nodetool sjk

Runs Swiss Java Knife (SJK) commands to execute, troubleshoot, and monitor the database using MBeans.


nodetool sjk options command command_options
Syntax conventions
Syntax conventions Description


Literal keyword.


Not literal.


Variable value. Replace with a valid option or user-defined value.

[ ]

Optional. Square brackets ( [ ] ) surround optional command arguments. Do not type the square brackets.

( )

Group. Parentheses ( ( ) ) identify a group to choose from. Do not type the parentheses.


Or. A vertical bar ( | ) separates alternative elements. Type any one of the elements. Do not type the vertical bar.


Repeatable. An ellipsis ( ... ) indicates that you can repeat the syntax element as often as required.

'Literal string'

Single quotation ( ' ) marks must surround literal strings in CQL statements. Use single quotation marks to preserve upper case.

{ key:value }

Map collection. Braces ( { } ) enclose map collections or key value pairs. A colon separates the key and the value.


Set, list, map, or tuple. Angle brackets ( < > ) enclose data types in a set, list, map, or tuple. Separate the data types with a comma.


End CQL statement. A semicolon ( ; ) terminates all CQL statements.

[ -- ]

Separate the command line options from the command arguments with two hyphens ( -- ). This syntax is useful when arguments might be mistaken for command line options.

' <schema> …​ </schema> '

Search CQL only: Single quotation marks ( ' ) surround an entire XML schema declaration.


Search CQL only: Identify the entity and literal value to overwrite the XML element in the schema and solrconfig files.

Connection options

How to connect and authenticate for all nodetool commands.

Connection options
Short Long Description



Hostname or IP address.



Port number.



Password file path.






Remote JMX agent username.


Separates an option from an argument that could be mistaken for an option.


General Swiss Java Knife options.


Displays a list of all SJK commands.


Displays command specific help, for example nodetool sjk ttop --help.

-X, --verbose

Displays detailed diagnostics.


DataStax Enterprise (DSE) supports running SJK commands from nodetool.


Prints serialized MBeans to JSON format.

The nodetool sjk mxdump command tries to print all exposed MBeans to the console. The command can fail if it encounters an improperly formatted MBean that exposes a non-serializable type. To interact with a specific list of MBeans, use the nodetool sjk mx command.

To avoid errors if a non-serializable type (such as an mx4j MBean) is returned, run the nodetool sjk mxdump command with the -q (query) switch:

nodetool sjk mxdump -q
-q, --query

Output selected MBeans by specifying the ObjectName; match patterns using the asterisk (*) and question mark (?) wildcard characters.

For example, to get all values for Garbage Collector:

nodetool sjk mxdump -q java.lang:type=GarbageCollector,name=*

Print GC (garbage collection) log messages for remote process.

To print the GC log messages:

nodetool sjk gc

No options for GC.


Heap histogram (hh) prints the class histogram, similar to jmap -histo. When no options are specified, prints complete histogram for all objects.

For package installations, run nodetool with the account that runs the database.

For example, to print a histogram for young with a sample duration of 10000 milliseconds on a system with DataStax Enterprise package installation:

sudo -u cassandra nodetool sjk hh --young --sample-depth 10000ms -n 10
-d, --sample-depth

Specify an integer and unit to set the sample duration for --dead-young or --young; default: 10000ms. To set the unit, use the following notation:

  • ms (milliseconds)

  • s (seconds)

  • m (minutes)

  • h (hours)

  • d (days)


Prints histogram of dead objects.


Prints histogram for sample of dead young objects. Use with -d to set the duration.


Prints histogram of live objects.

-n, --top-number

Limits the number of buckets for N top buckets; default: 2147483647.


Prints histrogram for a sample of the new objects. Use with -d to set the duration.


Provides query and execution for Mbeans from the nodetool interface.

-all, --allMatched

Process all matched MBeans.

-a, --arguments

Arguments for MBean operation invocation.

-f, --field, --attribute

MBean attribute

-b, --bean

Mbean name.

-mc, --call

Invokes MBean method. Default false.

-mg, --get

Retrieves value of MBean attribute. Default false.

-mi, --info

Display metadata for MBean. Default false.


Table column width threshold for formatting tabular data. Default 40.

-op, --operation

MBean operation name to be called.


Avoid non-essential output; default: false.

-ms, --set

Sets value for MBean attribute; default: false.

-v, --value

Value to set for MBean attribute.


Enhanced version of jps tool from the Java Development Kit (JDK) that lists the instrumented HotSpot Java Virtual Machines (JVMs) on the target system.

-fd, --filter-description

Use a wildcard expression to match the process description.

-fp, --filter-property

Use a wildcard expressions to match JVM system properties.

-pd, --process-details

Prints custom information related to a process; set to PID, MAIN, FDQN_MAIN, ARGS, Dsys-prop, or Dsys-prop.


Prints custom information related to the specified JVM flag.


Stack Capture dumps stack traces to file for further processing.

-e, --empty

Set to true to retain threads without stack trace in dump (ignored by default); default: false.

-f, --filter

Filters threads by name using Java RegEx syntax; default: .*

The default value, period (.) followed by asterisk (*), allows any number of any characters, including nulls.

-l, --limit

Target number of traces to collect, once reached command terminates where 0 is unlimited; default: 0.

-m, --match-frame

Set to filtering string and only traces containing are included in the dump.

-o, --output

Write the thread dump to the specified a file name.

-r, --rotate

When specified output file would be rotated every N traces. Specify 0 for no rotation; default: 0.

-i, --sampler-interval

Interval between polling MBeans; default: 0.

-t, --timeout

Time until command terminate even without enough traces collected; default: 30000.


Stack Copy utility copies and filters dumps.

-e, --empty

Set to true to retain threads without stack trace in dump (ignored by default); default: false.

-i, --input

Input files.


One or more masking rules, for example com.mycompany:com.somecompany.

Default: null.

-m, --match-frame

Frame filter, only traces containing the string are included in dump.

-o, --output

Set to filename. Writes thread dump to the specified file.

-ss, --subsample

If below 1.0 some frames are randomly thrown away. For example, 0.1 retains only every 10th frame; default: 1.0.

-tf, --thread-filter

Filter threads by name using Java RegEx syntax; default: .*


Stack Sample Analyzer for stack trace dumps.


Prints summary for provided categorization; no summary printed by default.

-cf, --categorizer-file

Path to file with stack trace categorization definition.

-co, --csv-output

Output data in CSV format; default: false.

-f, --file

Path to stack dump file.


Exports flame graph to SVG format; default: not included.


Prints frame histogram; default: not included.

-nc, --named-class

Defines name stack trace. Use with other options.


Use name=filter expression notation; default: no expression.


Print traces from file; default: not included.

-rc, --rainbow

List of filters for rainbow coloring.


Provides additional information about SSan options; default: not shown.

-si, --summary-info

Lists summaries.


Prints per thread information summary; default: false.

-tn, --thread-name

Filters thread name using Java RegEx syntax.

-tr, --time-range

Filters time range.

-tz, --time-zone

Time zone used for timestamps; default: UTC. Use --ssa-help for timezone notation.


Inserts a flame graph title; default: Flame Graph.

-tf, --trace-filter

Applies filter to traces before processing. Use --ssa-help for more details about filter notation.

-tt, --trace-trim

Positional filter trim frames to process. Use --ssa-help for more details about trace filters.


Flame graph width in pixels; default: 1200.


Displays top threads from JVM process.

-f, --filter

Wildcard expression to filter threads by name.

-o, --order

Sort order. Value tags: CPU, USER, SYS, ALLOC, NAME; default: CPU.

-ri, --report-interval

Interval between CPU usage reports in milliseconds; default: 10000ms.

-si, --sampler-interval

Interval between polling MBeans; default: 500.

-n, --top-number

Number of threads to show; default: 20.


Get status for the EndpointStateTracker MBean

nodetool sjk mx -b com.datastax.bdp:type=core,name=EndpointStateTracker -f Blacklisted --get

Set status to true for the EndpointStateTracker MBean

nodetool sjk mx -b com.datastax.bdp:type=core,name=EndpointStateTracker -f Blacklisted --set -v true

Get status of node1

nodetool sjk mx -b com.datastax.bdp:type=core,name=EndpointStateTracker -mc -op getBlacklistedStatus -a node1

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