Re: [ERROR] OutOfMemoryError: Increase heap size or lower gwt.jjs.maxThreads

Thank You 

JENS & COLIN for providing your inputs and valueable suggestions. We have applied the same in our application and here is the result:

currently our defferedJs are as follows:

                   

 

but after we removed all split points and only kept some major ones, here is the result:

                    

Now! our WAR is compiling (single permutation) in 10.25 mins only. We are testing our application workflow as many of the differedJS files are greater than 1 mb. We'll try to reduce the size. 

We again want to express our gratitude to JENS & COLIN for showing the right path towards the root cause along with the solution.  

Whereas GWT 2.6.1 upgradation is concerned, we would like to say, yes! we are actively developing the application and are intrested in upgrading GWT 2.6.1. But there are some issues which are required to be addressed. Many time earlier we have planned the upgradation, but dropped the idea due to not having the clear answers on bellow mentioned points. 

1. Which version of GWT we should move to? As many of the latest technologies are rolling arround and GWT in itself also have released many versions after 2.6.1. Meanwhile J2CL had also been launched. Migrating a huge application rapidly is not possible, so we want to be very sure.   

2. We are using "Apache Netbeans IDE" from a long time and now the team is also very much famlier with it. Upgraded GWT4NB plugin was missing from market place. Can we go for upgradation without changing IDE?

3. We are using "JDK 1.8". Do we required to upgrade JDK too?

4. We are using "PAYARA-WEB-SERVER" in both development + Production environment. GWT upgraded versions are comming with inbuild JETTY servers. Can we use "PAYARA-WEB-SERVER" in development after upgradtion or we have to stick wit JETTY only?

5. We are using "ANT build" not "Maven build" means we are not having any type of POM files.  

6. We are using sencha (gxt 3.1.1) mainly for GRID functionality. Upgrading GWT will fall dependency is on SENCHA-GXT and upgraded SENCHA-GXT is paid. What are its alternative?

7. Our application is having GWT standard architecure eg: (client + shared + server) in the same application. We want to split our application as client & server seperate. Where we want to move server part in SPRING-BOOT without any major changes. Is it possible?    

For detail discussions we can connect on viny.jais@gmail.com. We welcome any type of suggestions or involvement on the same. 

On Wednesday, September 25, 2024 at 7:14:35 PM UTC+5:30 Colin Alworth wrote:

Agreed with Jens, definitely look at your split point usage. In the war that you have, you have a .cache.html file that you mentioned, 4.7MB. In that same dir, there should be a deferredjs/ directory - can you list its contents? It should have a directory per permutation (so, just one, named the same as your .cache.html file), and inside that, there should be some number of .cache.js files. How many are there, and what is their size range (like the .gwt.rpc table you made)?

Odds are very high that a significant number of them are quite small, and so shouldn't be created at all, so you can either remove them from your code (by finding their GWT.runAsync(...) calls), or use the compiler's built-in feature to try to minimize them, `-XfragmentCount=N`. That N is treated as a suggestion, and the compiler will create approximately that many split points in the final output - if that number is substantially less than the number of GWT.runAsync() calls, you probably will see a substantial compile time and memory usage improvement.

If most/all of the split points are small (say, under 100KB), you might consider disabling split points entirely to skip this processing step. There will be an increase in your initial page size, but possibly a manageable one.

But the most important thing when using split points is to measure impact on the user - when you load the page, watch the Network tab in browser tools, and see how much you are actually deferring, how many split points are being loaded, and how big they are. Odds are pretty high that the very last (going by file name) split point is loaded very soon after page load, and that this file is one of the biggest if not the biggest, which itself suggests that some work is necessary to improve your page loading experience. That split point is the "leftover" chunk, and represents any code shared by two or more chunks - using the -XfragmentCount feature is very likely to reduce its size, but modeling how your page loads and application builds is more complex than can be written in an email.

One more simple point: consider turning off the compiler report flag if you aren't actively using the results, it will take extra memory, compile time, and disk space. It would be helpful to turn it back on periodically, but shouldn't be necessary to keep it on all the time for all developers. This tool assists in some of the "why are my split points the way they are" debugging, but if the compile doesn't succeed anyway, odds are no one is looking at it.

Finally, GWT 2.6.1 is more than a decade old - if you're actively developing this application, strongly consider updating.

On Wednesday, September 25, 2024 at 4:40:36 AM UTC-5 Jens wrote:

Are you using a lot of code split points? 61GB memory seems pretty high. Someone else once posted a similar question and this person had ~100 split points which significantly impacted compilation. The more split points you have the more complex analysis will be in order to determine if some code is unique to a split point.

As comparision I have an app that produces 10MB JS in total per permutation and compiles fine using 4GB memory. It uses about 12 split points.

viny...@gmail.com schrieb am Dienstag, 24. September 2024 um 17:58:36 UTC+2:

Hi everyone,

We have stucked in a very strange / awkward situation. Our running GWT 2.6.1 application started crashing at the time of compilation since 2 days back.

We are using netbeans IDE (non-maven). we are sharing our app-information as follows:

1. "WAR" SIZE : 591MB

2. Total "*.gwt.rpc" files : 891 files (we have attached some of the *.gwt.rpc files for ref.)

                    

3. "*.cache.html" SIZE : 4.15 MB 

4. Earlier when WAR was compiling it was taking max 50 minutes for full comilation (single permutation) on hardware of (64 GB RAM, 4 Core, Xeon (R) CPU E3-1225 v5 @3.30 GHz,  window-server 2019 standard)  

5. using JVM option -Xmx61440M (gwt-conpilation config attached for ref.)

6. Currently we are getting following error: 

Compile with -strict or with -logLevel set to TRACE or DEBUG to see all errors.
   Compiling 1 permutation
      Compiling permutation 0...
      [ERROR] OutOfMemoryError: Increase heap size or lower gwt.jjs.maxThreads
java.lang.OutOfMemoryError: Java heap space
at sun.nio.cs.StreamEncoder.write(StreamEncoder.java:133)
at java.io.OutputStreamWriter.write(OutputStreamWriter.java:220)
at java.io.Writer.write(Writer.java:157)
at com.google.gwt.core.ext.soyc.impl.DependencyRecorder.flushOutput(DependencyRecorder.java:136)
at com.google.gwt.core.ext.soyc.impl.DependencyRecorder.endDependencyGraph(DependencyRecorder.java:70)
at com.google.gwt.dev.jjs.impl.codesplitter.CodeSplitter.computeComplementCfaForFragments(CodeSplitter.java:325)
at com.google.gwt.dev.jjs.impl.codesplitter.CodeSplitter.computeExclusivityMapWithFixups(CodeSplitter.java:362)
at com.google.gwt.dev.jjs.impl.codesplitter.CodeSplitter.execImpl(CodeSplitter.java:480)
at com.google.gwt.dev.jjs.impl.codesplitter.CodeSplitter.exec(CodeSplitter.java:115)
at com.google.gwt.dev.jjs.JavaToJavaScriptCompiler.compilePermutation(JavaToJavaScriptCompiler.java:423)
at com.google.gwt.dev.jjs.UnifiedAst.compilePermutation(UnifiedAst.java:137)
at com.google.gwt.dev.CompilePerms.compile(CompilePerms.java:195)
at com.google.gwt.dev.ThreadedPermutationWorkerFactory$ThreadedPermutationWorker.compile(ThreadedPermutationWorkerFactory.java:50)
at com.google.gwt.dev.PermutationWorkerFactory$Manager$WorkerThread.run(PermutationWorkerFactory.java:73)
at java.lang.Thread.run(Thread.java:750)
         [ERROR] Out of memory; to increase the amount of memory, use the -Xmx flag at startup (java -Xmx128M ...)
      [ERROR] Unrecoverable exception, shutting down
com.google.gwt.core.ext.UnableToCompleteException: (see previous log entries)
at com.google.gwt.dev.ThreadedPermutationWorkerFactory$ThreadedPermutationWorker.compile(ThreadedPermutationWorkerFactory.java:56)
at com.google.gwt.dev.PermutationWorkerFactory$Manager$WorkerThread.run(PermutationWorkerFactory.java:73)
at java.lang.Thread.run(Thread.java:750)
      [ERROR] Not all permutation were compiled , completed (0/1)
F:\users\Avinash\forNewPlugin\aarogya\nbproject\build-gwt.xml:333: The following error occurred while executing this line:
F:\users\Avinash\forNewPlugin\aarogya\nbproject\build-gwt.xml:482: Java returned: 1

BUILD FAILED (total time: 39 minutes 36 seconds) 

We request you all to please provide any help / guidance on the same. 

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