Mysql Fulltext Index with AND condition accross multiple tables is slow - mysql

Question

I have two huge tables (55M rows) with the following structure:
CREATE TABLE `chapters` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`toc` varchar(5000) COLLATE utf8mb4_unicode_ci NOT NULL,
`author` varchar(5000) COLLATE utf8mb4_unicode_ci NOT NULL,
`ari_id` bigint(20) NOT NULL,
PRIMARY KEY (`id`),
KEY `ari_id` (`ari_id`),
FULLTEXT KEY `toc` (`toc`),
FULLTEXT KEY `author` (`author`)
) ENGINE=InnoDB AUTO_INCREMENT=52251463 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci
CREATE TABLE `books` (
`ID` int(15) unsigned NOT NULL AUTO_INCREMENT,
`Title` varchar(2000) COLLATE utf8mb4_unicode_ci DEFAULT '',
`Author` varchar(2000) COLLATE utf8mb4_unicode_ci DEFAULT '',
`isOpenAccess` tinyint(1) NOT NULL,
`ari_id` bigint(20) NOT NULL,
PRIMARY KEY (`ID`),
UNIQUE KEY `ari_id` (`ari_id`),
FULLTEXT KEY `Title` (`Title`),
FULLTEXT KEY `Author` (`Author`),
) ENGINE=InnoDB AUTO_INCREMENT=2627161 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci
I am using the following query for searching:
SELECT b.ari_id, b.Title, b.Author, t.toc, t.author
FROM books b
INNER JOIN chapters t
ON b.ari_id = t.ari_id
WHERE MATCH(t.toc) AGAINST('power*' IN BOOLEAN MODE)
AND b.isOpenaccess = 1
LIMIT 300
It is returning the results in about 12 seconds. Is there any chance that I can speed up the response time?
Second when I try to search from two fulltext indexes using "AND" operator, it takes forever to respond (146 seconds). The query I am running is as follows:
SELECT toc, author
FROM tocs
WHERE MATCH(toc) AGAINST('high*' IN BOOLEAN MODE)
AND MATCH(author) AGAINST('max*' IN BOOLEAN MODE)
LIMIT 300

Answer 1

In books, ari_id could be the PRIMARY KEY and you could get rid of id. (This may or may not help performance.)
MySQL likes to run the FULLTEXT part of the WHERE first, then AND with the other tests.
This:
WHERE MATCH(toc) AGAINST('high*' IN BOOLEAN MODE)
AND MATCH(author) AGAINST('max*' IN BOOLEAN MODE)
can be sped up with FULLTEXT(toc, author) and
WHERE MATCH(toc, author) AGAINST('high* max*' IN BOOLEAN MODE)
But it will find extra rows. (Eg, the toc has both high and max, but author has neither.)
A similar trick is not possible when doing FT queries on each of two Joined tables.
OTOH, by having a 3rd table with all of columns, plus ari_id, would let you combine the tests into a single MATCH. Then follow by further refinement.