Daniel Barclay (Drill) created DRILL-3014:
---------------------------------------------
Summary: Casting unknown field yield different result from casting
null, and bad error message
Key: DRILL-3014
URL: https://issues.apache.org/jira/browse/DRILL-3014
Project: Apache Drill
Issue Type: Bug
Reporter: Daniel Barclay (Drill)
Casting null to INTEGER works as expected like this:
{noformat}
0: jdbc:drill:zk=local> select cast(NULL AS INTEGER) from
`dfs.tmp`.`simple.csv`;
+------------+
| EXPR$0 |
+------------+
| null |
+------------+
1 row selected (0.15 seconds)
0: jdbc:drill:zk=local>
{noformat}
(File "{{simple.csv}}" contains one line containing simply "{{a,b,c,d}}".)
However, casting an unknown column yields an error:
{noformat}
0: jdbc:drill:zk=local> select cast(noSuchField AS INTEGER) from
`dfs.tmp`.`simple.csv`;
Error: SYSTEM ERROR: null
Fragment 0:0
[Error Id: a0b348ec-f2c5-4f66-9f05-591399f3c315 on dev-linux2:31010]
(state=,code=0)
0: jdbc:drill:zk=local>
{noformat}
This looks like a JDK {{NumberFormatException}} that wasn't handled properly*,
and looks like the logical null from the non-existent column was turned into
the string "{{null}}" before the cast to {{INTEGER}}.
Is that a bug or is it intentional that the non-existent field in this case is
not actually treated as being all nulls (as non-existent fields are in at least
some other places)?
(*For most NumberFormatExceptions, the message text does not contain the
information that the kind of exception was a number-format exception--that
information is only in the class name. In particular that information is not
in the message text returned by getMessage().
Drill code that can throw a {{NumberFormatException}} (e.g., cast functions and
other code that calls, e.g., {{Integer.parse(...)}}) should either immediately
wrap it in a {{UserException}}, or at least wrap it in another
{{NumberFormatException}} with fuller message text.)
This seem to confirm that it's a {{NumberFormatException}} (note the
first-column value "{{a}}"):
{noformat}
select cast(columns[0] AS INTEGER) from `dfs.tmp`.`simple.csv`;
Error: SYSTEM ERROR: a
Fragment 0:0
[Error Id: 9d6107dc-dc2a-40ce-9676-6387ab427098 on dev-linux2:31010]
(state=,code=0)
0: jdbc:drill:zk=local>
{noformat}
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