Unable to change query values in wordpress query.php - mysql

Question

My website having woo commerce theme is very slow in loading specially product summary page takes almost 3 minutes in loading.Now i want to change product summary page main query but unable to find way so that i will be able to change/optimize my query.Query output value is given below.I change $query in Query.php but when i execute page then there is no change in query and it is showing same query.Please guide if any other change is necessary.
Previous and new values in query.php are given below.
Previous value
$query = $wpdb->prepare("SELECT post_id
FROM $wpdb->postmeta, $wpdb->posts
WHERE ID = post_id
AND post_type = %s
AND meta_key = '_wp_old_slug'
AND meta_value = %s",
$post_type, $wp_query->query_vars['name']);
New value(want to use this value instead of above)
$query = $wpdb->prepare("SELECT post_id
FROM $wpdb->postmeta, $wpdb->posts
WHERE ID = post_id" );
Query value used for page data
SELECT SQL_CALC_FOUND_ROWS wp_bkkf_posts.ID
FROM wp_bkkf_posts
INNER JOIN wp_bkkf_postmeta
ON ( wp_bkkf_posts.ID = wp_bkkf_postmeta.post_id )
WHERE 1=1
AND ( ( wp_bkkf_postmeta.meta_key = '_visibility'
AND wp_bkkf_postmeta.meta_value IN ('visible','catalog') ) )
AND wp_bkkf_posts.post_type = 'product'
AND (wp_bkkf_posts.post_status = 'publish'
OR wp_bkkf_posts.post_status = 'private')
GROUP BY wp_bkkf_posts.ID
ORDER BY wp_bkkf_posts.menu_order ASC, wp_bkkf_posts.post_title ASC
LIMIT 0, 12
Actually i don't want to use following values in query.
AND ( ( wp_bkkf_postmeta.meta_key = '_visibility'
AND wp_bkkf_postmeta.meta_value IN ('visible','catalog') ) )
AND wp_bkkf_posts.post_type = 'product'
AND (wp_bkkf_posts.post_status = 'publish'
OR wp_bkkf_posts.post_status = 'private')
Show create table output is given below
CREATE TABLE `wp_bkkf_postmeta` (
`meta_id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
`post_id` bigint(20) unsigned NOT NULL DEFAULT '0',
`meta_key` varchar(255) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
`meta_value` longtext COLLATE utf8mb4_unicode_ci,
PRIMARY KEY (`meta_id`),
KEY `post_id` (`post_id`),
KEY `meta_key` (`meta_key`(191))
) ENGINE=MyISAM AUTO_INCREMENT=30883570 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci
CREATE TABLE `wp_bkkf_posts` (
`ID` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
`post_author` bigint(20) unsigned NOT NULL DEFAULT '0',
`post_date` datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
`post_date_gmt` datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
`post_content` longtext COLLATE utf8mb4_unicode_ci NOT NULL,
`post_title` text COLLATE utf8mb4_unicode_ci NOT NULL,
`post_excerpt` text COLLATE utf8mb4_unicode_ci NOT NULL,
`post_status` varchar(20) COLLATE utf8mb4_unicode_ci NOT NULL DEFAULT 'publish',
`comment_status` varchar(20) COLLATE utf8mb4_unicode_ci NOT NULL DEFAULT 'open',
`ping_status` varchar(20) COLLATE utf8mb4_unicode_ci NOT NULL DEFAULT 'open',
`post_password` varchar(20) COLLATE utf8mb4_unicode_ci NOT NULL DEFAULT '',
`post_name` varchar(200) COLLATE utf8mb4_unicode_ci NOT NULL DEFAULT '',
`to_ping` text COLLATE utf8mb4_unicode_ci NOT NULL,
`pinged` text COLLATE utf8mb4_unicode_ci NOT NULL,
`post_modified` datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
`post_modified_gmt` datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
`post_content_filtered` longtext COLLATE utf8mb4_unicode_ci NOT NULL,
`post_parent` bigint(20) unsigned NOT NULL DEFAULT '0',
`guid` varchar(255) COLLATE utf8mb4_unicode_ci NOT NULL DEFAULT '',
`menu_order` int(11) NOT NULL DEFAULT '0',
`post_type` varchar(20) COLLATE utf8mb4_unicode_ci NOT NULL DEFAULT 'post',
`post_mime_type` varchar(100) COLLATE utf8mb4_unicode_ci NOT NULL DEFAULT '',
`comment_count` bigint(20) NOT NULL DEFAULT '0',
PRIMARY KEY (`ID`),
KEY `post_name` (`post_name`(191)),
KEY `type_status_date` (`post_type`,`post_status`,`post_date`,`ID`),
KEY `post_parent` (`post_parent`),
KEY `post_author` (`post_author`),
KEY `post_idx` (`post_type`,`post_status`)
) ENGINE=MyISAM AUTO_INCREMENT=1556181 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci
If anyone have idea regarding $query value change then please guide,also please share other file names where change required..thanks.

Answer 1

SELECT MAX(CHAR_LENGTH(meta_key)) FROM wp_bkkf_postmeta;
If that comes out less than 191, then do these:
ALTER TABLE wp_bkkf_postmeta
MODIFY `meta_key` varchar(191) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
DROP KEY `post_id`,
ADD INDEX pm (post_id, meta_key);
Consider getting rid of SQL_CALC_FOUND_ROWS; it probably is a slowdown. However losing that will lose the "out of ..." clause on the page.
If you toss the entire WHERE then the JOIN and GROUP BY can go away, too:
SELECT SQL_CALC_FOUND_ROWS wp_bkkf_posts.ID
FROM wp_bkkf_posts
ORDER BY wp_bkkf_posts.menu_order ASC, wp_bkkf_posts.post_title ASC
LIMIT 0, 12
That will run faster. Still, it will need to scan the entire 1.5 million row table. Why you would want that particular ORDER BY?