tomcat memory usage monitoring

No matter how careful you are, it is impossible to completely avoid bad code. At this time, some tools are required to help us check whether there is any place in the code that will cause memory leakage. The ddms in Android tools comes with a very good memory monitoring tool heap (here I use the ADT plug-in of eclipse, and take the real machine as an example, the

Tomcat itself cannot run directly on the computer, it needs to rely on a hardware-based operating system and a Java virtual machine. When the Java program starts, the JVM allocates an initial memory and maximum memory to the application. This initial memory and maximum internal presence will affect the performance of t

Http://ttlnews.blogspot.com/2010/01/attacking-memory-problems-on-android.htmlThis article was written in January 2010, some of which are already unsuitable for the android mechanism now.I've divided the memory issues into two types: oom and Stack OverflowThe maximum heap memory that an Android process can allocate (heap memories) is 16M (now different from custom

initialization heap performs the size of the memory that the virtual machine requests to the system at startup. Generally speaking, this parameter is not important. However, some applications in a large load of the case will be a sharp use of more memory, at this time this parameter is very important, if the virtual machine is set up at the start of the memory i

, Head-n 100 will display the first 100 lines More queries Maximum access per minute awk ' {print $} ' Access_log |cut-c 14-18|sort|uniq-c|sort-nr|head the highest hourly access number awk ' {print $} ' acces S_log |cut-c 14-15|sort|uniq-c|sort-nr|head-n Specifies the number of accesses per second of a minute grep ' 01/nov/2013:15:59 ' access.log | cut-d ' ["- F 2 | awk ' {print $} ' | Sort | uniq-c | Sort-nr | Head-60 2. Record CPU and

of cut, it can use some regular separators to get a rowFor example:a:b such a line of string, we want to get a, then we can write: cut-d ":"-F 1 It means: use: Split and then get the first line,-d followed by what symbol is divided, the topic is " : ", of course, can be " ;" Wait, and then the-F is the number of columns I want to print out 3) grep This command is a powerful text search tool, such as we want to search in a textFor example:Let's start by creating a simengphp.txt, and t

JVM manages two types of memory, heap and non-heap. Heap is used by developers. It is created at JVM startup. Non-heap is reserved for JVM and used to store class information. Unlike the heap, GC does not release space during runtime. I. memory overflow type 1. java. lang. OutOfMemoryError: PermGen spaceJVM manages two types of memory, heap and non-heap. Heap is

Use alter index ××monitoring usage; statement to monitor the index usage, altermonitoring With the accumulation of time, in the absence of good planning, the database may have a large number of indexes that are not used for a long time. If you can quickly locate these indexes so that they can be cleared, they will be placed in the case. We can use the "alter inde

/application_1411897705890_0181/container_1411897705890_0181_01_000012/stdout2>/data/yarn/logs/application_1411897705890_0181/container_1411897705890_0181_01_000012/stderr|-28481284742847428474(java)23563971630285824264098/usr/java/jdk1.7.0_67/bin/java-Djava.net.preferIPv4Stack=true-Dhadoop.metrics.log.level=WARN-Xmx1024m-Djava.io.tmpdir=/data/yarn/local/usercache/hadoop/appcache/application_1411897705890_0181/container_1411897705890_0181_01_000012/tmp-Dlog4j.configuration=container-log4j.proper

System optimization is a complex, complex, and long-term task. The following subsystems are usually monitored: CPU, Memory, IO, Network, etc. I. CPU performance indicators CPU utilization: User Time Context switch: It is associated with the CPU usage. If the CPU usage is in good state, a large number of context switches are acceptable. Runnable queue: three thre

Tomcat Memory and optimizationIntroduction of TOMCAT Operating environmentThe 1.Tomcat itself cannot run directly on the computer and relies on the hardware-based operating system and the Java Virtual machine;2.Java when the program starts, the JVM allocates an initial memory