When altering a partition table to set it as "DISTRIBUTED RANDOMLY" the following error is reported:
gpadmin=# ALTER TABLE IF EXISTS sch01.part01 SET WITH (REORGANIZE=TRUE) DISTRIBUTED RANDOMLY;
ERROR: tuple already updated by self (heapam.c:4265)
Code bug in Greenplum Database 7.x
There is no workaround for the issue.
Upgrade to Greenplum 7.6.1 or above to get the fix.