Github user gatorsmile commented on a diff in the pull request: https://github.com/apache/spark/pull/16636#discussion_r99458457 --- Diff: sql/hive/src/main/scala/org/apache/spark/sql/hive/HiveUtils.scala --- @@ -455,4 +462,133 @@ private[spark] object HiveUtils extends Logging { case (decimal, DecimalType()) => decimal.toString case (other, tpe) if primitiveTypes contains tpe => other.toString } + + /** Converts the native StructField to Hive's FieldSchema. */ + private def toHiveColumn(c: StructField): FieldSchema = { + val typeString = if (c.metadata.contains(HiveUtils.hiveTypeString)) { + c.metadata.getString(HiveUtils.hiveTypeString) + } else { + c.dataType.catalogString + } + new FieldSchema(c.name, typeString, c.getComment.orNull) + } + + /** Builds the native StructField from Hive's FieldSchema. */ + private def fromHiveColumn(hc: FieldSchema): StructField = { + val columnType = try { + CatalystSqlParser.parseDataType(hc.getType) + } catch { + case e: ParseException => + throw new SparkException("Cannot recognize hive type string: " + hc.getType, e) + } + + val metadata = new MetadataBuilder().putString(HiveUtils.hiveTypeString, hc.getType).build() + val field = StructField( + name = hc.getName, + dataType = columnType, + nullable = true, + metadata = metadata) + Option(hc.getComment).map(field.withComment).getOrElse(field) + } + + // TODO: merge this with HiveClientImpl#toHiveTable + /** Converts the native table metadata representation format CatalogTable to Hive's Table. */ + def toHiveTable(catalogTable: CatalogTable): HiveTable = { + // We start by constructing an API table as Hive performs several important transformations + // internally when converting an API table to a QL table. + val tTable = new org.apache.hadoop.hive.metastore.api.Table() + tTable.setTableName(catalogTable.identifier.table) + tTable.setDbName(catalogTable.database) + + val tableParameters = new java.util.HashMap[String, String]() + tTable.setParameters(tableParameters) + catalogTable.properties.foreach { case (k, v) => tableParameters.put(k, v) } + + tTable.setTableType(catalogTable.tableType match { + case CatalogTableType.EXTERNAL => HiveTableType.EXTERNAL_TABLE.toString + case CatalogTableType.MANAGED => HiveTableType.MANAGED_TABLE.toString + case CatalogTableType.VIEW => HiveTableType.VIRTUAL_VIEW.toString + }) + + val sd = new org.apache.hadoop.hive.metastore.api.StorageDescriptor() + tTable.setSd(sd) + + // Note: In Hive the schema and partition columns must be disjoint sets + val (partCols, schema) = catalogTable.schema.map(toHiveColumn).partition { c => + catalogTable.partitionColumnNames.contains(c.getName) + } + sd.setCols(schema.asJava) + tTable.setPartitionKeys(partCols.asJava) + + catalogTable.storage.locationUri.foreach(sd.setLocation) + catalogTable.storage.inputFormat.foreach(sd.setInputFormat) + catalogTable.storage.outputFormat.foreach(sd.setOutputFormat) + + val serdeInfo = new org.apache.hadoop.hive.metastore.api.SerDeInfo + catalogTable.storage.serde.foreach(serdeInfo.setSerializationLib) + sd.setSerdeInfo(serdeInfo) + + val serdeParameters = new java.util.HashMap[String, String]() + catalogTable.storage.properties.foreach { case (k, v) => serdeParameters.put(k, v) } + serdeInfo.setParameters(serdeParameters) + + new HiveTable(tTable) + } + + /** + * Converts the native partition metadata representation format CatalogTablePartition to + * Hive's Partition. + */ + def toHivePartition( + catalogTable: CatalogTable, + hiveTable: HiveTable, + partition: CatalogTablePartition): HivePartition = { + val tPartition = new org.apache.hadoop.hive.metastore.api.Partition + tPartition.setDbName(catalogTable.database) + tPartition.setTableName(catalogTable.identifier.table) + tPartition.setValues(catalogTable.partitionColumnNames.map(partition.spec(_)).asJava) + + val sd = new org.apache.hadoop.hive.metastore.api.StorageDescriptor() + tPartition.setSd(sd) + + // Note: In Hive the schema and partition columns must be disjoint sets + val schema = catalogTable.schema.map(toHiveColumn).filter { c => + !catalogTable.partitionColumnNames.contains(c.getName) + } + sd.setCols(schema.asJava) + + partition.storage.locationUri.foreach(sd.setLocation) + partition.storage.inputFormat.foreach(sd.setInputFormat) + partition.storage.outputFormat.foreach(sd.setOutputFormat) + + val serdeInfo = new org.apache.hadoop.hive.metastore.api.SerDeInfo + sd.setSerdeInfo(serdeInfo) + // maps and lists should be set only after all elements are ready (see HIVE-7975) + partition.storage.serde.foreach(serdeInfo.setSerializationLib) + + val serdeParameters = new java.util.HashMap[String, String]() + catalogTable.storage.properties.foreach { case (k, v) => serdeParameters.put(k, v) } + partition.storage.properties.foreach { case (k, v) => serdeParameters.put(k, v) } + serdeInfo.setParameters(serdeParameters) + + new HivePartition(hiveTable, tPartition) + } + + /** + * Infers the schema for Hive serde tables and returns the CatalogTable with the inferred schema. + * When the tables are data source tables or the schema already exists, returns the original + * CatalogTable. + */ + def inferSchema(table: CatalogTable): CatalogTable = { + if (DDLUtils.isDatasourceTable(table) || table.schema.nonEmpty) { + table + } else { + val hiveTable = toHiveTable(table) + // Note: Hive separates partition columns and the schema, but for us the + // partition columns are part of the schema + val partCols = hiveTable.getPartCols.asScala.map(fromHiveColumn) + val schema = StructType(hiveTable.getCols.asScala.map(fromHiveColumn) ++ partCols) + table.copy(schema = schema, partitionColumnNames = partCols.map(_.name)) --- End diff -- I think it should not be changed. Let me remove it.
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