External scan error: There are more external files (URLs) than primary segments that can read them (COptTasks.cpp:1756)

[来熊]

Hi,all:
    I am testing hawq 2.0.0 , and I find a problem like this:
 I load data from an external table (created using "like target_table" 
statement) ,
if the target table was distributed by some column(s), it raise this error:
 External scan error: There are more external files (URLs) than primary 
segments that can read them (COptTasks.cpp:1756)
if the target table was distributed randomly, it works well,
I don't set any parameter special,does anybody know how to resolve this problem?
thanks a lot.