Unable to read multiple files from specific HDFS directory through Vertica connector

I am trying to import multiple files (some of the files start with "e" letter and they exists directly under "tmp") from specific directory in HDFS but I receiving an error message 

COPY xx.temp_table SOURCE Hdfs(url='http://m4:50070/webhdfs/v1/tmp/*',username='admin') 


ERROR 0:  Error calling prepare() in User Function HdfsFactory at [src/Hdfs.cpp:414], error code: 0, message: [http://m4:50070/webhdfs/v1/tmp/_logs] is a directory.

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but if I execute the copy command as follow, that command execute well

COPY xx.temp_table SOURCE Hdfs(url='http://m4:50070/webhdfs/v1/tmp/e*',username='admin')  

what I can do in order to load all of the files that exist under "tmp" directory?