[impala] 01/02: IMPALA-10398: Altering an Iceberg table might throw NullPointerException

[tarmstrong]

This is an automated email from the ASF dual-hosted git repository.

tarmstrong pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/impala.git

commit 8de7bf773ded7e6db9a0463222e7f552fd20735f
Author: Zoltan Borok-Nagy <borokna...@cloudera.com>
AuthorDate: Wed Dec 16 15:01:35 2020 +0100

    IMPALA-10398: Altering an Iceberg table might throw NullPointerException
    
    IcebergSchemaConverter has a static thread local member which might
    not have a value in the current thread when nextId() is invoked. In
    that case the thread local integer's get() method returns a null and
    we get a NullPointerException when we want to convert it to a builtin
    int.
    
    This patch initializes the thread local variable with an anonymous
    subclass of ThreadLocal that overrides the 'initialValue()' method
    which returns 0 instead of null.
    
    Testing
     * tested manually by restarting the impala cluster and issuing
       ALTER TABLE .. ADD COLUMNS <columns with complex types>
     * looped test_alter_iceberg_tables for a while
    
    Change-Id: I4e8b7c655558898bd13c5288b466d5bf3d258392
    Reviewed-on: http://gerrit.cloudera.org:8080/16882
    Reviewed-by: Gabor Kaszab <gaborkas...@cloudera.com>
    Tested-by: Impala Public Jenkins <impala-public-jenk...@cloudera.com>
---
 .../main/java/org/apache/impala/util/IcebergSchemaConverter.java   | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git 
a/fe/src/main/java/org/apache/impala/util/IcebergSchemaConverter.java 
b/fe/src/main/java/org/apache/impala/util/IcebergSchemaConverter.java
index 763c4fb..736a265 100644
--- a/fe/src/main/java/org/apache/impala/util/IcebergSchemaConverter.java
+++ b/fe/src/main/java/org/apache/impala/util/IcebergSchemaConverter.java
@@ -42,7 +42,12 @@ public class IcebergSchemaConverter {
   // them from multiple threads. Hence we use this thread-local integer to 
generate
   // unique field ids for each schema element. Please note that Iceberg only 
care about
   // the uniqueness of the field ids, but they will be reassigned by Iceberg.
-  private static ThreadLocal<Integer> iThreadLocal = new ThreadLocal<>();
+  private static ThreadLocal<Integer> iThreadLocal = new 
ThreadLocal<Integer>() {
+    @Override
+    public Integer initialValue() {
+        return 0;
+    }
+  };
 
   /**
    * Transform iceberg type to impala type