.. -*- rst -*-

Log
===

Groonga has two log files. They are process log and query
log. Process log is for all of :doc:`executables/groonga`
works. Query log is just for query processing.

.. _process-log:

Process log
-----------

Process log is enabled by default. Log path can be customized by
:option:`groonga --log-path` option. Each log has its log level. If a
log is smaller than Groonga process' log level, it's not logged. Log
level can be customized by :option:`groonga -l` or
:doc:`commands/log_level`.

Format
^^^^^^

Process log uses the following format::

  #{TIME_STAMP}|#{L}| #{MESSAGE}

Some multi-process based applications such as
:doc:`/reference/executables/groonga-httpd` and `PGroonga
<https://pgroonga.github.io/>`_ use the following format::

  #{TIME_STAMP}|#{L}|#{PID}: #{MESSAGE}

You can also show context ID that is also used in :ref:`query-log`. If
you also show context ID, you can associate related logs in
:ref:`process-log` and :ref:`query-log` easily::

  #{TIME_STAMP}|#{L}|#{PID}|#{CONTEXT_ID}: #{MESSAGE}

See :option:`groonga --log-flags` how to show PID, context ID and so
on.

Example::

  2011-07-05 08:35:09.276421|n| grn_init
  2011-07-05 08:35:09.276553|n| RLIMIT_NOFILE(4096,4096)

Example with PID::

  2011-07-05 08:35:09.276421|n|1129: grn_init
  2011-07-05 08:35:09.276553|n|1129: RLIMIT_NOFILE(4096,4096)

Example with PID and context ID::

  2025-01-27 16:39:40.709869|n|3901936|0x55788b59dbe0: grn_init: <14.0.9-27-gd6cd635>
  2025-01-27 16:39:40.710013|n|3901936|0x55788b59dbe0: vm.overcommit_memory kernel parameter should be 1: <0>: See INFO level log to resolve this
  2025-01-27 16:39:42.052517|n|3901936|0x55788b59dbe0: grn_fin (0)

``TIME_STAMP``
^^^^^^^^^^^^^^

It's time stamp uses the following format::

  YYYY-MM-DD hh:mm:ss.SSSSSS

.. list-table::
   :header-rows: 1

   * - Format
     - Description
   * - ``YYYY``
     - Year with four digits.
   * - ``MM``
     - Month with two digits.
   * - ``DD``
     - Day with two digits.
   * - ``hh``
     - Hour with two digits.
   * - ``mm``
     - Minute with two digits.
   * - ``ss``
     - Second with two digits.
   * - ``SSSSSS``
     - Microsecond with six digits.

Example::

  2011-07-05 06:25:18.345734

``L``
^^^^^

Log level with a character. Here is a character and log
level map.

.. list-table::
   :header-rows: 1

   * - Format
     - Description
   * - ``E``
     - Emergency
   * - ``A``
     - Alert
   * - ``C``
     - Critical
   * - ``e``
     - Error
   * - ``w``
     - Warning
   * - ``n``
     - Notification
   * - ``i``
     - Information
   * - ``d``
     - Debug
   * - ``-``
     - Dump

Example::

  E

``PID``
^^^^^^^

The process ID.

Example::

  1129

``MESSAGE``
^^^^^^^^^^^

Details about the log with free format.

Example::

  log opened.

.. _query-log:

Query log
---------

Query log is disabled by default. It can be enabled by
:option:`groonga --query-log-path` option.

Format
^^^^^^

Query log uses the following formats::

  #{TIME_STAMP}|#{MESSAGE}
  #{TIME_STAMP}|#{CONTEXT_ID}|#{QUERY_STATUS}#{QUERY}
  #{TIME_STAMP}|#{CONTEXT_ID}|#{QUERY_STATUS}#{ELAPSED_TIME} #{PROGRESS}
  #{TIME_STAMP}|#{CONTEXT_ID}|#{QUERY_STATUS}#{ELAPSED_TIME} #{RETURN_CODE}

Example::

  2011-07-05 06:25:19.458756|45ea3034|>select Properties --limit 0
  2011-07-05 06:25:19.458829|45ea3034|:000000000072779 select(19)
  2011-07-05 06:25:19.458856|45ea3034|:000000000099998 output(0)
  2011-07-05 06:25:19.458875|45ea3034|<000000000119062 rc=0
  2011-07-05 06:25:19.458986|45ea3034|>quit

``TIME_STAMP``
^^^^^^^^^^^^^^

It's time stamp uses the following format::

  YYYY-MM-DD hh:mm:ss.SSSSSS

.. list-table::
   :header-rows: 1

   * - Format
     - Description
   * - ``YYYY``
     - Year with four digits.
   * - ``MM``
     - Month with two digits.
   * - ``DD``
     - Day with two digits.
   * - ``hh``
     - Hour with two digits.
   * - ``mm``
     - Minute with two digits.
   * - ``ss``
     - Second with two digits.

``SSSSSS``
  Microsecond with six digits.

Example::

  2011-07-05 06:25:18.345734

``CONTEXT_ID``
^^^^^^^^^^^^^^

ID of a context. Groonga process creates contexts to process requests
concurrently. Each context outputs some logs for a request. This ID can
be used to extract a log sequence by a context.

Example::

  45ea3034

``QUERY_STATUS``
^^^^^^^^^^^^^^^^

.. list-table::
   :header-rows: 1

   * - Format
     - Description
   * - ``>``
     - A character that indicates query is started.
   * - ``:``
     - A character that indicates query is processing.
   * - ``<``
     - A character that indicates query is finished.

``MESSAGE``
^^^^^^^^^^^

Details about the log with free format.

Example::

  query log opened.

``QUERY``
^^^^^^^^^

A query to be processed.

Example::

  select users --match_columns hobby --query music

``ELAPSED_TIME``
^^^^^^^^^^^^^^^^

Elapsed time in nanoseconds since query is started.

Example::

  000000000075770
  (It means 75,770 nanoseconds.)

``PROGRESS``
^^^^^^^^^^^^

A processed work at the time.

Example::

  select(313401)
  (It means that 'select' is processed and 313,401 records are remained.)

``RETURN_CODE``
^^^^^^^^^^^^^^^

A return code for the query.

Example::

  rc=0
  (It means return code is 0. 0 means GRN_SUCCESS.)