lttng-clear — Clear a tracing session
lttng clear command clears one or more tracing sessions, that is,
it deletes the contents of their tracing buffers and all their local and
streamed trace data.
If no options are specified, the current tracing session is cleared (see lttng-create(1) for more information about the current tracing session).
SESSION is specified, the existing tracing session named
If a tracing session is configured in snapshot mode (see the
--snapshot option), only the
tracing buffers are cleared.
For a given tracing session, if at least one rotation occurred (see lttng-rotate(1)), only its tracing buffers and its current trace chunk are cleared; its archived trace chunks are not cleared.
--disallow-clear option and the
LTTNG_RELAYD_DISALLOW_CLEAR environment variable of
lttng-relayd(8) can disable remote clearing operations. If LTTng
sends tracing data over the network for
SESSION (or for any tracing
session with the
--all option) to a relay daemon configured as
lttng clear fails.
Set to 1 to abort the process after the first error is encountered.
$HOME environment variable. Useful when the user
running the commands has a non-writable home directory.
Absolute path to the man pager to use for viewing help information
about LTTng commands (using lttng-help(1) or
lttng COMMAND --help).
Path in which the
session.xsd session configuration XML
schema may be found.
Full session daemon binary path.
--sessiond-path option has precedence over this
Note that the lttng-create(1) command can spawn an LTTng session daemon automatically if none is running. See lttng-sessiond(8) for the environment variables influencing the execution of the session daemon.
User LTTng runtime configuration.
This is where the per-user current tracing session is stored between executions of lttng(1). The current tracing session can be set with lttng-set-session(1). See lttng-create(1) for more information about tracing sessions.
Default output directory of LTTng traces. This can be overridden
--output option of the lttng-create(1)
User LTTng runtime and configuration directory.
$LTTNG_HOME defaults to
$HOME when not explicitly set.
Command warning (something went wrong during the command)
If you encounter any issue or usability problem, please report it on the LTTng bug tracker.
Special thanks to Michel Dagenais and the DORSAL laboratory at École Polytechnique de Montréal for the LTTng journey.
Also thanks to the Ericsson teams working on tracing which helped us greatly with detailed bug reports and unusual test cases.