DB error mySQL please advise

WordPress database error MySQL server has gone away for query SELECT meta_id FROM wp_z4xa79_postmeta WHERE meta_key = ‘fsb_social_facebook’ AND post_id = 75765 made by do_action(‘wp_ajax_nopriv_fsb_load_stats’), call_user_func_array, floating_social_bar->load_stats, floating_social_bar->do_stats_update, update_post_meta, update_metadata, referer:

http://ww.wp.xz.cn/plugins/floating-social-bar/