stefankandic commented on code in PR #46280: URL: https://github.com/apache/spark/pull/46280#discussion_r1603651070
########## sql/api/src/main/scala/org/apache/spark/sql/types/StructField.scala: ########## @@ -63,7 +66,61 @@ case class StructField( ("name" -> name) ~ ("type" -> dataType.jsonValue) ~ ("nullable" -> nullable) ~ - ("metadata" -> metadata.jsonValue) + ("metadata" -> metadataJson) + } + + private def metadataJson: JValue = { + val metadataJsonValue = metadata.jsonValue + metadataJsonValue match { + case JObject(fields) if collationMetadata.nonEmpty => + val collationFields = collationMetadata.map(kv => kv._1 -> JString(kv._2)).toList + JObject(fields :+ (DataType.COLLATIONS_METADATA_KEY -> JObject(collationFields))) + + case _ => metadataJsonValue + } + } + + /** Map of field path to collation name. */ + private lazy val collationMetadata: Map[String, String] = { + val fieldToCollationMap = mutable.Map[String, String]() + + def visitRecursively(dt: DataType, path: String): Unit = dt match { + case at: ArrayType => + processDataType(at.elementType, path + ".element") + + case mt: MapType => + processDataType(mt.keyType, path + ".key") + processDataType(mt.valueType, path + ".value") + + case st: StringType if isCollatedString(st) => + fieldToCollationMap(path) = schemaCollationValue(st) + + case _ => + } + + def processDataType(dt: DataType, path: String): Unit = { + if (isCollatedString(dt)) { + fieldToCollationMap(path) = schemaCollationValue(dt) + } else { + visitRecursively(dt, path) + } + } + + visitRecursively(dataType, name) + fieldToCollationMap.toMap + } + + private def isCollatedString(dt: DataType): Boolean = dt match { + case st: StringType => !st.isUTF8BinaryCollation + case _ => false + } + + private def schemaCollationValue(dt: DataType): String = dt match { + case st: StringType => + val collation = CollationFactory.fetchCollation(st.collationId) + collation.identifier().toStringWithoutVersion() Review Comment: for writing statistics - version change invalidates them -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org