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About Denodo Distributed File System Custom Wrapper

Hi team, I am reading your document "https://community.denodo.com/docs/html/document/denodoconnects/6.0/Denodo%20Distributed%20File%20System%20Custom%20Wrapper%20-%20User%20Manual" for create data source on hadoop and wants to read parquet file. I saw there is some step about how to create data soruce and wrapper for hdfs(dfs) partquet file in the manual, and also some information in the manual about "How to connect to MapR XD (MapR-FS)". I am confused, what is the relationship for the two? are they two options to connect hdfs parquet file? I suppose both two can let denodo connect hadoop partuqet file, correct? Also for using the wrapper that denodo provided "(H)DFSParquetFileWrapper", how do I know the port for the hdfs URI, is it 7222 or 8020 or something else? Also, for the parquet path in the base view, is it the physical path or an hdfs path? thanks for answering
user
19-07-2021 04:19:02 -0400

4 Answers

Hi, MapR is a proprietary file system for MapR distribution and is highly compatible with the Apache Hadoop distributed file system (HDFS). As MapR distribution supports HDFS-compatible API, you can use the DFS Custom Wrapper to connect to files in MapR FileSystem and the [How to connect to MapR XD (MapR-FS)](https://community.denodo.com/docs/html/document/denodoconnects/6.0/Denodo%20Distributed%20File%20System%20Custom%20Wrapper%20-%20User%20Manual#h.uh74iyufo83a) section explains the steps for establishing the connection. Regarding your second question, the URI for accessing the HDFS is "**hdfs://<ip>:<port>**" and the default port 8020 is used to access HDFS by HDFS API. Lastly, the parquet path in the base view should be the input path for the file or the directory containing the files. Hope this helps!
Denodo Team
20-07-2021 08:24:00 -0400
Hi team, Not understand the point: based on the document, Can I understand, two ways for Mapr files system parquet file fetch in denodo from hadoop: 1. in the begining part "Creating a Distributed File System Data Source" in the link https://community.denodo.com/docs/html/document/denodoconnects/6.0/Denodo%20Distributed%20File%20System%20Custom%20Wrapper%20-%20User%20Manual 2. in the end part "How to connect to MapR XD (MapR-FS)" Can I understand both of them can connect MARP file system data, or for mapr, we can only use this way "How to connect to MapR XD (MapR-FS)"? Anctualy, for us, I found port 8020 is not avaiable, 7222 is the opening port for us hadoop cluster. Please help on above, we are keen to know it.
user
20-07-2021 10:59:17 -0400
Hi team, any update for above, Can you provide me the answer for above question?
user
29-07-2021 10:56:12 -0400
Hi, Yes, your understanding is correct. You can connect to the MapR file system using either of the methods for accessing the MapR files system parquet files. * **Creating a Distributed File System Data Source** section - for creating the data source with (H)DFSDelimitedTextFileWrapper. * **How to connect to MapR XD (MapR-FS)** section - for creating a custom data source. Regarding the next question, 8020 is the default port for hadoop and if you are able to access the hadoop system with the port 7222, you could use this port. Hope this Helps!
Denodo Team
02-08-2021 05:21:06 -0400
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