nodetool settraceprobability

Sets the probability for tracing any given request to value.

Probabilistic tracing identifies which queries are responsible for intermittent query performance problems. You can trace some or all statements sent to a cluster. Tracing a request usually requires at least 10 rows to be inserted.

A probability of 1.0 traces all requests, whereas a value less than 1 samples only a percentage of statements. For example, 0.1 traces 10% of requests.

On large and active systems, system-wide tracing will have a performance impact. Unless the load is very light, tracing 100% of requests will probably overwhelm the system. For large systems, start with a small fraction, such as 0.001, and increase only if necessary.

The trace information is stored in the system_traces keyspace. This keyspace holds the sessions and events tables that can be easily queried. Query the parameters map and thread column in the system_traces.sessions and tables for probabilistic tracing information.

To get the current trace probability setting, use nodetool gettraceprobability.


nodetool [<connection_options>] settraceprobability
[--] <value>
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.


The short- and long-form options are comma-separated.

Connection options

-h, --host hostname

The hostname or IP address of a remote node or nodes. When omitted, the default is the local machine.

-p, --port jmx_port

The JMX port number.

-pw, --password jmxpassword

The JMX password for authenticating with secure JMX. If a password is not provided, you are prompted to enter one.

-pwf, --password-file jmx_password_filepath

The filepath to the file that stores JMX authentication credentials.

-u, --username jmx_username

The username for authenticating with secure JMX.

Command arguments


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

  • 0 - disables trace probability. Default.

  • number between 0 and 1 - trace probability to represent a percentage.

  • 1 - enables for all requests.


Set probability for tracing a request at 60%

nodetool settraceprobability 0.6

Enable tracing for all requests

nodetool settraceprobability 1

Disable request tracing

nodetool settraceprobability 0

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