ChartFX open file limit on the server

Charlie · February 9, 2009

We are using ChartFX 7 for Java to make charts that are refreshing every second.

An example provided by SoftwareFX for refreshing the chart made out of a query to a db is shown in the code that follows.

We came accross the following problem, inside the chartfx70/temp directory there are the PNG and the CHS files
that are created for each chart, while updating the chart the chartfx server creates new PNG & CHS files and never releases the resources.

With 2 charts per page and 1 second refresh rates and 15 users we have a total of 108000 files/hour.

After a few hours we end up with a huge amount of open files that in windows slows down the application and in linux we have problems with the open files limit of the kernel (see lsof, ulimit).

One answer was to write a script that deletes the files, but even after deleting the files the file handles in the kernel are still all taken and no new files
can be opened.

How should we instruct the chart server to release the resources after the update is executed ?

Code for charts that update provided by SoftwareFX Suport:

<%@page import="com.softwarefx.chartfx.server.*"%>
<%@page import="com.softwarefx.chartfx.server.dataproviders.*"%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Passing Data: JDBC</title>
</head>
<script LANGUAGE = "JavaScript">
var ascendent = true;
var timerID = null
var delay = 5000

function InitializeTimer()
{
StartTheTimer()
}

function StartTheTimer()
{
var param = "";
if (ascendent)
param = "asc";
else
param = "desc";

SFX_processing = false;
SFX_SendUserCallback('chart1', param, false);

ascendent = !ascendent;
timerID = self.setTimeout("StartTheTimer()", delay)
}
function SFX_UpdateControls(id,callbackReturn) {
if (callbackReturn != "")
alert(callbackReturn);
}

</SCRIPT>

<body>
<input type="submit" name="Button1" value="Start" id="Button1" style="font-family: Arial;
font-size: 9pt; width: 56px;" onclick="InitializeTimer()"/>

<%!
public class UserCallBackEventHandler implements com.softwarefx.chartfx.server.UserCallbackListener {

public void userCallbackEventHandler(UserCallbackEvent e) {
ChartServer chart1 = (ChartServer) e.getSource();

chart1.getDataSourceSettings().getFields().clear();

java.sql.ResultSet rs = null;
java.sql.Connection conn = null;
String query = "SELECT * FROM SampleFinancial ORDER BY Field1 " + e.getParam();
try {
Class.forName("org.hsqldb.jdbcDriver");
String database = "jdbc:hsqldb:file:" + getServletContext().getRealPath("/") + "/data/sampledb/sampledb";
conn = java.sql.DriverManager.getConnection(database, "SA", "");
java.sql.Statement stmt = conn.createStatement();
rs = stmt.executeQuery(query);
} catch (Exception ex) {
}
JDBCDataProvider provider = new JDBCDataProvider(rs);
chart1.getDataSourceSettings().getFields().add(new FieldMap("Field1", FieldUsage.LABEL));
chart1.getDataSourceSettings().getFields().add(new FieldMap("Field2", FieldUsage.VALUE));
chart1.getDataSourceSettings().getFields().add(new FieldMap("Field3", FieldUsage.VALUE));
chart1.getDataSourceSettings().setDataSource(provider);
try {
conn.close();
} catch (Exception ex) {
}

chart1.recalculateScale();
}
}

%>
<%
ChartServer chart1 = new ChartServer(pageContext, request, response);
chart1.setID("chart1");
chart1.setUseCallbacksForEvents(true);
chart1.addUserCallbackListener(new UserCallBackEventHandler());

chart1.setWidth(600);
chart1.setHeight(400);

java.sql.ResultSet rs = null;
java.sql.Connection conn = null;
String query = "";

try {
Class.forName("org.hsqldb.jdbcDriver");
String database = "jdbc:hsqldb:file:" + application.getRealPath("/") + "/data/sampledb/sampledb";
conn = java.sql.DriverManager.getConnection(database, "SA", "");
java.sql.Statement stmt = conn.createStatement();
query = "SELECT * FROM SampleFinancial";
rs = stmt.executeQuery(query);
} catch (Exception e) {
out.println(e.getMessage());
}

JDBCDataProvider provider = new JDBCDataProvider(rs);
chart1.getDataSourceSettings().getFields().add(new FieldMap("Field1", FieldUsage.LABEL));
chart1.getDataSourceSettings().getFields().add(new FieldMap("Field2", FieldUsage.VALUE));
chart1.getDataSourceSettings().getFields().add(new FieldMap("Field3", FieldUsage.VALUE));
chart1.getDataSourceSettings().setDataSource(provider);

conn.close();

chart1.getAxisX().getLabelsFormat().setFormat(AxisFormat.DATE);

SeriesAttributes series0 = chart1.getSeries().get(0);
series0.setGallery(Gallery.LINES);
series0.getLine().setWidth((short) 2);
series0.setMarkerShape(MarkerShape.NONE);
series0.setAxisY(chart1.getAxisY());

SeriesAttributes series1 = chart1.getSeries().get(1);
series1.setGallery(Gallery.AREA);
series1.getBorder().setVisible(true);
series1.setAxisY(chart1.getAxisY2());

chart1.getAxisY().getGrids().getMajor().setVisible(true);
Axis axis = chart1.getAxisY2();
axis.setMax(200000000);
axis.setMin(0);
axis.setVisible(false);
chart1.getPlotAreaMargin().setRight(30);

chart1.recalculateScale();

chart1.getSeries().get(0).setText("Price");
chart1.getSeries().get(1).setText("Volume");

chart1.renderControl();
%>
</body>
</html>

rubyrubin · December 1, 2009

Hi -

Is there any answer to this question? We are looking to deploy ChartFX on a production server, but if this is an ongoing issue, we will not be able to. Thanks.

- Aaron

Charlie · December 2, 2009

We have received a patch from ChartFX and it works fine now,

not sure if it has been included in the latest service pack,

if not so you can still ask for the patch from ChartFX.

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ChartFX open file limit on the server

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