Kouhei Sutou
null+****@clear*****
Thu Dec 27 17:09:28 JST 2012
Kouhei Sutou 2012-12-27 17:09:28 +0900 (Thu, 27 Dec 2012) New Revision: ab19ae95cc39fe3aa9b3a4dd8e0c287c16dce429 https://github.com/groonga/groonga/commit/ab19ae95cc39fe3aa9b3a4dd8e0c287c16dce429 Log: doc: add documentation about tables Added files: doc/source/reference/tables.txt Modified files: doc/source/reference.txt Modified: doc/source/reference.txt (+1 -0) =================================================================== --- doc/source/reference.txt 2012-12-27 11:28:28 +0900 (87e1492) +++ doc/source/reference.txt 2012-12-27 17:09:28 +0900 (613a1c1) @@ -12,6 +12,7 @@ reference/output reference/command reference/type + reference/tables reference/tokenizers reference/query_expanders reference/pseudo_column Added: doc/source/reference/tables.txt (+108 -0) 100644 =================================================================== --- /dev/null +++ doc/source/reference/tables.txt 2012-12-27 17:09:28 +0900 (53aaae6) @@ -0,0 +1,108 @@ +.. -*- rst -*- + +.. highlightlang:: none + +Tables +====== + +Summary +------- + +Table in groonga manages relation between ID and key. Table provides +both fast ID search by key and fast key search by ID. + +Groonga provides four table types. They are ``TABLE_NO_KEY``, +``TABLE_HASH_KEY``, ``TABLE_PAT_KEY`` and ``TABLE_DAT_KEY``. + +Characteristics +--------------- + +Here is a chracteristic table of all tables in groonga. (``TABLE_`` +prefix is omitted in the table.) + ++--------------+------------+--------------+-------------+-------------+ +| | ``NO_KEY`` | ``HASH_KEY`` | ``PAT_KEY`` | ``DAT_KEY`` | ++--------------+------------+--------------+-------------+-------------+ +| Data | Array | Hash table | Patricia | Double | +| structure | | | trie | array | +| | | | | trie | ++--------------+------------+--------------+-------------+-------------+ +| ID | o | o | o | o | +| support | | | | | ++--------------+------------+--------------+-------------+-------------+ +| Key | x | o | o | o | +| support | | | | | ++--------------+------------+--------------+-------------+-------------+ +| Value | o | o | o | x | +| support | | | | | ++--------------+------------+--------------+-------------+-------------+ +| Key -> ID | - | oo | x | o | +| speed | | | | | +| (o -> fast) | | | | | +| (x -> slow) | | | | | ++--------------+------------+--------------+-------------+-------------+ +| Update | ooo | o | o | x | +| speed | | | | | +| (o -> fast) | | | | | +| (x -> slow) | | | | | ++--------------+------------+--------------+-------------+-------------+ +| Size | ooo | o | oo | x | +| (o -> small) | | | | | +| (x -> large) | | | | | ++--------------+------------+--------------+-------------+-------------+ +| Key | - | x | x | o | +| update | | | | | ++--------------+------------+--------------+-------------+-------------+ +| Common | - | x | o | o | +| prefix | | | | | +| search | | | | | ++--------------+------------+--------------+-------------+-------------+ +| Predictive | - | x | o | o | +| search | | | | | ++--------------+------------+--------------+-------------+-------------+ + +``TABLE_NO_KEY`` +^^^^^^^^^^^^^^^^ + +``TABLE_NO_KEY`` is very fast and very small but it doesn't support +key. ``TABLE_NO_KEY`` is a only table that doesn't support key. + +You cannot use ``TABLE_NO_KEY`` for lexicon for fulltext search +because lexicon stores tokens as key. ``TABLE_NO_KEY`` is useful for +no key records such as log. + +``TABLE_HASH_KEY`` +^^^^^^^^^^^^^^^^ + +``TABLE_HASH_KEY`` is fast but it doesn't support advanced search +functions such as common prefix search and predictive search. + +``TABLE_HASH_KEY`` is useful for index for exact search such as tag +search. + +``TABLE_PAT_KEY`` +^^^^^^^^^^^^^^^^ + +``TABLE_PAT_KEY`` is small and supports advanced search functions. + +``TABLE_PAT_KEY`` is useful for lexicon for fulltext search and +index for range search. + +``TABLE_DAT_KEY`` +^^^^^^^^^^^^^^^^ + +``TABLE_DAT_KEY`` is fast and supports key update but it is large. It +is not suitable for storing many records. ``TABLE_DAT_KEY`` is a only +table that supports key update. + +``TABLE_DAT_KEY`` is used in groonga database. Groonga database needs +to convert object name such as ``ShortText``, ``TokenBigram`` and +table names to object ID. And groonga database needs to rename object +name. Those features are implemented by ``TABLE_DAT_KEY``. The number +of objects is small. So large data size demerit of ``TABLE_DAT_KEY`` +can be ignored. + +See also +-------- + +* :doc:`/reference/commands/table_create` -------------- next part -------------- HTML����������������������������...Télécharger
