lttng-regenerate(1)
===================
:revdate: 18 January 2018


NAME
----
lttng-regenerate - Manage an LTTng tracing session's data regeneration


SYNOPSIS
--------
Regenerate the metadata of a session:

[verse]
*lttng* ['linkgenoptions:(GENERAL OPTIONS)'] *regenerate metadata* [option:--session='SESSION']

Regenerate the state dump of a session:

[verse]
*lttng* ['linkgenoptions:(GENERAL OPTIONS)'] *regenerate statedump* [option:--session='SESSION']

DESCRIPTION
-----------
The `lttng regenerate` command regenerates specific data of a tracing session.

As of this version, the `metadata` and `statedump` actions are
available.


Regenerating a tracing session's metadata
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The `lttng regenerate metadata` action can be used to resample the offset
between the system's monotonic clock and the wall-clock time.

This action is meant to be used to resample the wall-clock time following a
major link:https://en.wikipedia.org/wiki/Network_Time_Protocol[NTP] correction.
As such, a system booting with an incorrect wall time can be traced before its
wall time is NTP-corrected. Regenerating the tracing session's metadata ensures
that trace viewers can accurately determine the events time relative to Unix
Epoch.

If you use man:lttng-rotate(1) or man:lttng-enable-rotation(1) to make
tracing session rotations, this action regenerates the current and
next trace chunks's metadata files.


Regenerating a tracing session's state dump
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The `lttng regenerate statedump` action can be used to collect up-to-date state
dump information during the tracing session. This is particularly useful in
snapshot (see man:lttng-snapshot(1)) or trace file rotation (see
man:lttng-enable-channel(1)) modes where the state dump information may be
lost.


include::common-cmd-options-head.txt[]


option:-s 'SESSION', option:--session='SESSION'::
    Regenerate the data of the tracing session named 'SESSION'
    instead of the current tracing session.


include::common-cmd-help-options.txt[]


LIMITATIONS
-----------
The `lttng regenerate metadata` command can only be used on kernel and
user space tracing sessions (using per-user buffering), in non-live
mode.

See man:lttng-enable-channel(1) for more information about
buffering schemes and man:lttng-create(1) for more information
about the different tracing session modes.


include::common-cmd-footer.txt[]


SEE ALSO
--------
man:lttng(1)
