plan: push down constant filters over join properly (#9848)#10049

Merged

zz-jason merged 5 commits intopingcap:release-2.1from eurekaka:pick_const_pushdown_2.1

Apr 8, 2019

+94-10

Commits on Apr 8, 2019

Merge branch 'release-2.1' into pick_const_pushdown_2.1
zz-jason
authored