Problem: Below query is slow query, minimum execution time is 3.x sec and as the category id increase in "IN" clause execution of query taking more that a minute.

QUERY:

explain SELECT a.* FROM label a INNER JOIN category_label c ON a.id = c.label_id INNER JOIN product_label p ON a.id = p.label_id INNER JOIN product p2 ON p.product_id = p2.id INNER JOIN category c2 ON p2.category_id = c2.id INNER JOIN category c3 ON (c2.lft BETWEEN c3.lft AND c3.rgt) INNER JOIN user u ON ((u.id = p2.user_id AND u.is_active = 1)) INNER JOIN country c4 ON (p2.country_id = c4.id) WHERE (c.category_id IN ('843', '848', '849', '853', '856', '858') AND a.is_filterable = 1 AND a.type <> "textarea" AND c2.rgt = (c2.lft + 1) AND c3.id IN ('843', '848', '849', '853', '856', '858') AND c4.id IN ('190') AND p2.status = 1) GROUP BY a.id ORDER BY a.sort_order

query explanation - ****** 1. row *** id: 1 select_type: SIMPLE table: c4 type: const possible_keys: PRIMARY key: PRIMARY key_len: 4 ref: const rows: 1 Extra: Using index; Using temporary; Using filesort *** 2. row *** id: 1 select_type: SIMPLE table: c3 type: range possible_keys: PRIMARY,lft_rgt_inx key: PRIMARY key_len: 4 ref: NULL rows: 6 Extra: Using where *** 3. row *** id: 1 select_type: SIMPLE table: c type: range possible_keys: PRIMARY,label_id,category_id key: PRIMARY key_len: 4 ref: NULL rows: 197 Extra: Using where; Using index; Using join buffer *** 4. row ****** id: 1 select_type: SIMPLE table: a type: eq_ref possible_keys: PRIMARY key: PRIMARY key_len: 4 ref: c.label_id rows: 1 Extra: Using where

****** 5. row *** id: 1 select_type: SIMPLE table: p type: ref possible_keys: product_id,label_id key: label_id key_len: 4 ref: c.label_id rows: 3827 Extra: *** 6. row *** id: 1 select_type: SIMPLE table: p2 type: eq_ref possible_keys: PRIMARY,category_id,user_id,country_id key: PRIMARY key_len: 8 ref: p.product_id rows: 1 Extra: Using where *** 7. row *** id: 1 select_type: SIMPLE table: c2 type: eq_ref possible_keys: PRIMARY,lft_rgt_inx key: PRIMARY key_len: 4 ref: p2.category_id rows: 1 Extra: Using where *** 8. row ****** id: 1 select_type: SIMPLE table: u type: eq_ref possible_keys: PRIMARY key: PRIMARY key_len: 4 ref: p2.user_id rows: 1 Extra: Using where

Show create table -

labelMaster ( id int(11) NOT NULL AUTO_INCREMENT, name varchar(255) NOT NULL, type varchar(50) NOT NULL COMMENT 'textbox, checkbox, selectbox, textarea', show_filter tinyint(1) NOT NULL DEFAULT '1', select_all_level int(11) NOT NULL, PRIMARY KEY (id) ) ENGINE=InnoDB

CREATE TABLE categoryMaster ( id int(11) NOT NULL AUTO_INCREMENT, parent_id int(11) NOT NULL DEFAULT '0', lft int(11) NOT NULL DEFAULT '0', rgt int(11) NOT NULL DEFAULT '0', level tinyint(4) NOT NULL DEFAULT '0', product_count int(11) NOT NULL, PRIMARY KEY (id), UNIQUE KEY lft_rgt_inx (lft,rgt), KEY parent_id (parent_id) ) ENGINE=InnoDB

CREATE TABLE productMaster ( id bigint(20) NOT NULL AUTO_INCREMENT, name varchar(255) NOT NULL, category_id int(11) NOT NULL, status tinyint(1) NOT NULL DEFAULT '-1' , user_id int(11) NOT NULL, label_value_ids varchar (255), product_source_url varchar(255) NOT NULL, country_id int(4) NOT NULL, state_id int(5) NOT NULL, PRIMARY KEY (id), KEY category_id (category_id), KEY user_id (user_id), KEY x_area_id (x_area_id), KEY state_id (state_id), KEY country_id (country_id), FULLTEXT KEY name (name), FULLTEXT KEY label_value_ids (label_value_ids) ) ENGINE=MyISAM

CREATE TABLE product_label ( id bigint(20) NOT NULL AUTO_INCREMENT, product_id bigint(20) NOT NULL, label_id int(11) NOT NULL, label_value varchar(1200) DEFAULT NULL, category_id int(11) NOT NULL, PRIMARY KEY (id), KEY product_id (product_id), KEY category_id (category_id), KEY label_id (label_id) ) ENGINE=InnoDB

CREATE TABLE label_values ( id int(11) NOT NULL AUTO_INCREMENT, label_id int(11) NOT NULL, value varchar(255) NOT NULL, sort_order smallint(6) NOT NULL DEFAULT '0', PRIMARY KEY (id), KEY label_id (label_id), CONSTRAINT label_values_ibfk_1 FOREIGN KEY (label_id) REFERENCES label (id) ON DELETE CASCADE ) ENGINE=InnoDB

CREATE TABLE category_label ( category_id int(11) NOT NULL, label_id int(11) NOT NULL, is_listview tinyint(1) NOT NULL, sort_order smallint(2) NOT NULL, PRIMARY KEY (category_id,label_id), KEY label_id (label_id), KEY category_id (category_id) ) ENGINE=MyISAM

Please suggest me how can i rewrite the qurey to reduce execution time and make website fast.

also I have tried to change database engine.

Please note: The query already using cache.