## With ngram_token_size=3
## with MyISAM

bin/mysql -uroot -S /tmp/mysql_ushastry.sock
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mysql> show variables like '%token%';
create database if not exists test;
use test;
drop table if exists fts_test;
CREATE TABLE fts_test(
  code varchar(20) NOT NULL,
  name varchar(80) NOT NULL,
  PRIMARY KEY (code),
  FULLTEXT KEY fx_name(name) WITH PARSER ngram
) ENGINE=myisam;
+--------------------------+-------+
| Variable_name            | Value |
+--------------------------+-------+
| innodb_ft_max_token_size | 84    |
| innodb_ft_min_token_size | 3     |
| ngram_token_size         | 3     |
+--------------------------+-------+
3 rows in set (0.00 sec)

mysql> create database if not exists test;
Query OK, 1 row affected (0.00 sec)

mysql> use test;
Database changed
mysql> drop table if exists fts_test;
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> CREATE TABLE fts_test(
    ->   code varchar(20) NOT NULL,
    ->   name varchar(80) NOT NULL,
    ->   PRIMARY KEY (code),
    ->   FULLTEXT KEY fx_name(name) WITH PARSER ngram
    -> ) ENGINE=myisam;
Query OK, 0 rows affected (0.00 sec)

mysql>
mysql> insert into fts_test values ('WEL','WELLINGTON');
insert into fts_test values ('WFD','WHITEFIELD');
insert into fts_test values ('YGL','YELGUR');
insert into fts_test values ('YNK','YELHANKA JN');
insert into fts_test values ('DLI','DELHI');
insert into fts_test values ('DAZ','DELHI AZADPUR');
Query OK, 1 row affected (0.01 sec)

mysql> insert into fts_test values ('WFD','WHITEFIELD');
Query OK, 1 row affected (0.00 sec)

mysql> insert into fts_test values ('YGL','YELGUR');
Query OK, 1 row affected (0.00 sec)

mysql> insert into fts_test values ('YNK','YELHANKA JN');
Query OK, 1 row affected (0.00 sec)

mysql> insert into fts_test values ('DLI','DELHI');
Query OK, 1 row affected (0.00 sec)

mysql> insert into fts_test values ('DAZ','DELHI AZADPUR');
Query OK, 1 row affected (0.00 sec)

mysql> select * from fts_test where match(name) against ('DEL' in boolean mode);
+------+---------------+
| code | name          |
+------+---------------+
| DLI  | DELHI         |
| DAZ  | DELHI AZADPUR |
+------+---------------+
2 rows in set (0.00 sec)

mysql> select * from fts_test where match(name) against ('YEL' in boolean mode);
+------+-------------+
| code | name        |
+------+-------------+
| YGL  | YELGUR      |
| YNK  | YELHANKA JN |
+------+-------------+
2 rows in set (0.00 sec)

mysql> select * from fts_test where match(name) against ('WEL' in boolean mode);
+------+------------+
| code | name       |
+------+------------+
| WEL  | WELLINGTON |
+------+------------+
1 row in set (0.00 sec)

## With Innodb


mysql> create database if not exists test;
select * from fts_test where match(name) against ('YEL' in boolean mode);
select * from fts_test where match(name) against ('WEL' in booQuery OK, 1 row affected, 1 warning (0.00 sec)
l
ean mode);mysql> use test;
Database changed
mysql> drop table if exists fts_test;
Query OK, 0 rows affected (0.00 sec)

mysql> CREATE TABLE fts_test(
    ->   code varchar(20) NOT NULL,
    ->   name varchar(80) NOT NULL,
    ->   PRIMARY KEY (code),
    ->   FULLTEXT KEY fx_name(name) WITH PARSER ngram
    -> ) ENGINE=innodb;
Query OK, 0 rows affected (0.02 sec)

mysql>
mysql> insert into fts_test values ('WEL','WELLINGTON');
Query OK, 1 row affected (0.00 sec)

mysql> insert into fts_test values ('WFD','WHITEFIELD');
Query OK, 1 row affected (0.00 sec)

mysql> insert into fts_test values ('YGL','YELGUR');
Query OK, 1 row affected (0.00 sec)

mysql> insert into fts_test values ('YNK','YELHANKA JN');
Query OK, 1 row affected (0.00 sec)

mysql> insert into fts_test values ('DLI','DELHI');
Query OK, 1 row affected (0.00 sec)

mysql> insert into fts_test values ('DAZ','DELHI AZADPUR');
Query OK, 1 row affected (0.00 sec)

mysql>
mysql> select * from fts_test where match(name) against ('DEL' in boolean mode);
Empty set (0.00 sec)

mysql> select * from fts_test where match(name) against ('YEL' in boolean mode);
+------+-------------+
| code | name        |
+------+-------------+
| YGL  | YELGUR      |
| YNK  | YELHANKA JN |
+------+-------------+
2 rows in set (0.00 sec)

mysql> select * from fts_test where match(name) against ('WEL' in boolean mode);
+------+------------+
| code | name       |
+------+------------+
| WEL  | WELLINGTON |
+------+------------+
1 row in set (0.00 sec)

## With ngram_token_size=2 i.e default

- with myisam
mysql> CREATE TABLE fts_test(
    ->   code varchar(20) NOT NULL,
    ->   name varchar(80) NOT NULL,
    ->   PRIMARY KEY (code),
    ->   FULLTEXT KEY fx_name(name) WITH PARSER ngram
    -> ) ENGINE=myisam;
select * from fts_test where match(name) against ('DEL' in boolean mode);
select * from fts_test where match(name) against ('YEL' in boolean mode);
select * from fts_test where match(name) against ('WEL' in boolean mode);Query OK, 0 rows affected (0.00 sec)

mysql>
mysql> insert into fts_test values ('WEL','WELLINGTON');
Query OK, 1 row affected (0.00 sec)

mysql> insert into fts_test values ('WFD','WHITEFIELD');
Query OK, 1 row affected (0.00 sec)

mysql> insert into fts_test values ('YGL','YELGUR');
Query OK, 1 row affected (0.00 sec)

mysql> insert into fts_test values ('YNK','YELHANKA JN');
Query OK, 1 row affected (0.00 sec)

mysql> insert into fts_test values ('DLI','DELHI');
Query OK, 1 row affected (0.00 sec)

mysql> insert into fts_test values ('DAZ','DELHI AZADPUR');
Query OK, 1 row affected (0.00 sec)

mysql>
mysql> select * from fts_test where match(name) against ('DEL' in boolean mode);
+------+---------------+
| code | name          |
+------+---------------+
| WEL  | WELLINGTON    |
| WFD  | WHITEFIELD    |
| YGL  | YELGUR        |
| YNK  | YELHANKA JN   |
| DLI  | DELHI         |
| DAZ  | DELHI AZADPUR |
+------+---------------+
6 rows in set (0.00 sec)

mysql> select * from fts_test where match(name) against ('YEL' in boolean mode);
+------+---------------+
| code | name          |
+------+---------------+
| WEL  | WELLINGTON    |
| WFD  | WHITEFIELD    |
| YGL  | YELGUR        |
| YNK  | YELHANKA JN   |
| DLI  | DELHI         |
| DAZ  | DELHI AZADPUR |
+------+---------------+
6 rows in set (0.00 sec)

mysql> select * from fts_test where match(name) against ('WEL' in boolean mode);
+------+---------------+
| code | name          |
+------+---------------+
| WEL  | WELLINGTON    |
| WFD  | WHITEFIELD    |
| YGL  | YELGUR        |
| YNK  | YELHANKA JN   |
| DLI  | DELHI         |
| DAZ  | DELHI AZADPUR |
+------+---------------+
6 rows in set (0.00 sec)

- with innodb

mysql> CREATE TABLE fts_test(
    ->   code varchar(20) NOT NULL,
    ->   name varchar(80) NOT NULL,
    ->   PRIMARY KEY (code),
    ->   FULLTEXT KEY fx_name(name) WITH PARSER ngram
    -> ) ENGINE=innodb;
Query OK, 0 rows affected (0.02 sec)

mysql>
mysql> insert into fts_test values ('WEL','WELLINGTON');
Query OK, 1 row affected (0.01 sec)

mysql> insert into fts_test values ('WFD','WHITEFIELD');
Query OK, 1 row affected (0.00 sec)

mysql> insert into fts_test values ('YGL','YELGUR');
Query OK, 1 row affected (0.00 sec)

mysql> insert into fts_test values ('YNK','YELHANKA JN');
Query OK, 1 row affected (0.00 sec)

mysql> insert into fts_test values ('DLI','DELHI');
Query OK, 1 row affected (0.00 sec)

mysql> insert into fts_test values ('DAZ','DELHI AZADPUR');
Query OK, 1 row affected (0.00 sec)

mysql>
mysql> select * from fts_test where match(name) against ('DEL' in boolean mode);
+------+---------------+
| code | name          |
+------+---------------+
| WEL  | WELLINGTON    |
| WFD  | WHITEFIELD    |
| YGL  | YELGUR        |
| YNK  | YELHANKA JN   |
| DLI  | DELHI         |
| DAZ  | DELHI AZADPUR |
+------+---------------+
6 rows in set (0.00 sec)

mysql> select * from fts_test where match(name) against ('YEL' in boolean mode);
+------+-------------+
| code | name        |
+------+-------------+
| YGL  | YELGUR      |
| YNK  | YELHANKA JN |
+------+-------------+
2 rows in set (0.00 sec)

mysql> select * from fts_test where match(name) against ('WEL' in boolean mode);
+------+------------+
| code | name       |
+------+------------+
| WEL  | WELLINGTON |
+------+------------+
1 row in set (0.00 sec)

## Workaround is to use own stopword list for all InnoDB tables
################## we have FR Bug #84420 already for this

mysql> create database test;
Query OK, 1 row affected (0.00 sec)

mysql> use test
Database changed
mysql> CREATE TABLE my_stopwords(value VARCHAR(30)) ENGINE = INNODB;
Query OK, 0 rows affected (0.00 sec)

mysql> SET GLOBAL innodb_ft_server_stopword_table = 'test/my_stopwords';
Query OK, 0 rows affected (0.00 sec)

mysql> show variables like '%token%';
use test;
drop table if exists fts_test;
CREATE TABLE fts_test(
  code varchar(20) NOT NULL,
+--------------------------+-------+
| Variable_name            | Value |
+--------------------------+-------+
| innodb_ft_max_token_size | 84    |
| innodb_ft_min_token_size | 3     |
| ngram_token_size         | 2     |
+--------------------------+-------+
3 rows in set (0.00 sec)

mysql> create database if not exists test;
Query OK, 1 row affected, 1 warning (0.00 sec)

mysql> use test;
Database changed
mysql> drop table if exists fts_test;
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> CREATE TABLE fts_test(
    ->   code varchar(20) NOT NULL,
    ->   name varchar(80) NOT NULL,
    ->   PRIMARY KEY (code),
    ->   FULLTEXT KEY fx_name(name) WITH PARSER ngram
    -> ) ENGINE=innodb;
insert into fts_test values ('WEL','WELLINGTON');
insert into fts_test values ('WFD','WHITEFIELD');
insert into fts_test values ('YGL','YELGUR');
insert into fts_test values ('YNK','YELHANKA JN');
insert into fts_test values ('DLI','DELHI');
insert into fts_test values ('DAZ','DELHI AZADPUR');

select * from fts_test where match(name) against ('DEL' in boolean mode);
select * from fts_test where match(name) against ('YEL' in boolean mode);
select * from fts_test where match(name) against ('WEL' in boolean mode);Query OK, 0 rows affected (0.01 sec)

mysql>
mysql> insert into fts_test values ('WEL','WELLINGTON');
Query OK, 1 row affected (0.01 sec)

mysql> insert into fts_test values ('WFD','WHITEFIELD');
Query OK, 1 row affected (0.00 sec)

mysql> insert into fts_test values ('YGL','YELGUR');
Query OK, 1 row affected (0.00 sec)

mysql> insert into fts_test values ('YNK','YELHANKA JN');
Query OK, 1 row affected (0.00 sec)

mysql> insert into fts_test values ('DLI','DELHI');
Query OK, 1 row affected (0.00 sec)

mysql> insert into fts_test values ('DAZ','DELHI AZADPUR');
Query OK, 1 row affected (0.00 sec)

mysql>
mysql> select * from fts_test where match(name) against ('DEL' in boolean mode);
+------+---------------+
| code | name          |
+------+---------------+
| DLI  | DELHI         |
| DAZ  | DELHI AZADPUR |
+------+---------------+
2 rows in set (0.00 sec)

mysql> select * from fts_test where match(name) against ('YEL' in boolean mode);
+------+-------------+
| code | name        |
+------+-------------+
| YGL  | YELGUR      |
| YNK  | YELHANKA JN |
+------+-------------+
2 rows in set (0.00 sec)

mysql> select * from fts_test where match(name) against ('WEL' in boolean mode);
+------+------------+
| code | name       |
+------+------------+
| WEL  | WELLINGTON |
+------+------------+
1 row in set (0.00 sec)