error (connection pointer is NULL) when using hawq pxf

[gang.wang]

Hi，hawq team:


I have met an error using hawq pxf.


Here is myenvironment：
10.0.0.11，10.0.0.12，10.0.0.13 for hdfs
10.0.0.14，10.0.0.15，10.0.0.16 for hawq and pxf.
centos 7.4
hawq version:2.2.0


I followed the example on 
‘''https://cwiki.apache.org/confluence/display/HAWQ/PXF+Build+and+Install''’ for
'''CREATE EXTERNAL TABLE pxf_hdfs_textsimple ...’''


But,when I query the external table ,I got the error below:


postgres=# select * from pxf_hdfs_textsimple;
ERROR: Error dispatching to seg0 skyaxe-computing-0.localdomain:40000: 
connection pointer is NULL
DETAIL:
Master unable to connect to seg0 skyaxe-computing-0.localdomain:40000: could 
not connect to server: Connection refused
Is the server running on host "10.0.0.14" and accepting
TCP/IP connections on port 40000?


Mail attachments is pg_log.


Thanks!