bp_core_get_active_member_count()

function bp_core_get_active_member_count() {
	global $wpdb;

	$count = get_transient( 'bp_active_member_count' );
	if ( false === $count ) {
		$bp = buddypress();

		// Avoid a costly join by splitting the lookup.
		if ( is_multisite() ) {
			$sql = "SELECT ID FROM {$wpdb->users} WHERE (user_status != 0 OR deleted != 0 OR user_status != 0)";
		} else {
			$sql = "SELECT ID FROM {$wpdb->users} WHERE user_status != 0";
		}

		$exclude_users     = $wpdb->get_col( $sql );
		$exclude_users_sql = !empty( $exclude_users ) ? "AND user_id NOT IN (" . implode( ',', wp_parse_id_list( $exclude_users ) ) . ")" : '';
		$count             = (int) $wpdb->get_var( $wpdb->prepare( "SELECT COUNT(user_id) FROM {$bp->members->table_name_last_activity} WHERE component = %s AND type = 'last_activity' {$exclude_users_sql}", $bp->members->id ) );

		set_transient( 'bp_active_member_count', $count );
	}

	/**
	 * Filters the total number of members for the installation limited to those with last_activity.
	 *
	 * @since BuddyPress 1.6.0
	 *
	 * @param int $count Total number of active members.
	 */
	return apply_filters( 'bp_core_get_active_member_count', $count );
}