Don't let transform_null_equals=on affect CASE foo WHEN NULL ... constructs. transform_null_equals is only supposed to affect "foo = NULL" expressions given directly by the user, not the internal "foo = NULL" expression generated from CASE-WHEN.
Don't let transform_null_equals=on affect CASE foo WHEN NULL ... constructs.
transform_null_equals is only supposed to affect "foo = NULL" expressions
given directly by the user, not the internal "foo = NULL" expression
generated from CASE-WHEN.

This fixes bug #6242, reported by Sergey. Backpatch to all supported
branches.

edespino/gpdb,rvs/gpdb,cjcjameson/gpdb,Quikling/gpdb,edespino/gpdb,lintzc/gpdb,ashwinstar/gpdb,greenplum-db/gpdb,0x0FFF/gpdb,edespino/gpdb,zaksoup/gpdb,chrishajas/gpdb,CraigHarris/gpdb,CraigHarris/gpdb,rvs/gpdb,0x0FFF/gpdb,janebeckman/gpdb,Chibin/gpdb,xuegang/gpdb,Quikling/gpdb,xuegang/gpdb,Chibin/gpdb,Chibin/gpdb,chrishajas/gpdb,ahachete/gpdb,rvs/gpdb,chrishajas/gpdb,CraigHarris/gpdb,yuanzhao/gpdb,adam8157/gpdb,CraigHarris/gpdb,greenplum-db/gpdb,lintzc/gpdb,kaknikhil/gpdb,xuegang/gpdb,adam8157/gpdb,Chibin/gpdb,Quikling/gpdb,edespino/gpdb,CraigHarris/gpdb,jmcatamney/gpdb,Quikling/gpdb,50wu/gpdb,CraigHarris/gpdb,lintzc/gpdb,rvs/gpdb,jmcatamney/gpdb,Quikling/gpdb,yuanzhao/gpdb,lisakowen/gpdb,0x0FFF/gpdb,zaksoup/gpdb,jmcatamney/gpdb,chrishajas/gpdb,xinzweb/gpdb,Quikling/gpdb,yuanzhao/gpdb,yuanzhao/gpdb,yuanzhao/gpdb,ahachete/gpdb,janebeckman/gpdb,adam8157/gpdb,yuanzhao/gpdb,ashwinstar/gpdb,0x0FFF/gpdb,kaknikhil/gpdb,zaksoup/gpdb,royc1/gpdb,ahachete/gpdb,xinzweb/gpdb,chrishajas/gpdb,50wu/gpdb,Chibin/gpdb,royc1/gpdb,royc1/gpdb,Quikling/gpdb,janebeckman/gpdb,Chibin/gpdb,zaksoup/gpdb,50wu/gpdb,lintzc/gpdb,adam8157/gpdb,royc1/gpdb,50wu/gpdb,lintzc/gpdb,zaksoup/gpdb,edespino/gpdb,jmcatamney/gpdb,kaknikhil/gpdb,kaknikhil/gpdb,rvs/gpdb,lisakowen/gpdb,adam8157/gpdb,ashwinstar/gpdb,CraigHarris/gpdb,yuanzhao/gpdb,janebeckman/gpdb,Quikling/gpdb,lintzc/gpdb,Chibin/gpdb,xinzweb/gpdb,xuegang/gpdb,edespino/gpdb,ashwinstar/gpdb,cjcjameson/gpdb,ahachete/gpdb,chrishajas/gpdb,lintzc/gpdb,cjcjameson/gpdb,chrishajas/gpdb,Chibin/gpdb,Chibin/gpdb,50wu/gpdb,janebeckman/gpdb,adam8157/gpdb,0x0FFF/gpdb,cjcjameson/gpdb,ashwinstar/gpdb,lisakowen/gpdb,lintzc/gpdb,xinzweb/gpdb,rvs/gpdb,royc1/gpdb,cjcjameson/gpdb,edespino/gpdb,kaknikhil/gpdb,cjcjameson/gpdb,royc1/gpdb,edespino/gpdb,yuanzhao/gpdb,lintzc/gpdb,ahachete/gpdb,ahachete/gpdb,xuegang/gpdb,jmcatamney/gpdb,kaknikhil/gpdb,rvs/gpdb,greenplum-db/gpdb,cjcjameson/gpdb,lisakowen/gpdb,jmcatamney/gpdb,rvs/gpdb,Quikling/gpdb,cjcjameson/gpdb,lisakowen/gpdb,rvs/gpdb,Chibin/gpdb,50wu/gpdb,0x0FFF/gpdb,xuegang/gpdb,CraigHarris/gpdb,xinzweb/gpdb,xinzweb/gpdb,CraigHarris/gpdb,greenplum-db/gpdb,chrishajas/gpdb,kaknikhil/gpdb,royc1/gpdb,xuegang/gpdb,jmcatamney/gpdb,lisakowen/gpdb,ashwinstar/gpdb,cjcjameson/gpdb,50wu/gpdb,edespino/gpdb,ahachete/gpdb,xinzweb/gpdb,lisakowen/gpdb,lisakowen/gpdb,Quikling/gpdb,yuanzhao/gpdb,adam8157/gpdb,janebeckman/gpdb,greenplum-db/gpdb,jmcatamney/gpdb,zaksoup/gpdb,greenplum-db/gpdb,janebeckman/gpdb,rvs/gpdb,0x0FFF/gpdb,edespino/gpdb,kaknikhil/gpdb,greenplum-db/gpdb,janebeckman/gpdb,kaknikhil/gpdb,ahachete/gpdb,zaksoup/gpdb,zaksoup/gpdb,greenplum-db/gpdb,kaknikhil/gpdb,cjcjameson/gpdb,xinzweb/gpdb,janebeckman/gpdb,yuanzhao/gpdb,royc1/gpdb,adam8157/gpdb,janebeckman/gpdb,xuegang/gpdb,ashwinstar/gpdb,0x0FFF/gpdb,50wu/gpdb,ashwinstar/gpdb,xuegang/gpdb