Java应用线上问题排查工具整理

$ jstat -help
Usage: jstat -help|-options
       jstat -<option> [-t] [-h<lines>] <vmid> [<interval> [<count>]]

Definitions:
  <option>      An option reported by the -options option
  <vmid>        Virtual Machine Identifier. A vmid takes the following form:
                     <lvmid>[@<hostname>[:<port>]]
                Where <lvmid> is the local vm identifier for the target
                Java virtual machine, typically a process id; <hostname> is
                the name of the host running the target Java virtual machine;
                and <port> is the port number for the rmiregistry on the
                target host. See the jvmstat documentation for a more complete
                description of the Virtual Machine Identifier.
  <lines>       Number of samples between header lines.
  <interval>    Sampling interval. The following forms are allowed:
                    <n>["ms"|"s"]
                Where <n> is an integer and the suffix specifies the units as
                milliseconds("ms") or seconds("s"). The default units are "ms".
  <count>       Number of samples to take before terminating.
  -J<flag>      Pass <flag> directly to the runtime system.

# 查看指定进程的GC概要信息，自动刷新频率为1000ms
$ jstat -gcutil 进程ID 1000

$ jstack -h
Usage:
    jstack [-l] <pid>
        (to connect to running process)
    jstack -F [-m] [-l] <pid>
        (to connect to a hung process)
    jstack [-m] [-l] <executable> <core>
        (to connect to a core file)
    jstack [-m] [-l] [server_id@]<remote server IP or hostname>
        (to connect to a remote debug server)

Options:
    -F  to force a thread dump. Use when jstack <pid> does not respond (process is hung)
    -m  to print both java and native frames (mixed mode)
    -l  long listing. Prints additional information about locks
    -h or -help to print this help message

# 将指定Java进程的线程堆栈日志输出到文件中
$ jstack 进程ID > stack.tdump

# 当Java进程夯住没有响应时，需要使用-F选项参数
$ jstack -F 进程ID > stack.tdump

#!/bin/bash
# Desc: 查看Java进程CPU使用率高的线程堆栈信息
# File: show_java_process_thread_stack.sh

echo "Show java process thread stack"
pid=$1
if [ ! "$pid" ]; then
	echo "Usage: sh $0 pid"
	echo "  e.g: sh $0 1234"
	echo ""
	exit 1
fi

top -H -p "$pid"|head -20
echo ""

top_thread_id=`top -H -p $pid|head -8|awk '/java/{print $2}'`
#echo "top cpu thread: $top_thread_id"

thread_id_hex=`printf "%x" "$top_thread_id"`
#echo "$thread_id_hex"
jstack "$pid"|grep "$thread_id_hex" -A 100 > jstack_tmp
cat jstack_tmp
rm -rf jstack_tmp

#echo "Done."

# 当没有参数时，显示第一页线程的信息
# 默认按照CPU增量时间降序排列，只显示第一页数据
$ thread

# 展示当前最忙的前N个线程并打印堆栈
$ thread -n 3

# 显示指定线程的运行堆栈
$ thread 进程ID

# 找出当前阻塞其他线程的线程
# 只支持找出synchronized关键字阻塞住的线程
$ thread -b

# 指定采样时间间隔
$ thread -i 1000 # 统计最近1000ms内的线程CPU时间
$ thread -n 3 -i 1000 # 列出1000ms内最忙的3个线程栈

$ jmap -help
Usage:
    jmap [option] <pid>
        (to connect to running process)
    jmap [option] <executable <core>
        (to connect to a core file)
    jmap [option] [server_id@]<remote server IP or hostname>
        (to connect to remote debug server)

where <option> is one of:
    <none>               to print same info as Solaris pmap
    -heap                to print java heap summary
    -histo[:live]        to print histogram of java object heap; if the "live"
                         suboption is specified, only count live objects
    -clstats             to print class loader statistics
    -finalizerinfo       to print information on objects awaiting finalization
    -dump:<dump-options> to dump java heap in hprof binary format
                         dump-options:
                           live         dump only live objects; if not specified,
                                        all objects in the heap are dumped.
                           format=b     binary format
                           file=<file>  dump heap to <file>
                         Example: jmap -dump:live,format=b,file=heap.bin <pid>
    -F                   force. Use with -dump:<dump-options> <pid> or -histo
                         to force a heap dump or histogram when <pid> does not
                         respond. The "live" suboption is not supported
                         in this mode.
    -h | -help           to print this help message
    -J<flag>             to pass <flag> directly to the runtime system

# 导出指定进程的堆dump文件
$ jmap -dump:format=b,file=/tmp/heapdump.hprof 进程ID

# 当Java进程夯住没有响应时，需要使用-F选项参数
$ jmap -F -dump:format=b,file=/tmp/heapdump.hprof 进程ID

# dump到指定文件
$ heapdump /tmp/dump.hprof

# 只dump live对象
$ heapdump --live /tmp/dump.hprof

# dump到临时文件
$ heapdump

# 指定了最小堆和最大堆的大小
# 设置生成gc日志文件
# 设置在出现OutOfMemoryError错误自动生成堆内存dump文件
$ java -Xms1024m -Xmx1024m -Xloggc:/tmp/gc.log -XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:NumberOfGCLogFiles=10 -XX:GCLogFileSize=2M -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=/tmp/headpdump.hprof -jar test.jar
# 当然，如果进行了JVM优化，还需要包含其他一些参数，比如：指定GC垃圾回收器等