com.datastax.driver.core

Class ExecutionInfo

java.lang.Object

com.datastax.driver.core.ExecutionInfo

public class ExecutionInfo
extends Object

Basic information on the execution of a query.

Constructor Summary

Constructors

Constructor and Description
ExecutionInfo(int speculativeExecutions, int successfulExecutionIndex, List<Host> triedHosts, ConsistencyLevel achievedConsistency, Map<String,ByteBuffer> customPayload)

Method Summary

Modifier and Type	Method and Description
ConsistencyLevel	getAchievedConsistencyLevel() If the query returned without achieving the requested consistency level due to the RetryPolicy, this return the biggest consistency level that has been actually achieved by the query.
Map<String,ByteBuffer>	getIncomingPayload() Return the incoming payload, that is, the payload that the server sent back with its response, if any, or null, if the server did not include any custom payload.
PagingState	getPagingState() The paging state of the query.
byte[]	getPagingStateUnsafe() Returns the "raw" paging state of the query.
Host	getQueriedHost() Return the Cassandra host that coordinated this query.
QueryTrace	getQueryTrace() Return the query trace if tracing was enabled on this query.
ListenableFuture<QueryTrace>	getQueryTraceAsync() Placeholder for async query trace retrieval (not implemented yet).
int	getSpeculativeExecutions() The number of speculative executions that were started for this query.
Statement	getStatement() Get the statement that has been executed.
int	getSuccessfulExecutionIndex() The index of the execution that completed this query.
List<Host>	getTriedHosts() The list of tried hosts for this query.
List<String>	getWarnings() Returns the server-side warnings for this query.
boolean	isSchemaInAgreement() Whether the cluster had reached schema agreement after the execution of this query.

Methods inherited from class java.lang.Object

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

Constructor Detail

ExecutionInfo

public ExecutionInfo(int speculativeExecutions,
                     int successfulExecutionIndex,
                     List<Host> triedHosts,
                     ConsistencyLevel achievedConsistency,
                     Map<String,ByteBuffer> customPayload)

Method Detail

getTriedHosts

public List<Host> getTriedHosts()

The list of tried hosts for this query.

In general, this will be a singleton list with the host that coordinated that query. However:

• if a host is tried by the driver but is dead or in error, that host is recorded and the query is retried;
• on a timeout or unavailable exception, some RetryPolicy may retry the query on the same host, so the same host might appear twice.
• if speculative executions are enabled, this will also contain hosts that were tried by other executions (however, note that this only contains hosts which timed out, or for which a response was received; if an execution is waiting for a response from a host and another execution completes the request in the meantime, then the host of the first execution will not be in that list).

If you are only interested in fetching the final (and often only) node coordinating the query, getQueriedHost() provides a shortcut to fetch the last element of the list returned by this method.

Returns:

the list of tried hosts for this query, in the order tried.

getQueriedHost

public Host getQueriedHost()

Return the Cassandra host that coordinated this query.

This is a shortcut for getTriedHosts().get(getTriedHosts().size() - 1).

Returns:

return the Cassandra host that coordinated this query.

getSpeculativeExecutions

public int getSpeculativeExecutions()

The number of speculative executions that were started for this query.

This does not include the initial, normal execution of the query. Therefore, if speculative executions are disabled, this will always be 0. If they are enabled and one speculative execution was triggered in addition to the initial execution, this will be 1, etc.

See Also:

getSuccessfulExecutionIndex(), Cluster.Builder.withSpeculativeExecutionPolicy(com.datastax.driver.core.policies.SpeculativeExecutionPolicy)

getSuccessfulExecutionIndex

public int getSuccessfulExecutionIndex()

The index of the execution that completed this query.

0 represents the initial, normal execution of the query, 1 represents the first speculative execution, etc.

See Also:

getSpeculativeExecutions(), Cluster.Builder.withSpeculativeExecutionPolicy(com.datastax.driver.core.policies.SpeculativeExecutionPolicy)

getAchievedConsistencyLevel

public ConsistencyLevel getAchievedConsistencyLevel()

If the query returned without achieving the requested consistency level due to the RetryPolicy, this return the biggest consistency level that has been actually achieved by the query.

Note that the default RetryPolicy (DefaultRetryPolicy) will never allow a query to be successful without achieving the initially requested consistency level and hence with that default policy, this method will always return null. However, it might occasionally return a non-null with say, DowngradingConsistencyRetryPolicy.

Returns:

null if the original consistency level of the query was achieved, or the consistency level that was ultimately achieved if the RetryPolicy triggered a retry at a different consistency level than the original one.

getQueryTrace

public QueryTrace getQueryTrace()

Return the query trace if tracing was enabled on this query.

Note that accessing the fields of the the returned object will trigger a blocking background query.

Returns:

the QueryTrace object for this query if tracing was enable for this query, or null otherwise.

getQueryTraceAsync

public ListenableFuture<QueryTrace> getQueryTraceAsync()

Placeholder for async query trace retrieval (not implemented yet).

Async query trace retrieval will be implemented in a future version. This method is added now to avoid breaking binary compatibility later. The current implementation merely wraps the result of getQueryTrace() in an immediate future; it will still trigger a blocking query when the query trace's fields are accessed.

Returns:

currently, an immediate future containing the result of getQueryTrace().

getPagingState

public PagingState getPagingState()

The paging state of the query.

This object represents the next page to be fetched if this query is multi page. It can be saved and reused later on the same statement.

Returns:

the paging state or null if there is no next page.

See Also:

Statement.setPagingState(PagingState)

getPagingStateUnsafe

public byte[] getPagingStateUnsafe()

Returns the "raw" paging state of the query.

Contrary to getPagingState(), there will be no validation when this is later reinjected into a statement.

Returns:

the paging state or null if there is no next page.

See Also:

Statement.setPagingStateUnsafe(byte[])

isSchemaInAgreement

public boolean isSchemaInAgreement()

Whether the cluster had reached schema agreement after the execution of this query.

After a successful schema-altering query (ex: creating a table), the driver will check if the cluster's nodes agree on the new schema version. If not, it will keep retrying for a given delay (configurable via Cluster.Builder.withMaxSchemaAgreementWaitSeconds(int)).

If this method returns false, clients can call Metadata.checkSchemaAgreement() later to perform the check manually.

Note that the schema agreement check is only performed for schema-altering queries For other query types, this method will always return true.

Returns:

whether the cluster reached schema agreement, or true for a non schema-altering statement.

getWarnings

public List<String> getWarnings()

Returns the server-side warnings for this query.

This feature is only available with ProtocolVersion.V4 or above; with lower versions, the returned list will always be empty.

Returns:

the warnings, or an empty list if there are none.

Since:

2.2

getIncomingPayload

public Map<String,ByteBuffer> getIncomingPayload()

Return the incoming payload, that is, the payload that the server sent back with its response, if any, or null, if the server did not include any custom payload.

This method returns a read-only view of the original map, but its values remain inherently mutable. Callers should take care not to modify the returned map in any way.

This feature is only available with ProtocolVersion.V4 or above; with lower versions, this method will always return null.

Returns:

the custom payload that the server sent back with its response, if any, or null, if the server did not include any custom payload.

Since:

2.2

getStatement

public Statement getStatement()

Get the statement that has been executed.

Returns:

the statement executed.