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 system_traces.events tables for probabilistic tracing information.

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

Synopsis

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

Definition

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.