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https://issues.apache.org/jira/browse/ACCUMULO-3509?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15081796#comment-15081796
]
ASF GitHub Bot commented on ACCUMULO-3509:
------------------------------------------
Github user joshelser commented on a diff in the pull request:
https://github.com/apache/accumulo/pull/62#discussion_r48780266
--- Diff:
test/src/test/java/org/apache/accumulo/test/functional/SessionBlockVerifyIT.java
---
@@ -0,0 +1,181 @@
+/*
+ * 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.accumulo.test.functional;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+
+import org.apache.accumulo.core.client.BatchWriter;
+import org.apache.accumulo.core.client.BatchWriterConfig;
+import org.apache.accumulo.core.client.Connector;
+import org.apache.accumulo.core.client.IteratorSetting;
+import org.apache.accumulo.core.client.Scanner;
+import org.apache.accumulo.core.client.admin.ActiveScan;
+import org.apache.accumulo.core.client.admin.InstanceOperations;
+import org.apache.accumulo.core.conf.AccumuloConfiguration;
+import org.apache.accumulo.core.conf.Property;
+import org.apache.accumulo.core.data.Key;
+import org.apache.accumulo.core.data.Mutation;
+import org.apache.accumulo.core.data.Range;
+import org.apache.accumulo.core.data.Value;
+import org.apache.accumulo.core.security.Authorizations;
+import org.apache.accumulo.harness.AccumuloClusterIT;
+import org.apache.accumulo.minicluster.impl.MiniAccumuloConfigImpl;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.io.Text;
+import org.junit.Before;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Verify that we have resolved blocking issue by ensuring that we have
not lost scan sessions which we know to currently be running
+ */
+public class SessionBlockVerifyIT extends AccumuloClusterIT {
+ private static final Logger log =
LoggerFactory.getLogger(SessionBlockVerifyIT.class);
+
+ @Override
+ public void configureMiniCluster(MiniAccumuloConfigImpl cfg,
Configuration hadoopCoreSite) {
+ Map<String,String> siteConfig = cfg.getSiteConfig();
+ cfg.setNumTservers(1);
+ siteConfig.put(Property.TSERV_SESSION_MAXIDLE.getKey(), "1s");
+ siteConfig.put(Property.TSERV_READ_AHEAD_MAXCONCURRENT.getKey(), "11");
+ cfg.setSiteConfig(siteConfig);
+ }
+
+ @Override
+ protected int defaultTimeoutSeconds() {
+ return 60;
+ }
+
+ private String sessionIdle = null;
+
+ @Before
+ public void reduceSessionIdle() throws Exception {
+
+ InstanceOperations ops = getConnector().instanceOperations();
+ sessionIdle =
ops.getSystemConfiguration().get(Property.TSERV_SESSION_MAXIDLE.getKey());
+ ops.setProperty(Property.TSERV_SESSION_MAXIDLE.getKey(), "1s");
+ log.info("Waiting for existing session idle time to expire");
+ Thread.sleep(AccumuloConfiguration.getTimeInMillis(sessionIdle));
+ log.info("Finished waiting");
+ }
+
+ ExecutorService service = Executors.newFixedThreadPool(10);
+
+ @Test
+ public void run() throws Exception {
+ Connector c = getConnector();
+ String tableName = getUniqueNames(1)[0];
+ c.tableOperations().create(tableName);
+
+ BatchWriter bw = c.createBatchWriter(tableName, new
BatchWriterConfig());
+
+ for (int i = 0; i < 1000; i++) {
+ Mutation m = new Mutation(new Text(String.format("%08d", i)));
+ for (int j = 0; j < 3; j++)
+ m.put(new Text("cf1"), new Text("cq" + j), new Value((i + "_" +
j).getBytes(UTF_8)));
+
+ bw.addMutation(m);
+ }
+
+ bw.close();
+
+ Scanner scanner = c.createScanner(tableName, new Authorizations());
+ scanner.setReadaheadThreshold(20000);
+ scanner.setRange(new Range(String.format("%08d", 0),
String.format("%08d", 1000)));
+
+ // test by making a slow iterator and then a couple of fast ones.
+ // when then checking we shouldn't have any running except the slow
iterator
+ IteratorSetting setting = new IteratorSetting(21, SlowIterator.class);
+ SlowIterator.setSeekSleepTime(setting, Long.MAX_VALUE);
+ SlowIterator.setSleepTime(setting, Long.MAX_VALUE);
+ scanner.addScanIterator(setting);
+
+ final Iterator<Entry<Key,Value>> slow = scanner.iterator();
+
+ final List<Future<Boolean>> callables = new
ArrayList<Future<Boolean>>();
+ for (int i = 0; i < 10; i++) {
+ Future<Boolean> callable = service.submit(new Callable<Boolean>() {
+ public Boolean call() {
+ while (slow.hasNext()) {
+
+ slow.next();
+ }
+ return slow.hasNext();
+ }
+ });
+ callables.add(callable);
+ }
+
+ Thread.sleep(10000);
+ log.info("Starting");
+ // let's add more for good measure.
+ for (int i = 0; i < 2; i++) {
+ Scanner scanner2 = c.createScanner(tableName, new Authorizations());
+
+ scanner2.setRange(new Range(String.format("%08d", 0),
String.format("%08d", 1000)));
+
+ scanner2.setBatchSize(1);
+ Iterator<Entry<Key,Value>> iter = scanner2.iterator();
+ sinkKeyValues(iter);
+
+ }
+
+ int sessionsFound = 0;
+ // we have configured 1 tserver, so we can grab the one and only
+ String tserver =
c.instanceOperations().getTabletServers().iterator().next();
+
+ final List<ActiveScan> scans =
c.instanceOperations().getActiveScans(tserver);
+
+ for (ActiveScan scan : scans) {
+ // only here to minimize chance of seeing meta extent scans
+
+ if (tableName.equals(scan.getTable()) && scan.getSsiList().size() >
0) {
+ assertEquals("Not the expected iterator", 1,
scan.getSsiList().size());
+ assertTrue("Not the expected iterator",
scan.getSsiList().iterator().next().contains("SlowIterator"));
+ sessionsFound++;
+ }
+
+ }
+
+ assertEquals("Must have ten sessions to ensure 3509 is resolved", 10,
sessionsFound);
+ for (Future<Boolean> callable : callables) {
+ callable.cancel(true);
+ }
+ service.shutdown();
+ }
+
+ private void sinkKeyValues(Iterator<Entry<Key,Value>> iter) throws
Exception {
+ while (iter.hasNext()) {
--- End diff --
Could you do a quick summation of the values you read to make sure you got
all of the expected key-value pairs?
> Scanner lock cause Tablet lock, hence preventing idle scans from being swept,
> hence blocking SimpleTimer thread
> ----------------------------------------------------------------------------------------------------------------
>
> Key: ACCUMULO-3509
> URL: https://issues.apache.org/jira/browse/ACCUMULO-3509
> Project: Accumulo
> Issue Type: Bug
> Components: tserver
> Affects Versions: 1.6.0
> Reporter: marco polo
> Assignee: marco polo
> Fix For: 1.6.5, 1.7.1, 1.8.0
>
>
> Synchronization with Tablet$Scanner via a read() will block close() being
> called via the sweep method in TabletServer. As a result, the SimpleTimer
> thread does not continue, and idle threads grow until the scan completes.
> My patch, which is forthcoming, converts synchronized methods to use a fair
> lock. If the lock is held by a read call, the close call will attempt to
> obtain it, time out, and return indicating a close was not successful. The
> sweep will continue, and the SimpleTimer thread will respawn later,
> attempting closure on those Tablets at a later time.
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