bp_blogs_total_blogs_for_user() queries database on each page view in multisite

[wpdennis]

bp_blogs_total_blogs_for_user() gets triggered by BP_Blogs_Component->setup_nav() in multisite environments.

If the visitor isn't logged in, this is resulting in a database query on each page view. The caching fails, since the result for logged out users is always 0:

if ( !$count = wp_cache_get( 'bp_total_blogs_for_user_' . $user_id, 'bp' ) ) {

---

Maybe bp_blogs_total_blogs_for_user() could return 0 if the current user isn't logged in:

if (!is_user_logged_in())
    return 0;

And/or the caching condition should be:

if ( false === $count = wp_cache_get( 'bp_total_blogs_for_user_' . $user_id, 'bp' ) ) {

[wpdennis]

Something like this seems to work:

function bp_blogs_total_blogs_for_user( $user_id = 0 ) {

	if ( empty( $user_id ) )
		$user_id = ( bp_displayed_user_id() ) ? bp_displayed_user_id() : bp_loggedin_user_id();

	if ( absint($user_id) === 0 )
		return 0;

	if (false === $count = wp_cache_get( 'bp_total_blogs_for_user_' . $user_id, 'bp' ) ) {
		$count = BP_Blogs_Blog::total_blog_count_for_user( $user_id );
		wp_cache_set( 'bp_total_blogs_for_user_' . $user_id, $count, 'bp' );
	}

	return $count;
}

[r-a-y]

wpdennis: Always love your tickets relating performance!

Confirmed. Going to try and sneak this in to 2.1.

[boonebgorges]

We also need to add the strict type check, in case a legitimately logged-in user has 0 blogs - we don't want that to result in a cache miss.

[r-a-y]

Good catch! I think there are some older functions that suffer from not using the strict type check as well during cache checks.

[boonebgorges]

In 8935:

Improvements to bp_blogs_total_blogs_for_user()

• Don't bother to check the cache or perform DB queries for users who are not logged in
• Do a strict type check when checking the cache, to ensure that a cached value of 0 does not result in an unnecessary database hit

Fixes #5815

Props wpdennis, r-a-y