1LTTNG-REGENERATE(1)              LTTng Manual              LTTNG-REGENERATE(1)
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NAME

6       lttng-regenerate - Manage an LTTng tracing session's data regeneration
7

SYNOPSIS

9       Regenerate the metadata of a session:
10
11       lttng [GENERAL OPTIONS] regenerate metadata [--session=SESSION]
12
13       Regenerate the state dump of a session:
14
15       lttng [GENERAL OPTIONS] regenerate statedump [--session=SESSION]
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DESCRIPTION

18       The lttng regenerate command regenerates specific data of a tracing
19       session.
20
21       As of this version, the metadata and statedump actions are available.
22
23   Regenerating a tracing session’s metadata
24       The lttng regenerate metadata action can be used to resample the offset
25       between the system’s monotonic clock and the wall-clock time.
26
27       This action is meant to be used to resample the wall-clock time
28       following a major NTP
29       <https://en.wikipedia.org/wiki/Network_Time_Protocol> correction. As
30       such, a system booting with an incorrect wall time can be traced before
31       its wall time is NTP-corrected. Regenerating the tracing session’s
32       metadata ensures that trace viewers can accurately determine the events
33       time relative to Unix Epoch.
34
35       If you use lttng-rotate(1) or lttng-enable-rotation(1) to make tracing
36       session rotations, this action regenerates the current and next trace
37       chunks’s metadata files.
38
39   Regenerating a tracing session’s state dump
40       The lttng regenerate statedump action can be used to collect up-to-date
41       state dump information during the tracing session. This is particularly
42       useful in snapshot (see lttng-snapshot(1)) or trace file rotation (see
43       lttng-enable-channel(1)) modes where the state dump information may be
44       lost.
45

OPTIONS

47       General options are described in lttng(1).
48
49       -s SESSION, --session=SESSION
50           Regenerate the data of the tracing session named SESSION instead of
51           the current tracing session.
52
53   Program information
54       -h, --help
55           Show command help.
56
57           This option, like lttng-help(1), attempts to launch /usr/bin/man to
58           view the command’s man page. The path to the man pager can be
59           overridden by the LTTNG_MAN_BIN_PATH environment variable.
60
61       --list-options
62           List available command options.
63

LIMITATIONS

65       The lttng regenerate metadata command can only be used on kernel and
66       user space tracing sessions (using per-user buffering), in non-live
67       mode.
68
69       See lttng-enable-channel(1) for more information about buffering
70       schemes and lttng-create(1) for more information about the different
71       tracing session modes.
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ENVIRONMENT VARIABLES

74       LTTNG_ABORT_ON_ERROR
75           Set to 1 to abort the process after the first error is encountered.
76
77       LTTNG_HOME
78           Overrides the $HOME environment variable. Useful when the user
79           running the commands has a non-writable home directory.
80
81       LTTNG_MAN_BIN_PATH
82           Absolute path to the man pager to use for viewing help information
83           about LTTng commands (using lttng-help(1) or lttng COMMAND --help).
84
85       LTTNG_SESSION_CONFIG_XSD_PATH
86           Path in which the session.xsd session configuration XML schema may
87           be found.
88
89       LTTNG_SESSIOND_PATH
90           Full session daemon binary path.
91
92           The --sessiond-path option has precedence over this environment
93           variable.
94
95       Note that the lttng-create(1) command can spawn an LTTng session daemon
96       automatically if none is running. See lttng-sessiond(8) for the
97       environment variables influencing the execution of the session daemon.
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FILES

100       $LTTNG_HOME/.lttngrc
101           User LTTng runtime configuration.
102
103           This is where the per-user current tracing session is stored
104           between executions of lttng(1). The current tracing session can be
105           set with lttng-set-session(1). See lttng-create(1) for more
106           information about tracing sessions.
107
108       $LTTNG_HOME/lttng-traces
109           Default output directory of LTTng traces. This can be overridden
110           with the --output option of the lttng-create(1) command.
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112       $LTTNG_HOME/.lttng
113           User LTTng runtime and configuration directory.
114
115       $LTTNG_HOME/.lttng/sessions
116           Default location of saved user tracing sessions (see lttng-save(1)
117           and lttng-load(1)).
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119       /usr/local/etc/lttng/sessions
120           System-wide location of saved tracing sessions (see lttng-save(1)
121           and lttng-load(1)).
122
123           Note
124           $LTTNG_HOME defaults to $HOME when not explicitly set.
125

EXIT STATUS

127       0
128           Success
129
130       1
131           Command error
132
133       2
134           Undefined command
135
136       3
137           Fatal error
138
139       4
140           Command warning (something went wrong during the command)
141

BUGS

143       If you encounter any issue or usability problem, please report it on
144       the LTTng bug tracker <https://bugs.lttng.org/projects/lttng-tools>.
145

RESOURCES

147       ·   LTTng project website <https://lttng.org>
148
149       ·   LTTng documentation <https://lttng.org/docs>
150
151       ·   Git repositories <http://git.lttng.org>
152
153       ·   GitHub organization <http://github.com/lttng>
154
155       ·   Continuous integration <http://ci.lttng.org/>
156
157       ·   Mailing list <http://lists.lttng.org> for support and development:
158           lttng-dev@lists.lttng.org
159
160       ·   IRC channel <irc://irc.oftc.net/lttng>: #lttng on irc.oftc.net
161

COPYRIGHTS

163       This program is part of the LTTng-tools project.
164
165       LTTng-tools is distributed under the GNU General Public License version
166       2 <http://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html>. See the
167       LICENSE <https://github.com/lttng/lttng-tools/blob/master/LICENSE> file
168       for details.
169

THANKS

171       Special thanks to Michel Dagenais and the DORSAL laboratory
172       <http://www.dorsal.polymtl.ca/> at École Polytechnique de Montréal for
173       the LTTng journey.
174
175       Also thanks to the Ericsson teams working on tracing which helped us
176       greatly with detailed bug reports and unusual test cases.
177

SEE ALSO

179       lttng(1)
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183LTTng 2.11.1                    18 January 2018            LTTNG-REGENERATE(1)
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