The TRACING command is a toggle that allows the tracing functionality to be turned on:
TRACING ONNow Tracing is enabledTRACINGTracing is currently enabled. Use TRACING OFF to disable
Tracing is useful in that it can show why particular queries may be running slowly. A tracing report allows you to view things about a query, such as the following:
- Nodes contacted
- Number of SSTables read
- Number of tombstones encountered
- How long the query took to run
Tracing will be covered in more detail in Chapter 5, Performance Tuning.