INNODB_FT_INDEX_CACHE: Contains token
information about newly inserted rows in a
FULLTEXT index. To avoid expensive index
reorganization during DML operations, the information about newly
indexed words is stored separately, and combined with the main
search index only when OPTIMIZE
TABLE is run, when the server is shut down, or when the
cache size exceeds a limit defined by
innodb_ft_cache_size or
innodb_ft_total_cache_size.
Before you query this table, set the configuration variable
innodb_ft_aux_table to the name
(including the database name) of the table that contains the
FULLTEXT index, for example
test/articles.
For related usage information and examples, see Section 14.15.4, “InnoDB INFORMATION_SCHEMA FULLTEXT Index Tables”.
Table 21.11 INNODB_FT_INDEX_CACHE Columns
| Column name | Description |
|---|---|
WORD | A word extracted from the text of a newly inserted row. |
FIRST_DOC_ID | The first document ID that this word appears in the
FULLTEXT index. |
LAST_DOC_ID | The last document ID that this word appears in the
FULLTEXT index. |
DOC_COUNT | The number of rows this word appears in the FULLTEXT
index. The same word can occur several times within the
cache table, once for each combination of
DOC_ID and POSITION
values. |
DOC_ID | The document ID of the newly inserted row. This value might reflect the
value of an ID column that you defined for the underlying
table, or it can be a sequence value generated by
InnoDB when the table does not contain
a suitable column. |
POSITION | The position of this particular instance of the word within the relevant
document identified by the DOC_ID
value. The value does not represent an absolute position;
it is an offset added to the POSITION
of the previous instance of that word. |
Notes:
This table initially appears empty, until you set the value of
the configuration variable
innodb_ft_aux_table. The
following example demonstrates how to use the
innodb_ft_aux_table option to
show information about a FULLTEXT index for
a specified table.
mysql>USE test;mysql>CREATE TABLE articles ( id INT UNSIGNED AUTO_INCREMENT NOT NULL PRIMARY KEY, title VARCHAR(200), body TEXT, FULLTEXT (title,body) ) ENGINE=InnoDB;mysql>INSERT INTO articles (title,body) VALUES ('MySQL Tutorial','DBMS stands for DataBase ...'), ('How To Use MySQL Well','After you went through a ...'), ('Optimizing MySQL','In this tutorial we will show ...'), ('1001 MySQL Tricks','1. Never run mysqld as root. 2. ...'), ('MySQL vs. YourSQL','In the following database comparison ...'), ('MySQL Security','When configured properly, MySQL ...');mysql>SET GLOBAL innodb_ft_aux_table = 'test/articles';Query OK, 0 rows affected (0.00 sec) mysql>USE INFORMATION_SCHEMA;mysql>SELECT word, doc_count, doc_id, position FROM INNODB_FT_INDEX_CACHE LIMIT 5;+------------+-----------+--------+----------+ | word | doc_count | doc_id | position | +------------+-----------+--------+----------+ | 1001 | 1 | 4 | 0 | | after | 1 | 2 | 22 | | comparison | 1 | 5 | 44 | | configured | 1 | 6 | 20 | | database | 2 | 1 | 31 | +------------+-----------+--------+----------+
Use DESCRIBE or
SHOW COLUMNS to view additional
information about the columns of this table including data
types and default values.
You must have the PROCESS
privilege to query this table.
For more information about InnoDB
FULLTEXT search, see
Section 14.8.10, “InnoDB FULLTEXT Indexes”, and
Section 12.9, “Full-Text Search Functions”.