为什么WP_Query的's'=>'keyword'只搜索'post_title'，为什么不搜索'post_content'？

Question

I am writing a search query for my custom post. I am using search parameter of WP_Query for this then it has to search for both 'post_title' & 'post_content' but it is searching only for 'post_title' and not searching the 'post_content'. below is my code :

 $institute_name = get_user_meta($user_ID, 'inistitute_name', true);
 add_filter( 'posts_where' , array($this,'posts_where' ));
 $paged = (get_query_var('page')) ? get_query_var('page') : 1;
         $args = array(
            'post_type' => 'mypost',
            array( 's' => $keyword ),
            'meta_query' => array (
                array (
                  'key' => 'inistitute_name',
                  'value' => array ($institute_name),
                  'compare' => 'IN'
                )
            ),
            'posts_per_page' => -1,
            'paged' => $paged,
            'post_status' => 'publish',
            );
$the_query = new WP_Query($args);
remove_filter( 'posts_where',  array($this,'posts_where' ));
echo "<pre>";
print_r($the_query);
echo "</pre>";

If I print that result then I am getting the query like below:

SELECT wp_dxwe_posts.* FROM wp_dxwe_posts INNER JOIN wp_dxwe_postmeta ON 
( wp_dxwe_posts.ID = wp_dxwe_postmeta.post_id ) WHERE 1=1  AND 
( (wp_dxwe_postmeta.meta_key = 'inistitute_name' AND 
CAST(wp_dxwe_postmeta.meta_value AS CHAR) IN ('ITeLearn') )) 
AND wp_dxwe_posts.post_type = 'mypost' AND ((wp_dxwe_posts.post_status = 'publish')) 
AND post_title LIKE '%launch%' GROUP BY wp_dxwe_posts.ID 
ORDER BY wp_dxwe_posts.post_date DESC 

As I said it is working fine for only 'post_title' but why it is not working for 'post_content'. Can anyone please tell me what's wrong in this code? Thanks in advance.

Answer 1

没有适当的全文索引，搜索整个实体的速度将太慢，以至于扩展到在较大的站点上，这最终可能会降低服务器的性能。