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Vert.x performance drop when starting with -cluster option

I'm wondering if any one experienced the same problem.
We have a Vert.x application and in the end it's purpose is to insert 600 million rows into a Cassandra cluster. We are testing the speed of Vert.x in combination with Cassandra by doing tests in smaller amounts.
If we run the fat jar (build with Shade plugin) without the -cluster option, we are able to insert 10 million records in about a minute. When we add the -cluster option (eventually we will run the Vert.x application in cluster) it takes about 5 minutes for 10 million records to insert.
Does anyone know why?
We know that the Hazelcast config will create some overhead, but never thought it would be 5 times slower. This implies we will need 5 EC2 instances in cluster to get the same result when using 1 EC2 without the cluster option.
As mentioned, everything runs on EC2 instances:
2 Cassandra servers on t2.small
1 Vert.x server on t2.2xlarge

You are actually running into corner cases of the Vert.x Hazelcast Cluster manager.
First of all you are using a worker Verticle to send your messages (30000001). Under the hood Hazelcast is blocking and thus when you send a message from a worker the version 3.3.3 does not take that in account. Recently we added this fix https://github.com/vert-x3/issues/issues/75 (not present in 3.4.0.Beta1 but present in 3.4.0-SNAPSHOTS) that will improve this case.
Second when you send all your messages at the same time, it runs into another corner case that prevents the Hazelcast cluster manager to use a cache of the cluster topology. This topology cache is usually updated after the first message has been sent and sending all the messages in one shot prevents the usage of the ache (short explanation HazelcastAsyncMultiMap#getInProgressCount will be > 0 and prevents the cache to be used), hence paying the penalty of an expensive lookup (hence the cache).
If I use Bertjan's reproducer with 3.4.0-SNAPSHOT + Hazelcast and the following change: send message to destination, wait for reply. Upon reply send all messages then I get a lot of improvements.
Without clustering : 5852 ms
With clustering with HZ 3.3.3 :16745 ms
With clustering with HZ 3.4.0-SNAPSHOT + initial message : 8609 ms
I believe also you should not use a worker verticle to send that many messages and instead send them using an event loop verticle via batches. Perhaps you should explain your use case and we can think about the best way to solve it.

When you're you enable clustering (of any kind) to an application you are making your application more resilient to failures but you're also adding a performance penalty.
For example your current flow (without clustering) is something like:
client ->
vert.x app ->
in memory same process eventbus (negletible) ->
handler -> cassandra
<- vert.x app
<- client
Once you enable clustering:
client ->
vert.x app ->
serialize request ->
network request cluster member ->
deserialize request ->
handler -> cassandra
<- serialize response
<- network reply
<- deserialize response
<- vert.x app
<- client
As you can see there are many encode decode operations required plus several network calls and this all gets added to your total request time.
In order to achive best performance you need to take advantage of locality the closer you are of your data store usually the fastest.

Just to add the code of the project. I guess that would help.
Sender verticle:
public class ProviderVerticle extends AbstractVerticle {
#Override
public void start() throws Exception {
IntStream.range(1, 30000001).parallel().forEach(i -> {
vertx.eventBus().send("clustertest1", Json.encode(new TestCluster1(i, "abc", LocalDateTime.now())));
});
}
#Override
public void stop() throws Exception {
super.stop();
}
}
And the inserter verticle
public class ReceiverVerticle extends AbstractVerticle {
private int messagesReceived = 1;
private Session cassandraSession;
#Override
public void start() throws Exception {
PoolingOptions poolingOptions = new PoolingOptions()
.setCoreConnectionsPerHost(HostDistance.LOCAL, 2)
.setMaxConnectionsPerHost(HostDistance.LOCAL, 3)
.setCoreConnectionsPerHost(HostDistance.REMOTE, 1)
.setMaxConnectionsPerHost(HostDistance.REMOTE, 3)
.setMaxRequestsPerConnection(HostDistance.LOCAL, 20)
.setMaxQueueSize(32768)
.setMaxRequestsPerConnection(HostDistance.REMOTE, 20);
Cluster cluster = Cluster.builder()
.withPoolingOptions(poolingOptions)
.addContactPoints(ClusterSetup.SEEDS)
.build();
System.out.println("Connecting session");
cassandraSession = cluster.connect("kiespees");
System.out.println("Session connected:\n\tcluster [" + cassandraSession.getCluster().getClusterName() + "]");
System.out.println("Connected hosts: ");
cassandraSession.getState().getConnectedHosts().forEach(host -> System.out.println(host.getAddress()));
PreparedStatement prepared = cassandraSession.prepare(
"insert into clustertest1 (id, value, created) " +
"values (:id, :value, :created)");
PreparedStatement preparedTimer = cassandraSession.prepare(
"insert into timer (name, created_on, amount) " +
"values (:name, :createdOn, :amount)");
BoundStatement timerStart = preparedTimer.bind()
.setString("name", "clusterteststart")
.setInt("amount", 0)
.setTimestamp("createdOn", new Timestamp(new Date().getTime()));
cassandraSession.executeAsync(timerStart);
EventBus bus = vertx.eventBus();
System.out.println("Bus info: " + bus.toString());
MessageConsumer<String> cons = bus.consumer("clustertest1");
System.out.println("Consumer info: " + cons.address());
System.out.println("Waiting for messages");
cons.handler(message -> {
TestCluster1 tc = Json.decodeValue(message.body(), TestCluster1.class);
if (messagesReceived % 100000 == 0)
System.out.println("Message received: " + messagesReceived);
BoundStatement boundRecord = prepared.bind()
.setInt("id", tc.getId())
.setString("value", tc.getValue())
.setTimestamp("created", new Timestamp(new Date().getTime()));
cassandraSession.executeAsync(boundRecord);
if (messagesReceived % 100000 == 0) {
BoundStatement timerStop = preparedTimer.bind()
.setString("name", "clusterteststop")
.setInt("amount", messagesReceived)
.setTimestamp("createdOn", new Timestamp(new Date().getTime()));
cassandraSession.executeAsync(timerStop);
}
messagesReceived++;
//message.reply("OK");
});
}
#Override
public void stop() throws Exception {
super.stop();
cassandraSession.close();
}
}

VSAM file locking when writing to it using Java JDBC

This is my first time trying to read and write to a VSAM file. What I did was:
Created a Map for the File using VSE Navigator
Added the Java beans VSE Connector library to my eclipse Java project
Use the code show below to Write and Read to the KSDS file.
Reading the file is not a problem but when I tried to write to the file it only works if I go on the mainframe and close the File before running my java program but it locks the file for like an hour. You cannot open the file on the mainframe or do anything to it.
Anybody can help with this problem. Is there a special setting that I need to set up for the file on the mainframe ? Why do you first need to close the file on CICS to be able to write to it ? And why does it locks the file after writing to it ?
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.sql.*;
public class testVSAM {
public static void main(String argv[]){
Integer test = Integer.valueOf(2893);
String vsamCatalog = "VSESP.USER.CATALOG";
String FlightCluster = "FLIGHT.ORDERING.FLIGHTS";
String FlightMapName = "FLIGHT.TEST2.MAP";
try{
String ipAddr = "10.1.1.1";
String userID = "USER1";
String password = "PASSWORD";
java.sql.Connection jdbcCon;
java.sql.Driver jdbcDriver = (java.sql.Driver) Class.forName(
"com.ibm.vse.jdbc.VsamJdbcDriver").newInstance();
// Build the URL to use to connect
String url = "jdbc:vsam:"+ipAddr;
// Assign properties for the driver
java.util.Properties prop = new java.util.Properties();
prop.put("port", test);
prop.put("user", userID);
prop.put("password", password);
// Connect to the driver
jdbcCon = DriverManager.getConnection(url,prop);
try {
java.sql.PreparedStatement pstmt = jdbcCon.prepareStatement(
"INSERT INTO "+vsamCatalog+"\\"+FlightCluster+"\\"+FlightMapName+
" (RS_SERIAL1,RS_SERIAL2,RS_QTY1,RS_QTY2,RS_UPDATE,RS_UPTIME,RS_EMPNO,RS_PRINTFLAG,"+
"RS_PART_S,RS_PART_IN_A_P,RS_FILLER)"+" VALUES(?,?,?,?,?,?,?,?,?,?,?)");
//pstmt.setString(1, "12345678901234567890123003");
pstmt.setString(1, "1234567890");
pstmt.setString(2,"1234567890123");
pstmt.setInt(3,00);
pstmt.setInt(4,003);
pstmt.setString(5,"151209");
pstmt.setString(6, "094435");
pstmt.setString(7,"09932");
pstmt.setString(8,"P");
pstmt.setString(9,"Y");
pstmt.setString(10,"Y");
pstmt.setString(11," ");
// Execute the query
int num = pstmt.executeUpdate();
System.out.println(num);
pstmt.close();
}
catch (SQLException t)
{
System.out.println(t.toString());
}
try
{
// Get a statement
java.sql.Statement stmt = jdbcCon.createStatement();
// Execute the query ...
java.sql.ResultSet rs = stmt.executeQuery(
"SELECT * FROM "+vsamCatalog+"\\"+FlightCluster+"\\"+FlightMapName);
while (rs.next())
{
System.out.println(rs.getString("RS_SERIAL1") + " " + rs.getString("RS_SERIAL2")+ " " + rs.getString("RS_UPTIME")+ " " + rs.getString("RS_UPDATE"));
}
rs.close();
stmt.close();
}
catch (SQLException t)
{
}
}
catch (Exception e)
{
// do something appropriate with the exception, *at least*:
e.printStackTrace();
}
}
}
Note: the OS is z/VSE

The short answer to your original question is that KSDS VSAM is not a DBMS.
As you have discovered, you can define the VSAM file such that you can update it both from batch and from CICS, but as #BillWoodger points out, you must serialize your updates yourself.
Another approach would be to do all updates from the CICS region, and have your Java application send a REST or SOAP or MQ message to CICS to request its updates. This does require there be a CICS program to catch the requests from the Java application and perform the updates.

The IBM Mainframe under z/VSE has different partitions that run different jobs. For example partition F7 CICS, partition F8 Batch Jobs, ETC.
When you define a new VSAM file you have to set the SHAREOPTIONS of the file. When I define the file I set the SHAREOPTIONS (2 3). 2 Means that only one partition can write to the file.
So when the batch program (in a different partition to the CICS partition) which is called from Java was trying to write to the file it was not able to write to the file unless I close the file in CICS first.
To fix it I REDEFINE the CICS file with SHAREOPTIONS (4 3). 4 Means that multiple partitions of the Mainframe can write to it. Fixing the problem
Below is a part of the definition code where you set the SHAREOPTION:
* $$ JOB JNM=DEFFI,CLASS=9,DISP=D,PRI=9
* $$ LST CLASS=X,DISP=H,PRI=2,REMOTE=0,USER=JAVI
// JOB DEFFI
// EXEC IDCAMS,SIZE=AUTO
DEFINE CLUSTER -
( -
NAME (FLIGHT.ORDERING.FLIGHTS) -
RECORDS (2000 1000) -
INDEXED -
KEYS (26 0) -
RECORDSIZE (128 128) -
SHAREOPTIONS (4 3) -
VOLUMES (SYSWKE) -
) -
.
.
.

Get the number of open connections in mongoDB using java

My program requires a large number of connections to be open (Mongo). I get the error :
Too many connections open, can't open anymore
after 819 connections. I already know we can increase this limit. But that's not what I have in mind. I'm thinking of closing the MongoClient object, and then creating a new one again after 800 connections.
My thinking is that with a new mongoClient object all the connections will be closed and when I start/create it again, the connections will be opened again until 800.
Thus not giving the error. (Let me know if this approach is totally wrong/ won't give the required results.)
For this I need to know the number of connections opened ATM. Is there any way to get this information using java?

You can get connection information by using the db.serverStatus() command. It has a connections subdocument which contains the total/available connections information.
For more information :
Documentation of server status
Details of connections block

Check the number of MongoDB connections using MongoDB Scala driver:
Create a MongoDB client:
import org.mongodb.scala._
import scala.collection.JavaConverters._
import scala.concurrent.Await
import scala.concurrent.duration._
import scala.util.{Failure, Success, Try}
// To directly connect to the default server localhost on port 27017
val mongodbClient: MongoClient = MongoClient()
// Use a Connection String
val mongodbClient: MongoClient = MongoClient("mongodb://localhost")
// or provide custom MongoClientSettings
val settings: MongoClientSettings = MongoClientSettings.builder()
.applyToClusterSettings(b => b.hosts(List(new ServerAddress("localhost")).asJava).
.build()
val mongodbClient: MongoClient = MongoClient(settings)
Call getNoOfMongodbConnection by passing mongodbClient:
val result = getNoOfMongodbConnection(mongodbClient)
Method to get the number of connections(current, available and total)
def getNoOfMongodbConnection(mongodbClient: MongoClient) = {
val adminDatabase = mongodbClient.getDatabase("admin")
val serverStatus = adminDatabase.runCommand(Document("serverStatus" -> 1)).toFuture()
Try {
Await.result(serverStatus, 10 seconds)
} match {
case Success(x) => {
val connection = x.get("connections")
logger.info("Number of mongodb connection:--> " + connection)
connection
}
case Failure(ex) => {
logger.error("Got error while getting the number of Mongodb connection:---> " + ex.printStackTrace())
None
}
}
}

Mongodb connection issue with java

i am having mongoDB connections issue in java , this is my connection class
public MongoDbUtil() {
try {
System.out.println("1");
String host = "127.0.0.1" ;
String dbName = "m_prod" ;
int port =27017 ;
System.out.println("2");
Mongo m = new Mongo();
System.out.println("3");
ds = new Morphia().createDatastore(m,dbName);
System.out.println("4");
ds.ensureIndexes();
System.out.println("5");
ds.ensureCaps();
System.out.println("1");
} catch(Exception e) {
System.out.println("catch");
}finally{
System.out.println("finally");
System.out.println(ds==null);
} }
only 1 and 2 is printing, after that 'finally' is printing also 'ds' is null, there is no any exception happen ('catch' is not printing)
Mongo server is up and running and i can access from command prompt (Linux) , the Other interesting thing is, its working fine when i call this method by unit test function, but for all other cases above issue happen , what can be the reason ?
Thanks

Mongo() is deprecated, you should use MongoClient() instead - see http://api.mongodb.org/java/2.11.0/com/mongodb/Mongo.html#Mongo()
Still it should find the deprecated constructor. Can you include the imports of your file, please?

If you're using the 3.0 driver, there's a driver-compat layer that will help you transition. You really should use the new API, though.

How do I access Windows Event Viewer log data from Java

Is there any way to access the Windows Event Log from a java class. Has anyone written any APIs for this, and would there be any way to access the data from a remote machine?
The scenario is:
I run a process on a remote machine, from a controlling Java process.
This remote process logs stuff to the Event Log, which I want to be able to see in the controlling process.
Thanks in advance.

http://www.j-interop.org/ is an open-source Java library that implements the DCOM protocol specification without using any native code. (i.e. you can use it to access DCOM objects on a remote Windows host from Java code running on a non-Windows client).
Microsoft exposes a plethora of system information via Windows Management Instrumentation (WMI). WMI is remotely accessible via DCOM, and considerable documentation on the subject exists on Microsoft's site. As it happens, you can access the Windows Event Logs via this remotely accessible interface.
By using j-interop you can create an instance of the WbemScripting.SWbemLocator WMI object remotely, then connect to Windows Management Instrumentation (WMI) services on the remote Windows host. From there you can submit a query that will inform you whenever a new event log entry is written.
Note that this does require that you have DCOM properly enabled and configured on the remote Windows host, and that appropriate exceptions have been set up in any firewalls. Details on this can be searched online, and are also referenced from the j-interop site, above.
The following example connects to a remote host using its NT domain, hostname, a username and a password, and sits in a loop, dumping every event log entry as they are logged by windows. The user must have been granted appropriate remote DCOM access permissions, but does not have to be an administrator.
import java.io.IOException;
import java.util.logging.Level;
import org.jinterop.dcom.common.JIException;
import org.jinterop.dcom.common.JISystem;
import org.jinterop.dcom.core.JIComServer;
import org.jinterop.dcom.core.JIProgId;
import org.jinterop.dcom.core.JISession;
import org.jinterop.dcom.core.JIString;
import org.jinterop.dcom.core.JIVariant;
import org.jinterop.dcom.impls.JIObjectFactory;
import org.jinterop.dcom.impls.automation.IJIDispatch;
public class EventLogListener
{
private static final String WMI_DEFAULT_NAMESPACE = "ROOT\\CIMV2";
private static JISession configAndConnectDCom( String domain, String user, String pass ) throws Exception
{
JISystem.getLogger().setLevel( Level.OFF );
try
{
JISystem.setInBuiltLogHandler( false );
}
catch ( IOException ignored )
{
;
}
JISystem.setAutoRegisteration( true );
JISession dcomSession = JISession.createSession( domain, user, pass );
dcomSession.useSessionSecurity( true );
return dcomSession;
}
private static IJIDispatch getWmiLocator( String host, JISession dcomSession ) throws Exception
{
JIComServer wbemLocatorComObj = new JIComServer( JIProgId.valueOf( "WbemScripting.SWbemLocator" ), host, dcomSession );
return (IJIDispatch) JIObjectFactory.narrowObject( wbemLocatorComObj.createInstance().queryInterface( IJIDispatch.IID ) );
}
private static IJIDispatch toIDispatch( JIVariant comObjectAsVariant ) throws JIException
{
return (IJIDispatch) JIObjectFactory.narrowObject( comObjectAsVariant.getObjectAsComObject() );
}
public static void main( String[] args )
{
if ( args.length != 4 )
{
System.out.println( "Usage: " + EventLogListener.class.getSimpleName() + " domain host username password" );
return;
}
String domain = args[ 0 ];
String host = args[ 1 ];
String user = args[ 2 ];
String pass = args[ 3 ];
JISession dcomSession = null;
try
{
// Connect to DCOM on the remote system, and create an instance of the WbemScripting.SWbemLocator object to talk to WMI.
dcomSession = configAndConnectDCom( domain, user, pass );
IJIDispatch wbemLocator = getWmiLocator( host, dcomSession );
// Invoke the "ConnectServer" method on the SWbemLocator object via it's IDispatch COM pointer. We will connect to
// the default ROOT\CIMV2 namespace. This will result in us having a reference to a "SWbemServices" object.
JIVariant results[] =
wbemLocator.callMethodA( "ConnectServer", new Object[] { new JIString( host ), new JIString( WMI_DEFAULT_NAMESPACE ),
JIVariant.OPTIONAL_PARAM(), JIVariant.OPTIONAL_PARAM(), JIVariant.OPTIONAL_PARAM(), JIVariant.OPTIONAL_PARAM(), new Integer( 0 ),
JIVariant.OPTIONAL_PARAM() } );
IJIDispatch wbemServices = toIDispatch( results[ 0 ] );
// Now that we have a SWbemServices DCOM object reference, we prepare a WMI Query Language (WQL) request to be informed whenever a
// new instance of the "Win32_NTLogEvent" WMI class is created on the remote host. This is submitted to the remote host via the
// "ExecNotificationQuery" method on SWbemServices. This gives us all events as they come in. Refer to WQL documentation to
// learn how to restrict the query if you want a narrower focus.
final String QUERY_FOR_ALL_LOG_EVENTS = "SELECT * FROM __InstanceCreationEvent WHERE TargetInstance ISA 'Win32_NTLogEvent'";
final int RETURN_IMMEDIATE = 16;
final int FORWARD_ONLY = 32;
JIVariant[] eventSourceSet =
wbemServices.callMethodA( "ExecNotificationQuery", new Object[] { new JIString( QUERY_FOR_ALL_LOG_EVENTS ), new JIString( "WQL" ),
new JIVariant( new Integer( RETURN_IMMEDIATE + FORWARD_ONLY ) ) } );
IJIDispatch wbemEventSource = (IJIDispatch) JIObjectFactory.narrowObject( ( eventSourceSet[ 0 ] ).getObjectAsComObject() );
// The result of the query is a SWbemEventSource object. This object exposes a method that we can call in a loop to retrieve the
// next Windows Event Log entry whenever it is created. This "NextEvent" operation will block until we are given an event.
// Note that you can specify timeouts, see the Microsoft documentation for more details.
while ( true )
{
// this blocks until an event log entry appears.
JIVariant eventAsVariant = (JIVariant) ( wbemEventSource.callMethodA( "NextEvent", new Object[] { JIVariant.OPTIONAL_PARAM() } ) )[ 0 ];
IJIDispatch wbemEvent = toIDispatch( eventAsVariant );
// WMI gives us events as SWbemObject instances (a base class of any WMI object). We know in our case we asked for a specific object
// type, so we will go ahead and invoke methods supported by that Win32_NTLogEvent class via the wbemEvent IDispatch pointer.
// In this case, we simply call the "GetObjectText_" method that returns us the entire object as a CIM formatted string. We could,
// however, ask the object for its property values via wbemEvent.get("PropertyName"). See the j-interop documentation and examples
// for how to query COM properties.
JIVariant objTextAsVariant = (JIVariant) ( wbemEvent.callMethodA( "GetObjectText_", new Object[] { new Integer( 1 ) } ) )[ 0 ];
String asText = objTextAsVariant.getObjectAsString().getString();
System.out.println( asText );
}
}
catch ( Exception e )
{
e.printStackTrace();
}
finally
{
if ( null != dcomSession )
{
try
{
JISession.destroySession( dcomSession );
}
catch ( Exception ex )
{
ex.printStackTrace();
}
}
}
}
}
~

On the Java side, you'll need a library that allows you to make native calls. Sun offers JNI, but it sounds like sort of a pain. Also consider:
https://github.com/twall/jna/
http://johannburkard.de/software/nativecall/
http://www.jinvoke.com/
On the Windows side, the function you're after is OpenEventLog. This should allow you to access a remote event log. See also Querying for Event Information.
If that doesn't sound right, I also found this for parsing the log files directly (not an approach I'd recommend but interesting nonetheless):
http://msdn.microsoft.com/en-us/library/bb309026.aspx
http://objectmix.com/java/75154-regarding-windows-event-log-file-parser-java.html

Read this article.
JNA 3.2.8 has both methods to read and write from the Windows event log.
You can see an example of write in log4jna.
Here's an example of read:
EventLogIterator iter = new EventLogIterator("Application");
while(iter.hasNext()) {
EventLogRecord record = iter.next();
System.out.println(record.getRecordNumber()
+ ": Event ID: " + record.getEventId()
+ ", Event Type: " + record.getType()
+ ", Event Source: " + record.getSource());
}

If you want true event log access from a remote machine, you will have to find a library which implements the EventLog Remoting Protocol Specification. Unfortunately, I have not yet found any such library in Java. However, much of the foundation for implementing this protocol has already been laid by the JCIFS and JARAPAC projects. The protocol itself (if I'm not mistaken) runs on top of the DCE/RPC protocol (implemented by JARAPAC) which itself runs on top of the SMB protocol (implemented by JCIFS).
I have already been using JCIFS and JARAPAC to implement some of EventLog's cousin protocols, such as remote registry access. I may be blind, but documentation seemed a little scarce regarding JARAPAC. If you are interested in implementing this, I can share with you what I have learned when I get some spare time!
Later!

there are a million (and one) options here ;)
you could look at sigar
http://cpansearch.perl.org/src/DOUGM/hyperic-sigar-1.6.3-src/docs/javadoc/org/hyperic/sigar/win32/EventLog.html
mind the licensing though....
or you could be quick and dirty and just periodically execute (and capture the output)
D:>cscript.exe c:\WINDOWS\system32\eventquery.vbs /v
then use event filtering params to refine the results etc...
http://technet.microsoft.com/en-us/library/cc772995(WS.10).aspx