jvm performance tuning interview questions

the JVM of the server version. You can compare and test the performance of the JVM and server versions of the Client Version to determine which version of JVM is used. In addition, you can also consider replacing the JVM of other vendors, such as Oracle's jrockit. Tomcat a

Configuration:Minheapfreeratio = 40Maxheapfreeratio = 70Maxheapsize = 1342177280 (1280.0MB)NewSize = 134217728 (128.0MB)Maxnewsize = 134217728 (128.0MB)Oldsize = 402653184 (384.0MB)Newratio = 15Survivorratio = 1024PermSize = 100663296 (96.0MB)MaxPermSize = 100663296 (96.0MB)Heap Usage:New Generation (Eden + 1 Survivor Space):Capacity = 134152192 (127.9375MB)used = 22525464 (21.481956481933594MB)Free = 111626728 (106.4555435180664MB)16.790977220856742% usedEden Space:Capacity = 134086656 (127.87

on static file compression />2. Optimizing the JVM for catalina.shOpen the Tomcat path \bin\ catalina.sh, add at the top, red part please adjust according to the actual situationJava_opts= "-server-showversion-xms12g-xmx12g-xx:permsize=256m-xx:maxpermsize=256m "java_opts= "$JAVA _opts-d64-xx:cicompilercount=8-xx:+usecompressedoops"java_opts= "$JAVA _opts-xx:survivorratio=4-xx:targetsurvivorratio=90"java_opts= "$JAVA _opts-xx:reservedcodecachesize=256

Recently, on a project, the backend mule es CPU was found to be high. After Jstat-gcutil JVM process number 1000 10 analysis, found FGC times, more.After the GC observation, there are a large number of new generation objects, directly into the Laosheng generation.Modify mule/conf/wrapper.conf. Add the following options.Wrapper.java.additional.5=-xx:+printgcdetailsWrapper.java.additional.6=-xx:+printgcdatestampsWrapper.java.additional.7=-verbose:gcWrap

What is ANR?Application Not RespondingThe main cause of ANR:The responsiveness of the application is monitored by the activitymanager and WindowManager system services, which can cause the ANR to be monitored when the main thread in the activity clicks more than 5 seconds to respond or if the wood responds in the broadcast UI thread for more than 10 seconds. Here's a list of the details: The main thread is blocked by I/O operations (the network IO is not allowed in the main thread after

Detailed understanding and performance tuning of the JVM's garbage collection mechanism (ii) 2008-05-28 16:39 ReproducedGC Overview of 1.JVM 　　The GC, or garbage collection mechanism, is the memory that the JVM uses to free objects that are no longer in use. The Java language does not require the

manager is gone and the data is lost. If at this point, Stage0 's executor is dead, block manager is gone; at this point, Stage1 's executor task, though driver, gets the address of its own data. , but actually to find the other side of the block manager to get the data, is not get the time, will run the job (jar) in Spark-submit, client (standalone client, yarn client), Log will be printed on this machineShuffle output file not found ...Dagscheduler,resubmitting task, will hang up all the time

process-verify 00:10:24 minutesSection 90th class loading process-ready 00:05:40 minutes91st class loading process-parsing 00:14:04 minutesSection 92nd Class loading procedure-initialize 00:19:41 minutes93rd class loader 00:22:41 min94th Session Parent delegation Model 00:17:03 min95th Section Runtime stack frame structure 00:08:46 minSection 96th Local Variables table 00:20:48 min97th Operation Stack 00:08:36 min98th Session dynamic Connection 00:02:56 min99th section method return address and

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We are going to discuss with you today that we will correctly resolve the 12 difficult questions about DB2 performance tuning. If you are curious about the 12 difficult questions about DB2 performance tuning, the following article

limited.Heap area: Also known as dynamic memory allocation, usually refers to the program when it runs directly new memory, that is, an instance of the object. The Java garbage collector will be responsible for recycling this part if it is not in use.2. How to manage memory in Java　　　　　　　　　　3. Memory leaks in JavaA memory leak refers to a useless object (an object that is no longer being used) that keeps memory or useless objects from being released in a timely manner, resulting in a waste of m