The way UDF works is, you need to tell your ObjectInspector about your
primitive or JavaTypes. So in your case even if value is null, you should be
able to assign it as a String or any other object. Then invocation to
evaluate() function should know about type of java object.
-Vivek
________________________________________
From: Vivek Mishra
Sent: 05 December 2012 15:36
To: user@hive.apache.org
Subject: RE: handling null argument in custom udf
Could you please look into and share your task log/attemptlog for complete
error trace or actual error behind this?
-Vivek
________________________________________
From: Søren [s...@syntonetic.com]
Sent: 04 December 2012 20:28
To: user@hive.apache.org
Subject: Re: handling null argument in custom udf
Thanks. Did you mean I should handle null in my udf or my serde?
I did try to check for null inside the code in my udf, but it fails even before
it gets called.
This is from when the udf fails:
....
Caused by: org.apache.hadoop.hive.ql.metadata.HiveException: Unable to execute
method public org.apache.hadoop.io.Text
com.company.hive.myfun.evaluate(java.lang.Object,java.lang.Object)
on objectcom.company.hive.myfun@1412332 of class com.company.hive.myfun with
arguments {0:java.lang.Object, null} of size 2
It looks like there is a null, or is this error message misleading?
On 04/12/2012 15:43, Edward Capriolo wrote:
There is no null argument. You should handle the null case in your code.
If (arga == null)
Or optionally you could use a generic udf but a regular one should handle what
you are doing.
On Tuesday, December 4, 2012, Søren
<s...@syntonetic.com<mailto:s...@syntonetic.com>> wrote:
> Hi Hive community
>
> I have a custom udf, say myfun, written in Java which I utilize like this
>
> select myfun(col_a, col_b) from mytable where ....etc
>
> col_b is a string type and sometimes it is null.
>
> When that happens, my query crashes with
> ---------------
> java.lang.RuntimeException: org.apache.hadoop.hive.ql.metadata.HiveException:
> Hive Runtime Error while processing row
> {"col_a":"val","col_b":null}
> ...
> Caused by: org.apache.hadoop.hive.ql.metadata.HiveException: Unable to
> execute method public org.apache.hadoop.io.Text
> ---------------
>
> public final class myfun extends UDF {
> public Text evaluate(final Text argA, final Text argB) {
>
> I'm unsure how this should be fixed in a proper way. Is the framework looking
> for an overload of evaluate that would comply with the null argument?
>
> I need to say that the table is declared using my own json serde reading from
> S3. I'm not processing nulls in my serde in any special way because Hive
> seems to handle null in the right way when not passed to my own UDF.
>
> Are there anyone out there with ideas or experiences on this issue?
>
> thanks in advance
> Søren
>
>
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