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The following is a list of tracing levels and the types of information (tracing types) that they include. These levels reflect the settings specified in the Database Tracing wizard. For a description of the various tracing types, see Diagnostic tracing types.
Estimated impacts to performance reflect the assumption that tracing data is sent to a tracing database on another database server (recommended).
Level 0 This level keeps the tracing session running, but does not send any tracing data to the tracing tables.
Level 1 Performance counters are gathered, as well as a sampling of executed statements (once every five seconds). For this level, the tracing types include:
volatile_statistics, with sampling every 1 second
non_volatile_statistics, with sampling every 60 seconds
This level has a negligible impact on performance.
Level 2 This level gathers performance counters and records all executed statements, as well as a sampling of executed plans (once every five seconds). For this level, the tracing types include:
volatile_statistics, with sampling every 1 second
non_volatile_statistics, with sampling every 60 seconds
statements
plans, sampling every 5 seconds
This level has a medium impact on performance—up to, but not more than, a 20% overhead.
Level 3 This level records the same details as Level 2 but with more frequent plan samples (once every 2 seconds) and detailed blocking and deadlock information. For this level, the tracing types include:
volatile_statistics, with sampling every 1 second
non_volatile_statistics, with sampling every 60 seconds
statements
blocking
deadlock
statements_with_variables
plans, with sampling every 2 seconds
This level has the greatest impact on performance—greater than 20% overhead.