org.apache.lens.driver.jdbc

Class JDBCDriver

java.lang.Object

org.apache.lens.server.api.driver.AbstractLensDriver

org.apache.lens.driver.jdbc.JDBCDriver

All Implemented Interfaces:

Externalizable, Serializable, LensDriver

public class JDBCDriver
extends AbstractLensDriver

This driver is responsible for running queries against databases which can be queried using the JDBC API.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	JDBCDriver.DummyQueryRewriter The Class DummyQueryRewriter.

Field Summary

Fields

Modifier and Type	Field and Description
static AtomicInteger	THID The Constant THID.

Constructor Summary

Constructors

Constructor and Description
JDBCDriver()

Method Summary

Methods

Modifier and Type	Method and Description
boolean	cancelQuery(QueryHandle handle) Cancel the execution of the query, specified by the handle.
void	close() Close the driver, releasing all resouces used up by the driver.
void	closePreparedQuery(QueryPrepareHandle handle) Close the prepare query specified by the prepared handle, releases all the resources held by the prepared query.
void	closeQuery(QueryHandle handle) Close the query specified by the handle, releases all the resources held by the query.
void	closeResultSet(QueryHandle handle) Close the resultset for the query.
void	configure(org.apache.hadoop.conf.Configuration conf, String driverType, String driverName) Configure driver with Configuration passed.
QueryCost	estimate(AbstractQueryContext qctx) Estimate the cost of execution for given query.
LensResultSet	execute(QueryContext context) Blocking execute of the query.
void	executeAsync(QueryContext context) Asynchronously execute the query.
DriverQueryPlan	explain(AbstractQueryContext explainCtx) Explain the given query.
DriverQueryPlan	explainAndPrepare(PreparedQueryContext pContext) Explain and prepare the given query.
LensResultSet	fetchResultSet(QueryContext context) Fetch the results of the query, specified by the handle.
org.apache.hadoop.conf.Configuration	getConf() Get driver configuration
com.google.common.collect.ImmutableSet<QueryLaunchingConstraint>	getQueryConstraints()
com.google.common.collect.ImmutableSet<WaitingQueriesSelectionPolicy>	getWaitingQuerySelectionPolicies()
void	prepare(PreparedQueryContext pContext) Prepare the given query.
void	readExternal(ObjectInput arg0)
void	registerDriverEventListener(LensEventListener<DriverEvent> driverEventListener) Add a listener for driver events.
void	registerForCompletionNotification(QueryHandle handle, long timeoutMillis, QueryCompletionListener listener) Register for query completion notification.
void	updateStatus(QueryContext context) Get status of the query, specified by the handle.
void	validate(AbstractQueryContext pContext) Validate query using prepare
void	writeExternal(ObjectOutput arg0)

Methods inherited from class org.apache.lens.server.api.driver.AbstractLensDriver

decidePriority, getFullyQualifiedName, toString

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

THID

public static final AtomicInteger THID

The Constant THID.

Constructor Detail

JDBCDriver

public JDBCDriver()

Method Detail

getConf

public org.apache.hadoop.conf.Configuration getConf()

Get driver configuration

configure

public void configure(org.apache.hadoop.conf.Configuration conf,
             String driverType,
             String driverName)
               throws LensException

Description copied from interface: LensDriver

Configure driver with Configuration passed.

Specified by:

configure in interface LensDriver

Overrides:

configure in class AbstractLensDriver

Parameters:

conf - The configuration object

driverType - Type of the driver (Example: hive, jdbc, el)

driverName - Name of this driver

Throws:

LensException - the lens exception

estimate

public QueryCost estimate(AbstractQueryContext qctx)
                   throws LensException

Description copied from interface: LensDriver

Estimate the cost of execution for given query. This should be returned with very less latency - should return within 10s of milli seconds.

Parameters:

qctx - The query context

Returns:

The QueryCostTO object

Throws:

LensException - the lens exception if driver cannot estimate

explain

public DriverQueryPlan explain(AbstractQueryContext explainCtx)
                        throws LensException

Explain the given query.

Parameters:

explainCtx - The explain context

Returns:

The query plan object;

Throws:

LensException - the lens exception

validate

public void validate(AbstractQueryContext pContext)
              throws LensException

Validate query using prepare

Parameters:

pContext -

Throws:

LensException

prepare

public void prepare(PreparedQueryContext pContext)
             throws LensException

Prepare the given query.

Parameters:

pContext - the context

Throws:

LensException - the lens exception

explainAndPrepare

public DriverQueryPlan explainAndPrepare(PreparedQueryContext pContext)
                                  throws LensException

Explain and prepare the given query.

Parameters:

pContext - the context

Returns:

The query plan object;

Throws:

LensException - the lens exception

closePreparedQuery

public void closePreparedQuery(QueryPrepareHandle handle)
                        throws LensException

Close the prepare query specified by the prepared handle, releases all the resources held by the prepared query.

Parameters:

handle - The query handle

Throws:

LensException - the lens exception

execute

public LensResultSet execute(QueryContext context)
                      throws LensException

Blocking execute of the query.

Parameters:

context - the context

Returns:

returns the result set

Throws:

LensException - the lens exception

executeAsync

public void executeAsync(QueryContext context)
                  throws LensException

Asynchronously execute the query.

Parameters:

context - The query context

Throws:

LensException - the lens exception

registerForCompletionNotification

public void registerForCompletionNotification(QueryHandle handle,
                                     long timeoutMillis,
                                     QueryCompletionListener listener)
                                       throws LensException

Register for query completion notification.

Parameters:

handle - the handle

timeoutMillis - the timeout millis

listener - the listener

Throws:

LensException - the lens exception

updateStatus

public void updateStatus(QueryContext context)
                  throws LensException

Get status of the query, specified by the handle.

Parameters:

context - The query handle

Throws:

LensException - the lens exception

fetchResultSet

public LensResultSet fetchResultSet(QueryContext context)
                             throws LensException

Fetch the results of the query, specified by the handle.

Parameters:

context - the context

Returns:

returns the LensResultSet.

Throws:

LensException - the lens exception

closeResultSet

public void closeResultSet(QueryHandle handle)
                    throws LensException

Close the resultset for the query.

Parameters:

handle - The query handle

Throws:

LensException - the lens exception

cancelQuery

public boolean cancelQuery(QueryHandle handle)
                    throws LensException

Cancel the execution of the query, specified by the handle.

Parameters:

handle - The query handle.

Returns:

true if cancel was successful, false otherwise

Throws:

LensException - the lens exception

closeQuery

public void closeQuery(QueryHandle handle)
                throws LensException

Close the query specified by the handle, releases all the resources held by the query.

Parameters:

handle - The query handle

Throws:

LensException - the lens exception

close

public void close()
           throws LensException

Close the driver, releasing all resouces used up by the driver.

Throws:

LensException - the lens exception

registerDriverEventListener

public void registerDriverEventListener(LensEventListener<DriverEvent> driverEventListener)

Add a listener for driver events.

Parameters:

driverEventListener - the driver event listener

getWaitingQuerySelectionPolicies

public com.google.common.collect.ImmutableSet<WaitingQueriesSelectionPolicy> getWaitingQuerySelectionPolicies()

Returns:

The WaitingQueriesSelectionPolicys to be used to select waiting queries eligible to be moved out of waiting state. If there are no driver level waiting query selection policies, then an empty set is returned. null is never returned.

readExternal

public void readExternal(ObjectInput arg0)
                  throws IOException,
                         ClassNotFoundException

Throws:

IOException

ClassNotFoundException

writeExternal

public void writeExternal(ObjectOutput arg0)
                   throws IOException

Throws:

IOException

getQueryConstraints

@Generated(value="lombok")
public com.google.common.collect.ImmutableSet<QueryLaunchingConstraint> getQueryConstraints()

Returns:

The QueryLaunchingConstraints to be checked before launching a query on driver. If there are no driver level constraints, then an empty set is returned. null is never returned.