Oops, missed one fix for EquivalenceClass rearrangement.
Oops, missed one fix for EquivalenceClass rearrangement.

Now that we're expecting a mergeclause's left_ec/right_ec to persist from
the initial assignments, we can't just blithely zero these out when
transforming such a clause in adjust_appendrel_attrs.  But really it should
be okay to keep the parent's values, since a child table's derived Var
ought to be equivalent to the parent Var for all EquivalenceClass purposes.
(Indeed, I'm wondering whether we couldn't find a way to dispense with
add_child_rel_equivalences altogether.  But this is wrong in any case.)

Postgres-XL/Postgres-XL,jmcatamney/gpdb,postmind-net/postgres-xl,jmcatamney/gpdb,snaga/postgres-xl,50wu/gpdb,ashwinstar/gpdb,50wu/gpdb,postmind-net/postgres-xl,arcivanov/postgres-xl,adam8157/gpdb,oberstet/postgres-xl,xinzweb/gpdb,yazun/postgres-xl,ashwinstar/gpdb,greenplum-db/gpdb,ashwinstar/gpdb,tpostgres-projects/tPostgres,adam8157/gpdb,greenplum-db/gpdb,Postgres-XL/Postgres-XL,ovr/postgres-xl,ovr/postgres-xl,snaga/postgres-xl,lisakowen/gpdb,zeroae/postgres-xl,adam8157/gpdb,greenplum-db/gpdb,Postgres-XL/Postgres-XL,jmcatamney/gpdb,greenplum-db/gpdb,ashwinstar/gpdb,yazun/postgres-xl,ashwinstar/gpdb,techdragon/Postgres-XL,xinzweb/gpdb,tpostgres-projects/tPostgres,arcivanov/postgres-xl,zeroae/postgres-xl,greenplum-db/gpdb,jmcatamney/gpdb,oberstet/postgres-xl,jmcatamney/gpdb,xinzweb/gpdb,adam8157/gpdb,50wu/gpdb,ashwinstar/gpdb,zeroae/postgres-xl,greenplum-db/gpdb,adam8157/gpdb,snaga/postgres-xl,Postgres-XL/Postgres-XL,greenplum-db/gpdb,50wu/gpdb,kmjungersen/PostgresXL,kmjungersen/PostgresXL,jmcatamney/gpdb,jmcatamney/gpdb,oberstet/postgres-xl,yazun/postgres-xl,arcivanov/postgres-xl,xinzweb/gpdb,oberstet/postgres-xl,postmind-net/postgres-xl,xinzweb/gpdb,kmjungersen/PostgresXL,lisakowen/gpdb,ovr/postgres-xl,greenplum-db/gpdb,oberstet/postgres-xl,50wu/gpdb,pavanvd/postgres-xl,zeroae/postgres-xl,zeroae/postgres-xl,lisakowen/gpdb,50wu/gpdb,xinzweb/gpdb,adam8157/gpdb,snaga/postgres-xl,tpostgres-projects/tPostgres,Postgres-XL/Postgres-XL,adam8157/gpdb,arcivanov/postgres-xl,ovr/postgres-xl,snaga/postgres-xl,lisakowen/gpdb,postmind-net/postgres-xl,lisakowen/gpdb,ashwinstar/gpdb,jmcatamney/gpdb,50wu/gpdb,yazun/postgres-xl,pavanvd/postgres-xl,yazun/postgres-xl,pavanvd/postgres-xl,lisakowen/gpdb,arcivanov/postgres-xl,tpostgres-projects/tPostgres,lisakowen/gpdb,ovr/postgres-xl,kmjungersen/PostgresXL,ashwinstar/gpdb,postmind-net/postgres-xl,lisakowen/gpdb,adam8157/gpdb,xinzweb/gpdb,techdragon/Postgres-XL,techdragon/Postgres-XL,pavanvd/postgres-xl,arcivanov/postgres-xl,tpostgres-projects/tPostgres,pavanvd/postgres-xl,xinzweb/gpdb,techdragon/Postgres-XL,kmjungersen/PostgresXL,50wu/gpdb,techdragon/Postgres-XL