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https://issues.apache.org/jira/browse/DRILL-6625?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16604682#comment-16604682
]
Abhishek Ravi commented on DRILL-6625:
--------------------------------------
Had some time to dig further into this issue. [~ben-zvi] - mentioned that the
issues are seen when running on Mac and they seem to be intermittent failures.
h3. h3. Issue 1 - "{{The server disconnected before a response was received"}}
In {{KafkaMessageGenerator}}, the following properties are set when creating a
producer.
{code}
producerProperties.put(ProducerConfig.RETRIES_CONFIG, 0);
producerProperties.put(ProducerConfig.MAX_IN_FLIGHT_REQUESTS_PER_CONNECTION, 1);
producerProperties.put(ProducerConfig.REQUEST_TIMEOUT_MS_CONFIG, 1000);
{code}
Consider slower systems or heavily loaded system, where the acknowledgement for
the message produced did not arrive in 1000ms - since {{RETRIES_CONFIG}} is set
to 0, produce will fail with {{org.apache.kafka.common.errors.NetworkException:
The server disconnected before a response was received.}}
Although, the unit tests never failed in my environment, I was able to
reproduce this error by reducing the value for {{REQUEST_TIMEOUT_MS_CONFIG}} to
as low as *50 ms*.
{noformat}
23:19:55.136 [main] ERROR o.a.d.e.s.k.KafkaMessageGenerator -
org.apache.kafka.common.errors.NetworkException: The server disconnected before
a response was received.
java.util.concurrent.ExecutionException:
org.apache.kafka.common.errors.NetworkException: The server disconnected before
a response was received.
at
org.apache.kafka.clients.producer.internals.FutureRecordMetadata.valueOrError(FutureRecordMetadata.java:94)
~[kafka-clients-0.11.0.1.jar:na]
at
org.apache.kafka.clients.producer.internals.FutureRecordMetadata.get(FutureRecordMetadata.java:64)
~[kafka-clients-0.11.0.1.jar:na]
at
org.apache.kafka.clients.producer.internals.FutureRecordMetadata.get(FutureRecordMetadata.java:29)
~[kafka-clients-0.11.0.1.jar:na]
at
org.apache.drill.exec.store.kafka.KafkaMessageGenerator.populateJsonMsgIntoKafka(KafkaMessageGenerator.java:126)
~[test-classes/:na]
at
org.apache.drill.exec.store.kafka.TestKafkaSuit.initKafka(TestKafkaSuit.java:88)
[test-classes/:na]
{noformat}
h3. h3. ISSUE 2 - {{Failed to fetch messages within 200 milliseconds}}
Again, this issue may occur in slower systems or systems under heavy load where
a consumer poll did not return messages within {{Poll Timeout}} set.
For unit tests, {{KAFKA_POLL_TIMEOUT}} is set to *200 ms*.
{code}
testNoResult(String.format("alter session set `%s` = %d",
ExecConstants.KAFKA_POLL_TIMEOUT, 200));
{code}
If a poll does not return a message within this time then following exception
is thrown.
{{org.apache.drill.exec.rpc.RpcException:
org.apache.drill.common.exceptions.UserRemoteException: DATA_READ ERROR: Failed
to fetch messages within 10 milliseconds. Consider increasing the value of the
property : store.kafka.poll.timeout}}
I was able to reproduce this issue by reducing {{KAFKA_POLL_TIMEOUT}} value to
as low as *50 ms.*
h3. h3. Solution
* The value for producer {{REQUEST_TIMEOUT_MS_CONFIG}} should be increased (to
say 10s) and similarly the value for consumer {{KAFKA_POLL_TIMEOUT}} should
also be increased.
* We should increase producer {{RETRIES_CONFIG}} to allow retries. We can
eliminate the possibility of having duplicate messages by using *{{Idempotent
Producer}}*{{.}}
[~akumarb2010], [~kkhatua] - any thoughts?
> Intermittent failures in Kafka unit tests
> -----------------------------------------
>
> Key: DRILL-6625
> URL: https://issues.apache.org/jira/browse/DRILL-6625
> Project: Apache Drill
> Issue Type: Bug
> Components: Storage - Other
> Affects Versions: 1.13.0
> Reporter: Boaz Ben-Zvi
> Assignee: Abhishek Ravi
> Priority: Major
> Fix For: 1.15.0
>
>
> The following failures have been seen (consistently on my Mac, or
> occasionally on Jenkins) when running the unit tests, in the Kafka test suit.
> After the failure, maven hangs for a long time.
> Cost was 0.0 (instead of 26.0) :
> {code:java}
> Running org.apache.drill.exec.store.kafka.KafkaFilterPushdownTest
> 16:46:57.748 [main] ERROR org.apache.drill.TestReporter - Test Failed (d:
> -65.3 KiB(73.6 KiB), h: -573.5 MiB(379.5 MiB), nh: 1.2 MiB(117.1 MiB)):
> testPushdownWithOr(org.apache.drill.exec.store.kafka.KafkaFilterPushdownTest)
> java.lang.AssertionError: Unable to find expected string "kafkaScanSpec"
> : {
> "topicName" : "drill-pushdown-topic"
> },
> "cost" : 26.0 in plan: {
> "head" : {
> "version" : 1,
> "generator" : {
> "type" : "ExplainHandler",
> "info" : ""
> },
> "type" : "APACHE_DRILL_PHYSICAL",
> "options" : [ {
> "kind" : "STRING",
> "accessibleScopes" : "ALL",
> "name" : "store.kafka.record.reader",
> "string_val" :
> "org.apache.drill.exec.store.kafka.decoders.JsonMessageReader",
> "scope" : "SESSION"
> }, {
> "kind" : "LONG",
> "accessibleScopes" : "ALL",
> "name" : "planner.width.max_per_node",
> "num_val" : 2,
> "scope" : "SESSION"
> }, {
> "kind" : "BOOLEAN",
> "accessibleScopes" : "ALL",
> "name" : "exec.errors.verbose",
> "bool_val" : true,
> "scope" : "SESSION"
> }, {
> "kind" : "LONG",
> "accessibleScopes" : "ALL",
> "name" : "store.kafka.poll.timeout",
> "num_val" : 200,
> "scope" : "SESSION"
> } ],
> "queue" : 0,
> "hasResourcePlan" : false,
> "resultMode" : "EXEC"
> },
> "graph" : [ {
> "pop" : "kafka-scan",
> "@id" : 6,
> "userName" : "",
> "kafkaStoragePluginConfig" : {
> "type" : "kafka",
> "kafkaConsumerProps" : {
> "bootstrap.servers" : "127.0.0.1:63751",
> "group.id" : "drill-test-consumer"
> },
> "enabled" : true
> },
> "columns" : [ "`**`" ],
> "kafkaScanSpec" : {
> "topicName" : "drill-pushdown-topic"
> },
> "cost" : 0.0
> }, {
> {code}
> Or occasionally:
> {code}
> -------------------------------------------------------
> T E S T S
> -------------------------------------------------------
> 11:52:57.571 [main] ERROR o.a.d.e.s.k.KafkaMessageGenerator -
> org.apache.kafka.common.errors.NetworkException: The server disconnected
> before a response was received.
> java.util.concurrent.ExecutionException:
> org.apache.kafka.common.errors.NetworkException: The server disconnected
> before a response was received.
> {code}
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