https://community.cloudera.com/t5/Support-Questions/How-to-convert-unix-timestamp-to-datetime-in-Apache-NiFi/m-p/224745#M186609 <A rel="user" href="https://community.cloudera.com/users/1186/isoardi.html" nodeid="1186">@Davide Isoardi</A><P>-</P><P>The UpdateAttribute processor does not read the content of a FlowFile. In order for the above Expression Language statements to work, the incoming FlowFile's must have FlowFile attributes "user" and "datetime" created on them.<BR />-<BR />Stop the UpdateAttribute processor and allow a few FlowFiles to queue. Then list that queue and verify what attributes currently exist on those listed FlowFiles.</P><P>-</P><P>Thanks,</P><P>Matt</P> Mon, 23 Apr 2018 21:47:11 GMT MattWho 2018-04-23T21:47:11Z