ALTER TABLE index ADD COLUMN column_name [{INTEGER|INT|BIGINT|FLOAT|BOOL|MULTI|MULTI64|JSON|STRING|TIMESTAMP|TEXT [INDEXED [ATTRIBUTE]]}] [engine='columnar']
ALTER TABLE index DROP COLUMN column_nameIt supports adding one field at a time for RT indexes. Supported data types are:
int- integer attributetimestamp- timestamp attributebigint- big integer attributefloat- float attributebool- boolean attributemulti- multi-valued integer attributemulti64- multi-valued bigint attributejson- json attributestring/text attribute/string attribute- string attributetext/text indexed stored/string indexed stored- full-text indexed field with original value stored in docstoretext indexed/string indexed- full-text indexed field, indexed only (the original value is not stored in docstore)text indexed attribute/string indexed attribute- full text indexed field + string attribute (not storing the original value in docstore)text stored/string stored- the value will be only stored in docstore, not full-text indexed, not a string attribute- adding
engine='columnar'to any attribute (except for json) will make it stored in the columnar storage
- Querying an index is impossible while a column is being added.
- Newly created attribute's values are set to 0.
ALTERwill not work for distributed indexes and indexes without any attributes.DROP COLUMNwill fail if an index has only one field.- When dropping a field which is both a full-text field and a string attribute the first
ALTER DROPdrops the attribute, the second one drops the full-text field. - Adding/dropping full-text field is only supported in RT mode.
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- Example
Example
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⚙
mysql> desc rt;
+------------+-----------+
| Field | Type |
+------------+-----------+
| id | bigint |
| text | field |
| group_id | uint |
| date_added | timestamp |
+------------+-----------+
mysql> alter table rt add column test integer;
mysql> desc rt;
+------------+-----------+
| Field | Type |
+------------+-----------+
| id | bigint |
| text | field |
| group_id | uint |
| date_added | timestamp |
| test | uint |
+------------+-----------+
mysql> alter table rt drop column group_id;
mysql> desc rt;
+------------+-----------+
| Field | Type |
+------------+-----------+
| id | bigint |
| text | field |
| date_added | timestamp |
| test | uint |
+------------+-----------+
mysql> alter table rt add column title text indexed;
mysql> desc rt;
+------------+-----------+------------+
| Field | Type | Properties |
+------------+-----------+------------+
| id | bigint | |
| text | text | indexed |
| title | text | indexed |
| date_added | timestamp | |
| test | uint | |
+------------+-----------+------------+
mysql> alter table rt add column title text attribute;
mysql> desc rt;
+------------+-----------+------------+
| Field | Type | Properties |
+------------+-----------+------------+
| id | bigint | |
| text | text | indexed |
| title | text | indexed |
| date_added | timestamp | |
| test | uint | |
| title | string | |
+------------+-----------+------------+
mysql> alter table rt drop column title;
mysql> desc rt;
+------------+-----------+------------+
| Field | Type | Properties |
+------------+-----------+------------+
| id | bigint | |
| text | text | indexed |
| title | text | indexed |
| date_added | timestamp | |
| test | uint | |
+------------+-----------+------------+
mysql> alter table rt drop column title;
mysql> desc rt;
+------------+-----------+------------+
| Field | Type | Properties |
+------------+-----------+------------+
| id | bigint | |
| text | text | indexed |
| date_added | timestamp | |
| test | uint | |
+------------+-----------+------------+ALTER RTINDEX index RECONFIGUREALTER can also reconfigure an RT index in plain mode, so that new tokenization, morphology and other text processing settings from the configuration file take effect on the newly INSERT-ed rows, while retaining the existing rows as they were. Internally, it forcibly saves the current RAM chunk as a new disk chunk and adjusts the index header, so that the new rows are tokenized using the new rules.
‹›
- Example
Example
📋
⚙
mysql> show index rt settings;
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| settings | |
+---------------+-------+
1 row in set (0.00 sec)
mysql> alter rtindex rt reconfigure;
Query OK, 0 rows affected (0.00 sec)
mysql> show index rt settings;
+---------------+----------------------+
| Variable_name | Value |
+---------------+----------------------+
| settings | morphology = stem_en |
+---------------+----------------------+
1 row in set (0.00 sec)