Information Schema INNODB_FT_INDEX_TABLE Table

The Information Schema INNODB_FT_INDEX_TABLE table contains information about InnoDB fulltext indexes. To avoid re-organizing the fulltext index each time a change is made, which would be very expensive, new changes are stored separately and only integrated when an OPTIMIZE TABLE is run. See the INNODB_FT_INDEX_CACHE table.

The SUPER privilege is required to view the table, and it also requires the innodb_ft_aux_table system variable to be set.

It has the following columns:

ColumnDescription
WORDWord from the text of a column with a fulltext index. Words can appear multiple times in the table, once per DOC_ID and POSITION combination.
FIRST_DOC_IDFirst document ID where this word appears in the index.
LAST_DOC_IDLast document ID where this word appears in the index.
DOC_COUNTNumber of rows containing this word in the index.
DOC_IDDocument ID of the newly added row, either an appropriate ID column or an internal InnoDB value.
POSITIONPosition of this word instance within the DOC_ID, as an offset added to the previous POSITION instance.

Note that for OPTIMIZE TABLE to process InnoDB fulltext index data, the innodb_optimize_fulltext_only system variable needs to be set to 1. When this is done, and an OPTIMIZE TABLE statement run, the INNODB_FT_INDEX_CACHE table will be emptied, and the INNODB_FT_INDEX_TABLE table will be updated.

Examples

SELECT * FROM INNODB_FT_INDEX_TABLE;
Empty set (0.00 sec)

SET GLOBAL innodb_optimize_fulltext_only =1;

OPTIMIZE TABLE test.ft_innodb;
+----------------+----------+----------+----------+
| Table          | Op       | Msg_type | Msg_text |
+----------------+----------+----------+----------+
| test.ft_innodb | optimize | status   | OK       |
+----------------+----------+----------+----------+

SELECT * FROM INNODB_FT_INDEX_TABLE;
+------------+--------------+-------------+-----------+--------+----------+
| WORD       | FIRST_DOC_ID | LAST_DOC_ID | DOC_COUNT | DOC_ID | POSITION |
+------------+--------------+-------------+-----------+--------+----------+
| and        |            4 |           5 |         2 |      4 |        0 |
| and        |            4 |           5 |         2 |      5 |        0 |
| arrived    |            4 |           4 |         1 |      4 |       20 |
| ate        |            1 |           5 |         2 |      1 |        4 |
| ate        |            1 |           5 |         2 |      5 |        8 |
| everybody  |            1 |           1 |         1 |      1 |        8 |
| goldilocks |            4 |           4 |         1 |      4 |        9 |
| hungry     |            3 |           3 |         1 |      3 |        8 |
| pear       |            5 |           5 |         1 |      5 |       14 |
| she        |            5 |           5 |         1 |      5 |        4 |
| then       |            4 |           4 |         1 |      4 |        4 |
| wicked     |            2 |           2 |         1 |      2 |        4 |
| witch      |            2 |           2 |         1 |      2 |       11 |
+------------+--------------+-------------+-----------+--------+----------+
Content reproduced on this site is the property of its respective owners, and this content is not reviewed in advance by MariaDB. The views, information and opinions expressed by this content do not necessarily represent those of MariaDB or any other party.