*: clean up log (#2030)
*: clean up log (#2030)

We should not print too long query into log.
ngaut/tidb,ueizhou/tidb,simon-xia/tidb,Nify/tidb,mccxj/tidb,simon-xia/tidb,zimulala/tidb,XuHuaiyu/tidb,myrice/tidb,louishust/tidb,Cofyc/tidb,ming-relax/tidb,8cbx/tidb,Cofyc/tidb,qhsong/tidb,liyu4/tidb,silentred/tidb,kyle-wang/tidb,ngaut/tidb,wusphinx/tidb,anywhy/tidb,ngaut/tidb,louishust/tidb,Nify/tidb,pingcap/tidb,zimulala/tidb,silentred/tidb,CodeRushing/tidb,zs634134578/tidb,silenceper/tidb,kyle-wang/tidb,ueizhou/tidb,zs634134578/tidb,cosmtrek/tidb,kyle-wang/tidb,JinheLin/tidb,ming-relax/tidb,mccxj/tidb,kyle-wang/tidb,andelf/tidb,kyle-wang/tidb,qhsong/tidb,ngaut/tidb,qiuyesuifeng/tidb,qiuyesuifeng/tidb,pingcap/tidb,silenceper/tidb,tiancaiamao/tidb,EvilMcJerkface/tidb,coocood/tidb,EvilMcJerkface/tidb,anywhy/tidb,andelf/tidb,CodeRushing/tidb,ngaut/tidb,gaocegege/tidb,liyu4/tidb,wusphinx/tidb,spongedu/tidb,c4pt0r/tidb,XuHuaiyu/tidb,pingcap/tidb,cosmtrek/tidb,astaxie/tidb,pingcap/tidb,yangwenmai/tidb,spongedu/tidb,tiancaiamao/tidb,astaxie/tidb,c4pt0r/tidb,coocood/tidb,kyle-wang/tidb,yuanwhy/tidb,myrice/tidb,pingcap/tidb,gaocegege/tidb,c4pt0r/tidb,yangwenmai/tidb,pingcap/tidb,c4pt0r/tidb,8cbx/tidb,yuanwhy/tidb,ngaut/tidb,c4pt0r/tidb,c4pt0r/tidb,JinheLin/tidb