$
lttng regenerate metadata
lttng-regenerate — Regenerate specific data of an LTTng recording session
Regenerate the metadata of a recording session:
lttng [GENERAL OPTIONS] regenerate metadata [--session=SESSION]
Regenerate the state dump event records of a recording session:
lttng [GENERAL OPTIONS] regenerate statedump [--session=SESSION]
The lttng regenerate command regenerates specific data of:
--session=SESSION option
The recording session named SESSION.
--session option
The current recording session (see lttng-concepts(7) to learn more about the current recording session).
See lttng-concepts(7) to learn more about recording sessions.
As of this version, the metadata and statedump targets are
available.
See the “EXAMPLES” section below for usage examples.
Use the metadata target to resample the offset between the monotonic
clock and the wall time of the system, and then regenerate the metadata
stream files.
More specifically, you may want to resample the wall time following a major NTP correction. As such, LTTng can trace a system booting with an incorrect wall time before its wall time is NTP-corrected. Regenerating the metadata of the selected recording session ensures that trace readers can accurately determine the event record timestamps relative to the Unix epoch.
Note that if you plan to rotate (see lttng-concepts(7) to learn more) the selected recording session, this target only regenerates the metadata stream files of the current and next trace chunks.
Important:You can only use the metadata target when the selected
recording session:
Is not in live mode (--live option of
lttng-create(1)).
If it has user space channels, they’re configured to use a
per-user buffer ownership model (--buffer-ownership=user
option of lttng-enable-channel(1)).
See lttng-concepts(7) to learn more about channels.
Use the statedump target to collect up-to-date state dump information
and create corresponding event records.
This is particularly useful if the selected recording session is in
snapshot mode (--snapshot option of the lttng-create(1)
command) or if LTTng rotates trace files for one of its channels (see
lttng-concepts(7)): in both cases, the state dump information may be
lost.
See lttng(1) for GENERAL OPTIONS.
-h, --help
Show help.
This option attempts to launch /usr/bin/man to view this manual page.
Override the manual pager path with the LTTNG_MAN_BIN_PATH environment
variable.
--list-options
List available command options and quit.
Success
Command error
Undefined command
Fatal error
Command warning (something went wrong during the command)
LTTNG_ABORT_ON_ERROR
Set to 1 to abort the process after the first error is
encountered.
LTTNG_HOME
Path to the LTTng home directory.
Defaults to $HOME.
Useful when the Unix user running the commands has a non-writable home directory.
LTTNG_MAN_BIN_PATH
Absolute path to the manual pager to use to read the LTTng
command-line help (with lttng-help(1) or with the
--help option) instead of /usr/bin/man.
LTTNG_SESSION_CONFIG_XSD_PATH
Path to the directory containing the session.xsd recording session
configuration XML schema.
LTTNG_SESSIOND_PATH
Absolute path to the LTTng session daemon binary (see lttng-sessiond(8)) to spawn from the lttng-create(1) command.
The --sessiond-path general option overrides this environment
variable.
$LTTNG_HOME/.lttngrc
Unix user’s LTTng runtime configuration.
This is where LTTng stores the name of the Unix user’s current recording session between executions of lttng(1). lttng-create(1) and lttng-set-session(1) set the current recording session.
$LTTNG_HOME/lttng-traces
Default output directory of LTTng traces in local and snapshot modes.
Override this path with the --output option of the
lttng-create(1) command.
$LTTNG_HOME/.lttng
Unix user’s LTTng runtime and configuration directory.
$LTTNG_HOME/.lttng/sessions
Default directory containing the Unix user’s saved recording session configurations (see lttng-save(1) and lttng-load(1)).
/etc/lttng/sessions
Directory containing the system-wide saved recording session configurations (see lttng-save(1) and lttng-load(1)).
Note:$LTTNG_HOME defaults to the value of the HOME environment
variable.
Example:Regenerate the metadata of the current recording session.
$
lttng regenerate metadata
Example:Regenerate the state dump event records of a specific recording session.
See the --session option.
$
lttng regenerate statedump --session=my-session
Mailing list for support and
development: lttng-dev@lists.lttng.org
IRC channel: #lttng on irc.oftc.net
This program is part of the LTTng-tools project.
LTTng-tools is distributed under the
GNU General
Public License version 2. See the
LICENSE file
for details.
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.