plan: fix comment.
plan: fix comment.

zimulala/tidb,c4pt0r/tidb,qhsong/tidb,cosmtrek/tidb,zimulala/tidb,JinheLin/tidb,c4pt0r/tidb,simon-xia/tidb,mccxj/tidb,CodeRushing/tidb,myrice/tidb,myrice/tidb,c4pt0r/tidb,qhsong/tidb,pingcap/tidb,tiancaiamao/tidb,XuHuaiyu/tidb,gaocegege/tidb,8cbx/tidb,cosmtrek/tidb,Nify/tidb,CodeRushing/tidb,kyle-wang/tidb,astaxie/tidb,wusphinx/tidb,andelf/tidb,pingcap/tidb,ngaut/tidb,silenceper/tidb,spongedu/tidb,Cofyc/tidb,kyle-wang/tidb,coocood/tidb,zs634134578/tidb,EvilMcJerkface/tidb,astaxie/tidb,ngaut/tidb,liyu4/tidb,ngaut/tidb,Nify/tidb,ngaut/tidb,silentred/tidb,pingcap/tidb,yangwenmai/tidb,yuanwhy/tidb,8cbx/tidb,yangwenmai/tidb,mccxj/tidb,gaocegege/tidb,pingcap/tidb,liyu4/tidb,wusphinx/tidb,JinheLin/tidb,pingcap/tidb,EvilMcJerkface/tidb,anywhy/tidb,ueizhou/tidb,c4pt0r/tidb,qiuyesuifeng/tidb,louishust/tidb,zs634134578/tidb,pingcap/tidb,anywhy/tidb,qiuyesuifeng/tidb,spongedu/tidb,kyle-wang/tidb,silentred/tidb,simon-xia/tidb,louishust/tidb,ming-relax/tidb,coocood/tidb,kyle-wang/tidb,kyle-wang/tidb,silenceper/tidb,Cofyc/tidb,ngaut/tidb,c4pt0r/tidb,ngaut/tidb,tiancaiamao/tidb,XuHuaiyu/tidb,andelf/tidb,kyle-wang/tidb,ming-relax/tidb,yuanwhy/tidb,c4pt0r/tidb,ueizhou/tidb