com.datastax.driver.core.exceptions

Class ReadFailureException

java.lang.Object

java.lang.Throwable

java.lang.Exception

java.lang.RuntimeException

com.datastax.driver.core.exceptions.DriverException

com.datastax.driver.core.exceptions.QueryExecutionException

com.datastax.driver.core.exceptions.QueryConsistencyException

com.datastax.driver.core.exceptions.ReadFailureException

All Implemented Interfaces:

CoordinatorException, Serializable

public class ReadFailureException
extends QueryConsistencyException

A non-timeout error during a read query.

This happens when some of the replicas that were contacted by the coordinator replied with an error.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
ReadFailureException(ConsistencyLevel consistency, int received, int required, int failed, boolean dataPresent) Deprecated. Legacy constructor for backward compatibility.
ReadFailureException(ConsistencyLevel consistency, int received, int required, int failed, Map<InetAddress,Integer> failuresMap, boolean dataPresent) This constructor should only be used internally by the driver when decoding error responses.
ReadFailureException(EndPoint endPoint, ConsistencyLevel consistency, int received, int required, int failed, boolean dataPresent) Deprecated. Legacy constructor for backward compatibility.
ReadFailureException(EndPoint endPoint, ConsistencyLevel consistency, int received, int required, int failed, Map<InetAddress,Integer> failuresMap, boolean dataPresent)

Method Summary

Modifier and Type	Method and Description
ReadFailureException	copy() Copy the exception.
ReadFailureException	copy(EndPoint endPoint)
int	getFailures() Returns the number of replicas that experienced a failure while executing the request.
Map<InetAddress,Integer>	getFailuresMap() Returns the a failure reason code for each node that failed.
boolean	wasDataRetrieved() Whether the actual data was amongst the received replica responses.

Methods inherited from class com.datastax.driver.core.exceptions.QueryConsistencyException

getAddress, getConsistencyLevel, getEndPoint, getHost, getReceivedAcknowledgements, getRequiredAcknowledgements

Methods inherited from class java.lang.Throwable

addSuppressed, fillInStackTrace, getCause, getLocalizedMessage, getMessage, getStackTrace, getSuppressed, initCause, printStackTrace, printStackTrace, printStackTrace, setStackTrace, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

ReadFailureException

public ReadFailureException(ConsistencyLevel consistency,
                            int received,
                            int required,
                            int failed,
                            Map<InetAddress,Integer> failuresMap,
                            boolean dataPresent)

This constructor should only be used internally by the driver when decoding error responses.

ReadFailureException

@Deprecated
public ReadFailureException(ConsistencyLevel consistency,
                                        int received,
                                        int required,
                                        int failed,
                                        boolean dataPresent)

Deprecated. Legacy constructor for backward compatibility.

ReadFailureException

public ReadFailureException(EndPoint endPoint,
                            ConsistencyLevel consistency,
                            int received,
                            int required,
                            int failed,
                            Map<InetAddress,Integer> failuresMap,
                            boolean dataPresent)

ReadFailureException

@Deprecated
public ReadFailureException(EndPoint endPoint,
                                        ConsistencyLevel consistency,
                                        int received,
                                        int required,
                                        int failed,
                                        boolean dataPresent)

Deprecated. Legacy constructor for backward compatibility.

Method Detail

getFailures

public int getFailures()

Returns the number of replicas that experienced a failure while executing the request.

Returns:

the number of failures.

getFailuresMap

public Map<InetAddress,Integer> getFailuresMap()

Returns the a failure reason code for each node that failed.

At the time of writing, the existing reason codes are:

• 0x0000: the error does not have a specific code assigned yet, or the cause is unknown.
• 0x0001: The read operation scanned too many tombstones (as defined by tombstone_failure_threshold in cassandra.yaml, causing a TombstoneOverwhelmingException.

(please refer to the Cassandra documentation for your version for the most up-to-date list of errors)

This feature is available for protocol v5 or above only. With lower protocol versions, the map will always be empty.

Returns:

a map of IP addresses to failure codes.

wasDataRetrieved

public boolean wasDataRetrieved()

Whether the actual data was amongst the received replica responses.

During reads, Cassandra doesn't request data from every replica to minimize internal network traffic. Instead, some replicas are only asked for a checksum of the data. A read timeout may occurred even if enough replicas have responded to fulfill the consistency level if only checksum responses have been received. This method allows to detect that case.

Returns:

whether the data was amongst the received replica responses.

copy

public ReadFailureException copy()

Description copied from class: DriverException

Copy the exception.

This returns a new exception, equivalent to the original one, except that because a new object is created in the current thread, the top-most element in the stacktrace of the exception will refer to the current thread (this is mainly intended for internal use by the driver). The cause of the copied exception will be the original exception.

Overrides:

copy in class DriverException

Returns:

a copy/clone of this exception.

copy

public ReadFailureException copy(EndPoint endPoint)