Archive

Posts Tagged ‘Tomcat’

Choosing the optimal configurations for GeoServer

December 29, 2011 1 comment

What I wanted to do

Setup GeoServer with optimal performance. I define optimal performance as fast response with large number of concurrent users (HTTP request of WMS). The GeoServer will be serving vector line data with 80K features. The vector lines are currently stored as a feature class in ArcSDE with Oracle.

Problems

I have identified several parameters/configurations could improve the performance of GeoServer at OpenGeo and GeoServer’s documentation. In particular, here are a list of big questions that I need to answer:

1. What are the optimal JVM options

2. Which application server shall I use to serve GeoServer, Tomcat or Glassfish?

3. Which source data format shall I use to feed GeoServer? Shall I stay with ArcSDE or shall I export the feature class to a shapefile?

Here is the verision of some applications that I used:

  • Tomcat 6.0.33
  • Glassfish 3.1
  • GeoServer 2.1.1
  • JRE 1.6
  • ArcSDE 9.3.1
  • Oracle 11g

Solution

To find answers, I need to do some testing and find out what set of configurations give me the fastest HTTP response when GeoServer handles WMS request. To measure the testing result, I found an excellent tool called JMeter. It basically issues customized HTTP request to specified web service and measures the response time. It can also do the testing for multiple-user scenario.

I started with JVM options. A benchmark was established with default JVM settings, Tomcat, ArcSDE as source data format, and single user scenario. Then I changed one parameter for JVM option at a time, measured the response time and compared the result against the benchmark.

After finding the optimal JVM options, I switch the source data format from ArcSDE to shapefile and continue to run the testing on single user scenario.

Then I switched to multiple-user scenario with 10 users sending requests at 1 second interval. In this case, GeoServer’s performance decreases dramatically for either shapefile or ArcSDE as source data format.

I also did similar test with Glassfish.

Here is my findings:

Optimal JVM options: -server -Xms1024m -Xmx1024m -XX:MaxPermSize=512m -XX:+UseParNewGC. Of course, these options depend on the hardware configuration of my machine

Tomcat vs. Glassfish

  • In single user case: Glassfish is faster than Tomcat
  • In multiple user case: Tomcat is faster than Glassfish but more volatile. On average, Tomcat responses faster. But comparing with Glassfish, a lot more of Tomcat’s responses are either faster or slower, making the response time less predictable in Tomcat.
  • With user number increases, response time increases too. But Glassfish’s response time increases more than Tomcat for the same number of user increase

ArcSDE/RDBMS vs. Shapefile

  • In general, shapefile is faster than ArcSDE/RDBMS. In single user scenario, shapefile is more than 10 times faster than ArcSDE. This is reasonable because when ArcSDE is involved there is overhead of connecting to database. Even if there is database connection pooling in Tomcat, the overhead is still very costly
  • In multiple user case: response time increase for ArcSDE is less than shapefile. This is reasonable as RDBMS is designed to handle concurrent users scenario
  • In my 10-concurrent user scenario, even shapefile’s performance decreased more dramatically than ArcSDE with user increase, it still perform about 10 times better than ArcSDE. But I think with more and more concurrent users (100, 1K even 10K), ArcSDE/RDBMS’s performance should eventually out beat shapefile

So, if I want stability in performance, fast response time, AND if I predict only very small number of concurrent users, I should go with Glassfish and shapefile. In the case of large number of concurrent users, it seems that the combination of Tomcat and ArcSDE/RDBMS  should lead to better performance.

Advertisements

Setup GWT Development Mode with Tomcat in Eclipse

October 20, 2011 11 comments

Update

A much better solution that I found recently is to create a Google Web Project and make it into a Dynamic Web Project so that one can hot deploy the GWT stuff the same way as JSP and servlet. The example is given with Glassfish.

http://rmapper.wordpress.com/2011/02/02/gwt-development-mode-with-hot-deployed-glassfish-in-eclipse-2/

forget about the following:
Old crap

After developing GWT application with NetBeans for several weeks, I found that I need to give up NetBeans and switch to Eclipse.

On one hand, to develop GWT application with NetBeans is easy to start. A GWT4NB plugin and necessary GWT SDK will allow you to build GWT apps. Debugging with Tomcat is extremely straightforward. Since I already have Tomcat setup for NetBeans, there was nothing in particular that I did after installing GWT4NB and GWT SDK to be able to debug GWT application with Tomcat. Moreover, my GeoServer for development has been running on Tomcat. Although I could take advantage of the embedded GWT development mode with Jetty, I really want my GWT application to run on localhost:8080 with Tomcat so that I can issue HTTP request from GWT app to GeoServer.

On the other hand, GWT Designer doesn’t work with NetBeans. This has not become an issue until I started to build complex GWT widgets using SmartGWT. Without GWT Designer, it was overwhelmingly painful to tweak the GWT application (which remind me my good old days with Visual Studio).

Problem: Setup Eclipse to include GWT and configure GWT in Eclipse to work with Tomcat at development mode

Solution:

1. I followed Set up Eclipse instruction to install Eclipse and include GWT

2. Go to Compile & Debug to find instruction to debug with my own server. The instruction’s step-by-step description of how to use -noserver confused me. So here are the steps that I have summarized to hopefully make a starter like myself understand better. Basically 1) you need to setup a place holder in Tomcat so that Eclipse can deploy your modified code to Tomcat in the GWT development mode, and 2) you need to tell Eclipse where to deploy in the GWT development mode.

  1. Compile your GWT project in Eclipse with Google Plugin for Eclipse: Right click on your project -> Google -> GWT Compile
  2. Create place holder on Tomcat. After compile, find your project folder in Eclipse workspace. Locate YourProject/war directory. Copy all stuff under the war directory to the webapps folder under your Tomcat installation. You need to create a new folder under webapps to hold the stuff copied from war directory. You are essentially deploying your compiled GWT project to Tomcat
  3. Configure GWT development mode. In Eclipse, right click on your project -> Debug as -> Debug Configurations -> Web Application -> your project -> Go to Server tab -> uncheck “Run built-in server” -> Go to GWT tab -> in URL, put the URL from which you access the project deployed on Tomcat. For example, http://localhost:8080/myproject/index.html
  4. Click Debug. Now you should see that the development mode generates URL based on http://localhost:8080.
  5. Now launch the development mode URL and try to modify some contents in your project source code. For example, change the html title name and save. After that, refresh the URL on browser. And you should see your changes applied to your deployed project on Tomcat in development mode.

Note that at this point the development mode will only transfer the code that you have modified under src/. Other so called static contents such as your .html and .css would not be transferred to Tomcat. What you might have noticed is that if you edit .css file under war directory, you edits won’t go to Tomcat. My work around is to create an ant script under my project in Eclipse and ask the script to copy .html and .css to the webapps/myproject on Tomcat. Now every time I make change to .html and .css, I will run the ant script before refreshing the webpage.

Categories: Web GIS Tags: , , ,