Changeset: c205dbf4bd36 for MonetDB
URL: http://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=c205dbf4bd36
Added Files:
java/tests/Test_Csendthread.java
Modified Files:
java/src/nl/cwi/monetdb/jdbc/MonetConnection.java
java/tests/build.xml
Branch: Oct2012
Log Message:
SendThread: shutdown thread on Connection close
Wouter Alink reported a large number of "hanging" threads after having
used many Connections that had to send large queries (hence SendThread
started). These were left-over SendThreads that were never cleaned up.
Cleanup SendThreads as part of the MonetConnection.close() method. This
patch is inspired by the work of Wouter.
diffs (155 lines):
diff --git a/java/src/nl/cwi/monetdb/jdbc/MonetConnection.java
b/java/src/nl/cwi/monetdb/jdbc/MonetConnection.java
--- a/java/src/nl/cwi/monetdb/jdbc/MonetConnection.java
+++ b/java/src/nl/cwi/monetdb/jdbc/MonetConnection.java
@@ -333,6 +333,11 @@ public class MonetConnection extends Mon
}
// close the socket
server.close();
+ // close active SendThread if any
+ if (sendThread != null) {
+ sendThread.shutdown();
+ sendThread = null;
+ }
// report ourselves as closed
closed = true;
}
@@ -2561,6 +2566,8 @@ public class MonetConnection extends Mon
private final static int WAIT = 0;
/** The state QUERY represents this thread to be executing a
query */
private final static int QUERY = 1;
+ /** The state SHUTDOWN is the final state that ends this thread
*/
+ private final static int SHUTDOWN = -1;
private String[] templ;
private String query;
@@ -2596,6 +2603,8 @@ public class MonetConnection extends Mon
// woken up, eh?
}
}
+ if (state == SHUTDOWN)
+ break;
// state is QUERY here
try {
@@ -2630,7 +2639,7 @@ public class MonetConnection extends Mon
sendLock.lock();
try {
if (state != WAIT)
- throw new SQLException("SendThread
already in use!", "M0M03");
+ throw new SQLException("SendThread
already in use or shutting down!", "M0M03");
this.templ = templ;
this.query = query;
@@ -2652,18 +2661,30 @@ public class MonetConnection extends Mon
sendLock.lock();
try {
// make sure the thread is in WAIT state, not
QUERY
- while (state != WAIT) {
+ while (state == QUERY) {
try {
waiting.await();
} catch (InterruptedException e) {
// just try again
}
}
+ if (state == SHUTDOWN)
+ error = "SendThread is shutting down";
} finally {
sendLock.unlock();
}
return error;
}
+
+ /**
+ * Requests this SendThread to stop.
+ */
+ public void shutdown() {
+ sendLock.lock();
+ state = SHUTDOWN;
+ sendLock.unlock();
+ this.interrupt(); // break any wait conditions
+ }
}
// }}}
}
diff --git a/java/tests/Test_Csendthread.java b/java/tests/Test_Csendthread.java
new file mode 100644
--- /dev/null
+++ b/java/tests/Test_Csendthread.java
@@ -0,0 +1,51 @@
+/*
+ * The contents of this file are subject to the MonetDB Public License
+ * Version 1.1 (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.monetdb.org/Legal/MonetDBLicense
+ *
+ * Software distributed under the License is distributed on an "AS IS"
+ * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
+ * License for the specific language governing rights and limitations
+ * under the License.
+ *
+ * The Original Code is the MonetDB Database System.
+ *
+ * The Initial Developer of the Original Code is CWI.
+ * Portions created by CWI are Copyright (C) 1997-July 2008 CWI.
+ * Copyright August 2008-2012 MonetDB B.V.
+ * All Rights Reserved.
+ */
+
+import java.sql.*;
+
+public class Test_Csendthread {
+ public static void main(String[] args) throws Exception {
+ Class.forName("nl.cwi.monetdb.jdbc.MonetDriver");
+
+ System.out.println("0. active threads: " +
Thread.activeCount());
+
+ StringBuilder sb = new StringBuilder();
+ sb.append("SELECT 1");
+ for (int i = 0; i < 256; i++) {
+ sb.append("-- ADDING DUMMY TEXT AS COMMENT TO MAKE THE
QUERY VERY VERY VERY VERY LONG\n");
+ }
+ sb.append(";\n");
+ String longQuery = sb.toString();
+
+ for (int i = 0; i < 10; i++) {
+ for (int j = 0; j < 10; j++) {
+ Connection conn =
DriverManager.getConnection(args[0]);
+ try {
+ Statement st = conn.createStatement();
+ st.execute(longQuery);
+ st.close();
+ } finally {
+ conn.close();
+ }
+ }
+ System.out.println("1. active threads: " +
Thread.activeCount());
+ }
+ System.out.println("2. active threads: " +
Thread.activeCount());
+ }
+}
diff --git a/java/tests/build.xml b/java/tests/build.xml
--- a/java/tests/build.xml
+++ b/java/tests/build.xml
@@ -108,6 +108,8 @@ All Rights Reserved.
<antcall target="Test_Creplysize" />
<antcall target="Test_Csavepoints" />
<antcall target="Test_Ctransaction" />
+ <antcall target="Test_Creplysize" />
+ <antcall target="Test_Csendthread" />
<antcall target="Test_Dobjects" />
<antcall target="Test_PSgeneratedkeys" />
<antcall target="Test_PSlargeresponse" />
@@ -184,6 +186,12 @@ All Rights Reserved.
</antcall>
</target>
+ <target name="Test_Csendthread">
+ <antcall target="test_class">
+ <param name="test.class" value="Test_Csendthread" />
+ </antcall>
+ </target>
+
<target name="Test_Dobjects">
<antcall target="test_class">
<param name="test.class" value="Test_Dobjects" />
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