我对hawq中的pxf和外部表有问题。
我在集群中有七个数据节点（和七个hawq段），并在每个节点上安装了pxf。我在这个站点上创建了基于“testpxf”的表。
create table语句：

CREATE EXTERNAL TABLE pxf_hdfs_textsimple_kol0(location text, month text, num_orders int, total_sales float8)
LOCATION ('pxf://Node1:51200/tmp/pxf_test/pxf_hdfs_simple.txt?PROFILE=HdfsTextSimple')
FORMAT 'TEXT' (delimiter=E',');

但我在获取数据方面有问题。当我尝试运行简单查询时：

SELECT * FROM pxf_hdfs_textsimple;

我得到错误：

ERROR:  remote component error (0): (libchurl.c:897)

这就是全部。在hawq主节点日志中，我看到：

2018-01-04 18:43:06.902998 CET,"hawq","postgres",p19781,th-319940160,"[local]",,2018-01-04 18:43:06 CET,16768,con26,,seg-10000,,,x16768,sx1,"LOG","00000","no master mirroring standby configuration found",,,,,,,0,,"cdblink.c",159,
2018-01-04 18:43:10.759145 CET,"hawq","poligon",p19820,th-319940160,"[local]",,2018-01-04 18:43:10 CET,0,con27,,seg-10000,,,,,"LOG","00000","getLocalTmpDirFromMasterConfig session_id:27 tmpdir:/tmp",,,,,,,0,,"postinit.c",470,
2018-01-04 18:43:20.600046 CET,"hawq","poligon",p19820,th-319940160,"[local]",,2018-01-04 18:43:10 CET,16773,con27,cmd7,seg-10000,,,x16773,sx1,"ERROR","XX000","remote component error (0): (libchurl.c:897)",,,,,,"select * from pxf_hdfs_textsimple ;",0,,"libchurl.c",897,"Stack trace:
1    0x8c165e postgres errstart (??:?)
2    0x8c34fb postgres elog_finish (??:?)
3    0x5124d6 postgres check_response_code (??:?)
4    0x512686 postgres churl_read_check_connectivity (??:?)
5    0x517b22 postgres <symbol not found> (pxfutils.c:?)
6    0x517d66 postgres call_rest (??:?)
7    0x5168c0 postgres <symbol not found> (pxfmasterapi.c:?)
8    0x516f97 postgres get_data_fragment_list (??:?)
9    0x512ff5 postgres map_hddata_2gp_segments (??:?)
10   0x73f8a2 postgres <symbol not found> (createplan.c:?)
11   0x73fdb5 postgres <symbol not found> (createplan.c:?)
12   0x741dec postgres create_plan (??:?)
13   0x74d1a6 postgres <symbol not found> (planner.c:?)
14   0x74eb3c postgres subquery_planner (??:?)
15   0x74f177 postgres <symbol not found> (planner.c:?)
16   0x74f72e postgres planner (??:?)
17   0x7e496a postgres pg_plan_queries (??:?)
18   0x7e4e05 postgres <symbol not found> (postgres.c:?)
19   0x7e6560 postgres PostgresMain (??:?)
20   0x799860 postgres <symbol not found> (postmaster.c:?)
21   0x79c5e9 postgres PostmasterMain (??:?)
22   0x4a2dff postgres main (??:?)
23   0x7fdfe9e2ab35 libc.so.6 __libc_start_main (??:0)
24   0x4a2e7c postgres <symbol not found> (??:?)
"

有人知道我做错了什么吗？通过pxf访问hdfs中的数据会导致什么问题？