Incessant (j)Stack
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Incessant (j)Stack

Script which calls jstack on a jvm instance incessantly, saves thread dumps in a directory, supports options to specifiy interval between taking thread dumps, number of thread dumps to take and keep.


Usage: [options] jvm-process-id -h for options

  -h, --help            show this help message and exit
  -d DIR, --dir=DIR     Directory to save threaddumps
                        (default: current dir)
  -i INTERVAL, --interval=INTERVAL
                        Interval (seconds) between successive thread dumps
                        (default: 60 seconds)
  -n NUMBER, --number=NUMBER
                        Number of thread dumps to take
                        (default: unlimited)
  -k KEEP, --keep=KEEP  Number of thread dumps to keep
                        (default: 1440)

Sample Usages

  • Take thread dumps once every minute, indefinitely, keeping latest 1 day worth of dumps (1440). This is the default without specifying any options.

    $ python <jvm-process-id>
  • Take thread dumps once every 5 munutes, indefinitely, keeping latest 500 dumps

    $ python -i 300 -k 500 <jvm-process-id>
  • Take thread dumps once every 30 seconds for 5 times and save them under dump directory

    $ python -i 30 -n 5 -d dump <jvm-process-id>


  • jstack in PATH

Thread dumps

A directory with YYYYMMDD-hhmmss format named with the script invocation time will be created under current directory or under the directory specified with -d option.

Command line of the jvm process which is being jstacked is saved into cmdline.txt file under the above directory

Thread dumps will be saved under the directory with YYYYMMDD-hhmmss.txt name formet with jstack invocation time.

For example:

    └── 20110402-184224                     # directory with script invocation time
        ├── 20110402-184224.txt             # thread dump 1
        ├── 20110402-184235.txt             # thread dump 2
        ├── 20110402-184246.txt             # .. and so on ..
        ├── 20110402-184256.txt
        ├── 20110402-184307.txt
        ├── 20110402-184318.txt
        ├── 20110402-184329.txt
        ├── 20110402-184339.txt
        ├── 20110402-184350.txt
        └── cmdline.txt                     # jvm process command line

Script Exit

Script will exit due to one of the following reasons

  1. Input and environment validation failures
  2. Number of thread dumps as specified by -n option were taken successfully
  3. jstack call encountered an error
  4. jstack call did not return within a 60 second timeout


  • Tested with Python 2.6.1, jstack (bundled with JDK 1.6.0_24) in Mac OSX 10.6.7


Please use the issue tracker associated with this repository. Please note that jstack is not available in Windows and Itanium platforms.