From 6a82f8c427733a02d162228468f4c6455e531a84 Mon Sep 17 00:00:00 2001
From: Kent Yao <yao@apache.org>
Date: Thu, 29 Apr 2021 10:48:23 +0800
Subject: [PATCH] [SPARK-34786][SQL][FOLLOWUP] Explicitly declare
 DecimalType(20, 0) for Parquet UINT_64

---
 .../datasources/parquet/ParquetSchemaConverter.scala          | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/parquet/ParquetSchemaConverter.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/parquet/ParquetSchemaConverter.scala
index 8c4e0881e08b5..e751c97a60c08 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/parquet/ParquetSchemaConverter.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/parquet/ParquetSchemaConverter.scala
@@ -141,7 +141,9 @@ class ParquetToSparkSchemaConverter(
         originalType match {
           case INT_64 | null => LongType
           case DECIMAL => makeDecimalType(Decimal.MAX_LONG_DIGITS)
-          case UINT_64 => DecimalType.LongDecimal
+          // The precision to hold the largest unsigned long is:
+          // `java.lang.Long.toUnsignedString(-1).length` = 20
+          case UINT_64 => DecimalType(20, 0)
           case TIMESTAMP_MICROS => TimestampType
           case TIMESTAMP_MILLIS => TimestampType
           case _ => illegalType()