Refactors Parquet write path to follow parquet-format

sql/catalyst/src/main/scala/org/apache/spark/sql/types/Decimal.scala

@@ -108,7 +108,9 @@ final class Decimal extends Ordered[Decimal] with Serializable {
    */
   def set(decimal: BigDecimal, precision: Int, scale: Int): Decimal = {
     this.decimalVal = decimal.setScale(scale, ROUNDING_MODE)
-    require(decimalVal.precision <= precision, "Overflowed precision")
+    require(
+      decimalVal.precision <= precision,
+      s"Decimal precision ${decimalVal.precision} exceeds max precision $precision")
     this.longVal = 0L
     this._precision = precision
     this._scale = scale

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/parquet/CatalystReadSupport.scala

@@ -110,7 +110,10 @@ private[parquet] object CatalystReadSupport {
    */
   def clipParquetSchema(parquetSchema: MessageType, catalystSchema: StructType): MessageType = {
     val clippedParquetFields = clipParquetGroupFields(parquetSchema.asGroupType(), catalystSchema)
-    Types.buildMessage().addFields(clippedParquetFields: _*).named("root")
+    Types
+      .buildMessage()
+      .addFields(clippedParquetFields: _*)
+      .named(CatalystSchemaConverter.SPARK_PARQUET_SCHEMA_NAME)
   }
 
   private def clipParquetType(parquetType: Type, catalystType: DataType): Type = {

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/parquet/CatalystRowConverter.scala

@@ -340,30 +340,36 @@ private[parquet] class CatalystRowConverter(
       val scale = decimalType.scale
 
       if (precision <= CatalystSchemaConverter.MAX_PRECISION_FOR_INT64) {
-        // Constructs a `Decimal` with an unscaled `Long` value if possible.  The underlying
-        // `ByteBuffer` implementation is guaranteed to be `HeapByteBuffer`, so here we are using
-        // `Binary.toByteBuffer.array()` to steal the underlying byte array without copying it.
-        val buffer = value.toByteBuffer
-        val bytes = buffer.array()
-        val start = buffer.position()
-        val end = buffer.limit()
-
-        var unscaled = 0L
-        var i = start
-
-        while (i < end) {
-          unscaled = (unscaled << 8) | (bytes(i) & 0xff)
-          i += 1
-        }
-
-        val bits = 8 * (end - start)
-        unscaled = (unscaled << (64 - bits)) >> (64 - bits)
+        // Constructs a `Decimal` with an unscaled `Long` value if possible.
+        val unscaled = binaryToUnscaledLong(value)
         Decimal(unscaled, precision, scale)
       } else {
         // Otherwise, resorts to an unscaled `BigInteger` instead.
         Decimal(new BigDecimal(new BigInteger(value.getBytes), scale), precision, scale)
       }
     }
+
+    private def binaryToUnscaledLong(binary: Binary): Long = {
+      // The underlying `ByteBuffer` implementation is guaranteed to be `HeapByteBuffer`, so here
+      // we are using `Binary.toByteBuffer.array()` to steal the underlying byte array without
+      // copying it.
+      val buffer = binary.toByteBuffer
+      val bytes = buffer.array()
+      val start = buffer.position()
+      val end = buffer.limit()
+
+      var unscaled = 0L
+      var i = start
+
+      while (i < end) {
+        unscaled = (unscaled << 8) | (bytes(i) & 0xff)
+        i += 1
+      }
+
+      val bits = 8 * (end - start)
+      unscaled = (unscaled << (64 - bits)) >> (64 - bits)
+      unscaled
+    }
   }
 
   /**

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/parquet/CatalystSchemaConverter.scala

@@ -47,7 +47,7 @@ import org.apache.spark.sql.{AnalysisException, SQLConf}
  *        [[StructType]].  Note that Spark SQL [[TimestampType]] is similar to Hive timestamp, which
  *        has optional nanosecond precision, but different from `TIME_MILLS` and `TIMESTAMP_MILLIS`
  *        described in Parquet format spec.  This argument only affects Parquet read path.
- * @param writeLegacyParquetFormat Whether to use legacy Parquet format compatible with Spark 1.4
+ * @param writeLegacyParquetFormat Whether to use legacy Parquet format compatible with Spark 1.5
  *        and prior versions when converting a Catalyst [[StructType]] to a Parquet [[MessageType]].
  *        When set to false, use standard format defined in parquet-format spec.  This argument only
  *        affects Parquet write path.
@@ -121,7 +121,7 @@ private[parquet] class CatalystSchemaConverter(
       val precision = field.getDecimalMetadata.getPrecision
       val scale = field.getDecimalMetadata.getScale
 
-      CatalystSchemaConverter.analysisRequire(
+      CatalystSchemaConverter.checkConversionRequirement(
         maxPrecision == -1 || 1 <= precision && precision <= maxPrecision,
         s"Invalid decimal precision: $typeName cannot store $precision digits (max $maxPrecision)")
 
@@ -155,7 +155,7 @@ private[parquet] class CatalystSchemaConverter(
         }
 
       case INT96 =>
-        CatalystSchemaConverter.analysisRequire(
+        CatalystSchemaConverter.checkConversionRequirement(
           assumeInt96IsTimestamp,
           "INT96 is not supported unless it's interpreted as timestamp. " +
             s"Please try to set ${SQLConf.PARQUET_INT96_AS_TIMESTAMP.key} to true.")
@@ -197,11 +197,11 @@ private[parquet] class CatalystSchemaConverter(
       //
       // See: https://github.com/apache/parquet-format/blob/master/LogicalTypes.md#lists
       case LIST =>
-        CatalystSchemaConverter.analysisRequire(
+        CatalystSchemaConverter.checkConversionRequirement(
           field.getFieldCount == 1, s"Invalid list type $field")
 
         val repeatedType = field.getType(0)
-        CatalystSchemaConverter.analysisRequire(
+        CatalystSchemaConverter.checkConversionRequirement(
           repeatedType.isRepetition(REPEATED), s"Invalid list type $field")
 
         if (isElementType(repeatedType, field.getName)) {
@@ -217,17 +217,17 @@ private[parquet] class CatalystSchemaConverter(
       // See: https://github.com/apache/parquet-format/blob/master/LogicalTypes.md#backward-compatibility-rules-1
       // scalastyle:on
       case MAP | MAP_KEY_VALUE =>
-        CatalystSchemaConverter.analysisRequire(
+        CatalystSchemaConverter.checkConversionRequirement(
           field.getFieldCount == 1 && !field.getType(0).isPrimitive,
           s"Invalid map type: $field")
 
         val keyValueType = field.getType(0).asGroupType()
-        CatalystSchemaConverter.analysisRequire(
+        CatalystSchemaConverter.checkConversionRequirement(
           keyValueType.isRepetition(REPEATED) && keyValueType.getFieldCount == 2,
           s"Invalid map type: $field")
 
         val keyType = keyValueType.getType(0)
-        CatalystSchemaConverter.analysisRequire(
+        CatalystSchemaConverter.checkConversionRequirement(
           keyType.isPrimitive,
           s"Map key type is expected to be a primitive type, but found: $keyType")
 
@@ -299,7 +299,10 @@ private[parquet] class CatalystSchemaConverter(
    * Converts a Spark SQL [[StructType]] to a Parquet [[MessageType]].
    */
   def convert(catalystSchema: StructType): MessageType = {
-    Types.buildMessage().addFields(catalystSchema.map(convertField): _*).named("root")
+    Types
+      .buildMessage()
+      .addFields(catalystSchema.map(convertField): _*)
+      .named(CatalystSchemaConverter.SPARK_PARQUET_SCHEMA_NAME)
   }
 
   /**
@@ -347,10 +350,10 @@ private[parquet] class CatalystSchemaConverter(
       // NOTE: Spark SQL TimestampType is NOT a well defined type in Parquet format spec.
       //
       // As stated in PARQUET-323, Parquet `INT96` was originally introduced to represent nanosecond
-      // timestamp in Impala for some historical reasons, it's not recommended to be used for any
-      // other types and will probably be deprecated in future Parquet format spec.  That's the
-      // reason why Parquet format spec only defines `TIMESTAMP_MILLIS` and `TIMESTAMP_MICROS` which
-      // are both logical types annotating `INT64`.
+      // timestamp in Impala for some historical reasons.  It's not recommended to be used for any
+      // other types and will probably be deprecated in some future version of parquet-format spec.
+      // That's the reason why parquet-format spec only defines `TIMESTAMP_MILLIS` and
+      // `TIMESTAMP_MICROS` which are both logical types annotating `INT64`.
       //
       // Originally, Spark SQL uses the same nanosecond timestamp type as Impala and Hive.  Starting
       // from Spark 1.5.0, we resort to a timestamp type with 100 ns precision so that we can store
@@ -361,7 +364,7 @@ private[parquet] class CatalystSchemaConverter(
       // currently not implemented yet because parquet-mr 1.7.0 (the version we're currently using)
       // hasn't implemented `TIMESTAMP_MICROS` yet.
       //
-      // TODO Implements `TIMESTAMP_MICROS` once parquet-mr has that.
+      // TODO Converts `TIMESTAMP_MICROS` once parquet-mr implements that.
       case TimestampType =>
         Types.primitive(INT96, repetition).named(field.name)
 
@@ -372,7 +375,7 @@ private[parquet] class CatalystSchemaConverter(
       // Decimals (legacy mode)
       // ======================
 
-      // Spark 1.4.x and prior versions only support decimals with a maximum precision of 18 and
+      // Spark 1.5.x and prior versions only support decimals with a maximum precision of 18 and
       // always store decimals in fixed-length byte arrays.  To keep compatibility with these older
       // versions, here we convert decimals with all precisions to `FIXED_LEN_BYTE_ARRAY` annotated
       // by `DECIMAL`.
@@ -423,7 +426,7 @@ private[parquet] class CatalystSchemaConverter(
       // ArrayType and MapType (legacy mode)
       // ===================================
 
-      // Spark 1.4.x and prior versions convert `ArrayType` with nullable elements into a 3-level
+      // Spark 1.5.x and prior versions convert `ArrayType` with nullable elements into a 3-level
       // `LIST` structure.  This behavior is somewhat a hybrid of parquet-hive and parquet-avro
       // (1.6.0rc3): the 3-level structure is similar to parquet-hive while the 3rd level element
       // field name "array" is borrowed from parquet-avro.
@@ -442,7 +445,7 @@ private[parquet] class CatalystSchemaConverter(
             .addField(convertField(StructField("array", elementType, nullable)))
             .named("bag"))
 
-      // Spark 1.4.x and prior versions convert ArrayType with non-nullable elements into a 2-level
+      // Spark 1.5.x and prior versions convert ArrayType with non-nullable elements into a 2-level
       // LIST structure.  This behavior mimics parquet-avro (1.6.0rc3).  Note that this case is
       // covered by the backwards-compatibility rules implemented in `isElementType()`.
       case ArrayType(elementType, nullable @ false) if writeLegacyParquetFormat =>
@@ -455,7 +458,7 @@ private[parquet] class CatalystSchemaConverter(
           // "array" is the name chosen by parquet-avro (1.7.0 and prior version)
           convertField(StructField("array", elementType, nullable), REPEATED))
 
-      // Spark 1.4.x and prior versions convert MapType into a 3-level group annotated by
+      // Spark 1.5.x and prior versions convert MapType into a 3-level group annotated by
       // MAP_KEY_VALUE.  This is covered by `convertGroupField(field: GroupType): DataType`.
       case MapType(keyType, valueType, valueContainsNull) if writeLegacyParquetFormat =>
         // <map-repetition> group <name> (MAP) {
@@ -523,11 +526,12 @@ private[parquet] class CatalystSchemaConverter(
   }
 }
 
-
 private[parquet] object CatalystSchemaConverter {
+  val SPARK_PARQUET_SCHEMA_NAME = "spark_schema"
+
   def checkFieldName(name: String): Unit = {
     // ,;{}()\n\t= and space are special characters in Parquet schema
-    analysisRequire(
+    checkConversionRequirement(
       !name.matches(".*[ ,;{}()\n\t=].*"),
       s"""Attribute name "$name" contains invalid character(s) among " ,;{}()\\n\\t=".
          |Please use alias to rename it.
@@ -539,7 +543,7 @@ private[parquet] object CatalystSchemaConverter {
     schema
   }
 
-  def analysisRequire(f: => Boolean, message: String): Unit = {
+  def checkConversionRequirement(f: => Boolean, message: String): Unit = {
     if (!f) {
       throw new AnalysisException(message)
     }
@@ -553,16 +557,8 @@ private[parquet] object CatalystSchemaConverter {
     numBytes
   }
 
-  private val MIN_BYTES_FOR_PRECISION = Array.tabulate[Int](39)(computeMinBytesForPrecision)
-
   // Returns the minimum number of bytes needed to store a decimal with a given `precision`.
-  def minBytesForPrecision(precision : Int) : Int = {
-    if (precision < MIN_BYTES_FOR_PRECISION.length) {
-      MIN_BYTES_FOR_PRECISION(precision)
-    } else {
-      computeMinBytesForPrecision(precision)
-    }
-  }
+  val minBytesForPrecision = Array.tabulate[Int](39)(computeMinBytesForPrecision)
 
   val MAX_PRECISION_FOR_INT32 = maxPrecisionForBytes(4) /* 9 */