java heap memory usage monitoring

Stack memoryThe stack memory stores a variable of the base type (int a = 3;) and a variable of the reference type (car car). When a variable is defined in a block of code, Java allocates memory space for the variable in the stack, and when the scope of the variable is exceeded, Java automatically frees the

Heap Area:1. All objects are stored, each containing a class-corresponding information. (The purpose of class is to get operation instructions)2.JVM only one heap area (heap) is shared by all threads, and the heap does not hold basic types and object references, only the object itselfStack area:1. Each thread contains

Java out-of-heap memory (direct memory unmanaged memory)The benefits of out-of-heap memory are: Can be extended to a larger memory spa

Java Memory allocation:1. RegistersWe have no control over the program.2. StackStores the basic types of variable data, local variables, and references to objects, but the objects themselves are not stored in the stack, but are stored in the heap (new objects) or in a constant pool (string constant objects are stored in a constant pool. ）3. HeapHolds an array of

Java stack memory and heap memoryThe stack memory stores local variables, and the heap memory stores objects. The class where the member variables are located is instantiated and stored in the

The NIO buffer provides a class--directbuffer that can directly access the system's physical memory without having to go through the JVM's memory. The Directbuffer class inherits from Bytebuffer, but unlike normal bytebuffer, ordinary bytebuffer still allocates memory on the JVM heap, its maximum

First, install the JprofilerDownload 5.1.2 from http://www.ej-technologies.com/and request a trial serial numberSecond, the main function of the introduction1. Memory ProfilerThe memory view portion of Jprofiler can provide a dynamic memory usage update view and a view that displays information about

line, direct operation stats, stats slabs and other commands for analysismemcached.php = "PHP system using Apache service, graphical interfaceDaemontools = "Don't know what it is, write it down first."Nagios = "Checktcp =" don't know what it is, write it down first.Optimization ideas1. Reasonable growth factor and control the reasonable consumption of memory2. cache update mechanism = Update the cache when it is about to expireMemcached Learning--memcached