.. Licensed under the Apache License, Version 2.0 (the "License"); you may not
.. use this file except in compliance with the License. You may obtain a copy of
.. the License at
..
..   http://www.apache.org/licenses/LICENSE-2.0
..
.. Unless required by applicable law or agreed to in writing, software
.. distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
.. WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
.. License for the specific language governing permissions and limitations under
.. the License.

.. default-domain:: config
.. highlight:: ini

========================
Miscellaneous Parameters
========================

.. _config/attachments:

Configuration of Attachment Storage
===================================

.. config:section:: attachments :: Configuration of Attachment Storage

    .. config:option:: compression_level

        Defines zlib compression level for the attachments from ``1`` (lowest,
        fastest) to ``9`` (highest, slowest). A value of ``0`` disables
        compression::

            [attachments]
            compression_level = 8

    .. config:option:: compressible_types

        Since compression is ineffective for some types of files, it is
        possible to let CouchDB compress only some types of attachments,
        specified by their MIME type::

            [attachments]
            compressible_types = text/*, application/javascript, application/json, application/xml

.. _config/stats:

Statistic Calculation
=====================

.. config:section:: stats :: Statistic Calculation

    .. config:option:: interval

        Interval between gathering statistics in seconds::

            [stats]
            interval = 10

.. _config/uuids:

UUIDs Configuration
===================

.. config:section:: uuids :: UUIDs Configuration

    .. config:option:: algorithm :: Generation Algorithm

        .. versionchanged:: 1.3 Added ``utc_id`` algorithm.

        CouchDB provides various algorithms to generate the UUID values that
        are  used for document `_id`'s by default::

            [uuids]
            algorithm = sequential

        Available algorithms:

        - ``random``: 128 bits of random awesome. All awesome, all the time:

          .. code-block:: javascript

              {
                  "uuids": [
                      "5fcbbf2cb171b1d5c3bc6df3d4affb32",
                      "9115e0942372a87a977f1caf30b2ac29",
                      "3840b51b0b81b46cab99384d5cd106e3",
                      "b848dbdeb422164babf2705ac18173e1",
                      "b7a8566af7e0fc02404bb676b47c3bf7",
                      "a006879afdcae324d70e925c420c860d",
                      "5f7716ee487cc4083545d4ca02cd45d4",
                      "35fdd1c8346c22ccc43cc45cd632e6d6",
                      "97bbdb4a1c7166682dc026e1ac97a64c",
                      "eb242b506a6ae330bda6969bb2677079"
                  ]
              }

        - ``sequential``: Monotonically increasing ids with random increments.
          The first 26 hex characters are random, the last 6 increment in
          random amounts until an overflow occurs. On overflow, the random
          prefix is regenerated and the process starts over.

          .. code-block:: javascript

              {
                  "uuids": [
                      "4e17c12963f4bee0e6ec90da54804894",
                      "4e17c12963f4bee0e6ec90da5480512f",
                      "4e17c12963f4bee0e6ec90da54805c25",
                      "4e17c12963f4bee0e6ec90da54806ba1",
                      "4e17c12963f4bee0e6ec90da548072b3",
                      "4e17c12963f4bee0e6ec90da54807609",
                      "4e17c12963f4bee0e6ec90da54807718",
                      "4e17c12963f4bee0e6ec90da54807754",
                      "4e17c12963f4bee0e6ec90da54807e5d",
                      "4e17c12963f4bee0e6ec90da54808d28"
                  ]
              }

        - ``utc_random``: The time since Jan 1, 1970 UTC, in microseconds. The
          first 14 characters are the time in hex. The last 18 are random.

          .. code-block:: javascript

              {
                  "uuids": [
                      "04dd32b3af699659b6db9486a9c58c62",
                      "04dd32b3af69bb1c2ac7ebfee0a50d88",
                      "04dd32b3af69d8591b99a8e86a76e0fb",
                      "04dd32b3af69f4a18a76efd89867f4f4",
                      "04dd32b3af6a1f7925001274bbfde952",
                      "04dd32b3af6a3fe8ea9b120ed906a57f",
                      "04dd32b3af6a5b5c518809d3d4b76654",
                      "04dd32b3af6a78f6ab32f1e928593c73",
                      "04dd32b3af6a99916c665d6bbf857475",
                      "04dd32b3af6ab558dd3f2c0afacb7d66"
                  ]
              }

        - ``utc_id``: The time since Jan 1, 1970 UTC, in microseconds, plus the
          ``utc_id_suffix`` string. The first 14 characters are the time in
          hex. The :option:`uuids/utc_id_suffix` string value is appended to
          these.

          .. code-block:: javascript

              {
                  "uuids": [
                      "04dd32bd5eabcc@mycouch",
                      "04dd32bd5eabee@mycouch",
                      "04dd32bd5eac05@mycouch",
                      "04dd32bd5eac28@mycouch",
                      "04dd32bd5eac43@mycouch",
                      "04dd32bd5eac58@mycouch",
                      "04dd32bd5eac6e@mycouch",
                      "04dd32bd5eac84@mycouch",
                      "04dd32bd5eac98@mycouch",
                      "04dd32bd5eacad@mycouch"
                  ]
              }

        .. note::
            **Impact of UUID choices:** the choice of UUID has a significant
            impact on the layout of the B-tree, prior to compaction.

            For example, using a sequential UUID algorithm while uploading a
            large batch of documents will avoid the need to rewrite many
            intermediate B-tree nodes. A random UUID algorithm may require
            rewriting intermediate nodes on a regular basis, resulting in
            significantly decreased throughput and wasted disk space space due to
            the append-only B-tree design.

            It is generally recommended to set your own UUIDs, or use the
            sequential algorithm unless you have a specific need and take into
            account the likely need for compaction to re-balance the B-tree and
            reclaim wasted space.

    .. config:option:: utc_id_suffix :: UTC ID Suffix

        .. versionadded:: 1.3

        The ``utc_id_suffix`` value will be appended to UUIDs generated by the
        ``utc_id`` algorithm. Replicating instances should have unique
        ``utc_id_suffix`` values to ensure uniqueness of ``utc_id`` ids. ::

            [uuid]
            utc_id_suffix = my-awesome-suffix

    .. config:option:: max_count :: Per-Request UUID Limit

        .. versionadded:: 1.5.1

        No more than this number of UUIDs will be sent in a single request. If
        more UUIDs are requested, an HTTP error response will be thrown. ::

            [uuid]
            max_count = 1000

.. _config/vendor:

Vendor information
==================

.. config:section:: vendor :: Vendor information

    .. versionadded:: 1.3

    CouchDB distributors have the option of customizing CouchDB's welcome
    message. This is returned when requesting ``GET /``. ::

        [vendor]
        name = The Apache Software Foundation
        version = 1.5.0

.. _config/csp:

Content-Security-Policy
=======================

.. config:section:: csp :: Content-Security-Policy

    Experimental support of CSP Headers for ``/_utils`` (Fauxton).

    .. config:option:: enable

        Enable the sending of the Header ``Content-Security-Policy``::

            [csp]
            enable = true

    .. config:option:: header_value

        You can change the default value for the Header which is sent::

            [csp]
            header_value = default-src 'self'; img-src *; font-src *;

.. _config/purge:

Configuration of Database Purge
===============================

.. config:section:: purge :: Configuration of Database Purge

    .. config:option:: max_document_id_number

        .. versionadded:: 3.0

        Sets the maximum number of documents allowed in a single purge request::

            [purge]
            max_document_id_number = 100

    .. config:option:: max_revisions_number

        .. versionadded:: 3.0

        Sets the maximum number of accumulated revisions allowed in a single purge
        request::

            [purge]
            max_revisions_number = 1000

    .. config:option:: index_lag_warn_seconds

        .. versionadded:: 3.0

        Sets the allowed duration when index is not updated for local purge checkpoint
        document. Default is 24 hours::

            [purge]
            index_lag_warn_seconds = 86400
