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git-maintenance(1)                 Git Manual                 git-maintenance(1)


       git-maintenance - Run tasks to optimize Git repository data


       git maintenance run [<options>]
       git maintenance start [--scheduler=<scheduler>]
       git maintenance (stop|register|unregister) [<options>]


       Run tasks to optimize Git repository data, speeding up other Git commands
       and reducing storage requirements for the repository.

       Git commands that add repository data, such as git add or git fetch, are
       optimized for a responsive user experience. These commands do not take
       time to optimize the Git data, since such optimizations scale with the
       full size of the repository while these user commands each perform a
       relatively small action.

       The git maintenance command provides flexibility for how to optimize the
       Git repository.


           Run one or more maintenance tasks. If one or more --task options are
           specified, then those tasks are run in that order. Otherwise, the
           tasks are determined by which maintenance.<task>.enabled config
           options are true. By default, only maintenance.gc.enabled is true.

           Start running maintenance on the current repository. This performs
           the same config updates as the register subcommand, then updates the
           background scheduler to run git maintenance run --scheduled on an
           hourly basis.

           Halt the background maintenance schedule. The current repository is
           not removed from the list of maintained repositories, in case the
           background maintenance is restarted later.

           Initialize Git config values so any scheduled maintenance will start
           running on this repository. This adds the repository to the
           maintenance.repo config variable in the current user's global config,
           or the config specified by --config-file option, and enables some
           recommended configuration values for maintenance.<task>.schedule. The
           tasks that are enabled are safe for running in the background without
           disrupting foreground processes.

           The register subcommand will also set the maintenance.strategy config
           value to incremental, if this value is not previously set. The
           incremental strategy uses the following schedule for each maintenance

           o   gc: disabled.

           o   commit-graph: hourly.

           o   prefetch: hourly.

           o   loose-objects: daily.

           o   incremental-repack: daily.

           git maintenance register will also disable foreground maintenance by
           setting = false in the current repository. This
           config setting will remain after a git maintenance unregister

           Remove the current repository from background maintenance. This only
           removes the repository from the configured list. It does not stop the
           background maintenance processes from running.

           The unregister subcommand will report an error if the current
           repository is not already registered. Use the --force option to
           return success even when the current repository is not registered.


           The commit-graph job updates the commit-graph files incrementally,
           then verifies that the written data is correct. The incremental write
           is safe to run alongside concurrent Git processes since it will not
           expire .graph files that were in the previous commit-graph-chain
           file. They will be deleted by a later run based on the expiration

           The prefetch task updates the object directory with the latest
           objects from all registered remotes. For each remote, a git fetch
           command is run. The configured refspec is modified to place all
           requested refs within refs/prefetch/. Also, tags are not updated.

           This is done to avoid disrupting the remote-tracking branches. The
           end users expect these refs to stay unmoved unless they initiate a
           fetch. With prefetch task, however, the objects necessary to complete
           a later real fetch would already be obtained, so the real fetch would
           go faster. In the ideal case, it will just become an update to a
           bunch of remote-tracking branches without any object transfer.

           Clean up unnecessary files and optimize the local repository. "GC"
           stands for "garbage collection," but this task performs many smaller
           tasks. This task can be expensive for large repositories, as it
           repacks all Git objects into a single pack-file. It can also be
           disruptive in some situations, as it deletes stale data. See git-
           gc(1) for more details on garbage collection in Git.

           The loose-objects job cleans up loose objects and places them into
           pack-files. In order to prevent race conditions with concurrent Git
           commands, it follows a two-step process. First, it deletes any loose
           objects that already exist in a pack-file; concurrent Git processes
           will examine the pack-file for the object data instead of the loose
           object. Second, it creates a new pack-file (starting with "loose-")
           containing a batch of loose objects. The batch size is limited to 50
           thousand objects to prevent the job from taking too long on a
           repository with many loose objects. The gc task writes unreachable
           objects as loose objects to be cleaned up by a later step only if
           they are not re-added to a pack-file; for this reason it is not
           advisable to enable both the loose-objects and gc tasks at the same

           The incremental-repack job repacks the object directory using the
           multi-pack-index feature. In order to prevent race conditions with
           concurrent Git commands, it follows a two-step process. First, it
           calls git multi-pack-index expire to delete pack-files unreferenced
           by the multi-pack-index file. Second, it calls git multi-pack-index
           repack to select several small pack-files and repack them into a
           bigger one, and then update the multi-pack-index entries that refer
           to the small pack-files to refer to the new pack-file. This prepares
           those small pack-files for deletion upon the next run of git
           multi-pack-index expire. The selection of the small pack-files is
           such that the expected size of the big pack-file is at least the
           batch size; see the --batch-size option for the repack subcommand in
           git-multi-pack-index(1). The default batch-size is zero, which is a
           special case that attempts to repack all pack-files into a single

           The pack-refs task collects the loose reference files and collects
           them into a single file. This speeds up operations that need to
           iterate across many references. See git-pack-refs(1) for more


           When combined with the run subcommand, run maintenance tasks only if
           certain thresholds are met. For example, the gc task runs when the
           number of loose objects exceeds the number stored in the
           config setting, or when the number of pack-files exceeds the
           gc.autoPackLimit config setting. Not compatible with the --schedule

           When combined with the run subcommand, run maintenance tasks only if
           certain time conditions are met, as specified by the
           maintenance.<task>.schedule config value for each <task>. This config
           value specifies a number of seconds since the last time that task
           ran, according to the maintenance.<task>.lastRun config value. The
           tasks that are tested are those provided by the --task=<task>
           option(s) or those with maintenance.<task>.enabled set to true.

           Do not report progress or other information over stderr.

           If this option is specified one or more times, then only run the
           specified tasks in the specified order. If no --task=<task> arguments
           are specified, then only the tasks with maintenance.<task>.enabled
           configured as true are considered. See the TASKS section for the list
           of accepted <task> values.

           When combined with the start subcommand, specify the scheduler for
           running the hourly, daily and weekly executions of git maintenance
           run. Possible values for <scheduler> are auto, crontab (POSIX),
           systemd-timer (Linux), launchctl (macOS), and schtasks (Windows).
           When auto is specified, the appropriate platform-specific scheduler
           is used; on Linux, systemd-timer is used if available, otherwise
           crontab. Default is auto.


       The git maintenance command is designed to simplify the repository
       maintenance patterns while minimizing user wait time during Git commands.
       A variety of configuration options are available to allow customizing
       this process. The default maintenance options focus on operations that
       complete quickly, even on large repositories.

       Users may find some cases where scheduled maintenance tasks do not run as
       frequently as intended. Each git maintenance run command takes a lock on
       the repository's object database, and this prevents other concurrent git
       maintenance run commands from running on the same repository. Without
       this safeguard, competing processes could leave the repository in an
       unpredictable state.

       The background maintenance schedule runs git maintenance run processes on
       an hourly basis. Each run executes the "hourly" tasks. At midnight, that
       process also executes the "daily" tasks. At midnight on the first day of
       the week, that process also executes the "weekly" tasks. A single process
       iterates over each registered repository, performing the scheduled tasks
       for that frequency. Depending on the number of registered repositories
       and their sizes, this process may take longer than an hour. In this case,
       multiple git maintenance run commands may run on the same repository at
       the same time, colliding on the object database lock. This results in one
       of the two tasks not running.

       If you find that some maintenance windows are taking longer than one hour
       to complete, then consider reducing the complexity of your maintenance
       tasks. For example, the gc task is much slower than the
       incremental-repack task. However, this comes at a cost of a slightly
       larger object database. Consider moving more expensive tasks to be run
       less frequently.

       Expert users may consider scheduling their own maintenance tasks using a
       different schedule than is available through git maintenance start and
       Git configuration options. These users should be aware of the object
       database lock and how concurrent git maintenance run commands behave.
       Further, the git gc command should not be combined with git maintenance
       run commands. git gc modifies the object database but does not take the
       lock in the same way as git maintenance run. If possible, use git
       maintenance run --task=gc instead of git gc.

       The following sections describe the mechanisms put in place to run
       background maintenance by git maintenance start and how to customize


       The standard mechanism for scheduling background tasks on POSIX systems
       is cron(8). This tool executes commands based on a given schedule. The
       current list of user-scheduled tasks can be found by running crontab -l.
       The schedule written by git maintenance start is similar to this:

           # The following schedule was created by Git
           # Any edits made in this region might be
           # replaced in the future by a Git command.

           0 1-23 * * * "/<path>/git" --exec-path="/<path>" for-each-repo --config=maintenance.repo maintenance run --schedule=hourly
           0 0 * * 1-6 "/<path>/git" --exec-path="/<path>" for-each-repo --config=maintenance.repo maintenance run --schedule=daily
           0 0 * * 0 "/<path>/git" --exec-path="/<path>" for-each-repo --config=maintenance.repo maintenance run --schedule=weekly


       The comments are used as a region to mark the schedule as written by Git.
       Any modifications within this region will be completely deleted by git
       maintenance stop or overwritten by git maintenance start.

       The crontab entry specifies the full path of the git executable to ensure
       that the executed git command is the same one with which git maintenance
       start was issued independent of PATH. If the same user runs git
       maintenance start with multiple Git executables, then only the latest
       executable is used.

       These commands use git for-each-repo --config=maintenance.repo to run git
       maintenance run --schedule=<frequency> on each repository listed in the
       multi-valued maintenance.repo config option. These are typically loaded
       from the user-specific global config. The git maintenance process then
       determines which maintenance tasks are configured to run on each
       repository with each <frequency> using the maintenance.<task>.schedule
       config options. These values are loaded from the global or repository
       config values.

       If the config values are insufficient to achieve your desired background
       maintenance schedule, then you can create your own schedule. If you run
       crontab -e, then an editor will load with your user-specific cron
       schedule. In that editor, you can add your own schedule lines. You could
       start by adapting the default schedule listed earlier, or you could read
       the crontab(5) documentation for advanced scheduling techniques. Please
       do use the full path and --exec-path techniques from the default schedule
       to ensure you are executing the correct binaries in your schedule.


       While Linux supports cron, depending on the distribution, cron may be an
       optional package not necessarily installed. On modern Linux
       distributions, systemd timers are superseding it.

       If user systemd timers are available, they will be used as a replacement
       of cron.

       In this case, git maintenance start will create user systemd timer units
       and start the timers. The current list of user-scheduled tasks can be
       found by running systemctl --user list-timers. The timers written by git
       maintenance start are similar to this:

           $ systemctl --user list-timers
           NEXT                         LEFT          LAST                         PASSED     UNIT                         ACTIVATES
           Thu 2021-04-29 19:00:00 CEST 42min left    Thu 2021-04-29 18:00:11 CEST 17min ago  git-maintenance@hourly.timer git-maintenance@hourly.service
           Fri 2021-04-30 00:00:00 CEST 5h 42min left Thu 2021-04-29 00:00:11 CEST 18h ago    git-maintenance@daily.timer  git-maintenance@daily.service
           Mon 2021-05-03 00:00:00 CEST 3 days left   Mon 2021-04-26 00:00:11 CEST 3 days ago git-maintenance@weekly.timer git-maintenance@weekly.service

       One timer is registered for each --schedule=<frequency> option.

       The definition of the systemd units can be inspected in the following


       git maintenance start will overwrite these files and start the timer
       again with systemctl --user, so any customization should be done by
       creating a drop-in file, i.e. a .conf suffixed file in the
       ~/.config/systemd/user/git-maintenance@.service.d directory.

       git maintenance stop will stop the user systemd timers and delete the
       above mentioned files.

       For more details, see systemd.timer(5).


       While macOS technically supports cron, using crontab -e requires elevated
       privileges and the executed process does not have a full user context.
       Without a full user context, Git and its credential helpers cannot access
       stored credentials, so some maintenance tasks are not functional.

       Instead, git maintenance start interacts with the launchctl tool, which
       is the recommended way to schedule timed jobs in macOS. Scheduling
       maintenance through git maintenance (start|stop) requires some launchctl
       features available only in macOS 10.11 or later.

       Your user-specific scheduled tasks are stored as XML-formatted .plist
       files in ~/Library/LaunchAgents/. You can see the currently-registered
       tasks using the following command:

           $ ls ~/Library/LaunchAgents/org.git-scm.git*

       One task is registered for each --schedule=<frequency> option. To inspect
       how the XML format describes each schedule, open one of these .plist
       files in an editor and inspect the <array> element following the
       <key>StartCalendarInterval</key> element.

       git maintenance start will overwrite these files and register the tasks
       again with launchctl, so any customizations should be done by creating
       your own .plist files with distinct names. Similarly, the git maintenance
       stop command will unregister the tasks with launchctl and delete the
       .plist files.

       To create more advanced customizations to your background tasks, see
       launchctl.plist(5) for more information.


       Windows does not support cron and instead has its own system for
       scheduling background tasks. The git maintenance start command uses the
       schtasks command to submit tasks to this system. You can inspect all
       background tasks using the Task Scheduler application. The tasks added by
       Git have names of the form Git Maintenance (<frequency>). The Task
       Scheduler GUI has ways to inspect these tasks, but you can also export
       the tasks to XML files and view the details there.

       Note that since Git is a console application, these background tasks
       create a console window visible to the current user. This can be changed
       manually by selecting the "Run whether user is logged in or not" option
       in Task Scheduler. This change requires a password input, which is why
       git maintenance start does not select it by default.

       If you want to customize the background tasks, please rename the tasks so
       future calls to git maintenance (start|stop) do not overwrite your custom


       Everything below this line in this section is selectively included from
       the git-config(1) documentation. The content is the same as what's found
           This boolean config option controls whether some commands run git
           maintenance run --auto after doing their normal work. Defaults to

           This string config option provides a way to specify one of a few
           recommended schedules for background maintenance. This only affects
           which tasks are run during git maintenance run --schedule=X commands,
           provided no --task=<task> arguments are provided. Further, if a
           maintenance.<task>.schedule config value is set, then that value is
           used instead of the one provided by maintenance.strategy. The
           possible strategy strings are:

           o   none: This default setting implies no task are run at any

           o   incremental: This setting optimizes for performing small
               maintenance activities that do not delete any data. This does not
               schedule the gc task, but runs the prefetch and commit-graph
               tasks hourly, the loose-objects and incremental-repack tasks
               daily, and the pack-refs task weekly.

           This boolean config option controls whether the maintenance task with
           name <task> is run when no --task option is specified to git
           maintenance run. These config values are ignored if a --task option
           exists. By default, only maintenance.gc.enabled is true.

           This config option controls whether or not the given <task> runs
           during a git maintenance run --schedule=<frequency> command. The
           value must be one of "hourly", "daily", or "weekly".
           This integer config option controls how often the commit-graph task
           should be run as part of git maintenance run --auto. If zero, then
           the commit-graph task will not run with the --auto option. A negative
           value will force the task to run every time. Otherwise, a positive
           value implies the command should run when the number of reachable
           commits that are not in the commit-graph file is at least the value
           of The default value is 100.
           This integer config option controls how often the loose-objects task
           should be run as part of git maintenance run --auto. If zero, then
           the loose-objects task will not run with the --auto option. A
           negative value will force the task to run every time. Otherwise, a
           positive value implies the command should run when the number of
           loose objects is at least the value of
  The default value is 100.
           This integer config option controls how often the incremental-repack
           task should be run as part of git maintenance run --auto. If zero,
           then the incremental-repack task will not run with the --auto option.
           A negative value will force the task to run every time. Otherwise, a
           positive value implies the command should run when the number of
           pack-files not in the multi-pack-index is at least the value of
  The default value is 10.


       Part of the git(1) suite

Git 2.39.0                         12/12/2022                 git-maintenance(1)

git 2.39.0 - Generated Tue Dec 13 08:51:03 CST 2022
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