Basics knowledge of Apache HTTP Server

I created this article as a reminder about some basics of Apache HTTP Server with real examples. I will present how to start apache,look for logs, and give information about the configuration.

The HTTP server handles request and does the mapping from URL to Filesystem locations. More information at

How do we start Apache ?

On Unix, the httpd program is run as a daemon that executes continuously in the background to handle requests.

According to the documentation, httpd should be invoked by a script called apachectl.

Let’s see with an example a running apache daemon. It happens I have an apache server on a test machine .

ps -edf | grep httpd
root     23154     1  0 10:44 ?        00:00:00 /usr/sbin/httpd.worker -f /var/apache/conf/httpd.conf -f /var/apache/conf/httpd.conf -k start

This command ps – edf tells us where is located the configuration file used for this apache running. On our machine exists many old install of apache. Therefore this command helps to find the right configuration file used by the current apache server.

One would wonder why httpd.worker is being run and not httpd? What is httpd.worker?
The answer to this question is here :

Basically at the installation of our product we install a new Apache/tomcat and deploy the application automatically. More information about how it is installed with shell scripts and deployed from Jenkins at

Here are the commands executed by the shell script to launch our Apache server when installing on our machine :

# Start the Apache http daemon
    write_log "Starting Apache..."
            export OPTIONS="-f ${ApacheDir}/conf/httpd.conf"
/usr/sbin/apachectl $OPTIONS -k start
#more code to handle the response

Where are the logs?

To my mind it is an important question if we want to troubleshoot problems on the server.
More about logging and how to understand the format of the logs :

Previously we find out where is the configuration for the httpd running at /var/apache/conf/httpd.conf. If I look into this file i can find where are located the log :

ErrorLog logs/error_log

Thus , on my server, the error log is located at /var/apache/logs/error_log

NOTE : If you have several Virtualhosts you will have one log for each of them.
It happens that on the directory /var/apache/logs there are more logs than just error_log. It is because we have defined some other configuration in /var/apache/conf.d.

For example if i want to find which module generate ssl_error_log, i will execute on the linux machine :

 grep -rnw '/var/apache' -e "ssl_error_log"
/var/apache/conf.d/mod_jk.conf:57:ErrorLog logs/ssl_error_log

Understand Apache Configuration

The following considerations are about about the HTTP Server configuration : “httpd.conf”, and other custom made configuration files.

What is the purpose of DocumentRoot ?

Extract from httpd.conf :

# DocumentRoot: The directory out of which you will serve your
# documents. By default, all requests are taken from this directory, but
# symbolic links and aliases may be used to point to other locations.
DocumentRoot "/var/apache/www/html"

Files and directories underneath the DocumentRoot make up the basic document tree which will be visible from the web.

Therefore what you see on a website is the tree structure under DocumentRoot :
Then a request for will cause httpd to attempt to serve the file /var/www/html/fish/index.html.

What does IfModule tag in configuration files ?

Did you notice


tag in configuration files of apache server and wondered what is it exactly ?

In the following example, the MimeMagicFile directive will be applied only if mod_mime_magic is available.

<IfModule mod_mime_magic.c>
    MimeMagicFile "conf/magic"

Therefore this tag will apply directives from module.

What is ServerName ?

Extract from httpd.conf :

# ServerName gives the name and port that the server uses to identify itself.
# This can often be determined automatically, but we recommend you specify
# it explicitly to prevent problems during startup.
# If this is not set to valid DNS name for your host, server-generated
# redirections will not work.  See also the UseCanonicalName directive.
# If your host doesn't have a registered DNS name, enter its IP address here.
# You will have to access it by its address anyway, and this will make
# redirections work in a sensible way.
ServerName apache-myinstance:8080

What is doing the directive Listen ?

The Listen directive tells the server to accept incoming requests only on the specified port(s) or address-and-port combinations.

For example we have on our server used two times the directive for

# Virtual HOST HTTP **
Listen apache-myinstance:8080
# Virtual HOST HTTPS **
Listen apache-myinstance:447

What is a Virtual Host ?

httpd is also capable of Virtual Hosting, where the server receives requests for more than one host. For example on the same server you would have and,etc.. running.

<VirtualHost apache-myinstance:447>

      JkMount /* myworker

ErrorLog logs/ssl_error_log
CustomLog logs/ssl_access.log java_format
LogLevel warn

SSLEngine on
SSLProtocol all -SSLv2
SSLCertificateFile /etc/certs/localhost.crt
SSLCertificateKeyFile /etc/certs/localhost.key

<Files ~ "\.(cgi|shtml|phtml|php3?)$">
    SSLOptions +StdEnvVars
<Directory "/var/www/cgi-bin">
    SSLOptions +StdEnvVars

SetEnvIf User-Agent ".*MSIE.*"          nokeepalive ssl-unclean-shutdown          downgrade-1.0 force-response-1.0


How to modify your git credentials when cloning from Git Extensions ?


I installed git extensions on Windows in order to use git on Windows. I had to clone a repository located on a distant server.


But I used a wrong login (mywronglogin). Here is the error :

"C:\Program Files (x86)\Git\bin\git.exe" clone -v --recurse-submodules --progress --branch develop "" "D:/my_repo_git"
Cloning into 'D:/my_repo_git/myproject'...
fatal: remote error: FATAL: R any myproject mywronglogin DENIED by fallthru
(or you mis-spelled the reponame)

Unfortunately from the user interface of git extensions it is not possible to modify the credentials !

I have done the following without success

  • Modifying login in git extensions UI
  • Looking for the configuration with my wronglogin in C:/Users/mylogin, the directory of git and git extensions
  • Modifying regedit
  • I tried to uninstall git exensions but after reinstall : i got the same issue !
  • Finally I found out about the credential helper for Windows which can cache git credentials.


I had to unset the cache credential in order to modify this login. Indeed the credentials are stored in the “credentials.helper” to avoid typing them every time. It is a nice feature except when you want you to modify the credentials for some reason.

I had to unset credentials like this :

git config --system --unset credential.helper

Now when you will clone the repo you will be asked for the login/password !
If you were not aware of this feature you can spend quite some time on this problem.

How to call asynchronously web servers with Javascript ?

Problem :

We wanted to display or hide information from more than five web servers when loading a homepage. Instead of waiting until all the servers reply to us ( synchronous method) the customer wanted to see the information as soon as the server would reply. This solution presents a better user experience because the webpage is more responsive.


I will decompose the solution in several parts and explain each steps

  • A HTML/W3.CSS webpage with a button calling the javascript method
  • The Javascript code calling multiple web servers
  • The Javascript class that call a web server
  • The callback method which handle the response of the web server
  • The Javascript function which updates the webpage after obtaining a response from the server.

HTML web page

The html webpage contains a button and a text input. The text input is sent to the web servers when we click the button.

This is a simple example of webpage

The link to my javascript file :

<script type="text/javascript" src="./webserver.js">
<script type="text/javascript" src="./request.js">

When we click on the button we call a javascript function which will use the text content of the input “myinput”.

 <input name="myinput" id="myinput" class="w3-input w3-border w3-light-grey" type="text">
<button class="w3-btn w3-blue-grey" onclick="callWeb()">Load Web Servers</button>

callWeb() is a Javascript function which will retrieve the input value and call web servers.

function callWeb() {
    var input = document.getElementById('myinput'),
       myinput = input.value;
    if (myinput) {
    } else {
       alert('Please enter an input!');

To avoid the error “The character encoding of the HTML document was not declared” : I have added these lines in the HTML :

<meta content="text/html;charset=utf-8" http-equiv="Content-Type">
<meta content="utf-8" http-equiv="encoding">

For information in this example I use W3.CSS for the style. It is a modern CSS framework with built-in responsiveness. It is an equivalent of Bootstrap. More information at

Javascript : Calling multiple web servers

I will present the javascript function which send the request and the callback function which handle the response .

function loadWebServers(input)
    var value1 = input
    var value2 = ''
    var value3 = ''

In this example we call only two web servers. loadWebABC call a web service with XML request. loadWebX call another web service with a JSON request.

function loadWebABC(value1)
MyClassRequest.sendXmlRequest("", "myinput=”+ value1, "callbackWebABC");

When the server replies, the callback will handle the response :

function callbackWebABC(xml)
    var rootInfo = xml.getElementsByTagName("root-info");
    //parse more information

Javascript : Detail of the class that call the web server

XmlHttpRequest is the class used to call distant web servers.

If you use XMLHttpRequest from an extension, you should use it asynchronously. In this case, you receive a callback when the data has been received, which lets the browser continue to work as normal while your request is being handled.

MyClassRequest is the equivalent of a class in Javascript world. It is defined in a file called request.js :

var MyClassRequest = {
	loading : false,

updaters : new Array(),

	Updater : function(request, backFunction, param, isXml, isJson) {
		this.request = request;
		this.backFunction = backFunction;
		this.param = param;
		this.isXml = isXml;
		this.cancelled = false;
		this.isJson = isJson;

	createRequest : function() {
		var request = false;
		try {
			request = new XMLHttpRequest();
		} catch (trymicrosoft) {
			try {
				request = new ActiveXObject("Msxml2.XMLHTTP");
			} catch (othermicrosoft) {
				try {
					request = new ActiveXObject("Microsoft.XMLHTTP");
				} catch (failed) {
					request = false;
		return request;

	sendXmlRequest : function(url, urlParam, backFunction, param) {
		return this
				.sendRequest(url, urlParam, backFunction, param, true, false);

	sendRequest : function(url, urlParam, backFunction, param, isXml, isJson, timeout) {
		 if (typeof(timeout)==='undefined') {
			 timeout = 0;
		var request = this.createRequest();

		if (!request) {
			alert("Request not supported");
			return -1;
		} else {
			var index = this.updaters.length;
			this.updaters[index] = new MyClassRequest.Updater(request,
					backFunction, param, isXml, isJson);"POST", url, true);
			request.onreadystatechange = MyClassRequest.receiveRequest;
			if (timeout != null && timeout > 0) {
				request.timeout = timeout;
				request.ontimeout = MyClassRequest.timeoutRequest;
					"application/x-www-form-urlencoded; charset=UTF-8");

			return index;

As you can see the function sendXmlRequest is a sub function of sendRequest. sendRequest will use the object XMLHttpRequest or an equivalent for microsoft supported browser. This important part in this function is :

request.onreadystatechange = MyClassRequest.receiveRequest;

It is receiveRequest function which will trigger the callback function defined previously.

receiveRequest : function() {
		var stillLoading = false;
		for ( var i = MyClassRequest.updaters.length - 1; i >= 0; i--) {
			var updater = MyClassRequest.updaters[i];
			if (updater != null) {
				if (updater.request.readyState == 4) {
					MyClassRequest.updaters[i] = null;
					if (updater.cancelled == false) {
						if (!updater.request.status == 200) {
							alert("No response from server");
						} else {
                                                        if (updater.backFunction) {
				} else {
					stillLoading = true;

callbackFunction is the function which will actually call our callback function when we receive correctly a response form the distant web server.

function callbackFunction(updater)

var func = new Function("response", "param",
					+ "(response, param)");
	if (updater.isXml) {
		var xml = updater.request.responseXML;
		if (MyClassRequest.checkErrors(xml)) {
			func(false, updater.param);
		} else {
			func(xml, updater.param);
	} else {


Javascript : update the webpage

In the previous callback method we use a function showOrDisplayInfo(). This function will display or hide element in the web page. This is a simplified version of the function but as you can see it modifies an HTML element to show or hide this element.

function showOrDisplayInfo(infoextracted) {
for (var infoin infoextracted)
      var idElementToShow ="elementX"+ infoin;
         show( idElementToShow );

function show(element)
  if (element)

function hide(element)
  if (element)

Difference between join fetch Hsql and standard SQL request.


I stumbled upon a problem with a HSQL request recently(Hibernate SQL language). The application using a Hsql request was not retrieving the information we wanted and we did not know why.

The SQL request retrieving correctly the information

The tables from the database(simplified) :

        ID          NAME    
        122        NAME_X

        MY_ID     MY_NAME       VarA 
        231       NAME_Y        value_expected
        Null      NAME_X        value_expected

This SQL request executed from SQL developer would retrieve the expected outcome from the tables.

t.VarA = 'value_expected' and
a.NAME=t.MY_NAME and (a.ID=t.MY_ID or a.ID is null).

Outcome :

Null           NAME_Y

The different behavior with looking similar HSQL request

The HSQL request( used with entities) in the java code was supposed to give the same results as the previous sql request. Here is the code of the hsql request :

StringBuilder clause = new StringBuilder(
"from MyAlarm a join fetch a.mytable t"
+" where t.VarA = 'value_expected' and"
+"(a.ID=t.MY_ID or a.ID is null)");

The problem when using this hsql request is that some of the request is done through entity objects (from MyAlarm a join fetch a.mytabl). The join is done in the entity class of the Entity MyAlarm :

@Table(name = "MY_ALARM")
@Cache(usage = CacheConcurrencyStrategy.NONE)
public class MyAlarm implements Serializable {
    @Column(name = "NAME")
    private String Name;
    @Column(name = "ID")
    private String Id;

 @ManyToOne(targetEntity=MyTable.class, optional = true, fetch=FetchType.LAZY)
,nullable = true, insertable = false
, updatable = false),
,nullable = true
, insertable = false
, updatable = false)</b>

This following join from the entity will never retrieve the row of the table MY_TABLE where ID is null because there is no ID null in the table ALARM. Therefore this hsql request is not not equivalent to the SQL request above.

Explanation about join fetch

The documentation about join fetch : “14.3. Associations and joins”

A good explanation of the difference between join and join fetch here :

How did I find the solution ?

As i said previously unit testing is the key to find the resolution of coding problems. It enables you to reproduce problems faster and it adds a regression test to your product. More information about unit testing

I reproduced the problem inside a unit test.It helped me a lot to understand the problem and how to solve it. To realise a unit test of hibernate request i use hsqldb,spring framework ,maven,etc..

The solution

I join the two tables “MyAlarm” and “MyTable” with the following conditions. The important part was to add (a.ID=t.MY_ID or a.ID is null). It is a condition necessary to respect the needs of the customer.

<b>select a from MyAlarm a, MyTable t</b> where 
t.VarA = 'value_expected' and
a.NAME=t.MY_NAME (a.ID=t.MY_ID or a.ID is null)

Basic automatic testing of machine learning algorithm in Python


I will present a basic solution to realize automatic testing for machine learning algorithm. There is many languages used for machine learning. Python is one of the most popular language for machine learning.It is not the fastest or the easiest language but it is a general purpose language that does a bit of everything.

I am gonna use the machine learning algorithm made by Michael E Nielsen It is coded in Python. This ebook explains Neural Networks and deep learning with code examples. That’s a really good article to start learning machine learning.

This article explains a machine learning algorithm (neural networks and deep learning) . Michael E Nielsen uses these algorithms to resolve the problem of recognizing handwritten numbers.


I will show the tools i use to code and test in Python language. Then i will present some of my basic unit test to test the code source of Michael E Nielsen. I will also present a short unit test for Stochastic Gradient Descent. Also i will show my solution to launch all Python tests from Jenkins

Develop and test Python code in Eclipse

There are many IDE to code in Python. I chose to use Eclipse with Pydev plugin. I used it because it is free and easy to use. I also use “git” for source control.

Once you have installed Pydev plugin in eclipse, you need to configure eclipse if you would like to run unit tests inside it. One of my problem was to run unit tests inside eclipse.

Neural networks project in Eclipse from the ebook

As you can see from the picture , my unit tests are in a folder called “test”. The “src” folder contains the source code of the neural networks algorithm. My initial problem was that my unit tests could not import the source code. For example I could not import the class Network.

The solution for this problem was to configure eclipse Pydev plugin  like in this link.

Go to the pane of “PyDev – PYTHONPATH” of the python project and add your source code in external libraries.

Configure Pydev to launch unit tests inside Eclipse

Now i can launch the test inside Eclipse.

Create Basic Unit Tests with Python

Assuming you are using version 3.7 you should inform yourself about unittest package from the Python manual .

This is the class i would like to test :

class Network(object):

def __init__(self, sizes):
        """The list ``sizes`` contains the number of neurons in the
        respective layers of the network.  For example, if the list
        was [2, 3, 1] then it would be a three-layer network, with the
        first layer containing 2 neurons, the second layer 3 neurons,
        and the third layer 1 neuron.  The biases and weights for the
        network are initialized randomly, using a Gaussian
        distribution with mean 0, and variance 1.  Note that the first
        layer is assumed to be an input layer, and by convention we
        won't set any biases for those neurons, since biases are only
        ever used in computing the outputs from later layers."""
        self.num_layers = len(sizes)
        self.sizes = sizes
        self.biases = [np.random.randn(y, 1) for y in sizes[1:]]
        self.weights = [np.random.randn(y, x)
                        for x, y in zip(sizes[:-1], sizes[1:])]

I am gonna test only few parts of the class Network and run a testcase from the chapter 1

This is my test class which test the Network class.

import unittest
import network
import mnist_loader

class test_network(unittest.TestCase):
    def testCaseRecognizeHandWrittenDigits(self):
        #loading the MNIST data
        training_data, validation_data, test_data = mnist_loader.load_data_wrapper()
        #set up a Network with 30 hidden neurons
        net = network.Network([784, 30, 10])
        #Finally, we'll use stochastic gradient descent to learn 
        #from the MNIST training_data over 30 epochs, with a mini-batch size of 10, and a learning rate of eta=3.0, 
        epochs = 3#30
        net.SGD(training_data, epochs, 10, 3.0, test_data=test_data)

    def testnetwork(self):
        print "init network"
        size = [784, 30, 10]
        net = network.Network(size)
        # verify the number of items in the collection size
        self.assertEqual(net.num_layers, 3)  

The test “testCaseRecognizeHandWrittenDigits” just launch one testcase of the chapter 1. It does not verify anything. It is checking if everything is compiling but we have no idea if the code is doing something useful.

The test “testnetwork” is a unit test for the object Network. We verify that the number of items is correct. When i launch the tests from eclipse the results are OK :

Run as Python Unittest from Eclipse

As you can see from the previous testcase i just run SGD over three epochs instead of 30.SGD is the method which implements stochastic gradient descent.

System Test of Stochastic Gradient Descent algorithm

Now i am gonna test SGD of the object Network2 of the code source.

In practice, stochastic gradient descent(SGD) is a commonly used and powerful technique for learning in neural networks, and it’s the basis for most of the learning techniques we’ll develop in this book.

The unit test I have created will tell us if the algorithm detect  handwritten numbers with more than 90% accuracy.

class test_network2(unittest.TestCase):
    def testCaseRecognizeHandWrittenDigits(self):
        #loading the MNIST data
        training_data, validation_data, test_data = mnist_loader.load_data_wrapper()
        #set up a Network with 30 hidden neurons
        net = network2.Network([784, 30, 10], cost=network2.CrossEntropyCost)
        #We set the learning rate to eta and we train for 3 epochs
        epochs = 3# for speed i chose 3 instead of 30
        global_evaluation_data = net.SGD(training_data, epochs, 10, 0.5, evaluation_data=test_data, monitor_evaluation_cost=True,monitor_evaluation_accuracy=True,monitor_training_cost=True, monitor_training_accuracy=True)
        total_accuracy_training_data = global_evaluation_data[1]
        # verify that accuracy of training data for all epoch is superiori to 90%
        for accuracy in total_accuracy_training_data :
            print accuracy
            percentage = accuracy / 10000.0
            print percentage
            self.assertGreater(percentage, 0.9, "accuracy must be superior to 90 percent for all epoch")

As you can see from the code the methode SGD returns the accuracy of the training data and also evaluation data. In the code I am just verifying that for all epochs the accuracy of the detection of handwritten images is superior to 90%. And this verification is done just for training data.

This is just an example of unit test for machine learning algorithm. By testing everyday this testcase with Jenkins , we verify that any modification in our algorithm won’t diminish the accuracy of the detection.

Here a caption of the result when i run the unit test from eclipse :

The accuracy of the training data for all epochs is superior to 90%

How to run Python tests from Jenkins ?

To launch all Python tests of the project everyday I use Jenkins and nose2.

On Ubuntu it is easy to install Nose2. Follow the instructions of this link .

Once nose2 is installed just go to the top directory of your python project for a test. Launch nose2 to run all the Python tests of your project. To give an example of the result with Neural Networks unit tests i have previously created :

All four tests i have created have been run with success

Finally create a new job from Jenkins.Configure the job to get the code from a git repository(for instance) and then launch all tests with nose2. See this link for more information about nose2 and Jenkins integration :


We can imagine many more tests for Neural Networks algorithm. We could test if the algorithm is learning fast or slow. We could check problems such as overfitting, underfitting, etc…

This article about TDD machine learning can give us more ideas about what to verify in our machine learning algorithms :

I may do another post later for more unit tests for these machine learning algorithms.




Mock HibernateTemplate with Mockito


Mockito is a useful Java library to create mock Objects for Java Unit Testing.

I used the framework Mockito in order to test objects difficult to test otherwise such as Struts method, Servlet, Hibernate , etc…

HibernateTemplate object to mock

This is the legacy code i wanted to test with Mockito. HibernateTemplate is a deprecated class but it is still used in this code.

Package com.dao.myclass;

import org.springframework.dao.DataAccessException;

import com.dao.ImyDAO;
import com.dao.exception.MyException;
import com.dao.myEntity;
import com.util.Logger;

public class MyHibernateImpl extends HibernateDaoSupport implements ImyDAO {

    public myEntity getMyEntity(String myNumber) throws MyException {
        try {
            if (myNumber == null) {
                        .error("myNumber : " + myNumber);
                return null;
            if (myNumber != null && myNumber.length() > 1) {
            myEntity thismyentity = (myEntity) getHibernateTemplate().get("com.dao.myEntity", myNumber);
            return thismyentity;
        } catch (final DataAccessException e) {
            throw new MyException("error.CodeMyEntity", e);


The line of code i had to difficulty to test without Mockito :

myEntity thismyentity = (myEntity) getHibernateTemplate().get("com.dao.myEntity", myNumber);

The code for myEntity :

@Table (name="MY_TABLE")
public class myEntity implements Serializable {

    private static final long serialVersionUID = 5447862515324364L;

    private String myNumber;

    @Column (name="MYCOLUMN")
    private String myColumn;

    public String getmyNumber() {
        return myNumber;
    public void setmyNumber(String myNumber) {
        this.myNumber = myNumber;
    public String getmyColumn() {
        return myColumn;
    public void setmyColumn(String myColumn) {
        this.myColumn = myColumn;

Mock the object HibernateTemplate

I need to mock the object HibernateTemplate in order to test this function. Here is my test class with Junit :

public class TestMyHibernateImpl {

    HibernateTemplate mockTemplate;

I used the annotation @Mock for the creation of a mock object of HibernateTemplate. To use @Mock it is necessary to initialise MockitoAnnotations :

    public void initMocks() {

This is how I test the function getMyEntity:

    public void testCasEntityReturned() throws MyException {

        myEntity entity = new myEntity();
        String myNumber = "S54564121SD”;
        String myColumnValue = "myColumn";

        (Mockito.doReturn(entity).when(mockTemplate)).get("com.dao.myEntity", myNumber);
<b>// I tell Mockito to return an entity when this code is used later in getMyEntity(..)</b>

        MyHibernateImpl myColumn = new MyHibernateImpl();
        myEntity thismyentity = myColumn.getMyEntity(myNumber);
        Assert.assertEquals(myNumber, thismyentity.getmyNumber());
        Assert.assertEquals(myColumnValue, thismyentity.getmyColumn());


SQLLOADER has “ORA-01722: Number not valid ” with CSV File

The problem

While importing a csv file with sql loader i has this error :

Record 1: Rejected - Error on table MY_TABLE, column MY_COLUMN3 .
ORA-01722: Number not valid

Record 2: Rejected - Error on table MY_TABLE, column MY_COLUMN3 .
ORA-01722: Number not valid

  1 Row successfully loaded.
  11 Rows not loaded due to data errors.
  0 Rows not loaded because all WHEN clauses were failed.
  0 Rows not loaded because all fields were null.

I spent hours on this problems .

My configuration

My CTL file :


My table :

       ID                           NUMBER GENERATED BY DEFAULT AS IDENTITY,            
          MY_COLUMN1             FLOAT                      NOT NULL ,                 
MY_COLUMN2             FLOAT                      NOT NULL,
MY_COLUMN3             FLOAT                      NOT NULL,                 
    PCTFREE 10                                                                           

My CSV file :


The solution

First i checked what the error meant :

This error can mean there are blanks in the file but after checking the csv file there was none. However I noticed the last column MY_COLUMN3 causing problems had negative values. But according to oracle documentation the type Oracle FLOAT can handle negative values. And the ctl was correctly configured to handle negative values with MY_COLUMN3 DECIMAL EXTERNAL. So what is going on ?

Finally i discovered that after manually modifying the CSV file in the unix server the problem was solved ! So i figure out the problem was not coming from ctl file but from the csv file.

After many trials and errors I found out the file was a dos file

vi /data/myfile.csv
</data/myfile.csv" [noeol][dos] 13L, 832C

Actually this csv file is a file coming from Excel document on Windows and being transferred to the unix server.

So I tried the command dostounix and it fixes my issue !!!