[GitHub] [kafka] vvcephei commented on a change in pull request #8886: KAFKA-9891: fix corrupted StandbyTask state

[GitBox <gi...@apache.org>]

vvcephei commented on a change in pull request #8886:
URL: https://github.com/apache/kafka/pull/8886#discussion_r441635399



##########
File path: streams/src/test/java/org/apache/kafka/streams/integration/StandbyTaskEOSIntegrationTest.java
##########
@@ -0,0 +1,300 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.kafka.streams.integration;
+
+import org.apache.kafka.clients.consumer.ConsumerConfig;
+import org.apache.kafka.common.serialization.IntegerDeserializer;
+import org.apache.kafka.common.serialization.IntegerSerializer;
+import org.apache.kafka.common.serialization.Serdes;
+import org.apache.kafka.streams.KafkaStreams;
+import org.apache.kafka.streams.KeyValue;
+import org.apache.kafka.streams.StoreQueryParameters;
+import org.apache.kafka.streams.StreamsBuilder;
+import org.apache.kafka.streams.StreamsConfig;
+import org.apache.kafka.streams.integration.utils.EmbeddedKafkaCluster;
+import org.apache.kafka.streams.integration.utils.IntegrationTestUtils;
+import org.apache.kafka.streams.kstream.Transformer;
+import org.apache.kafka.streams.processor.ProcessorContext;
+import org.apache.kafka.streams.state.KeyValueIterator;
+import org.apache.kafka.streams.state.KeyValueStore;
+import org.apache.kafka.streams.state.QueryableStoreTypes;
+import org.apache.kafka.streams.state.Stores;
+import org.apache.kafka.test.TestUtils;
+import org.junit.Before;
+import org.junit.ClassRule;
+import org.junit.Test;
+
+import java.time.Duration;
+import java.util.Collections;
+import java.util.Properties;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import static org.apache.kafka.streams.integration.utils.IntegrationTestUtils.startApplicationAndWaitUntilRunning;
+import static org.apache.kafka.test.TestUtils.waitForCondition;
+
+/**
+ * An integration test to verify the conversion of a dirty-closed EOS
+ * task towards a standby task is safe across restarts of the application.
+ */
+public class StandbyTaskEOSIntegrationTest {

Review comment:
       should this be parameterized for both flavors of eos?

##########
File path: streams/src/main/java/org/apache/kafka/streams/processor/internals/StandbyTask.java
##########
@@ -85,6 +85,21 @@ public void initializeMetadata() {}
     public boolean initializeStateStores() {
         log.trace("Initializing state stores");
         registerStateStores();
+
+        if (eosEnabled) {
+            final Set<TopicPartition> partitionsToReinitialize = new HashSet<>();
+            for (final TopicPartition partition : stateMgr.checkpointed().keySet()) {

Review comment:
       I'm sure this works, but something seems odd about listing _checkpointed_ partitions to find ones that are _not checkpointed_. Maybe we need to encapsulate this search, or provide a more semantically appropriate "list all changelog partitions" method?

##########
File path: streams/src/main/java/org/apache/kafka/streams/processor/internals/StandbyTask.java
##########
@@ -85,6 +85,21 @@ public void initializeMetadata() {}
     public boolean initializeStateStores() {
         log.trace("Initializing state stores");
         registerStateStores();
+
+        if (eosEnabled) {

Review comment:
       I have always been, and continue to be, mystified about why we're 100% a-ok with having corrupted state stores in ALOS mode. I understand that there are some kinds of corruption that are unavoidable without some extra work in the stores, but this check is just explicitly ignoring detectable corruption, which seems a bit extreme. Can we remove this conditional? The rest of these checks seem to apply equally well under all execution semantic modes.




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