[SPARK-54206][CONNECT][FOLLOWUP] Use VARBINARY type and reasonable max length for BinaryType

### What changes were proposed in this pull request?

This PR improves the JDBC type mapping for BinaryType in the Spark Connect JDBC client

### Why are the changes needed?

- **Semantic correctness**: Types.VARBINARY (variable-length) better matches Spark's BinaryType semantics.

- **Industry alignment**:
SQL Server dialect already uses VARBINARY(MAX) for BinaryType .
Trino JDBC driver uses VARBINARY with a maximum of 1 GB.
MariaDB JDBC driver uses VARBINARY/LONGVARBINARY for blob types

### Does this PR introduce _any_ user-facing change?

Yes, but minimal impact.
Both BINARY and VARBINARY map to byte array types
The precision change is within reasonable bounds

### How was this patch tested?

Existing tests: All tests in `SparkConnectJdbcDataTypeSuite` pass.

### Was this patch authored or co-authored using generative AI tooling?

No

Closes #53252 from vinodkc/br_SPARK-54206_followup_fix.

Authored-by: vinodkc <[email protected]>
Signed-off-by: Dongjoon Hyun <[email protected]>
(cherry picked from commit 87a8b56)
Signed-off-by: Dongjoon Hyun <[email protected]>

Author: vinodkc

sql/connect/client/jdbc/src/main/scala/org/apache/spark/sql/connect/client/jdbc/util/JdbcTypeUtils.scala

@@ -39,7 +39,7 @@ private[jdbc] object JdbcTypeUtils {
     case DateType => Types.DATE
     case TimestampType => Types.TIMESTAMP
     case TimestampNTZType => Types.TIMESTAMP
-    case BinaryType => Types.BINARY
+    case BinaryType => Types.VARBINARY
     case _: TimeType => Types.TIME
     case other =>
       throw new SQLFeatureNotSupportedException(s"DataType $other is not supported yet.")
@@ -83,7 +83,7 @@ private[jdbc] object JdbcTypeUtils {
     case LongType => 19
     case FloatType => 7
     case DoubleType => 15
-    case StringType => 255
+    case StringType => Int.MaxValue
     case DecimalType.Fixed(p, _) => p
     case DateType => 10
     case TimestampType => 29

sql/connect/client/jdbc/src/test/scala/org/apache/spark/sql/connect/client/jdbc/SparkConnectJdbcDataTypeSuite.scala

@@ -216,9 +216,9 @@ class SparkConnectJdbcDataTypeSuite extends ConnectFunSuite with RemoteSparkSess
       assert(metaData.getColumnTypeName(1) === "STRING")
       assert(metaData.getColumnClassName(1) === "java.lang.String")
       assert(metaData.isSigned(1) === false)
-      assert(metaData.getPrecision(1) === 255)
+      assert(metaData.getPrecision(1) === Int.MaxValue)
       assert(metaData.getScale(1) === 0)
-      assert(metaData.getColumnDisplaySize(1) === 255)
+      assert(metaData.getColumnDisplaySize(1) === Int.MaxValue)
     }
   }
 
@@ -389,7 +389,7 @@ class SparkConnectJdbcDataTypeSuite extends ConnectFunSuite with RemoteSparkSess
 
       val metaData = rs.getMetaData
       assert(metaData.getColumnCount === 1)
-      assert(metaData.getColumnType(1) === Types.BINARY)
+      assert(metaData.getColumnType(1) === Types.VARBINARY)
       assert(metaData.getColumnTypeName(1) === "BINARY")
       assert(metaData.getColumnClassName(1) === "[B")
       assert(metaData.isSigned(1) === false)
@@ -405,7 +405,7 @@ class SparkConnectJdbcDataTypeSuite extends ConnectFunSuite with RemoteSparkSess
 
       val metaData = rs.getMetaData
       assert(metaData.getColumnCount === 1)
-      assert(metaData.getColumnType(1) === Types.BINARY)
+      assert(metaData.getColumnType(1) === Types.VARBINARY)
       assert(metaData.getColumnTypeName(1) === "BINARY")
       assert(metaData.getColumnClassName(1) === "[B")
     }