Update EXPLAIN documentation to reflect the fact that the planner now produces two cost numbers instead of one.
Update EXPLAIN documentation to reflect the fact that the
planner now produces two cost numbers instead of one.

CraigHarris/gpdb,xinzweb/gpdb,lisakowen/gpdb,CraigHarris/gpdb,kaknikhil/gpdb,ovr/postgres-xl,randomtask1155/gpdb,ahachete/gpdb,foyzur/gpdb,randomtask1155/gpdb,cjcjameson/gpdb,CraigHarris/gpdb,snaga/postgres-xl,rubikloud/gpdb,oberstet/postgres-xl,snaga/postgres-xl,atris/gpdb,cjcjameson/gpdb,janebeckman/gpdb,Quikling/gpdb,Chibin/gpdb,Quikling/gpdb,cjcjameson/gpdb,yazun/postgres-xl,chrishajas/gpdb,edespino/gpdb,greenplum-db/gpdb,atris/gpdb,50wu/gpdb,foyzur/gpdb,Chibin/gpdb,cjcjameson/gpdb,tpostgres-projects/tPostgres,janebeckman/gpdb,ashwinstar/gpdb,techdragon/Postgres-XL,rubikloud/gpdb,tangp3/gpdb,rvs/gpdb,50wu/gpdb,ahachete/gpdb,lpetrov-pivotal/gpdb,adam8157/gpdb,lintzc/gpdb,0x0FFF/gpdb,zaksoup/gpdb,Quikling/gpdb,cjcjameson/gpdb,xuegang/gpdb,postmind-net/postgres-xl,yuanzhao/gpdb,janebeckman/gpdb,atris/gpdb,edespino/gpdb,zaksoup/gpdb,0x0FFF/gpdb,greenplum-db/gpdb,50wu/gpdb,zaksoup/gpdb,chrishajas/gpdb,cjcjameson/gpdb,randomtask1155/gpdb,0x0FFF/gpdb,jmcatamney/gpdb,oberstet/postgres-xl,ashwinstar/gpdb,xuegang/gpdb,adam8157/gpdb,yuanzhao/gpdb,lpetrov-pivotal/gpdb,janebeckman/gpdb,foyzur/gpdb,50wu/gpdb,arcivanov/postgres-xl,lisakowen/gpdb,janebeckman/gpdb,tangp3/gpdb,kmjungersen/PostgresXL,adam8157/gpdb,lpetrov-pivotal/gpdb,greenplum-db/gpdb,zeroae/postgres-xl,yuanzhao/gpdb,jmcatamney/gpdb,pavanvd/postgres-xl,janebeckman/gpdb,royc1/gpdb,Chibin/gpdb,techdragon/Postgres-XL,randomtask1155/gpdb,Postgres-XL/Postgres-XL,janebeckman/gpdb,0x0FFF/gpdb,yazun/postgres-xl,lintzc/gpdb,atris/gpdb,edespino/gpdb,adam8157/gpdb,rvs/gpdb,ovr/postgres-xl,xinzweb/gpdb,zeroae/postgres-xl,lisakowen/gpdb,lintzc/gpdb,techdragon/Postgres-XL,kaknikhil/gpdb,ashwinstar/gpdb,tangp3/gpdb,zaksoup/gpdb,greenplum-db/gpdb,yuanzhao/gpdb,kmjungersen/PostgresXL,xuegang/gpdb,greenplum-db/gpdb,cjcjameson/gpdb,tangp3/gpdb,kaknikhil/gpdb,rubikloud/gpdb,greenplum-db/gpdb,Postgres-XL/Postgres-XL,yuanzhao/gpdb,oberstet/postgres-xl,xuegang/gpdb,50wu/gpdb,rvs/gpdb,randomtask1155/gpdb,randomtask1155/gpdb,tpostgres-projects/tPostgres,xuegang/gpdb,foyzur/gpdb,kaknikhil/gpdb,Quikling/gpdb,royc1/gpdb,zeroae/postgres-xl,chrishajas/gpdb,postmind-net/postgres-xl,kmjungersen/PostgresXL,pavanvd/postgres-xl,lisakowen/gpdb,Postgres-XL/Postgres-XL,ashwinstar/gpdb,yuanzhao/gpdb,zeroae/postgres-xl,lintzc/gpdb,lisakowen/gpdb,postmind-net/postgres-xl,rubikloud/gpdb,xuegang/gpdb,snaga/postgres-xl,xinzweb/gpdb,tangp3/gpdb,randomtask1155/gpdb,lpetrov-pivotal/gpdb,0x0FFF/gpdb,yazun/postgres-xl,lintzc/gpdb,ovr/postgres-xl,lintzc/gpdb,foyzur/gpdb,kmjungersen/PostgresXL,yuanzhao/gpdb,0x0FFF/gpdb,edespino/gpdb,rubikloud/gpdb,Quikling/gpdb,xuegang/gpdb,Chibin/gpdb,chrishajas/gpdb,ahachete/gpdb,0x0FFF/gpdb,Quikling/gpdb,snaga/postgres-xl,royc1/gpdb,edespino/gpdb,atris/gpdb,ahachete/gpdb,kaknikhil/gpdb,CraigHarris/gpdb,lintzc/gpdb,lintzc/gpdb,techdragon/Postgres-XL,CraigHarris/gpdb,tangp3/gpdb,zaksoup/gpdb,lisakowen/gpdb,kaknikhil/gpdb,adam8157/gpdb,adam8157/gpdb,tangp3/gpdb,yuanzhao/gpdb,CraigHarris/gpdb,postmind-net/postgres-xl,postmind-net/postgres-xl,ashwinstar/gpdb,arcivanov/postgres-xl,rvs/gpdb,ovr/postgres-xl,lpetrov-pivotal/gpdb,oberstet/postgres-xl,cjcjameson/gpdb,xinzweb/gpdb,atris/gpdb,ahachete/gpdb,ashwinstar/gpdb,yuanzhao/gpdb,atris/gpdb,xinzweb/gpdb,chrishajas/gpdb,chrishajas/gpdb,rvs/gpdb,royc1/gpdb,zaksoup/gpdb,edespino/gpdb,rvs/gpdb,rvs/gpdb,ahachete/gpdb,janebeckman/gpdb,royc1/gpdb,techdragon/Postgres-XL,jmcatamney/gpdb,jmcatamney/gpdb,jmcatamney/gpdb,rvs/gpdb,kaknikhil/gpdb,50wu/gpdb,Chibin/gpdb,cjcjameson/gpdb,arcivanov/postgres-xl,greenplum-db/gpdb,ahachete/gpdb,royc1/gpdb,lpetrov-pivotal/gpdb,lpetrov-pivotal/gpdb,pavanvd/postgres-xl,royc1/gpdb,Chibin/gpdb,xinzweb/gpdb,pavanvd/postgres-xl,tangp3/gpdb,royc1/gpdb,zaksoup/gpdb,cjcjameson/gpdb,Quikling/gpdb,Quikling/gpdb,rubikloud/gpdb,kaknikhil/gpdb,xinzweb/gpdb,edespino/gpdb,lisakowen/gpdb,jmcatamney/gpdb,yuanzhao/gpdb,rvs/gpdb,lintzc/gpdb,Postgres-XL/Postgres-XL,chrishajas/gpdb,CraigHarris/gpdb,janebeckman/gpdb,Postgres-XL/Postgres-XL,foyzur/gpdb,ashwinstar/gpdb,jmcatamney/gpdb,greenplum-db/gpdb,adam8157/gpdb,pavanvd/postgres-xl,yazun/postgres-xl,zaksoup/gpdb,chrishajas/gpdb,arcivanov/postgres-xl,rvs/gpdb,Chibin/gpdb,50wu/gpdb,tpostgres-projects/tPostgres,0x0FFF/gpdb,zeroae/postgres-xl,Quikling/gpdb,lpetrov-pivotal/gpdb,ahachete/gpdb,yazun/postgres-xl,rubikloud/gpdb,xuegang/gpdb,kaknikhil/gpdb,snaga/postgres-xl,lisakowen/gpdb,ovr/postgres-xl,adam8157/gpdb,janebeckman/gpdb,foyzur/gpdb,jmcatamney/gpdb,Quikling/gpdb,rubikloud/gpdb,atris/gpdb,xuegang/gpdb,oberstet/postgres-xl,CraigHarris/gpdb,Chibin/gpdb,kmjungersen/PostgresXL,ashwinstar/gpdb,tpostgres-projects/tPostgres,edespino/gpdb,tpostgres-projects/tPostgres,edespino/gpdb,Chibin/gpdb,kaknikhil/gpdb,randomtask1155/gpdb,xinzweb/gpdb,foyzur/gpdb,Chibin/gpdb,edespino/gpdb,arcivanov/postgres-xl,50wu/gpdb,CraigHarris/gpdb,arcivanov/postgres-xl