Dear all:
I'm a new Drill user using version 1.0 (we are going to be upgrading to the
latest MapR version, just not sure when).
We are querying JSON data that is not too deep but has a few levels. My
questions:
When I query one of the top level elements using sqlline the output
contains a string with the JSON nested under that element name. When I use
SQuirrel to do the same queries I get "<Error>" for any nested fields or
arrays. I was able to query elements that are arrays using
flatten(element). Is there a similar function to convert nested
JSON objects to strings? I tried using CAST(element as STRING) and
CAST(element as VARCHAR) and got this error:
Error: SYSTEM ERROR: org.apache.drill.exec.exception.SchemaChangeException:
Failure while trying to materialize incoming schema. Errors:
Error in expression at index -1. Error: Missing function implementation:
[castVARCHAR(MAP-REQUIRED, BIGINT-REQUIRED)]. Full expression: --UNKNOWN
EXPRESSION--..
I also tried CONVERT_FROM/CONVERT TO and got these.
Error: SYSTEM ERROR: org.apache.drill.exec.exception.SchemaChangeException:
Failure while trying to materialize incoming schema. Errors:
Error in expression at index -1. Error: Missing function implementation:
[convert_fromjson(MAP-REQUIRED)]. Full expression: --UNKNOWN EXPRESSION--..
Is it possible to convert from JSON to string using SQuirrel? I haven't
tried with raw JDBC Java code but that's next on my list.
I tried to use the JDBC driver in DB Visualizer and got this error. No
queries worked.
18:33:22 [ERROR ExecutorRunner-pool-3-thread-1 C.?] Internal error while
executing: select b.wcmo_deal.`INTEX$TRAN...
java.lang.UnsupportedOperationException
at
org.apache.drill.exec.vector.accessor.GenericAccessor.isNull(GenericAccessor.java:33)
at
org.apache.drill.exec.vector.accessor.BoundCheckingAccessor.isNull(BoundCheckingAccessor.java:49)
at
org.apache.drill.jdbc.impl.TypeConvertingSqlAccessor.isNull(TypeConvertingSqlAccessor.java:51)
at
org.apache.drill.jdbc.AvaticaDrillSqlAccessor.wasNull(AvaticaDrillSqlAccessor.java:81)
at
org.apache.drill.jdbc.DrillAccessorList.wasNull(DrillAccessorList.java:59)
at
org.apache.drill.jdbc.DrillCursor.wasNull(DrillCursor.java:210)
at
net.hydromatic.avatica.AvaticaResultSet.wasNull(AvaticaResultSet.java:201)
at com.onseven.dbvis.J.B.U.?(Z:399)
Are the newer JDBC drivers backwards compatible with the older servers?
A couple other questions. We have impersonation enabled. When I log in to
sqlline or SQuirrel with an account that as permission to read the
directory and files everything works ok. Otherwise I get an error "Table
xxxx not found". That is fine. How do I supply a username to the Drill
web interface? All queries using the web interface fail with the "Table
xxxx not found" error. I also ran across the REST interface information in
the user mailing list archives and tried that. I can query the
INFORMATION_SCHEMA but not our tables. I tried passing the username as
http://user:password@host:8047/query.json but that didn't work. How do I
supply a username to the REST API?
Finally, speaking of the REST API, once we have the authentication part
resolved, will it return actual nested JSON elements in the results if that
is what is in the file? (That is, not as a string, but as nested elements
in the result?). The JDBC interface seems to be strictly tabular (which
makes sense).
Thanks!
--
Sent from Gmail Mobile
