nodetool settraceprobability

Sets the probability of tracing a request.

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Synopsis

nodetool [connection_options] settraceprobability <probability>

Description

nodetool settraceprobability sets the probability (0.0 to 1.0) that any given request will be traced. Trace data is stored in the system_traces keyspace.

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Arguments

Argument	Description
probability	Trace probability (0.0 to 1.0)

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Examples

Enable 1% Tracing

nodetool settraceprobability 0.01

Enable Full Tracing

nodetool settraceprobability 1.0

Disable Tracing

nodetool settraceprobability 0.0

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When to Use

Performance Analysis

# Enable tracing
nodetool settraceprobability 0.1

# Query traces
cqlsh -e "SELECT * FROM system_traces.sessions LIMIT 10;"

# Disable after analysis
nodetool settraceprobability 0.0

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Best Practices

Performance Impact

Tracing adds overhead. Use low probabilities in production: - 0.001 (0.1%) for light sampling - 0.01 (1%) for moderate analysis - Higher values only for short periods

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Related Commands

Command	Relationship
gettraceprobability	View current probability