From 15539e54c2650a164f09c072f8fae934bb0468c9 Mon Sep 17 00:00:00 2001
From: Josh Rosen <joshrosen@databricks.com>
Date: Thu, 1 Sep 2016 16:45:26 -0700
Subject: [PATCH] [SPARK-17355] Workaround for HIVE-14684 /
HiveResultSetMetaData.isSigned exception
## What changes were proposed in this pull request?
Attempting to use Spark SQL's JDBC data source against the Hive ThriftServer results in a `java.sql.SQLException: Method` not supported exception from `org.apache.hive.jdbc.HiveResultSetMetaData.isSigned`. Here are two user reports of this issue:
- https://stackoverflow.com/questions/34067686/spark-1-5-1-not-working-with-hive-jdbc-1-2-0
- https://stackoverflow.com/questions/32195946/method-not-supported-in-spark
I have filed [HIVE-14684](https://issues.apache.org/jira/browse/HIVE-14684) to attempt to fix this in Hive by implementing the isSigned method, but in the meantime / for compatibility with older JDBC drivers I think we should add special-case error handling to work around this bug.
This patch updates `JDBCRDD`'s `ResultSetMetadata` to schema conversion to catch the "Method not supported" exception from Hive and return `isSigned = true`. I believe that this is safe because, as far as I know, Hive does not support unsigned numeric types.
## How was this patch tested?
Tested manually against a Spark Thrift Server.
Author: Josh Rosen <joshrosen@databricks.com>
Closes #14911 from JoshRosen/hive-jdbc-workaround.
---
.../sql/execution/datasources/jdbc/JDBCRDD.scala | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/jdbc/JDBCRDD.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/jdbc/JDBCRDD.scala
index 8d9048ab82..9b5088fbfd 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/jdbc/JDBCRDD.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/jdbc/JDBCRDD.scala
@@ -136,7 +136,16 @@ object JDBCRDD extends Logging {
val typeName = rsmd.getColumnTypeName(i + 1)
val fieldSize = rsmd.getPrecision(i + 1)
val fieldScale = rsmd.getScale(i + 1)
- val isSigned = rsmd.isSigned(i + 1)
+ val isSigned = {
+ try {
+ rsmd.isSigned(i + 1)
+ } catch {
+ // Workaround for HIVE-14684:
+ case e: SQLException if
+ e.getMessage == "Method not supported" &&
+ rsmd.getClass.getName == "org.apache.hive.jdbc.HiveResultSetMetaData" => true
+ }
+ }
val nullable = rsmd.isNullable(i + 1) != ResultSetMetaData.columnNoNulls
val metadata = new MetadataBuilder()
.putString("name", columnName)
--
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