Soren, Can you give the complete stack trace? Or share the code? Perhaps, the skeletal code. Look at Ceil UDF for example, it has a null check, you should be able to do something similar: https://github.com/apache/hive/blob/trunk/ql/src/java/org/apache/hadoop/hive/ql/udf/UDFCeil.java#L43
I would encourage you in the long run to use GenericUDF though. They are better performing because they don't use reflection. I wrote a blog post a while back to get people started with UDFs. It's at: http://mark.thegrovers.ca/1/post/2012/06/how-to-write-a-hive-udf.html Perhaps, I should put the content on Apache wiki but in the meanwhile, take a look at it... Using the Translate UDF as an example(reference: https://github.com/apache/hive/blob/trunk/ql/src/java/org/apache/hadoop/hive/ql/udf/generic/GenericUDFTranslate.java ) If you would like to have a column accept nulls: 1. Allow the argument type to be "void" type in initialize() like it's done at https://github.com/apache/hive/blob/trunk/ql/src/java/org/apache/hadoop/hive/ql/udf/generic/GenericUDFTranslate.java#L151 2. Handle null values appropriately in evaluate() like it's done at https://github.com/apache/hive/blob/trunk/ql/src/java/org/apache/hadoop/hive/ql/udf/generic/GenericUDFTranslate.java#L172 Good luck! Mark On Tue, Dec 4, 2012 at 6:58 AM, Søren <s...@syntonetic.com> wrote: > 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> 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 > > > > > > >
