Skip to content

Commit

Permalink
Use "name" not "key"
Browse files Browse the repository at this point in the history
  • Loading branch information
kou committed Dec 24, 2024
1 parent ad49371 commit 3b9c918
Showing 1 changed file with 9 additions and 9 deletions.
18 changes: 9 additions & 9 deletions docs/source/format/StatisticsSchema.rst
Original file line number Diff line number Diff line change
Expand Up @@ -145,33 +145,33 @@ Here is the details of the ``map`` of the ``statistics``:
field by type code not name. So we can use any valid name for
fields.

.. _statistics-schema-key:
.. _statistics-schema-name:

Standard statistics
-------------------

Each statistic kind has a name that appears as a key in the statistics
map for each column or entire table. ``dictionary<values: utf8,
indices: int32>`` is used to encode the key for space-efficiency.
indices: int32>`` is used to encode the name for space-efficiency.

We assign different names for variations of the same statistic instead
of using flags. For example, we assign different statistic names for
exact and approximate values of the "distinct count" statistic.

The colon symbol ``:`` is to be used as a namespace separator like
:ref:`format_metadata`. It can be used multiple times in a key.
:ref:`format_metadata`. It can be used multiple times in a name.

The ``ARROW`` prefix is a reserved namespace for pre-defined statistic
names in current and future versions of this specification.
User-defined statistics must not use it. For example, you can use your
product name as namespace such as ``MY_PRODUCT:my_statistics:exact``.

Here are pre-defined statistics keys:
Here are pre-defined statistics names:

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

* - Key
* - Name
- Data type
- Notes
* - ``ARROW:average_byte_width:exact``
Expand Down Expand Up @@ -257,7 +257,7 @@ Statistics:
:header-rows: 1

* - Target
- Key
- Name
- Value
* - Record batch
- The number of rows
Expand Down Expand Up @@ -403,7 +403,7 @@ Statistics:
:header-rows: 1

* - Target
- Key
- Name
- Value
* - Record batch
- The number of rows
Expand Down Expand Up @@ -600,7 +600,7 @@ Statistics:
:header-rows: 1

* - Target
- Key
- Name
- Value
* - Array
- The number of rows
Expand Down Expand Up @@ -710,7 +710,7 @@ Statistics:
:header-rows: 1

* - Target
- Key
- Name
- Value
* - Array
- The number of rows
Expand Down

0 comments on commit 3b9c918

Please sign in to comment.