You are viewing a plain text version of this content. The canonical link for it is here.
Posted to commits@lucene.apache.org by cp...@apache.org on 2016/10/24 18:32:18 UTC
[14/50] [abbrv] lucene-solr:jira/solr-8542-v2: SOLR-9417: Allow
daemons to terminate when they finish iterating a topic
SOLR-9417: Allow daemons to terminate when they finish iterating a topic
Project: http://git-wip-us.apache.org/repos/asf/lucene-solr/repo
Commit: http://git-wip-us.apache.org/repos/asf/lucene-solr/commit/f43742ac
Tree: http://git-wip-us.apache.org/repos/asf/lucene-solr/tree/f43742ac
Diff: http://git-wip-us.apache.org/repos/asf/lucene-solr/diff/f43742ac
Branch: refs/heads/jira/solr-8542-v2
Commit: f43742acc5148ea89a9a625818a7229d56e0558e
Parents: d03cc92
Author: Joel Bernstein <jb...@apache.org>
Authored: Wed Oct 19 13:16:01 2016 -0400
Committer: Joel Bernstein <jb...@apache.org>
Committed: Wed Oct 19 13:17:06 2016 -0400
----------------------------------------------------------------------
.../org/apache/solr/handler/StreamHandler.java | 4 +-
.../client/solrj/io/stream/DaemonStream.java | 44 ++++-
.../solrj/io/stream/StreamExpressionTest.java | 193 +++++++++++++++++--
3 files changed, 213 insertions(+), 28 deletions(-)
----------------------------------------------------------------------
http://git-wip-us.apache.org/repos/asf/lucene-solr/blob/f43742ac/solr/core/src/java/org/apache/solr/handler/StreamHandler.java
----------------------------------------------------------------------
diff --git a/solr/core/src/java/org/apache/solr/handler/StreamHandler.java b/solr/core/src/java/org/apache/solr/handler/StreamHandler.java
index b9f30bc..3e841bd 100644
--- a/solr/core/src/java/org/apache/solr/handler/StreamHandler.java
+++ b/solr/core/src/java/org/apache/solr/handler/StreamHandler.java
@@ -19,6 +19,7 @@ package org.apache.solr.handler;
import java.io.IOException;
import java.lang.invoke.MethodHandles;
import java.util.Collection;
+import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
@@ -97,7 +98,7 @@ public class StreamHandler extends RequestHandlerBase implements SolrCoreAware,
private StreamFactory streamFactory = new StreamFactory();
private static final Logger logger = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
private String coreName;
- private Map<String, DaemonStream> daemons = new HashMap<>();
+ private Map<String, DaemonStream> daemons = Collections.synchronizedMap(new HashMap());
@Override
public PermissionNameProvider.Name getPermissionName(AuthorizationContext request) {
@@ -245,6 +246,7 @@ public class StreamHandler extends RequestHandlerBase implements SolrCoreAware,
if(daemons.containsKey(daemonStream.getId())) {
daemons.remove(daemonStream.getId()).close();
}
+ daemonStream.setDaemons(daemons);
daemonStream.open(); //This will start the deamonStream
daemons.put(daemonStream.getId(), daemonStream);
rsp.add("result-set", new DaemonResponseStream("Deamon:"+daemonStream.getId()+" started on "+coreName));
http://git-wip-us.apache.org/repos/asf/lucene-solr/blob/f43742ac/solr/solrj/src/java/org/apache/solr/client/solrj/io/stream/DaemonStream.java
----------------------------------------------------------------------
diff --git a/solr/solrj/src/java/org/apache/solr/client/solrj/io/stream/DaemonStream.java b/solr/solrj/src/java/org/apache/solr/client/solrj/io/stream/DaemonStream.java
index 77648df..8214f9a 100644
--- a/solr/solrj/src/java/org/apache/solr/client/solrj/io/stream/DaemonStream.java
+++ b/solr/solrj/src/java/org/apache/solr/client/solrj/io/stream/DaemonStream.java
@@ -52,6 +52,8 @@ public class DaemonStream extends TupleStream implements Expressible {
private Exception exception;
private long runInterval;
private String id;
+ private Map<String, DaemonStream> daemons;
+ private boolean terminate;
private boolean closed = false;
private static final Logger logger = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
@@ -64,10 +66,13 @@ public class DaemonStream extends TupleStream implements Expressible {
StreamExpressionNamedParameter idExpression = factory.getNamedOperand(expression, "id");
StreamExpressionNamedParameter runExpression = factory.getNamedOperand(expression, "runInterval");
StreamExpressionNamedParameter queueExpression = factory.getNamedOperand(expression, "queueSize");
+ StreamExpressionNamedParameter terminateExpression = factory.getNamedOperand(expression, "terminate");
+
String id = null;
long runInterval = 0L;
int queueSize = 0;
+ boolean terminate = false;
if(idExpression == null) {
throw new IOException("Invalid expression id parameter expected");
@@ -82,24 +87,26 @@ public class DaemonStream extends TupleStream implements Expressible {
}
if(queueExpression != null) {
- queueSize= Integer.parseInt(((StreamExpressionValue)queueExpression.getParameter()).getValue());
+ queueSize= Integer.parseInt(((StreamExpressionValue) queueExpression.getParameter()).getValue());
}
- // validate expression contains only what we want.
- if(expression.getParameters().size() != streamExpressions.size() + 2 &&
- expression.getParameters().size() != streamExpressions.size() + 3) {
- throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - unknown operands found", expression));
+ if(terminateExpression != null) {
+ terminate = Boolean.parseBoolean(((StreamExpressionValue) terminateExpression.getParameter()).getValue());
}
if(1 != streamExpressions.size()){
throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - expecting a single stream but found %d",expression, streamExpressions.size()));
}
- init(tupleStream, id, runInterval, queueSize);
+ init(tupleStream, id, runInterval, queueSize, terminate);
+ }
+
+ public DaemonStream(TupleStream tupleStream, String id, long runInterval, int queueSize, boolean terminate) {
+ init(tupleStream, id, runInterval, queueSize, terminate);
}
public DaemonStream(TupleStream tupleStream, String id, long runInterval, int queueSize) {
- init(tupleStream, id, runInterval, queueSize);
+ this(tupleStream, id, runInterval, queueSize, false);
}
@Override
@@ -126,6 +133,7 @@ public class DaemonStream extends TupleStream implements Expressible {
expression.addParameter(new StreamExpressionNamedParameter("id", id));
expression.addParameter(new StreamExpressionNamedParameter("runInterval", Long.toString(runInterval)));
expression.addParameter(new StreamExpressionNamedParameter("queueSize", Integer.toString(queueSize)));
+ expression.addParameter(new StreamExpressionNamedParameter("terminate", Boolean.toString(terminate)));
return expression;
}
@@ -148,10 +156,16 @@ public class DaemonStream extends TupleStream implements Expressible {
}
public void init(TupleStream tupleStream, String id, long runInterval, int queueSize) {
+ init(tupleStream, id, runInterval, queueSize, false);
+ }
+
+ public void init(TupleStream tupleStream, String id, long runInterval, int queueSize, boolean terminate) {
this.tupleStream = tupleStream;
this.id = id;
this.runInterval = runInterval;
this.queueSize = queueSize;
+ this.terminate = terminate;
+
if(queueSize > 0) {
queue = new ArrayBlockingQueue(queueSize);
eatTuples = false;
@@ -228,6 +242,10 @@ public class DaemonStream extends TupleStream implements Expressible {
return tuple;
}
+ public void setDaemons(Map<String, DaemonStream> daemons) {
+ this.daemons = daemons;
+ }
+
private synchronized void incrementIterations() {
++iterations;
}
@@ -279,6 +297,18 @@ public class DaemonStream extends TupleStream implements Expressible {
errors = 0; // Reset errors on successful run.
if (tuple.fields.containsKey("sleepMillis")) {
this.sleepMillis = tuple.getLong("sleepMillis");
+
+ if(terminate && sleepMillis > 0) {
+ //TopicStream provides sleepMillis > 0 if the last run had no Tuples.
+ //This means the topic queue is empty. Time to terminate.
+ //Remove ourselves from the daemons map.
+ if(daemons != null) {
+ daemons.remove(id);
+ }
+ //Break out of the thread loop and end the run.
+ break OUTER;
+ }
+
this.runInterval = -1;
}
break INNER;
http://git-wip-us.apache.org/repos/asf/lucene-solr/blob/f43742ac/solr/solrj/src/test/org/apache/solr/client/solrj/io/stream/StreamExpressionTest.java
----------------------------------------------------------------------
diff --git a/solr/solrj/src/test/org/apache/solr/client/solrj/io/stream/StreamExpressionTest.java b/solr/solrj/src/test/org/apache/solr/client/solrj/io/stream/StreamExpressionTest.java
index 842f6a6..7b5777d 100644
--- a/solr/solrj/src/test/org/apache/solr/client/solrj/io/stream/StreamExpressionTest.java
+++ b/solr/solrj/src/test/org/apache/solr/client/solrj/io/stream/StreamExpressionTest.java
@@ -533,24 +533,24 @@ public class StreamExpressionTest extends SolrCloudTestCase {
// Basic test desc
expression = StreamExpressionParser.parse("top("
- + "n=2,"
- + "unique("
- + "search(" + COLLECTION + ", q=*:*, fl=\"id,a_s,a_i,a_f\", sort=\"a_f desc\"),"
- + "over=\"a_f\"),"
- + "sort=\"a_f desc\")");
+ + "n=2,"
+ + "unique("
+ + "search(" + COLLECTION + ", q=*:*, fl=\"id,a_s,a_i,a_f\", sort=\"a_f desc\"),"
+ + "over=\"a_f\"),"
+ + "sort=\"a_f desc\")");
stream = new RankStream(expression, factory);
tuples = getTuples(stream);
assert(tuples.size() == 2);
- assertOrder(tuples, 4,3);
+ assertOrder(tuples, 4, 3);
// full factory
stream = factory.constructStream("top("
- + "n=4,"
- + "unique("
- + "search(" + COLLECTION + ", q=*:*, fl=\"id,a_s,a_i,a_f\", sort=\"a_f asc, a_i asc\"),"
- + "over=\"a_f\"),"
- + "sort=\"a_f asc\")");
+ + "n=4,"
+ + "unique("
+ + "search(" + COLLECTION + ", q=*:*, fl=\"id,a_s,a_i,a_f\", sort=\"a_f asc, a_i asc\"),"
+ + "over=\"a_f\"),"
+ + "sort=\"a_f asc\")");
tuples = getTuples(stream);
assert(tuples.size() == 4);
@@ -827,7 +827,7 @@ public class StreamExpressionTest extends SolrCloudTestCase {
.withFunctionName("parallel", ParallelStream.class)
.withFunctionName("fetch", FetchStream.class);
- stream = factory.constructStream("parallel("+COLLECTION+", workers=2, sort=\"a_f asc\", fetch("+COLLECTION+", search(" + COLLECTION + ", q=*:*, fl=\"id,a_s,a_i,a_f\", sort=\"a_f asc\", partitionKeys=\"id\"), on=\"id=a_i\", batchSize=\"2\", fl=\"subject\"))");
+ stream = factory.constructStream("parallel(" + COLLECTION + ", workers=2, sort=\"a_f asc\", fetch(" + COLLECTION + ", search(" + COLLECTION + ", q=*:*, fl=\"id,a_s,a_i,a_f\", sort=\"a_f asc\", partitionKeys=\"id\"), on=\"id=a_i\", batchSize=\"2\", fl=\"subject\"))");
tuples = getTuples(stream);
assert(tuples.size() == 10);
@@ -853,7 +853,7 @@ public class StreamExpressionTest extends SolrCloudTestCase {
assertTrue("blah blah blah 9".equals(t.getString("subject")));
- stream = factory.constructStream("parallel("+COLLECTION+", workers=2, sort=\"a_f asc\", fetch("+COLLECTION+", search(" + COLLECTION + ", q=*:*, fl=\"id,a_s,a_i,a_f\", sort=\"a_f asc\", partitionKeys=\"id\"), on=\"id=a_i\", batchSize=\"3\", fl=\"subject\"))");
+ stream = factory.constructStream("parallel(" + COLLECTION + ", workers=2, sort=\"a_f asc\", fetch(" + COLLECTION + ", search(" + COLLECTION + ", q=*:*, fl=\"id,a_s,a_i,a_f\", sort=\"a_f asc\", partitionKeys=\"id\"), on=\"id=a_i\", batchSize=\"3\", fl=\"subject\"))");
tuples = getTuples(stream);
assert(tuples.size() == 10);
@@ -1003,6 +1003,45 @@ public class StreamExpressionTest extends SolrCloudTestCase {
}
+
+ @Test
+ public void testTerminatingDaemonStream() throws Exception {
+
+ new UpdateRequest()
+ .add(id, "0", "a_s", "hello", "a_i", "0", "a_f", "1")
+ .add(id, "2", "a_s", "hello", "a_i", "2", "a_f", "2")
+ .add(id, "3", "a_s", "hello", "a_i", "3", "a_f", "3")
+ .add(id, "4", "a_s", "hello", "a_i", "4", "a_f", "4")
+ .add(id, "1", "a_s", "hello", "a_i", "1", "a_f", "5")
+ .add(id, "5", "a_s", "hello", "a_i", "10", "a_f", "6")
+ .add(id, "6", "a_s", "hello", "a_i", "11", "a_f", "7")
+ .add(id, "7", "a_s", "hello", "a_i", "12", "a_f", "8")
+ .add(id, "8", "a_s", "hello", "a_i", "13", "a_f", "9")
+ .add(id, "9", "a_s", "hello", "a_i", "14", "a_f", "10")
+ .commit(cluster.getSolrClient(), COLLECTION);
+
+ StreamFactory factory = new StreamFactory()
+ .withCollectionZkHost(COLLECTION, cluster.getZkServer().getZkAddress())
+ .withFunctionName("topic", TopicStream.class)
+ .withFunctionName("daemon", DaemonStream.class);
+
+ StreamExpression expression;
+ DaemonStream daemonStream;
+
+ SolrClientCache cache = new SolrClientCache();
+ StreamContext context = new StreamContext();
+ context.setSolrClientCache(cache);
+ expression = StreamExpressionParser.parse("daemon(topic("+COLLECTION+","+COLLECTION+", q=\"a_s:hello\", initialCheckpoint=0, id=\"topic1\", rows=2, fl=\"id\""
+ + "), id=test, runInterval=1000, terminate=true, queueSize=50)");
+ daemonStream = (DaemonStream)factory.constructStream(expression);
+ daemonStream.setStreamContext(context);
+
+ List<Tuple> tuples = getTuples(daemonStream);
+ assertTrue(tuples.size() == 10);
+ cache.close();
+ }
+
+
@Test
public void testRollupStream() throws Exception {
@@ -1367,7 +1406,7 @@ public class StreamExpressionTest extends SolrCloudTestCase {
assert(tuples.size() == 9);
- assertOrder(tuples, 0,1,2,3,4,7,6,8,9);
+ assertOrder(tuples, 0, 1, 2, 3, 4, 7, 6, 8, 9);
//Test descending
@@ -1376,7 +1415,7 @@ public class StreamExpressionTest extends SolrCloudTestCase {
tuples = getTuples(pstream);
assert(tuples.size() == 8);
- assertOrder(tuples, 9,8,6,4,3,2,1,0);
+ assertOrder(tuples, 9, 8, 6, 4, 3, 2, 1, 0);
}
@@ -1627,7 +1666,7 @@ public class StreamExpressionTest extends SolrCloudTestCase {
stream = new LeftOuterJoinStream(expression, factory);
tuples = getTuples(stream);
assert(tuples.size() == 10);
- assertOrder(tuples, 7,6,3,4,5,1,1,15,15,2);
+ assertOrder(tuples, 7, 6, 3, 4, 5, 1, 1, 15, 15, 2);
// Results in both searches, no join matches
expression = StreamExpressionParser.parse("leftOuterJoin("
@@ -1637,7 +1676,7 @@ public class StreamExpressionTest extends SolrCloudTestCase {
stream = new LeftOuterJoinStream(expression, factory);
tuples = getTuples(stream);
assert(tuples.size() == 8);
- assertOrder(tuples, 1,15,2,3,4,5,6,7);
+ assertOrder(tuples, 1, 15, 2, 3, 4, 5, 6, 7);
// Differing field names
expression = StreamExpressionParser.parse("leftOuterJoin("
@@ -1647,7 +1686,7 @@ public class StreamExpressionTest extends SolrCloudTestCase {
stream = new LeftOuterJoinStream(expression, factory);
tuples = getTuples(stream);
assert(tuples.size() == 10);
- assertOrder(tuples, 1,1,15,15,2,3,4,5,6,7);
+ assertOrder(tuples, 1, 1, 15, 15, 2, 3, 4, 5, 6, 7);
}
@@ -1764,7 +1803,7 @@ public class StreamExpressionTest extends SolrCloudTestCase {
stream = new OuterHashJoinStream(expression, factory);
tuples = getTuples(stream);
assert(tuples.size() == 10);
- assertOrder(tuples, 1,1,15,15,2,3,4,5,6,7);
+ assertOrder(tuples, 1, 1, 15, 15, 2, 3, 4, 5, 6, 7);
// Basic desc
expression = StreamExpressionParser.parse("outerHashJoin("
@@ -1794,7 +1833,7 @@ public class StreamExpressionTest extends SolrCloudTestCase {
stream = new OuterHashJoinStream(expression, factory);
tuples = getTuples(stream);
assert(tuples.size() == 10);
- assertOrder(tuples, 1,1,15,15,2,3,4,5,6,7);
+ assertOrder(tuples, 1, 1, 15, 15, 2, 3, 4, 5, 6, 7);
}
@Test
@@ -3202,6 +3241,120 @@ public class StreamExpressionTest extends SolrCloudTestCase {
CollectionAdminRequest.deleteCollection("parallelDestinationCollection1").process(cluster.getSolrClient());
}
+
+ @Test
+ public void testParallelTerminatingDaemonUpdateStream() throws Exception {
+
+ CollectionAdminRequest.createCollection("parallelDestinationCollection1", "conf", 2, 1).process(cluster.getSolrClient());
+ AbstractDistribZkTestBase.waitForRecoveriesToFinish("parallelDestinationCollection1", cluster.getSolrClient().getZkStateReader(),
+ false, true, TIMEOUT);
+
+ new UpdateRequest()
+ .add(id, "0", "a_s", "hello", "a_i", "0", "a_f", "0", "s_multi", "aaaa", "s_multi", "bbbb", "i_multi", "4", "i_multi", "7")
+ .add(id, "2", "a_s", "hello", "a_i", "2", "a_f", "0", "s_multi", "aaaa1", "s_multi", "bbbb1", "i_multi", "44", "i_multi", "77")
+ .add(id, "3", "a_s", "hello", "a_i", "3", "a_f", "3", "s_multi", "aaaa2", "s_multi", "bbbb2", "i_multi", "444", "i_multi", "777")
+ .add(id, "4", "a_s", "hello", "a_i", "4", "a_f", "4", "s_multi", "aaaa3", "s_multi", "bbbb3", "i_multi", "4444", "i_multi", "7777")
+ .add(id, "1", "a_s", "hello", "a_i", "1", "a_f", "1", "s_multi", "aaaa4", "s_multi", "bbbb4", "i_multi", "44444", "i_multi", "77777")
+ .commit(cluster.getSolrClient(), "collection1");
+
+ StreamExpression expression;
+ TupleStream stream;
+ Tuple t;
+
+ String zkHost = cluster.getZkServer().getZkAddress();
+ StreamFactory factory = new StreamFactory()
+ .withCollectionZkHost("collection1", cluster.getZkServer().getZkAddress())
+ .withCollectionZkHost("parallelDestinationCollection1", cluster.getZkServer().getZkAddress())
+ .withFunctionName("topic", TopicStream.class)
+ .withFunctionName("update", UpdateStream.class)
+ .withFunctionName("parallel", ParallelStream.class)
+ .withFunctionName("daemon", DaemonStream.class);
+
+ //Copy all docs to destinationCollection
+ String updateExpression = "daemon(update(parallelDestinationCollection1, batchSize=2, topic(collection1, collection1, q=\"a_s:hello\", fl=\"id,a_s,a_i,a_f,s_multi,i_multi\", partitionKeys=\"a_f\", initialCheckpoint=0, id=\"topic1\")), terminate=true, runInterval=\"1000\", id=\"test\")";
+ TupleStream parallelUpdateStream = factory.constructStream("parallel(collection1, " + updateExpression + ", workers=\"2\", zkHost=\""+zkHost+"\", sort=\"batchNumber asc\")");
+ List<Tuple> tuples = getTuples(parallelUpdateStream);
+ assert(tuples.size() == 2);
+
+
+ ModifiableSolrParams sParams = new ModifiableSolrParams(StreamingTest.mapParams(CommonParams.QT, "/stream", "action", "list"));
+
+ int workersComplete = 0;
+
+ //Daemons should terminate after the topic is completed
+ //Loop through all shards and wait for the daemons to be gone from the listing.
+ for(JettySolrRunner jetty : cluster.getJettySolrRunners()) {
+ INNER:
+ while(true) {
+ SolrStream solrStream = new SolrStream(jetty.getBaseUrl().toString() + "/collection1", sParams);
+ solrStream.open();
+ Tuple tupleResponse = solrStream.read();
+ if (tupleResponse.EOF) {
+ solrStream.close();
+ ++workersComplete;
+ break INNER;
+ } else {
+ solrStream.close();
+ Thread.sleep(1000);
+ }
+ }
+ }
+
+ assertEquals(cluster.getJettySolrRunners().size(), workersComplete);
+
+ cluster.getSolrClient().commit("parallelDestinationCollection1");
+
+ //Ensure that destinationCollection actually has the new docs.
+ expression = StreamExpressionParser.parse("search(parallelDestinationCollection1, q=*:*, fl=\"id,a_s,a_i,a_f,s_multi,i_multi\", sort=\"a_i asc\")");
+ stream = new CloudSolrStream(expression, factory);
+ tuples = getTuples(stream);
+ assertEquals(5, tuples.size());
+
+ Tuple tuple = tuples.get(0);
+ assert(tuple.getLong("id") == 0);
+ assert(tuple.get("a_s").equals("hello"));
+ assert(tuple.getLong("a_i") == 0);
+ assert(tuple.getDouble("a_f") == 0.0);
+ assertList(tuple.getStrings("s_multi"), "aaaa", "bbbb");
+ assertList(tuple.getLongs("i_multi"), Long.parseLong("4"), Long.parseLong("7"));
+
+ tuple = tuples.get(1);
+ assert(tuple.getLong("id") == 1);
+ assert(tuple.get("a_s").equals("hello"));
+ assert(tuple.getLong("a_i") == 1);
+ assert(tuple.getDouble("a_f") == 1.0);
+ assertList(tuple.getStrings("s_multi"), "aaaa4", "bbbb4");
+ assertList(tuple.getLongs("i_multi"), Long.parseLong("44444"), Long.parseLong("77777"));
+
+ tuple = tuples.get(2);
+ assert(tuple.getLong("id") == 2);
+ assert(tuple.get("a_s").equals("hello"));
+ assert(tuple.getLong("a_i") == 2);
+ assert(tuple.getDouble("a_f") == 0.0);
+ assertList(tuple.getStrings("s_multi"), "aaaa1", "bbbb1");
+ assertList(tuple.getLongs("i_multi"), Long.parseLong("44"), Long.parseLong("77"));
+
+ tuple = tuples.get(3);
+ assert(tuple.getLong("id") == 3);
+ assert(tuple.get("a_s").equals("hello"));
+ assert(tuple.getLong("a_i") == 3);
+ assert(tuple.getDouble("a_f") == 3.0);
+ assertList(tuple.getStrings("s_multi"), "aaaa2", "bbbb2");
+ assertList(tuple.getLongs("i_multi"), Long.parseLong("444"), Long.parseLong("777"));
+
+ tuple = tuples.get(4);
+ assert(tuple.getLong("id") == 4);
+ assert(tuple.get("a_s").equals("hello"));
+ assert(tuple.getLong("a_i") == 4);
+ assert(tuple.getDouble("a_f") == 4.0);
+ assertList(tuple.getStrings("s_multi"), "aaaa3", "bbbb3");
+ assertList(tuple.getLongs("i_multi"), Long.parseLong("4444"), Long.parseLong("7777"));
+
+ CollectionAdminRequest.deleteCollection("parallelDestinationCollection1").process(cluster.getSolrClient());
+ }
+
+
+
////////////////////////////////////////////
@Test
public void testCommitStream() throws Exception {