java performance tuning tips

configuration. Linux is rich, powerful, and flexible, and you can do a variety of tasks with it, and in this article we'll discuss some tips for improving the performance of Linux servers.1. Tuning the Linux kernel elevator algorithm for disk I/OAfter selecting the file system, there are some kernel and mount options that may affect its

configuration.Linux is rich, powerful, and flexible, and you can do a variety of tasks with it, and in this article we'll discuss some tips for improving the performance of Linux servers.1. Tuning the Linux kernel elevator algorithm for disk I/OAfter selecting the file system, there are some kernel and mount options that may affect its

, connection pooling, and so on, in the design phase, as appropriate for the business. 2. Code tuning: Development PhaseThis is the developer is most familiar with, do the overloading should have feelings, the same function, good implementation and bad implementation is very far. be careful to avoid deadlocks, dead loops. 3. Database tuning: Development phaseJava programs can connect to a database using JDB

compressing and extending the heap space:-xx:minheapfreeratio: Sets the minimum idle scale for heap space. The default is 40. When the free memory in the heap space is less than this value, the JVM expands the heap space.-xx:maxheapfreeratio: Sets the maximum idle scale for heap space. The default is 70. When the free memory in the heap space is greater than this value, the heap space is compressed and a smaller heap is obtained.When-xms and-xmx are equal, both parameters of-xx:minheapfreeratio

Performance issues with Java EE applications are a very important issue for serious projects and products. In particular, enterprise-class applications, concurrent users, a large number of data transmission, business logic complex, occupy more system resources, so performance problems in enterprise-class applications become critical, it and the stability of the s

Reference indicators for performance Execution time-from the time the code starts running to the end CPU time--the time that a function or thread consumes the CPU Memory allocation-a scenario in which a program consumes memory at run time Disk throughput--Describe the use of IO Network throughput--describe the use of the network Response time-The response time that the system makes to a user's behavior or time

Tags: process optimizer consolidation requires merging auto overwrite session accessThe full execution order of the SELECT statement:The full execution order of the SQL SELECT statement: 1. The FROM clause assembles data from different data sources; 2. The WHERE clause filters the record rows based on the specified criteria, 3, the GROUP BY clause divides the data into multiple groupings, 4, uses the aggregation function for the calculation, 5, uses the HAVING clause to filter the grouping; 6, e

monitor local and remote Java processes, including monitoring memory, threading, method execution time, and more.3-1 monitoring local Java processes3-2 monitoring the remote Java process4th chapter monitoring and debugging based on BtraceThis chapter takes you to learn how to install Btrace, how to write btrace scripts to monitor and debug the code in a producti

　　A GUI program written in Java, the function is to analyze the log, it will be a number of the same format of the text log file read into the memory analysis processing, and then merge the results output.The number of files dozens of, the file size of a few KB, logging thousands of or so, this tool can be smooth processing, easy to meet the needs.However, because of the logging scheme tuning, the logging t

, the most important of which is how long the thread has been running. Consider this factor to allow each thread to get the chance to run. So, regardless of how low the priority of the thread is set, they always get the chance to run.In addition, the weight of the thread priority set on the different OS is different. On Unix-based systems, the execution time of a thread is a factor in the current priority of the dominant thread, which means that the thread priority set is rarely "referenced". On

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

an execution plan, and stored in a database of SQL statements, is a collection of control flow language, the speed of course fast. 48, the return value of the function is not too large, this overhead is very large. A user-defined function that executes as a cursor consumes a large amount of resources if a large result is returned with a stored procedure. 49, as far as possible to avoid repeated access to the same or several tables, especially the large number of data tables, you can consider th

Recreate the classic, uncover the face of the pseudo-tall, easy to handle jvm!1. JVM base (selection, memory model, GC, etc.)2. JVM Key Parameters3. JVM monitoring (commands, tools)4. Typical JVM performance issues (CPU, memory leak, thread lock, etc.)Address: http://edu.51cto.com/course/course_id-4868.htmlPS: with Tomcat video betterAddress: http://edu.51cto.com/course/course_id-4166.html"Video" Java JVM

1234 [ ~]# cat gc.log.0 | grep ‘Full GC‘1.652: [Full GC (System) 1.652: [CMS: 0K->21718K(262144K), 0.0837910 secs] 48398K->21718K(458752K), [CMS Perm : 16462K->16457K(21248K)], 0.0841650 secs] [Times: user=0.08 sys=0.00, real=0.08 secs] 664643.879: [GC 664643.879: [ParNew: 134434K->3202K(196608K), 0.0068030 secs] 327839K->196659K(458752K) icms_dc=0 , 0.0070080 secs] [Times: user=0.03 sys=0.00, real=0.01 secs] 1.625, 664643.879 is the time that the GC occurred, the number of seconds

1 , JAVA Performance Tuning-do not use expressions in loop conditionsWhen we learn about Java Performance Tuning, we often see this passage: In the case of No compilation optimization, in the loop, the loop condition will be repea

1 , JAVA Performance Tuning-Move the Try/catch block out of the loopIt is said that the Try/catch block into the circulation body, will greatly affect performance. The use of the Try/catch module makes the Java virtual machine do a lot of extra work. It's like saying to ever

this area is mainly for the recovery of constant pool and unloading of type, in general, the recovery of this area "score" is very difficult to be satisfactory, especially the type of unloading, the condition is very harsh, but this part of the area of the recovery is really necessary.　　Instead, run a constant pool as part of the method area. class file In addition to the class version, fields, methods, interfaces, and other descriptive information, there is also a constant pool, for the compil

** Copyright 2006 ATPCO Confidential and proprietary. All rights Reserved.*/Package com.zcd.test;Import Java.sql.Timestamp;public class Test {private int x;private static int staticx;public void stackaccess (int val) {int j = 0;for (int i = 0; i j + = 1;}}public void instanceaccess (int val) {int tempx=x;for (int i = 0; i TEMPX + = 1;}}public void staticaccess (int val) {int tempx=staticx;for (int i = 0; i TEMPX + = 1;}}public static void Main (string[] args) {System.out.println (New Timestamp (

1. Introduction:Javamelody can monitor Java or Java EE application servers in a running environment. It is displayed as a graph: Java memory and Java CPU usage, number of user sessions, JDBC connections, and HTTP requests, SQL requests, JSP pages and Business interface methods (EJB3, Spring, Guice), average execution t

monitor the connection pool found that only getting the connection did not release the connection operation, which appears to belong to 1. Due to the use of Eclipselink thought Entitymanager. Close () can release the connection, after reviewing the Eclipselink official documents, the original is improper use, the following is to obtain the connection details:Https://wiki.eclipse.org/EclipseLink/Examples/JPA/EMAPIJPA 2.0= Entitymanager.unwrap (java.sql.Connection. Class);... entitymanager.gettr