Performance Issues with GROUPS plugin

Hi,

I have found a performance issue when groups plugin is enabled and “SQL_CALC_FOUND_ROWS” in statements like this:

SELECT SQL_CALC_FOUND_ROWS wp_posts.ID
FROM wp_posts
WHERE 1 =1
AND wp_posts.post_type =  'post'
AND (
(
wp_posts.post_status =  'publish'
)
)
AND wp_posts.ID
IN (

SELECT ID
FROM wp_posts
WHERE ID NOT
IN (

SELECT post_id
FROM wp_postmeta
WHERE wp_postmeta.meta_key =  'groups-groups_read_post'
)
UNION ALL SELECT post_id AS ID
FROM wp_postmeta
WHERE wp_postmeta.meta_key =  'groups-groups_read_post'
AND wp_postmeta.meta_value
IN (
''
)
)
ORDER BY wp_posts.post_date DESC
LIMIT 0 , 16

Each of these queries take more than a second on a high performance server.
When I disable the Groups, the problem disappears.

My database has grown over the last few years, so it might be a following problem of a large database.

Anybody else expirienced such performance problems?

https://ww.wp.xz.cn/plugins/groups/