Thanks for clearing it up @Bryan Bende, much appreciated. ... View more

Thanks @Matt Clarke, much appreciated ... View more

Hi @Ashish Vishnoi. In the sqoop-export doco, it says: "The --input-null-string and --input-null-non-string arguments are optional. If --input-null-string is not specified, then the string "null" will be interpreted as null for string-type columns. If --input-null-non-string is not specified, then both the string "null" and the empty string will be interpreted as null for non-string columns. Note that, the empty string will be always interpreted as null for non-string columns, in addition to other string if specified by --input-null-non-string " There is another discussion here around a similar issue. If it doesn't work even for string columns, it may be that a workaround of some kind is needed. E.g. conversion of blanks to another character (or set of characters that wouldn't normally be a part of your data set) prior to export which can be converted back to blanks once in Teradata. Hope this helps. ... View more

Hi @mqureshi. Thanks for your response. Personally I have no motivation to use Federation I am just curious about it as I see it mentioned occasionally, and I hadn't really come across a concrete example of its practical application and how that would work. ... View more

Hi @mqureshi. How are the clients divided up between the namenodes? Can the whole cluster still interact fully? E.g. if pig and hive connect to different nameservices/namenodes can they still operate on the same data on HDFS? ... View more

Hi @Sridharan Govindaraj. Did running your command from Unix shell instead of HBase shell solve this issue? You might also want to fully qualify your hdfs file path: $ hbase org.apache.hadoop.hbase.mapreduce.ImportTsv -Dimporttsv.separator="," -Dimporttsv.columns="HBASE_ROW_KEY,id,temp:in,temp:out,vibration,pressure:in,pressure:out" sensor hdfs:///user/hbase.csv ... View more

Hi @Sunile Manjee @Steven O'Neill's solution above fixed the issue. Originally, trying to retrieve information for a cell which should be null looked like: Using REST API and going to the HBase URL: Internet explorer would download a 0KB file HBase Shell get command: 1 row returned, "timestamp=14856365476857, value=" After doing a pig filter and store for each individual column, trying to retrieve the same cell looks like: REST: http error 404 HBase Shell get: 0 rows returned So the empty cells were not being automatically dropped out plus HBase was storing the key for the cells with no value. ... View more

@Sunile Manjee thank you, yes I believe so. I have read both that every cell stores a full row key, and that empty cells do not exist at all in HBase. So I think I expect the behaviour of a get command for a specified cell to bring back either a key and a non-empty value, or nothing (no key) as it "does not exist". If I request a cell that I know does not exist e.g. a real key, real column family, fake column qualifier, I get no errors but 0 rows returned. However for a cell that "doesn't exist" based on a null value, I get one row returned (the key and empty value). How does the get command know to return the key if it isn't stored as a part of that cell? Does this come from metadata rather than the cell itself? In any case, I hope this explains my confusion. ... View more