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From "Muhammad Gelbana (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (DRILL-5194) UDF returns NULL as expected only if the input is a literal
Date Thu, 12 Jan 2017 11:35:51 GMT

    [ https://issues.apache.org/jira/browse/DRILL-5194?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15820799#comment-15820799
] 

Muhammad Gelbana commented on DRILL-5194:
-----------------------------------------

This issue duplicates this one: https://issues.apache.org/jira/browse/DRILL-5193

> UDF returns NULL as expected only if the input is a literal
> -----------------------------------------------------------
>
>                 Key: DRILL-5194
>                 URL: https://issues.apache.org/jira/browse/DRILL-5194
>             Project: Apache Drill
>          Issue Type: Bug
>          Components: Functions - Drill
>    Affects Versions: 1.9.0
>            Reporter: Muhammad Gelbana
>
> I defined the following UDF
> {code:title=SplitPartFunc.java|borderStyle=solid}
> import javax.inject.Inject;
> import org.apache.drill.exec.expr.DrillSimpleFunc;
> import org.apache.drill.exec.expr.annotations.FunctionTemplate;
> import org.apache.drill.exec.expr.annotations.Output;
> import org.apache.drill.exec.expr.annotations.Param;
> import org.apache.drill.exec.expr.holders.IntHolder;
> import org.apache.drill.exec.expr.holders.NullableVarCharHolder;
> import org.apache.drill.exec.expr.holders.VarCharHolder;
> import io.netty.buffer.DrillBuf;
> @FunctionTemplate(name = "split_string", scope = FunctionTemplate.FunctionScope.SIMPLE,
nulls = FunctionTemplate.NullHandling.NULL_IF_NULL)
> public class SplitPartFunc implements DrillSimpleFunc {
>     @Param
>     VarCharHolder input;
>     @Param(constant = true)
>     VarCharHolder delimiter;
>     @Param(constant = true)
>     IntHolder field;
>     @Output
>     NullableVarCharHolder out;
>     @Inject
>     DrillBuf buffer;
>     public void setup() {
>     }
>     public void eval() {
>         String stringValue = org.apache.drill.exec.expr.fn.impl.StringFunctionHelpers.toStringFromUTF8(input.start,
input.end, input.buffer);
>         out.buffer = buffer; //If I return before this statement, a NPE is thrown :(
>         if(stringValue == null){
>             return;
>         }
>         int fieldValue = field.value;
>         if(fieldValue <= 0){
>             return;         
>         }
>         String delimiterValue = org.apache.drill.exec.expr.fn.impl.StringFunctionHelpers.toStringFromUTF8(delimiter.start,
delimiter.end, delimiter.buffer);
>         if(delimiterValue == null){
>             return;
>         }
>         String[] splittedInput = stringValue.split(delimiterValue);
>         if(splittedInput.length < fieldValue){
>             return;
>         }
>         // put the output value in the out buffer
>         String outputValue = splittedInput[fieldValue - 1];
>         out.start = 0;
>         out.end = outputValue.getBytes().length;
>         buffer.setBytes(0, outputValue.getBytes());
>         out.isSet = 1;
>     }
> }
> {code}
> If I run the following query on the sample employees.json file (or actually a parquet,
after modifying the table and columns names)
> {code:title=SQL Query|borderStyle=solid}SELECT full_name, split_string(full_name, ' ',
4), split_string('Whatever', ' ', 4) FROM cp.employee.json LIMIT 1{code}
> I get the following result
> !https://i.stack.imgur.com/L8uQW.png!
> Shouldn't I be getting the column value and null for the other 2 columns ?



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