Eclipse is Slow – Finding out Why

8. January, 2015

In this article, I’m trying to collect the steps to find out the reason when Eclipse is suddenly slow:

  1. Java GC. To find out if that’s the culprit, go to Window -> Preferences -> General and enable “Show heap status”. You will get a little gauge at the bottom of the Window. If the gauge is almost full, then you probably have too little memory.
    Solutions:
    a) Give Eclipse more memory
    b) Close some projects
    c) Deinstall or disable unnecessary plugins
  2. Check the Eclipse Error Log. Maybe there is a problem under the hood.
  3. Some plugin is acting up. Enable Eclipse’s own logging (see below) and watch the console.
    Some plugins have their own console (Groovy, Maven). In the Console View, click the arrow of the “Open Console” button to get a list. The Stacktrace Console – a useful tool to examine stacktraces from some external source – is also hidden there.
  4. The metadata got corrupted. Clean it.

Enable Eclipse’s Console Logging

When you start a Java application inside of Eclipse, you can see the output in a console view. You can do the same for Eclipse itself.

Open eclipse.ini and add these lines right before -vm (or -vmargs, if there is no -vm line):

-console
-consoleLog
-debug

See “Debug Mode“, “Eclipse runtime options” and “FAQ How do I use the platform debug tracing facility”

On Windows, make sure Eclipse is started with java.exe instead of javaw.exe.

Eclipse will log errors and trace information to the console window. Check the output.

Enable Tracing

Many Eclipse plugins offer a range of trace options. You can see them if you open the plugin JARs. Look for a file called “.options”.

If you copy some of those into a file “.options” in the same folder as “eclipse.ini”, you can able various logging options.

Here is an example what the file could look like:

org.eclipse.ui/debug=true 
org.eclipse.ui/trace/graphics=true

Maven m2e Plugin

If the m2e plugin causes problems:

  1. Look into the Maven console.
  2. Try Maven from the command line to see whether it’s a problem with the project in general or with m2e.
  3. Tweak the logging options of m2e by editing 
    WORKSPACE_ROOT/.metadata/.plugins/org.eclipse.m2e.logback.configuration

m2e FAQ

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Posted by digulla

Jazoon 2013 – The Economies of Scaling Software

25. October, 2013

Jazoon 2013 badgeIf you’re small, scalability is not an issue. If you’re big, you can plan for it. But what if you wake up one morning and you suddenly find you’ve become the next Google?

In his talk “The Economies of Scaling Software“, Abdelmonaim Remani talks about what scaling means, how you can plan for it (even if you don’t expect it to happen) and all the nasty details that stand between you and success (slides on slideshare).

Today, the ubiquity of the Internet has blurred the lines between consumers and enterprises. They start to ask the same questions which eventually all boil down to: “How can I find what I’m looking for in a universe of haystacks?”

One day, many of us will find themselves with the need to scale because the performance of the old solution has become unbearable and all low-hanging fruit (faster CPU, more RAM) have been picked.

To solve this, you can look at the CPU (slide 16-35) or you can start to build clusters (36-45).

Or your I/O might be the bottleneck (slides 46-60). You can solve this by looking at NoSQL databases and caching.

Is the network the problem? (slides 61-75) Start with asynchronous processing, batch jobs, content delivery networks (CDN), DNS sharding or use a different protocol to connect the various parts of your system.

But how do you know what part is the bottleneck? The answer here is monitoring. (slide 77)

Note that scaling often helps with disaster recovery, you still have to plan for it – if all nodes of your cluster are in the same room, it’s still a single point of failure (slide 79)

Software isn’t everything. Don’t forget your team (slide 82)

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Posted by digulla

Efficient CSS

26. May, 2011

Is “.first” faster or slower than “li.first”?

This blog post has some answers: Efficiently Rendering CSS

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Posted by digulla

Another lesson in performance: NIO

29. December, 2010

Remember when I wondered how slow it is to copy data around in memory?

This time, I needed to load a 2MB file from disk and examine it for certain patterns.

The original from jazzy spell checker worked like this: It did a binary search in the file for a code. The code would be at the start of each line and be separated from the correct word by an asterisk: 

    AT*wide
    AT*widow
    AT*width
    AT*wight
    AT*wit

The search algorithm would seek somewhere in the file, skip the current line, read the next one, compare the code against the one we look for. If our code was smaller, we would seek backward; if it was larger, we would seek forward. Standard binary search.

Only it didn’t work. The test took 4 seconds to load the file without finding anything. Debugging recursive algorithms isn’t as nice as looking at them …

So I considered a different approach: I would load the whole file, character by character, and remember the lines with the same code in an index. A good time to have a look at NIO, especially the grep example.

Question: If it takes 4 seconds to seek ten times in a RandomAccessFile and read about 2000 bytes from it, how long would it take to read it character by character, examine each line, build an index and then load whole chunks (say, 1KB each) from the file when a word needs to be looked up? Plus the additional work of removing the code pattern from the chunk to produce a list of words …

Answer: 0.3 seconds. That’s more than ten times faster. And I could probably optimize the code some more.

Conclusion: When it comes to performance, measurement beats superstition.

And the new code is easy to understand, and to test, too! ^_^

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Posted by digulla

Firefox performance

24. November, 2010
Mozilla Firefox Icon

Image via Wikipedia

It’s 2010, Firefox is going 4.0 soon and it still has no way to tell why it’s sluggish.

Yes, it would be nice if the FF developers could make the browser so fast that it would never become sluggish in the first place. I just fear that this is simply not possible with the current design. Look at Chrome: Every tab runs in it’s own process. So what if one of them is slow? All the other still feel crisp.

On FF, if one tab takes over the machine, you’re doomed. Yes, I could disable JavaScript and every add-on individually. Why bother? Starting Chrome solves the issue in no time.

If you care, support Bug 505104: Please add a tool to gauge Addon performance.

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Posted by digulla

Extremely complex queries in BIRT reports

30. September, 2010

Sometimes, SQL just isn’t enough. What do you do when you just can’t get the SQL to run in under an hour while a little piece of Java code does the same query in a few seconds? Put the result into a report table and then run the report against that table.

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Posted by digulla

Sins of Commissions

18. July, 2010

If you plan to measure the performance of your employees or to improve their performance with a bonus, then you should read this: How Hard Could It Be? Sins of Commissions.

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Posted by digulla

Extending Tomcat WebappLoader to Share Library jars

16. March, 2010

If you’re like me and use Tomcat and you want to bring down the size of your WAR, you’re faced with one issue: All your applications need to use the same libraries (since there is only a single common/lib for everyone). So you’re either stuck with an old version or you need to upgrade all your apps at the same time. I just can see the budget guys shake their heads.

The solution is a list of directories in your context.xml which contain specific versions of the libraries you need. This way, you can install all the versions you need and each app can pick and choose.

For the complete solution, see the original article: Extending Tomcat WebappLoader to Share Library jars

OSS for teh win! 🙂

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Finding unindexed foreign key columns

15. December, 2009

If you’re using Oracle and you have tables with foreign keys, then you must remember to add indexes to all the columns in the referenced tables (i.e. the foreign tables). If your schema has more than two tables, it’s hard to make sure all the necessary indexes exist. Fret no more and let Oracle do (most of) the work for you:

select table_name, constraint_name,
       cname1 || nvl2(cname2,','||cname2,null) ||
       nvl2(cname3,','||cname3,null) || nvl2(cname4,','||cname4,null) ||
       nvl2(cname5,','||cname5,null) || nvl2(cname6,','||cname6,null) ||
       nvl2(cname7,','||cname7,null) || nvl2(cname8,','||cname8,null)
              columns
    from ( select b.table_name,
                  b.constraint_name,
                  max(decode( position, 1, column_name, null )) cname1,
                  max(decode( position, 2, column_name, null )) cname2,
                  max(decode( position, 3, column_name, null )) cname3,
                  max(decode( position, 4, column_name, null )) cname4,
                  max(decode( position, 5, column_name, null )) cname5,
                  max(decode( position, 6, column_name, null )) cname6,
                  max(decode( position, 7, column_name, null )) cname7,
                  max(decode( position, 8, column_name, null )) cname8,
                  count(*) col_cnt
             from (select substr(table_name,1,30) table_name,
                          substr(constraint_name,1,30) constraint_name,
                          substr(column_name,1,30) column_name,
                          position
                     from sys.user_cons_columns ) a,
                  sys.user_constraints b
            where a.constraint_name = b.constraint_name
              and b.constraint_type = 'R'
            group by b.table_name, b.constraint_name
         ) cons
   where col_cnt > ALL
           ( select count(*)
               from sys.user_ind_columns i
              where i.table_name = cons.table_name
                and i.column_name in (cname1, cname2, cname3, cname4,
                                      cname5, cname6, cname7, cname8 )
                and i.column_position <= cons.col_cnt
              group by i.index_name
           )

Isn’t it a beauty? Thanks to Tom.

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Why WYSIWYG doesn’t work II

7. December, 2009

In my old post “The Space Between Two Characters“, I wrote about some flaws of WYSIWYG. Since then, I got some feedback.

The real issue behind the issues with WYSIWYG is that it doesn’t work while you edit the document. The concept is flawed, not the implementation. It is flawed because it omits some vital information that you need for editing. The information is omitted because it doesn’t make sense anymore as soon as you print the document on paper. And WYSIWYG means “if you don’t see it, you won’t get it.”

So it makes sense to omit feedback on where ranges start and end, what kind of break follows after a line, there the handles for a table are. But most WYSIWYG editors today have a “show invisible” option. Word can show you all those invisible characters so you can see “oh, this is a tab and not a space”.

For this to work, we need a tight integration between the editor model, the renderer and the view. The problem here is, as usual, performance. If you add all the hooks you need to be able to show nice visual feedback in the view, printing to a printer will be slower.

How much? Well, not much. Anymore. You’re quadcore will be 95% bored. It will need memory. How much? Well, to remember the bounding boxes for all letters rendered on the screen takes at most 4’608’000 bytes (“i”, 8px font, 30″ display with 3840×1200). That might seem like a lot but almost no PC sold next year will have less then 4GB of RAM, not even the Netbooks. My mobile phone comes with 32GB!

For printing, the values are usually much smaller. A normal page of text has around 1’500 to 2’500 characters per page and for printing, you just need to remember the current and maybe the next page (unless you need a page count but with todays CPUs, you can layout the pages twice).

So the final obstacles is code complexity. OO has helped a lot to cut down complexity in algorithms but there are problems which you can’t solve nicely with OO, for example “run this algorithm but replace line 5 with …” or “before … run …”.

AOP has come to solve this but it has failed to deliver so far. Maybe this is because point-cuts are too complicated to formulate, maybe because the debuggers can’t handle this case well, maybe because the setup is too complex or the resulting code is too fragile. Or because people are afraid of the leap of faith it takes to use it.

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