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https://issues.apache.org/jira/browse/FLINK-9083?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16693703#comment-16693703
]
ASF GitHub Bot commented on FLINK-9083:
---------------------------------------
zentol 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_r235142071
##########
File path:
flink-connectors/flink-connector-cassandra/src/main/java/org/apache/flink/streaming/connectors/cassandra/CassandraSinkBase.java
##########
@@ -127,35 +144,112 @@ public void close() throws Exception {
}
@Override
- public void initializeState(FunctionInitializationContext context)
throws Exception {
- }
+ public void initializeState(FunctionInitializationContext context)
throws Exception {}
@Override
- public void snapshotState(FunctionSnapshotContext ctx) throws Exception
{
+ public void snapshotState(FunctionSnapshotContext context) throws
Exception {
checkAsyncErrors();
- waitForPendingUpdates();
+ flush();
checkAsyncErrors();
}
- private void waitForPendingUpdates() throws InterruptedException {
- synchronized (updatesPending) {
- while (updatesPending.get() > 0) {
- updatesPending.wait();
+ @Override
+ public void invoke(IN value) throws Exception {
+ checkAsyncErrors();
+ tryAcquire();
+ final ListenableFuture<V> result = send(value);
+ Futures.addCallback(result, new FutureCallback<V>() {
+ @Override
+ public void onSuccess(V ignored) {
+ release();
}
+
+ @Override
+ public void onFailure(Throwable currentError) {
+ setAsyncErrors(currentError);
+ release();
+ }
+ });
+ }
+
+ // ----------------------- User-Defined Sink Methods
----------------------
+
+ public abstract ListenableFuture<V> send(IN value);
+
+ // ------------------------- Configuration Methods
------------------------
+
+ /**
+ * Sets the maximum allowed number of concurrent requests for this sink.
+ *
+ * @param maxConcurrentRequests maximum number of concurrent requests
allowed
+ * @param timeout timeout duration when acquiring a permit to execute
+ * @param unit timeout unit when acquiring a permit to execute
+ */
+ public void setMaxConcurrentRequests(int maxConcurrentRequests, long
timeout, TimeUnit unit) {
+ Preconditions.checkArgument(maxConcurrentRequests >= 0,
"maxConcurrentRequests cannot be negative.");
+ Preconditions.checkArgument(timeout >= 0, "timeout cannot be
negative.");
+ this.maxConcurrentRequests = maxConcurrentRequests;
+ this.maxConcurrentRequestsTimeout = timeout;
+ this.maxConcurrentRequestsTimeoutUnit = unit;
+ }
+
+ // --------------------------- Cassandra Methods
--------------------------
+
+ protected Cluster createCluster() {
Review comment:
This methods seems unnecessary.
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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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