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DefaultRetryPolicyOnReadTimeout Method
Defines whether to retry and at which consistency level on a read timeout.

This method triggers a maximum of one retry, and only if enough replica had responded to the read request but data was not retrieved amongst those. Indeed, that case usually means that enough replica are alive to satisfy the consistency but the coordinator picked a dead one for data retrieval, not having detected that replica as dead yet. The reasoning for retrying then is that by the time we get the timeout the dead replica will likely have been detected as dead and the retry has a high change of success.

Namespace: Cassandra
Assembly: Cassandra (in Cassandra.dll) Version: 3.0.9 (git 5ca22bb)
Syntax
C#
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public RetryDecision OnReadTimeout(
	IStatement query,
	ConsistencyLevel cl,
	int requiredResponses,
	int receivedResponses,
	bool dataRetrieved,
	int nbRetry
)

Parameters

query
Type: CassandraIStatement
the original query that timed out.
cl
Type: CassandraConsistencyLevel
the original consistency level of the read that timed out.
requiredResponses
Type: SystemInt32
the number of responses that were required to achieve the requested consistency level.
receivedResponses
Type: SystemInt32
the number of responses that had been received by the time the timeout exception was raised.
dataRetrieved
Type: SystemBoolean
whether actual data (by opposition to data checksum) was present in the received responses.
nbRetry
Type: SystemInt32
the number of retry already performed for this operation.

Return Value

Type: RetryDecision
RetryDecision.Retry(cl) if no retry attempt has yet been tried and receivedResponses >= requiredResponses && !dataRetrieved, RetryDecision.Rethrow() otherwise.

Implements

IRetryPolicyOnReadTimeout(IStatement, ConsistencyLevel, Int32, Int32, Boolean, Int32)
See Also