Cyask! info: MySQL Query Error

Time: 2016-7-28 8:13pm
Script: /index.php

SQL: select qid,uid,username,title,sid1,sid2,sid3,score,asktime,answercount,mobile from cy_question where status=1 order by asktime DESC limit 46
Error: Error writing file '/var/tmp/MYO2v4Mk' (Errcode: 28)
Errno.: 3