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https://issues.apache.org/jira/browse/FLINK-9083?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16646576#comment-16646576
]
ASF GitHub Bot commented on FLINK-9083:
---------------------------------------
azagrebin commented on a change in pull request #6782: [FLINK-9083][Cassandra
Connector] Add async backpressure support to Cassandra Connector
URL: https://github.com/apache/flink/pull/6782#discussion_r224477067
##########
File path:
flink-connectors/flink-connector-cassandra/src/main/java/org/apache/flink/streaming/connectors/cassandra/CassandraSinkBase.java
##########
@@ -43,70 +48,82 @@
*/
public abstract class CassandraSinkBase<IN, V> extends RichSinkFunction<IN>
implements CheckpointedFunction {
protected final Logger log = LoggerFactory.getLogger(getClass());
- protected transient Cluster cluster;
- protected transient Session session;
- protected transient volatile Throwable exception;
- protected transient FutureCallback<V> callback;
+ // ------------------------ Default Configurations
------------------------
+
+ /**
+ * The default maximum number of concurrent requests. By default,
{@code Integer.MAX_VALUE}.
+ */
+ public static final int DEFAULT_MAX_CONCURRENT_REQUESTS =
Integer.MAX_VALUE;
+
+ /**
+ * The default timeout duration when acquiring a permit to execute. By
default, {@code Long.MAX_VALUE}.
+ */
+ public static final long DEFAULT_MAX_CONCURRENT_REQUESTS_TIMEOUT =
Long.MAX_VALUE;
+
+ /**
+ * The default timeout unit when acquiring a permit to execute. By
default, milliseconds.
+ */
+ public static final TimeUnit
DEFAULT_MAX_CONCURRENT_REQUESTS_TIMEOUT_UNIT = TimeUnit.MILLISECONDS;
+
+ // ------------------------- Configuration Fields
-------------------------
+
+ private int maxConcurrentRequests = DEFAULT_MAX_CONCURRENT_REQUESTS;
+ private long maxConcurrentRequestsTimeout =
DEFAULT_MAX_CONCURRENT_REQUESTS_TIMEOUT;
+ private TimeUnit maxConcurrentRequestsTimeoutUnit =
DEFAULT_MAX_CONCURRENT_REQUESTS_TIMEOUT_UNIT;
Review comment:
These parameters can be final actually because they are set only during
construction. If they would explode constructor too much, I would rather create
a separate immutable config class for them and all other possible sink base
options internally.
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> Add async backpressure support to Cassandra Connector
> -----------------------------------------------------
>
> Key: FLINK-9083
> URL: https://issues.apache.org/jira/browse/FLINK-9083
> Project: Flink
> Issue Type: Improvement
> Components: Cassandra Connector
> Reporter: Jacob Park
> Assignee: Jacob Park
> Priority: Minor
> Labels: pull-request-available
>
> As the CassandraSinkBase derivatives utilize async writes, they do not block
> the task to introduce any backpressure.
> I am currently using a semaphore to provide backpressure support by blocking
> at a maximum concurrent requests limit like how DataStax's Spark Cassandra
> Connector functions:
> [https://github.com/datastax/spark-cassandra-connector/blob/v2.0.7/spark-cassandra-connector/src/main/scala/com/datastax/spark/connector/writer/AsyncExecutor.scala#L18]
> This improvement has greatly improved the fault-tolerance of our Cassandra
> Sink Connector implementation on Apache Flink in production. I would like to
> contribute this feature back upstream.
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