Hi again, I have collect some more information regarding the problem I mentioned in my previous post. I take a thread dump during the compilation process and as I can see the thread that makes the compilation is the following: "http-8080-20" daemon prio=10 tid=0x00007f445054d800 nid=0x6abb runnable [0x00007f444db7f000] java.lang.Thread.State: RUNNABLE at org.eclipse.jdt.core.compiler.CharOperation.equals(CharOperation.java:1641) at org.eclipse.jdt.internal.compiler.util.HashtableOfPackage.put(HashtableOfPackage.java:69) at org.eclipse.jdt.internal.compiler.lookup.PackageBinding.addNotFoundPackage(PackageBinding.java:45) at org.eclipse.jdt.internal.compiler.lookup.PackageBinding.getPackage(PackageBinding.java:102) at org.eclipse.jdt.internal.compiler.lookup.CompilationUnitScope.buildTypeBindings(CompilationUnitScope.java:119) at org.eclipse.jdt.internal.compiler.lookup.LookupEnvironment.buildTypeBindings(LookupEnvironment.java:147) at org.eclipse.jdt.internal.compiler.Compiler.internalBeginToCompile(Compiler.java:701) at org.eclipse.jdt.internal.compiler.Compiler.beginToCompile(Compiler.java:376) at org.eclipse.jdt.internal.compiler.Compiler.compile(Compiler.java:420) at org.drools.commons.jci.compilers.EclipseJavaCompiler.compile(EclipseJavaCompiler.java:351) at org.drools.commons.jci.compilers.AbstractJavaCompiler.compile(AbstractJavaCompiler.java:51) at org.drools.rule.builder.dialect.java.JavaDialect.compileAll(JavaDialect.java:389) at org.drools.compiler.DialectCompiletimeRegistry.compileAll(DialectCompiletimeRegistry.java:56) at org.drools.compiler.PackageRegistry.compileAll(PackageRegistry.java:74) at org.drools.compiler.PackageBuilder.compileAll(PackageBuilder.java:690) at org.drools.compiler.PackageBuilder.addPackage(PackageBuilder.java:653) at org.drools.compiler.PackageBuilder.addPackageFromDrl(PackageBuilder.java:278) at org.drools.guvnor.server.contenthandler.DecisionTableXLSHandler.compile(DecisionTableXLSHandler.java:64) Supposing that there is not any way to reduce the memory/cpu usage and the time delay (1 hour for the compilation of 22K rules) of the compilation process, is there any way to reduce the priority of the above thread, so that the other threads will not be stacked, and to restore the priority after the end of the compilation process? Is this the appropriate forum to ask such kind of questions? If not where can I find some answers? -- View this message in context: http://drools.46999.n3.nabble.com/Drools-Guvnor-5-0-1-Memory-Usage-Tuning... Sent from the Drools: User forum mailing list archive at Nabble.com.