Simran, you can merge single JSON objects into a larger file before you put it to HDFS. There is a dedicated processor for this: Merge Content https://nifi.apache.org/docs/nifi-docs/components/org.apache.nifi/nifi-standard-nar/1.2.0/org.apache.nifi.processors.standard.MergeContent/index.html The processor also allows you to configure a property specifying the number of JSON you want to be merged into one single file: 'Minimum Number of Entries' As a side note, when you have a processor on your canvas, you can right click on it and go to 'Usage' to display the documentation of the processor. Hope that helps. ... View more

Hi, as of today you can not have different NIFI versions within the same NIFI Cluster (managed by Zookeeper), however you can setup different and separated clusters since Nifi as well as Zookeper can be run multiple times on the same servers since you only have to copy them into different folders and separate the config-files (nifi.properties, zoo.cfg etc.), and set different data-dirs / provenance-dirs etc. I would recommend to start with having two separated NIFI instances /opt/nifi1 and /opt/nifi2, each one with its own paths and ports configured in the nifi.properties file of each copy. And especially take care of the paths for content_repository database_repository flowfile_repository provenance_repository work directory logs directory This is often forgotten when copying a nifi instance 1 as a base to setup a second one. Just have a look at the parameters of the properties file. Hope that helps. ... View more

That is always a night mare in JAVA based tools. Hive relies on JAVA (plus SQL) so it respects the IEEE standard for number semantics. That means especially NaN (not a number) values in float columns are a tricky thing. First of all: Have you tested what is returned for the '#N/A' columns when you do a select? I guess it is rather 'NaN' than '#N/A'. So after testing the return value, I would suggest to test two approaches. Either try to use cast(): cast(dollar as String) <>'NaN' (because all possible NaN values are displayed as "NaN" even if they are not strictly "equal" in the arithmetical sense) or do the old trick and test the value of the column to fit a mathematical operation like e.g. dollar +1.0 > dollar ... View more

It is not supposed to generate unique values. The hash() function is working with ranges. It is supposed to index different ranges with integer values. Think about grouping similar ranges of values in a large data set into smaller subsets and have an index to find the respective subset. A good explanation can be found there: http://preshing.com/20110504/hash-collision-probabilities/ If you want to generate unique values, have a look at using UDF (reflect("java.util.UUID", "randomUUID")) ... View more

Hi, the PutEmail Processor supports the NIFI expression language for the parameter Subject. That means you can access all the attributes of your flow file and all your custom attributes or variables that you defined within the flow. To have a custom subject in your PutEmail processor for the error-handling case, you should connect the PutHDFS (or GetFile or both) processor to the PutEmail Processor for the failure path and configure the PutEmail processor. An example for a custom Subject could be: 'Hello from '${hostname}' the file '${filename}' caused an error at '${now} More Examples and some guidelines for the Nifi Expression Language are listed here: https://nifi.apache.org/docs/nifi-docs/html/expression-language-guide.html ... View more

It seems your spark driver is running with very small heap size, please try increasing the java.driver memory and see if it helps. Use this parameter (e.g.) when submitting the job: --driver-memory 1g ... View more

Do you have another application that reads from the Event Hub using EventProcessorHost? EventProcessorHost sets an epoch on the receiver to ensure that only one active reader for a given consumer group and an event hub partition is active. You can try it with a different consumer group. Other scenario where this could happen is if you turn on checkpointing on EventProcessorHost. Here is some guidelines from MS how to use the Epoch settings for asynch receivers: https://blogs.msdn.microsoft.com/gyan/2014/09/02/event-hubs-receiver-epoch/ ... View more

Ah, Hive has reached the maximum number of open transactions. There is the parameter hive.max.open.txns that limits the number (compare to https://cwiki.apache.org/confluence/display/Hive/Hive+Transactions ). Default Value is 100000 - this should be high enough, and I guess you did not change it, but maybe you want to check it. Not sure what is going on in your environment but maybe you want to have a look Chapter 6 of http://hortonworks.com/hadoop-tutorial/using-hive-acid-transactions-insert-update-delete-data/ to see how to manage your open transactions. Hope this helps. ... View more

Actually the NIFI canvas can be used by multiple sessions in parallel - just test it on your environment: Open it once in WebBrowser A and then in B (should be different ones eg. FireFox and Chrome etc.). However you are right - there needs to go some more improvement into the features to better support the management. Good news is that it is already considered important, have a look at https://cwiki.apache.org/confluence/display/NIFI/Configuration+Management+of+Flows Right now a good approach would be to group the different data flows in process groups for management and version controlling (via templates). ... View more

Hi Mud, well this is not to simple. The reason for this is that MS SQL does not support UPSERT ootb. If it would, then you could simple create an INSERT Statement in NIFI and replace the INSERT with UPSERT using the ReplaceText processor. (This approach is used when interacting with Apache Phoenix that supports the UPSERT SQL verb). However there are two options you have. First you could work with Triggers and simply catch your insert to check if it should be changed into an update. This will cost performance on DB side and it really depends on a) number of inserts and b) who else is interacting with your table. The second option would be to use the ExecuteProcess / Execute Script processor to invoke a shell or groovy script that will do the UPSERT for you. This approach will also cost some performance / additional I/O, but will do the job. This also allows you to either do the magic on DB layer (e.g. with an stored procedure) or in the script itself. Here is an example of a stored procedure approach (http://www.sergeyv.com/blog/archive/2010/09/10/sql-server-upsert-equivalent.aspx). There is also a entry here in the community where calling an stored procedure is explained: https://community.hortonworks.com/questions/26170/does-executesql-processor-allow-to-execute-stored.html HTH. PS: Same approach for using MERGE, even much simpler since MERGE is completely MS SQL Server based - you will first have to populate a source table in MS SQL Server and then invoke the MERGE script .... ... View more

To shortcut the procedure you can also set the other java version for the whole server: /usr/sbin/alternatives --config java This will change the java version for the whole system and not just Ambari and the HDP components. ... View more