时间：2023-03-17 03:52:01 | 来源：电子商务
时间：2023-03-17 03:52:01 来源：电子商务
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SELECT * FROM information_schema.INNODB_FT_DEFAULT_STOPWORD;如+-------+ | value | +-------+ | a | | about | | an | | are | | as | | at | | be | | by | | com | | de | | en | | for | | from |SET GLOBAL sync_binlog=100;SET GLOBAL innodb_flush_log_at_trx_commit=2;3、导入1kw 数据进行测试全文索引CREATE TABLE `article` ( `id` bigint(10) NOT NULL, `url` varchar(1024) CHARACTER SET latin1 NOT NULL DEFAULT '', `title` varchar(256) NOT NULL DEFAULT '', `source` varchar(32) DEFAULT '' COMMENT '真实来源', `keywords` varchar(32) DEFAULT NULL, `publish_time` timestamp NULL DEFAULT NULL, PRIMARY KEY (`id`), KEY `title_idx` (`title`)) ENGINE=InnoDB使用myloader 多线程导入测试数据，先把测试数据进行解压tar -zxf mydumper_dump_article.tar.gztime myloader -u $user -p $passwd -S $socket -t 32 -d /datas/dump_article -v 35、导入数据后总数据量和数据文件、索引文件大小SELECT COUNT(*) FROM `article`;+----------+| COUNT(*) |+----------+| 10000000 |+----------+1 row in set (7.85 sec)SELECT table_name, CONCAT(FORMAT(SUM(data_length) / 1024 / 1024,2),'M') AS dbdata_size, CONCAT(FORMAT(SUM(index_length) / 1024 / 1024,2),'M') AS dbindex_size, CONCAT(FORMAT(SUM(data_length + index_length) / 1024 / 1024 / 1024,2),'G') AS `db_size(G)`, AVG_ROW_LENGTH,table_rows,update_time FROM information_schema.tables WHERE table_schema = DATABASE() and table_name='article';+------------+-------------+--------------+------------+----------------+------------+---------------------+| table_name | dbdata_size | dbindex_size | db_size(G) | AVG_ROW_LENGTH | table_rows | update_time |+------------+-------------+--------------+------------+----------------+------------+---------------------+| article | 3,710.00M | 1,003.00M | 4.60G | 414 | 9388739 | 2019-07-05 15:31:37 |+------------+-------------+--------------+------------+----------------+------------+---------------------+select keywords from article limit 10;+-------------------------------------------------+| keywords |+-------------------------------------------------+| NULL || NULL || ,婚姻,爱情 || 发型,偏分,化妆,时尚 || 小A, || ,服装搭配,女性,时尚 || 漂亮,女性 || 情人节,东莞,女性 || 皮肤,护肤,护肤,食品营养,美容,养生 || 三里屯,北京,时尚 |+-------------------------------------------------+2、不建全文索引时搜索某个关键词select count(*) from article where keywords like '%时尚%';+----------+| count(*) |+----------+| 163 |+----------+1 row in set (7.56 sec)3、对关键词字段创建全文索引（以 , 作为分词）[mysqld]innodb_ft_min_token_size=23.1 设置自定义stopwords（即分词）USE mysql;CREATE TABLE my_stopwords(VALUE VARCHAR(30)) ENGINE = INNODB;INSERT INTO my_stopwords(VALUE) VALUE (',');SET GLOBAL innodb_ft_server_stopword_table = 'mysql/my_stopwords';SHOW GLOBAL VARIABLES WHERE Variable_name IN('innodb_ft_min_token_size','innodb_ft_server_stopword_table');+---------------------------------+--------------------+| Variable_name | Value |+---------------------------------+--------------------+| innodb_ft_min_token_size | 2 || innodb_ft_server_stopword_table | mysql/my_stopwords |+---------------------------------+--------------------+3.2 创建全文索引alter table article add fulltext index idx_full_keyword(keywords);* [ ] Query OK, 0 rows affected, 1 warning (1 min 27.92 sec)* [ ] Records: 0 Duplicates: 0 Warnings: 13.3 剩余磁盘空间需足够，原表4.6G，剩余5.7G磁盘，添加全文索引也会失败df -hFilesystem Size Used Avail Use% Mounted on/dev/vda1 7.8G 6.3G 1.2G 85% /tmpfs 1.9G 0 1.9G 0% /dev/shm/dev/mapper/vg_opt-lvol0 19G 12G 5.7G 68% /datas会创建原表大小的临时文件 8.6K Jul 5 16:19 #sql-5250_3533.frm 4.4G Jul 5 16:20 #sql-ib117-1768830977.ibdalter table article add fulltext index idx_full_keyword(keywords);ERROR 1114 (HY000): The table 'article' is full3.4 利用创建的全文索引进行查询某个关键词出现的次数select count(*) from article where match(keywords) against('%时尚%');+----------+| count(*) |+----------+| 163 |+----------+1 row in set (0.05 sec)3.5 如需同时完全匹配多个关键词，用布尔全文搜索select count(*) from article where match(keywords) against('+三里屯,北京' in boolean mode);+----------+| count(*) |+----------+| 1 |+----------+1 row in set (0.06 sec)表示匹配“三里屯” 或者 “北京”的记录数select count(*) from article where match(keywords) against('三里屯,北京');+----------+| count(*) |+----------+| 8 |+----------+1 row in set (0.06 sec)3.6 创建全文索引后，会创建一些其它文件96K Jul 5 16:30 FTS_00000000000000a7_00000000000000c0_INDEX_1.ibd96K Jul 5 16:30 FTS_00000000000000a7_00000000000000c0_INDEX_2.ibd96K Jul 5 16:30 FTS_00000000000000a7_00000000000000c0_INDEX_3.ibd96K Jul 5 16:30 FTS_00000000000000a7_00000000000000c0_INDEX_4.ibd128K Jul 5 16:30 FTS_00000000000000a7_00000000000000c0_INDEX_5.ibd256K Jul 5 16:30 FTS_00000000000000a7_00000000000000c0_INDEX_6.ibd96K Jul 5 16:29 FTS_00000000000000a7_BEING_DELETED_CACHE.ibd96K Jul 5 16:29 FTS_00000000000000a7_BEING_DELETED.ibd96K Jul 5 16:30 FTS_00000000000000a7_CONFIG.ibd96K Jul 5 16:29 FTS_00000000000000a7_DELETED_CACHE.ibd96K Jul 5 16:29 FTS_00000000000000a7_DELETED.ibdselect title from article limit 10;+------------------------------------------------------------------------------+| title |+------------------------------------------------------------------------------+| worth IT ||Launchpad 江南皮革厂小show ||Raw 幕后罕见一刻 “疯子”被抬回后台 ||Raw:公子大骂老爸你就是个绿茶 公子以一打四 ||四组30平米精装小户型，海量图片，附户型图 ||夜店女王性感烟熏猫眼妆 ||大秀哥重摔“巨石”强森 ||少女时代 崔秀英 服饰科普 林允儿 黄美英 金泰妍 郑秀晶 | |德阳户外踏青，花田自助烧烤 |+------------------------------------------------------------------------------+2、对title字段创建全文索引alter table article add fulltext index ft_index_title(title) with parser ngram;Query OK, 0 rows affected (3 min 29.22 sec)Records: 0 Duplicates: 0 Warnings: 03、会创建倒排索引（title字段越长长，创建的倒排索引越大）112M Jul 5 21:46 FTS_00000000000000a7_00000000000000cd_INDEX_1.ibd28M Jul 5 21:46 FTS_00000000000000a7_00000000000000cd_INDEX_2.ibd20M Jul 5 21:46 FTS_00000000000000a7_00000000000000cd_INDEX_3.ibd140M Jul 5 21:46 FTS_00000000000000a7_00000000000000cd_INDEX_4.ibd128M Jul 5 21:46 FTS_00000000000000a7_00000000000000cd_INDEX_5.ibd668M Jul 5 21:46 FTS_00000000000000a7_00000000000000cd_INDEX_6.ibd4、不建立全文索引搜索title的某个关键词select count(*) from article where title like '%户外%';+----------+| count(*) |+----------+| 22058 |+----------+1 row in set (8.60 sec)select count(*) from article where title like '%后台%';+----------+| count(*) |+----------+| 1142 |+----------+5、使用全文索引搜索某个关键词select count(*) from article where match(title) against('户外');+----------+| count(*) |+----------+| 22058 |+----------+1 row in set (0.07 sec)select count(*) from article where title like '%后台%';+----------+| count(*) |+----------+| 1142 |+----------+1 row in set (8.31 sec)6、注意当搜索的关键词字符数大于2 （ngram_token_size定义大小）会出现不一致问题普通搜索，实际中出现该关键词的记录数为6select count(*) from article where title like '%公子大%';+----------+| count(*) |+----------+| 6 |+----------+1 row in set (8.40 sec)全文搜索，出现关键字的记录数为9443select count(*) from article where match(title) against('公子大');+----------+| count(*) |+----------+| 9443 |+----------+1 row in set (0.06 sec)实际出现该关键字的记录数为1select count(*) from article where title like '%花田自助%';+----------+| count(*) |+----------+| 1 |+----------+1 row in set (8.33 sec)全文搜索出现该关键词的记录数为3202select count(*) from article where match(title) against('花田自助');+----------+| count(*) |+----------+| 3202 |+----------+1 row in set (0.06 sec)关键词：索引,真是,实现,简单
