Github user JoshRosen commented on a diff in the pull request:
https://github.com/apache/spark/pull/14907#discussion_r77099720
--- Diff:
sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/jdbc/JDBCRDD.scala
---
@@ -322,195 +237,15 @@ private[jdbc] class JDBCRDD(
}
}
- // A `JDBCValueGetter` is responsible for getting a value from
`ResultSet` into a field
- // for `MutableRow`. The last argument `Int` means the index for the
value to be set in
- // the row and also used for the value in `ResultSet`.
- private type JDBCValueGetter = (ResultSet, MutableRow, Int) => Unit
-
- /**
- * Creates `JDBCValueGetter`s according to [[StructType]], which can set
- * each value from `ResultSet` to each field of [[MutableRow]] correctly.
- */
- def makeGetters(schema: StructType): Array[JDBCValueGetter] =
- schema.fields.map(sf => makeGetter(sf.dataType, sf.metadata))
-
- private def makeGetter(dt: DataType, metadata: Metadata):
JDBCValueGetter = dt match {
- case BooleanType =>
- (rs: ResultSet, row: MutableRow, pos: Int) =>
- row.setBoolean(pos, rs.getBoolean(pos + 1))
-
- case DateType =>
- (rs: ResultSet, row: MutableRow, pos: Int) =>
- // DateTimeUtils.fromJavaDate does not handle null value, so we
need to check it.
- val dateVal = rs.getDate(pos + 1)
- if (dateVal != null) {
- row.setInt(pos, DateTimeUtils.fromJavaDate(dateVal))
- } else {
- row.update(pos, null)
- }
-
- // When connecting with Oracle DB through JDBC, the precision and
scale of BigDecimal
- // object returned by ResultSet.getBigDecimal is not correctly matched
to the table
- // schema reported by ResultSetMetaData.getPrecision and
ResultSetMetaData.getScale.
- // If inserting values like 19999 into a column with NUMBER(12, 2)
type, you get through
- // a BigDecimal object with scale as 0. But the dataframe schema has
correct type as
- // DecimalType(12, 2). Thus, after saving the dataframe into parquet
file and then
- // retrieve it, you will get wrong result 199.99.
- // So it is needed to set precision and scale for Decimal based on
JDBC metadata.
- case DecimalType.Fixed(p, s) =>
- (rs: ResultSet, row: MutableRow, pos: Int) =>
- val decimal =
- nullSafeConvert[java.math.BigDecimal](rs.getBigDecimal(pos + 1),
d => Decimal(d, p, s))
- row.update(pos, decimal)
-
- case DoubleType =>
- (rs: ResultSet, row: MutableRow, pos: Int) =>
- row.setDouble(pos, rs.getDouble(pos + 1))
-
- case FloatType =>
- (rs: ResultSet, row: MutableRow, pos: Int) =>
- row.setFloat(pos, rs.getFloat(pos + 1))
-
- case IntegerType =>
- (rs: ResultSet, row: MutableRow, pos: Int) =>
- row.setInt(pos, rs.getInt(pos + 1))
-
- case LongType if metadata.contains("binarylong") =>
- (rs: ResultSet, row: MutableRow, pos: Int) =>
- val bytes = rs.getBytes(pos + 1)
- var ans = 0L
- var j = 0
- while (j < bytes.size) {
- ans = 256 * ans + (255 & bytes(j))
- j = j + 1
- }
- row.setLong(pos, ans)
-
- case LongType =>
- (rs: ResultSet, row: MutableRow, pos: Int) =>
- row.setLong(pos, rs.getLong(pos + 1))
-
- case ShortType =>
- (rs: ResultSet, row: MutableRow, pos: Int) =>
- row.setShort(pos, rs.getShort(pos + 1))
-
- case StringType =>
- (rs: ResultSet, row: MutableRow, pos: Int) =>
- // TODO(davies): use getBytes for better performance, if the
encoding is UTF-8
- row.update(pos, UTF8String.fromString(rs.getString(pos + 1)))
-
- case TimestampType =>
- (rs: ResultSet, row: MutableRow, pos: Int) =>
- val t = rs.getTimestamp(pos + 1)
- if (t != null) {
- row.setLong(pos, DateTimeUtils.fromJavaTimestamp(t))
- } else {
- row.update(pos, null)
- }
-
- case BinaryType =>
- (rs: ResultSet, row: MutableRow, pos: Int) =>
- row.update(pos, rs.getBytes(pos + 1))
-
- case ArrayType(et, _) =>
- val elementConversion = et match {
- case TimestampType =>
- (array: Object) =>
- array.asInstanceOf[Array[java.sql.Timestamp]].map { timestamp
=>
- nullSafeConvert(timestamp, DateTimeUtils.fromJavaTimestamp)
- }
-
- case StringType =>
- (array: Object) =>
- array.asInstanceOf[Array[java.lang.String]]
- .map(UTF8String.fromString)
-
- case DateType =>
- (array: Object) =>
- array.asInstanceOf[Array[java.sql.Date]].map { date =>
- nullSafeConvert(date, DateTimeUtils.fromJavaDate)
- }
-
- case dt: DecimalType =>
- (array: Object) =>
- array.asInstanceOf[Array[java.math.BigDecimal]].map { decimal
=>
- nullSafeConvert[java.math.BigDecimal](
- decimal, d => Decimal(d, dt.precision, dt.scale))
- }
-
- case LongType if metadata.contains("binarylong") =>
- throw new IllegalArgumentException(s"Unsupported array element "
+
- s"type ${dt.simpleString} based on binary")
-
- case ArrayType(_, _) =>
- throw new IllegalArgumentException("Nested arrays unsupported")
-
- case _ => (array: Object) => array.asInstanceOf[Array[Any]]
- }
-
- (rs: ResultSet, row: MutableRow, pos: Int) =>
- val array = nullSafeConvert[Object](
- rs.getArray(pos + 1).getArray,
- array => new GenericArrayData(elementConversion.apply(array)))
- row.update(pos, array)
-
- case _ => throw new IllegalArgumentException(s"Unsupported type
${dt.simpleString}")
- }
-
/**
* Runs the SQL query against the JDBC driver.
*
*/
- override def compute(thePart: Partition, context: TaskContext):
Iterator[InternalRow] =
- new Iterator[InternalRow] {
--- End diff --
First, note that the old code was mis-idented, so it might have been easy
to miss that the entire method body was defining this iterator.
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