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)

execReadStoredProcedure

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

Description copied from class: AbstractLoadBalancer

Call a stored procedure that returns a ResultSet. This stored procedure can possibly perform writes and will therefore be executed by all nodes.

Specified by:

execReadStoredProcedure 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.execReadStoredProcedure(StoredProcedure, MetadataCache)

execWriteRequest

public int execWriteRequest(AbstractWriteRequest request)
                     throws AllBackendsFailedException,
                            java.sql.SQLException

Description copied from class: AbstractLoadBalancer

Perform a write request. This request should usually be broadcasted to all nodes.

Specified by:

execWriteRequest in class AbstractLoadBalancer

Parameters:

request - an AbstractWriteRequest

Returns:

number of rows affected by the request

Throws:

AllBackendsFailedException - if all backends failed to execute the request

java.sql.SQLException - if an error occurs

See Also:

AbstractLoadBalancer.execWriteRequest(org.objectweb.cjdbc.common.sql.AbstractWriteRequest)

execWriteRequestWithKeys

public ControllerResultSet execWriteRequestWithKeys(AbstractWriteRequest request,
                                                    MetadataCache metadataCache)
                                             throws AllBackendsFailedException,
                                                    java.sql.SQLException

Description copied from class: AbstractLoadBalancer

Perform a write request and return a ResultSet containing the auto generated keys.

Specified by:

execWriteRequestWithKeys in class AbstractLoadBalancer

Parameters:

request - an AbstractWriteRequest

metadataCache - MetadataCache (null if none)

Returns:

auto generated keys

Throws:

AllBackendsFailedException - if all backends failed to execute the request

java.sql.SQLException - if an error occurs

See Also:

AbstractLoadBalancer.execWriteRequestWithKeys(AbstractWriteRequest, MetadataCache)

execWriteStoredProcedure

public int execWriteStoredProcedure(StoredProcedure proc)
                             throws java.sql.SQLException

Description copied from class: AbstractLoadBalancer

Call a stored procedure that performs an update.

Specified by:

execWriteStoredProcedure in class AbstractLoadBalancer

Parameters:

proc - the stored procedure call

Returns:

number of rows affected

Throws:

java.sql.SQLException - if an error occurs

See Also:

AbstractLoadBalancer.execWriteStoredProcedure(org.objectweb.cjdbc.common.sql.StoredProcedure)

executeReadRequestOnBackend

private ControllerResultSet executeReadRequestOnBackend(SelectRequest request,
                                                        DatabaseBackend backend,
                                                        MetadataCache metadataCache)
                                                 throws java.sql.SQLException,
                                                        UnreachableBackendException

Execute a read request on the selected backend.

Parameters:

request - the request to execute

backend - the backend that will execute the request

metadataCache - MetadataCache (null if none)

Returns:

the ControllerResultSet

Throws:

java.sql.SQLException - if an error occurs

UnreachableBackendException

executeReadStoredProcedureOnBackend

private ControllerResultSet executeReadStoredProcedureOnBackend(StoredProcedure proc,
                                                                DatabaseBackend backend,
                                                                MetadataCache metadataCache)
                                                         throws java.sql.SQLException,
                                                                UnreachableBackendException

Execute a stored procedure on the selected backend.

Parameters:

proc - the stored procedure to execute

backend - the backend that will execute the request

metadataCache - MetadataCache (null if none)

Returns:

the ControllerResultSet

Throws:

java.sql.SQLException - if an error occurs

UnreachableBackendException

executeWriteRequestOnBackend

private int executeWriteRequestOnBackend(AbstractWriteRequest request,
                                         DatabaseBackend backend)
                                  throws java.sql.SQLException,
                                         UnreachableBackendException

Execute a write request on the selected backend.

Parameters:

request - the request to execute

backend - the backend that will execute the request

Returns:

the number of modified rows

Throws:

java.sql.SQLException - if an error occurs

UnreachableBackendException

executeWriteRequestWithKeysOnBackend

private ControllerResultSet executeWriteRequestWithKeysOnBackend(AbstractWriteRequest request,
                                                                 DatabaseBackend backend,
                                                                 MetadataCache metadataCache)
                                                          throws java.sql.SQLException,
                                                                 UnreachableBackendException

Execute a write request on the selected backend and return the autogenerated keys.

Parameters:

request - the request to execute

backend - the backend that will execute the request

metadataCache - MetadataCache (null if none)

Returns:

the ResultSet containing the auto-generated keys

Throws:

java.sql.SQLException - if an error occurs

UnreachableBackendException

executeWriteStoredProcedureOnBackend

private int executeWriteStoredProcedureOnBackend(StoredProcedure proc,
                                                 DatabaseBackend backend)
                                          throws java.sql.SQLException,
                                                 UnreachableBackendException

Execute a stored procedure on the selected backend.

Parameters:

proc - the stored procedure to execute

backend - the backend that will execute the request

Returns:

the ResultSet

Throws:

java.sql.SQLException - if an error occurs

UnreachableBackendException

begin

public void begin(TransactionMarkerMetaData tm)
           throws java.sql.SQLException

Description copied from class: AbstractLoadBalancer

Begin a new transaction.

Specified by:

begin in class AbstractLoadBalancer

Parameters:

tm - The transaction marker metadata

Throws:

java.sql.SQLException - if an error occurs

See Also:

AbstractLoadBalancer.begin(org.objectweb.cjdbc.controller.requestmanager.TransactionMarkerMetaData)

commit

public void commit(TransactionMarkerMetaData tm)
            throws java.sql.SQLException

Description copied from class: AbstractLoadBalancer

Commit a transaction.

Specified by:

commit in class AbstractLoadBalancer

Parameters:

tm - The transaction marker metadata

Throws:

java.sql.SQLException - if an error occurs

See Also:

AbstractLoadBalancer.commit(org.objectweb.cjdbc.controller.requestmanager.TransactionMarkerMetaData)

rollback

public void rollback(TransactionMarkerMetaData tm)
              throws java.sql.SQLException

Description copied from class: AbstractLoadBalancer

Rollback a transaction.

Specified by:

rollback in class AbstractLoadBalancer

Parameters:

tm - The transaction marker metadata

Throws:

java.sql.SQLException - if an error occurs

See Also:

AbstractLoadBalancer.rollback(org.objectweb.cjdbc.controller.requestmanager.TransactionMarkerMetaData)

rollback

public void rollback(TransactionMarkerMetaData tm,
                     java.lang.String savepointName)
              throws java.sql.SQLException

Rollback a transaction to a savepoint

Specified by:

rollback in class AbstractLoadBalancer

Parameters:

tm - The transaction marker metadata

savepointName - The name of the savepoint

Throws:

java.sql.SQLException - if an error occurs

releaseSavepoint

public void releaseSavepoint(TransactionMarkerMetaData tm,
                             java.lang.String name)
                      throws java.sql.SQLException

Release a savepoint from a transaction

Specified by:

releaseSavepoint in class AbstractLoadBalancer

Parameters:

tm - The transaction marker metadata

name - The name of the savepoint ro release

Throws:

java.sql.SQLException - if an error occurs

setSavepoint

public void setSavepoint(TransactionMarkerMetaData tm,
                         java.lang.String name)
                  throws java.sql.SQLException

Set a savepoint to a transaction.

Specified by:

setSavepoint in class AbstractLoadBalancer

Parameters:

tm - The transaction marker metadata

name - The name of the new savepoint

Throws:

java.sql.SQLException - if an error occurs

enableBackend

public void enableBackend(DatabaseBackend db,
                          boolean writeEnabled)
                   throws java.sql.SQLException

Enables a backend that was previously disabled. Asks the corresponding connection manager to initialize the connections if needed.

No sanity checks are performed by this function.

Specified by:

enableBackend in class AbstractLoadBalancer

Parameters:

db - the database backend to enable

writeEnabled - True if the backend must be enabled for writes

Throws:

java.sql.SQLException - if an error occurs

disableBackend

public void disableBackend(DatabaseBackend db)
                    throws java.sql.SQLException

Disables a backend that was previously enabled. Asks the corresponding connection manager to finalize the connections if needed.

No sanity checks are performed by this function.

Specified by:

disableBackend in class AbstractLoadBalancer

Parameters:

db - the database backend to disable

Throws:

java.sql.SQLException - if an error occurs

getNumberOfEnabledBackends

public int getNumberOfEnabledBackends()

Description copied from class: AbstractLoadBalancer

Get the number of currently enabled backends. 0 means that no backend is available.

Specified by:

getNumberOfEnabledBackends in class AbstractLoadBalancer

Returns:

number of currently enabled backends

See Also:

AbstractLoadBalancer.getNumberOfEnabledBackends()

getXmlImpl

public java.lang.String getXmlImpl()

Description copied from class: AbstractLoadBalancer

Get information about the Request Load Balancer in xml

Specified by:

getXmlImpl in class AbstractLoadBalancer

Returns:

String containing information, xml formatted

See Also:

AbstractLoadBalancer.getXmlImpl()

getParallelDBXml

public abstract java.lang.String getParallelDBXml()

Return the XML tags of the ParallelDB load balancer implementation.

Returns:

content of ParallelDB xml