Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

#731 Add an option to copy data type when copying metadata. #732

Merged
merged 2 commits into from
Dec 19, 2024
Merged
Show file tree
Hide file tree
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
Original file line number Diff line number Diff line change
Expand Up @@ -48,6 +48,21 @@ object SparkUtils extends Logging {
allExecutors.filter(!_.equals(driverHost)).toList.distinct
}

/**
* Returns true if Spark Data type is a primitive data type.
*
* @param dataType Spark data type
* @return true if the data type is primitive.
*/
def isPrimitive(dataType: DataType): Boolean = {
dataType match {
case _: ArrayType => false
case _: StructType => false
case _: MapType => false
case _ => true
}
}

/**
* Given an instance of DataFrame returns a dataframe with flattened schema.
* All nested structures are flattened and arrays are projected as columns.
Expand Down Expand Up @@ -248,12 +263,14 @@ object SparkUtils extends Logging {
* @param schemaTo Schema to copy metadata to.
* @param overwrite If true, the metadata of schemaTo is not retained
* @param sourcePreferred If true, schemaFrom metadata is used on conflicts, schemaTo otherwise.
* @param copyDataType If true, data type is copied as well. This is limited to primitive data types.
* @return Same schema as schemaTo with metadata from schemaFrom.
*/
def copyMetadata(schemaFrom: StructType,
schemaTo: StructType,
overwrite: Boolean = false,
sourcePreferred: Boolean = false): StructType = {
sourcePreferred: Boolean = false,
copyDataType: Boolean = false): StructType = {
def joinMetadata(from: Metadata, to: Metadata): Metadata = {
val newMetadataMerged = new MetadataBuilder

Expand All @@ -273,12 +290,16 @@ object SparkUtils extends Logging {
ar.elementType match {
case st: StructType if fieldFrom.dataType.isInstanceOf[ArrayType] && fieldFrom.dataType.asInstanceOf[ArrayType].elementType.isInstanceOf[StructType] =>
val innerStructFrom = fieldFrom.dataType.asInstanceOf[ArrayType].elementType.asInstanceOf[StructType]
val newDataType = StructType(copyMetadata(innerStructFrom, st).fields)
val newDataType = StructType(copyMetadata(innerStructFrom, st, overwrite, sourcePreferred, copyDataType).fields)
ArrayType(newDataType, ar.containsNull)
case at: ArrayType =>
processArray(at, fieldFrom, fieldTo)
case p =>
ArrayType(p, ar.containsNull)
if (copyDataType && fieldFrom.dataType.isInstanceOf[ArrayType] && isPrimitive(fieldFrom.dataType.asInstanceOf[ArrayType].elementType)) {
ArrayType(fieldFrom.dataType.asInstanceOf[ArrayType].elementType, ar.containsNull)
} else {
ArrayType(p, ar.containsNull)
}
}
}

Expand All @@ -295,13 +316,17 @@ object SparkUtils extends Logging {

fieldTo.dataType match {
case st: StructType if fieldFrom.dataType.isInstanceOf[StructType] =>
val newDataType = StructType(copyMetadata(fieldFrom.dataType.asInstanceOf[StructType], st).fields)
val newDataType = StructType(copyMetadata(fieldFrom.dataType.asInstanceOf[StructType], st, overwrite, sourcePreferred, copyDataType).fields)
fieldTo.copy(dataType = newDataType, metadata = newMetadata)
case at: ArrayType =>
val newType = processArray(at, fieldFrom, fieldTo)
fieldTo.copy(dataType = newType, metadata = newMetadata)
case _ =>
fieldTo.copy(metadata = newMetadata)
if (copyDataType && isPrimitive(fieldFrom.dataType)) {
fieldTo.copy(dataType = fieldFrom.dataType, metadata = newMetadata)
} else {
fieldTo.copy(metadata = newMetadata)
}
}
case None =>
fieldTo
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,24 @@ class SparkUtilsSuite extends AnyFunSuite with SparkTestBase with BinaryFileFixt
"""[{"id":4,"legs":[]}]""" ::
"""[{"id":5,"legs":null}]""" :: Nil

test("IsPrimitive should work as expected") {
assert(SparkUtils.isPrimitive(BooleanType))
assert(SparkUtils.isPrimitive(ByteType))
assert(SparkUtils.isPrimitive(ShortType))
assert(SparkUtils.isPrimitive(IntegerType))
assert(SparkUtils.isPrimitive(LongType))
assert(SparkUtils.isPrimitive(FloatType))
assert(SparkUtils.isPrimitive(DoubleType))
assert(SparkUtils.isPrimitive(DecimalType(10, 2)))
assert(SparkUtils.isPrimitive(StringType))
assert(SparkUtils.isPrimitive(BinaryType))
assert(SparkUtils.isPrimitive(DateType))
assert(SparkUtils.isPrimitive(TimestampType))
assert(!SparkUtils.isPrimitive(ArrayType(StringType)))
assert(!SparkUtils.isPrimitive(StructType(Seq(StructField("a", StringType)))))
assert(!SparkUtils.isPrimitive(MapType(StringType, StringType)))
}

test("Test schema flattening of multiple nested structure") {
val expectedOrigSchema =
"""root
Expand Down Expand Up @@ -626,6 +644,85 @@ class SparkUtilsSuite extends AnyFunSuite with SparkTestBase with BinaryFileFixt
assert(newDf.schema.fields.head.metadata.getLong("maxLength") == 120)
}

test("copyMetadata should copy primitive data types when it is enabled") {
val schemaFrom = StructType(
Seq(
StructField("int_field1", IntegerType, nullable = true, metadata = new MetadataBuilder().putString("comment", "Test1").build()),
StructField("string_field", StringType, nullable = true, metadata = new MetadataBuilder().putLong("maxLength", 120).build()),
StructField("int_field2", StructType(
Seq(
StructField("int_field20", IntegerType, nullable = true, metadata = new MetadataBuilder().putString("comment", "Test20").build())
)
), nullable = true),
StructField("struct_field2", StructType(
Seq(
StructField("int_field3", IntegerType, nullable = true, metadata = new MetadataBuilder().putString("comment", "Test3").build())
)
), nullable = true),
StructField("array_string", ArrayType(StringType), nullable = true, metadata = new MetadataBuilder().putLong("maxLength", 60).build()),
StructField("array_struct", ArrayType(StructType(
Seq(
StructField("int_field4", IntegerType, nullable = true, metadata = new MetadataBuilder().putString("comment", "Test4").build())
)
)), nullable = true)
)
)

val schemaTo = StructType(
Seq(
StructField("int_field1", BooleanType, nullable = true),
StructField("string_field", IntegerType, nullable = true),
StructField("int_field2", IntegerType, nullable = true),
StructField("struct_field2", StructType(
Seq(
StructField("int_field3", BooleanType, nullable = true)
)
), nullable = true),
StructField("array_string", ArrayType(IntegerType), nullable = true),
StructField("array_struct", ArrayType(StructType(
Seq(
StructField("int_field4", StringType, nullable = true)
)
)), nullable = true)
)
)

val schemaWithMetadata = SparkUtils.copyMetadata(schemaFrom, schemaTo, copyDataType = true)
val fields = schemaWithMetadata.fields

// Ensure data types are copied
// Expected schema:
// root
// |-- int_field1: boolean (nullable = true)
// |-- string_field: integer (nullable = true)
// |-- int_field2: integer (nullable = true)
// |-- struct_field2: struct (nullable = true)
// | |-- int_field3: boolean (nullable = true)
// |-- array_string: array (nullable = true)
// | |-- element: integer (containsNull = true)
// |-- array_struct: array (nullable = true)
// | |-- element: struct (containsNull = true)
// | | |-- int_field4: string (nullable = true)
assert(fields.head.dataType == IntegerType)
assert(fields(1).dataType == StringType)
assert(fields(2).dataType == IntegerType)
assert(fields(3).dataType.isInstanceOf[StructType])
assert(fields(4).dataType.isInstanceOf[ArrayType])
assert(fields(5).dataType.isInstanceOf[ArrayType])

assert(fields(3).dataType.asInstanceOf[StructType].fields.head.dataType == IntegerType)
assert(fields(4).dataType.asInstanceOf[ArrayType].elementType == StringType)
assert(fields(5).dataType.asInstanceOf[ArrayType].elementType.isInstanceOf[StructType])
assert(fields(5).dataType.asInstanceOf[ArrayType].elementType.asInstanceOf[StructType].fields.head.dataType == IntegerType)

// Ensure metadata is copied
assert(fields.head.metadata.getString("comment") == "Test1")
assert(fields(1).metadata.getLong("maxLength") == 120)
assert(fields(3).dataType.asInstanceOf[StructType].fields.head.metadata.getString("comment") == "Test3")
assert(fields(4).metadata.getLong("maxLength") == 60)
assert(fields(5).dataType.asInstanceOf[ArrayType].elementType.asInstanceOf[StructType].fields.head.metadata.getString("comment") == "Test4")
}

test("copyMetadata should retain metadata on conflicts by default") {
val df1 = List(1, 2, 3).toDF("col1")
val df2 = List(1, 2, 3).toDF("col1")
Expand Down
Loading