table of Contents
jmap use and memory leak analysis
Check the number and size of objects in memory
The memory usage dump to a file
Analysis of the dump file by jhat
Analysis of the dump file by MAT tool
jmap use and memory leak analysis
View memory usage
View tomcat memory usage: jmap -heap tomcat process ID
① heap memory configuration information see:
② view the heap memory usage:
Check the number and size of objects in memory
Use jmap -histo process ID | more to view the number and size of the object. In the Linux system, you can use pipes | more to a section of the output information. Windows systems can also be used.
Use jmap -histo: live process ID | more can view the number of active objects and size:
The memory usage dump to a file
dump down the file is a binary format.
Analysis of the dump file by jhat
The jvm memory dump to a file, the file is a binary file, not convenient to view, then we can see the aid jhat tools:
You can access through a browser to access port 9999 to dump down the file information:
OQL query links provided bottom of the page:
Queries link http: // xxx: 9999 / oql /
OQL query example (You can see some examples of statements by OQL Help):
The length of the query> = 100 string which:
select s from java.lang.String s where s.value.length >= 100
It can be seen that the string length is greater than 1000 web.xml configuration files such as:
Description profile in the form of a string are loaded into memory.
Analysis of the dump file by MAT tool
MAT Introduction
MAT download and install
Double click:
MAT using the steps
Steps for usage:
