shibd commented on code in PR #25293:
URL: https://github.com/apache/pulsar/pull/25293#discussion_r2944139870
##########
pulsar-broker/src/test/java/org/apache/pulsar/client/impl/TableViewTest.java:
##########
@@ -97,6 +102,17 @@ protected void cleanup() throws Exception {
super.internalCleanup();
}
+ @Test
+ public void testFailedCreateReader() throws Exception {
Review Comment:
This test needs to assert a throw exception.
In fact, this test duplication with
[broker/transaction/buffer/impl/TableViewTest.java](https://github.com/apache/pulsar/pull/25293/changes#diff-edfc112d734b7be5af2074033fa84f7f49e22ca47223cf064ae2bc19208eabb4)
##########
pulsar-broker/src/test/java/org/apache/pulsar/broker/transaction/buffer/impl/TableViewTest.java:
##########
@@ -0,0 +1,50 @@
+/*
+ * 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.pulsar.broker.transaction.buffer.impl;
+
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.function.Function;
+import org.apache.pulsar.broker.systopic.SystemTopicClient;
+import org.apache.pulsar.client.api.PulsarClientException;
+import org.apache.pulsar.common.naming.TopicName;
+import org.apache.pulsar.common.util.FutureUtil;
+import org.testng.Assert;
+import org.testng.annotations.Test;
+
+public class TableViewTest {
+
+ @Test
+ public void testFailedCreateReader() throws Exception {
Review Comment:
A more targeted test could focus on the actual contention this PR fixes:
- `ns1` gets a blocked `CompletableFuture<Reader<T>>`
- thread A calls `readLatest("public/ns1/t1")`
- before `future1` completes, thread B calls `readLatest("public/ns2/t2")`
- assert that `ns2` can still reach `readerCreator` and cache its own future
That is the observable difference from the old code: previously thread B
would be stuck behind the global `SimpleCache.get()` lock while thread A was
waiting inside the synchronized block.
Pseudo-code:
```java
CompletableFuture<Reader<Object>> future1 = new CompletableFuture<>();
CompletableFuture<Reader<Object>> future2 = new CompletableFuture<>();
CountDownLatch ns1Called = new CountDownLatch(1);
CountDownLatch ns2Called = new CountDownLatch(1);
readerCreator = topic -> {
if (topic.getNamespaceObject().toString().equals("public/ns1")) {
ns1Called.countDown();
return future1;
} else {
ns2Called.countDown();
return future2;
}
};
runAsync(() -> tableView.readLatest("public/ns1/t1"));
assertTrue(ns1Called.await(1, SECONDS));
runAsync(() -> tableView.readLatest("public/ns2/t2"));
assertTrue(ns2Called.await(1, SECONDS)); // this is the key assertion
future1.complete(mockReaderReturningNoEvents());
future2.complete(mockReaderReturningNoEvents());
```
If `ns2Called` cannot fire until `future1` completes, the old lock
amplification behavior is still present.
##########
pulsar-broker/src/test/java/org/apache/pulsar/broker/transaction/buffer/impl/TableViewTest.java:
##########
@@ -0,0 +1,50 @@
+/*
+ * 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.pulsar.broker.transaction.buffer.impl;
+
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.function.Function;
+import org.apache.pulsar.broker.systopic.SystemTopicClient;
+import org.apache.pulsar.client.api.PulsarClientException;
+import org.apache.pulsar.common.naming.TopicName;
+import org.apache.pulsar.common.util.FutureUtil;
+import org.testng.Assert;
+import org.testng.annotations.Test;
+
+public class TableViewTest {
+
+ @Test
+ public void testFailedCreateReader() throws Exception {
Review Comment:
This test covers the failure path, but it does not exercise the contention
scenario that this PR is actually fixing. Could we add a targeted concurrency
test where one namespace caches a blocked `CompletableFuture<Reader<T>>`, and
then a second `readLatest()` on another namespace is started before the first
future completes?
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