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https://issues.apache.org/jira/browse/HIVE-22161?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Gopal V updated HIVE-22161:
---------------------------
    Description: 
There's a hidden synchronization across threads when looking up isStateful and 
isDeterministic.

https://github.com/apache/hive/blob/master/common/src/java/org/apache/hive/common/util/AnnotationUtils.java#L27

{code}
  // to avoid https://bugs.openjdk.java.net/browse/JDK-7122142
  public static <T extends Annotation> T getAnnotation(Class<?> clazz, Class<T> 
annotationClass) {
    synchronized (annotationClass) {
      return clazz.getAnnotation(annotationClass);
    }
  }
{code}

This is serializing multiple threads initializing UDFs (or checking them during 
compilation) & also being locked across threads for each instance of 
GenericUDFOpEqual in the specific scenario.

https://bugs.openjdk.java.net/browse/JDK-7122142 is fixed in jdk8+

  was:
There's a hidden synchronization across threads when looking up isStateful and 
isDeterministic.

https://github.com/apache/hive/blob/master/common/src/java/org/apache/hive/common/util/AnnotationUtils.java#L27

{code}
  // to avoid https://bugs.openjdk.java.net/browse/JDK-7122142
  public static <T extends Annotation> T getAnnotation(Class<?> clazz, Class<T> 
annotationClass) {
    synchronized (annotationClass) {
      return clazz.getAnnotation(annotationClass);
    }
  }
{code}

This is serializing multiple threads initializing UDFs (or checking them during 
compilation) & also being locked across threads for each instance of 
GenericUDFOpEqual in the specific scenario.


> UDF: FunctionRegistry should cache statefulness of UDF
> ------------------------------------------------------
>
>                 Key: HIVE-22161
>                 URL: https://issues.apache.org/jira/browse/HIVE-22161
>             Project: Hive
>          Issue Type: Bug
>          Components: UDF
>            Reporter: Gopal V
>            Assignee: Gopal V
>            Priority: Major
>
> There's a hidden synchronization across threads when looking up isStateful 
> and isDeterministic.
> https://github.com/apache/hive/blob/master/common/src/java/org/apache/hive/common/util/AnnotationUtils.java#L27
> {code}
>   // to avoid https://bugs.openjdk.java.net/browse/JDK-7122142
>   public static <T extends Annotation> T getAnnotation(Class<?> clazz, 
> Class<T> annotationClass) {
>     synchronized (annotationClass) {
>       return clazz.getAnnotation(annotationClass);
>     }
>   }
> {code}
> This is serializing multiple threads initializing UDFs (or checking them 
> during compilation) & also being locked across threads for each instance of 
> GenericUDFOpEqual in the specific scenario.
> https://bugs.openjdk.java.net/browse/JDK-7122142 is fixed in jdk8+



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