Github user davies commented on a diff in the pull request:
https://github.com/apache/spark/pull/8747#discussion_r40961647
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/codegen/GenerateUnsafeProjection.scala
---
@@ -393,10 +393,278 @@ object GenerateUnsafeProjection extends
CodeGenerator[Seq[Expression], UnsafePro
case _ => input
}
+ val rowWriterClass = classOf[UnsafeRowWriter].getName
+ val arrayWriterClass = classOf[UnsafeArrayWriter].getName
+
+ // todo: if the nullability of field is correct, we can use it to save
null check.
+ private def writeStructToBuffer(
+ ctx: CodeGenContext,
+ input: String,
+ fieldTypes: Seq[DataType],
+ bufferHolder: String): String = {
+ val fieldEvals = fieldTypes.zipWithIndex.map { case (dt, i) =>
+ val fieldName = ctx.freshName("fieldName")
+ val code = s"final ${ctx.javaType(dt)} $fieldName =
${ctx.getValue(input, dt, i.toString)};"
+ val isNull = s"$input.isNullAt($i)"
+ GeneratedExpressionCode(code, isNull, fieldName)
+ }
+
+ s"""
+ if ($input instanceof UnsafeRow) {
+ $rowWriterClass.directWrite($bufferHolder, (UnsafeRow) $input);
+ } else {
+ ${writeExpressionsToBuffer(ctx, input, fieldEvals, fieldTypes,
bufferHolder)}
+ }
+ """
+ }
+
+ private def writeExpressionsToBuffer(
+ ctx: CodeGenContext,
+ row: String,
+ inputs: Seq[GeneratedExpressionCode],
+ inputTypes: Seq[DataType],
+ bufferHolder: String): String = {
+ val rowWriter = ctx.freshName("rowWriter")
+ ctx.addMutableState(rowWriterClass, rowWriter, s"this.$rowWriter = new
$rowWriterClass();")
+
+ val writeFields = inputs.zip(inputTypes).zipWithIndex.map {
+ case ((input, dt), index) =>
+ val tmpCursor = ctx.freshName("tmpCursor")
+
+ val setNull = dt match {
+ case t: DecimalType if t.precision > Decimal.MAX_LONG_DIGITS =>
+ // Can't call setNullAt() for DecimalType with precision
larger than 18.
+ s"$rowWriter.write($index, null, 0, 0);"
+ case _ => s"$rowWriter.setNullAt($index);"
+ }
+
+ val writeField = dt match {
+ case t: StructType =>
+ s"""
+ // Remember the current cursor so that we can calculate how
many bytes are
+ // written later.
+ final int $tmpCursor = $bufferHolder.cursor;
+ ${writeStructToBuffer(ctx, input.primitive,
t.map(_.dataType), bufferHolder)}
+ $rowWriter.setOffsetAndSize($index, $tmpCursor,
$bufferHolder.cursor - $tmpCursor);
+ """
+
+ case a @ ArrayType(et, _) =>
+ s"""
+ // Remember the current cursor so that we can calculate how
many bytes are
+ // written later.
+ final int $tmpCursor = $bufferHolder.cursor;
+ ${writeArrayToBuffer(ctx, input.primitive, et, bufferHolder)}
+ $rowWriter.setOffsetAndSize($index, $tmpCursor,
$bufferHolder.cursor - $tmpCursor);
+ $rowWriter.alignWords($bufferHolder.cursor - $tmpCursor);
+ """
+
+ case m @ MapType(kt, vt, _) =>
+ s"""
+ // Remember the current cursor so that we can calculate how
many bytes are
+ // written later.
+ final int $tmpCursor = $bufferHolder.cursor;
+ ${writeMapToBuffer(ctx, input.primitive, kt, vt,
bufferHolder)}
+ $rowWriter.setOffsetAndSize($index, $tmpCursor,
$bufferHolder.cursor - $tmpCursor);
+ $rowWriter.alignWords($bufferHolder.cursor - $tmpCursor);
+ """
+
+ case _ if ctx.isPrimitiveType(dt) =>
+ val fieldOffset = ctx.freshName("fieldOffset")
+ s"""
+ final long $fieldOffset = $rowWriter.getFieldOffset($index);
+ Platform.putLong($bufferHolder.buffer, $fieldOffset, 0L);
+ ${writePrimitiveType(ctx, input.primitive, dt,
s"$bufferHolder.buffer", fieldOffset)}
+ """
+
+ case t: DecimalType if t.precision <= Decimal.MAX_LONG_DIGITS =>
+ s"$rowWriter.writeCompactDecimal($index, ${input.primitive}, "
+
+ s"${t.precision}, ${t.scale});"
+
+ case t: DecimalType =>
+ s"$rowWriter.write($index, ${input.primitive}, ${t.precision},
${t.scale});"
+
+ case NullType => ""
+
+ case _ => s"$rowWriter.write($index, ${input.primitive});"
+ }
+
+ s"""
+ ${input.code}
+ if (${input.isNull}) {
+ $setNull
+ } else {
+ $writeField
+ }
+ """
+ }
+
+ s"""
+ $rowWriter.initialize($bufferHolder, ${inputs.length});
+ ${ctx.splitExpressions(row, writeFields)}
+ """
+ }
+
+ // todo: if the nullability of array element is correct, we can use it
to save null check.
+ private def writeArrayToBuffer(
+ ctx: CodeGenContext,
+ input: String,
+ elementType: DataType,
+ bufferHolder: String,
+ needHeader: Boolean = true): String = {
+ val arrayWriter = ctx.freshName("arrayWriter")
+ ctx.addMutableState(arrayWriterClass, arrayWriter,
+ s"this.$arrayWriter = new $arrayWriterClass();")
+ val numElements = ctx.freshName("numElements")
+ val index = ctx.freshName("index")
+ val element = ctx.freshName("element")
+
+ val jt = ctx.javaType(elementType)
+
+ val fixedElementSize = elementType match {
+ case t: DecimalType if t.precision <= Decimal.MAX_LONG_DIGITS => 8
+ case _ if ctx.isPrimitiveType(jt) => elementType.defaultSize
+ case _ => 0
+ }
+
+ val writeElement = elementType match {
+ case t: StructType =>
+ s"""
+ $arrayWriter.setOffset($index);
+ ${writeStructToBuffer(ctx, element, t.map(_.dataType),
bufferHolder)}
+ """
+
+ case a @ ArrayType(et, _) =>
+ s"""
+ $arrayWriter.setOffset($index);
+ ${writeArrayToBuffer(ctx, element, et, bufferHolder)}
+ """
+
+ case m @ MapType(kt, vt, _) =>
+ s"""
+ $arrayWriter.setOffset($index);
+ ${writeMapToBuffer(ctx, element, kt, vt, bufferHolder)}
+ """
+
+ case _ if ctx.isPrimitiveType(elementType) =>
+ // Should we do word align?
+ val dataSize = elementType.defaultSize
+
+ s"""
+ $arrayWriter.setOffset($index);
+ ${writePrimitiveType(ctx, element, elementType,
+ s"$bufferHolder.buffer", s"$bufferHolder.cursor")}
+ $bufferHolder.cursor += $dataSize;
+ """
+
+ case t: DecimalType if t.precision <= Decimal.MAX_LONG_DIGITS =>
+ s"$arrayWriter.writeCompactDecimal($index, $element,
${t.precision}, ${t.scale});"
+
+ case t: DecimalType =>
+ s"$arrayWriter.write($index, $element, ${t.precision},
${t.scale});"
+
+ case NullType => ""
+
+ case _ => s"$arrayWriter.write($index, $element);"
+ }
+
+ s"""
+ if ($input instanceof UnsafeArrayData) {
+ $arrayWriterClass.directWrite($bufferHolder, (UnsafeArrayData)
$input, $needHeader);
+ } else {
+ final int $numElements = $input.numElements();
+ $arrayWriter.initialize($bufferHolder, $numElements, $needHeader,
$fixedElementSize);
+
+ for (int $index = 0; $index < $numElements; $index++) {
+ if ($input.isNullAt($index)) {
+ $arrayWriter.setNullAt($index);
+ } else {
+ final $jt $element = ${ctx.getValue(input, elementType,
index)};
+ $writeElement
+ }
+ }
+ }
+ """
+ }
+
+ // todo: if the nullability of value element is correct, we can use it
to save null check.
+ private def writeMapToBuffer(
+ ctx: CodeGenContext,
+ input: String,
+ keyType: DataType,
+ valueType: DataType,
+ bufferHolder: String): String = {
+ val keys = ctx.freshName("keys")
+ val values = ctx.freshName("values")
+ val tmpCursor = ctx.freshName("tmpCursor")
+
+ s"""
+ final ArrayData $keys = $input.keyArray();
+ final ArrayData $values = $input.valueArray();
+
+ // Write the numElements into first 4 bytes.
+ Platform.putInt($bufferHolder.buffer, $bufferHolder.cursor,
$keys.numElements());
--- End diff --
Should we call grow first and zero out the unused 4 bytes?
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