Github user cloud-fan commented on a diff in the pull request:
https://github.com/apache/spark/pull/15996#discussion_r93722277
--- Diff:
sql/core/src/main/scala/org/apache/spark/sql/DataFrameWriter.scala ---
@@ -363,48 +365,125 @@ final class DataFrameWriter[T] private[sql](ds:
Dataset[T]) {
throw new AnalysisException("Cannot create hive serde table with
saveAsTable API")
}
- val tableExists =
df.sparkSession.sessionState.catalog.tableExists(tableIdent)
-
- (tableExists, mode) match {
- case (true, SaveMode.Ignore) =>
- // Do nothing
-
- case (true, SaveMode.ErrorIfExists) =>
- throw new AnalysisException(s"Table $tableIdent already exists.")
-
- case _ =>
- val existingTable = if (tableExists) {
-
Some(df.sparkSession.sessionState.catalog.getTableMetadata(tableIdent))
- } else {
- None
- }
- val storage = if (tableExists) {
- existingTable.get.storage
- } else {
- DataSource.buildStorageFormatFromOptions(extraOptions.toMap)
- }
- val tableType = if (tableExists) {
- existingTable.get.tableType
- } else if (storage.locationUri.isDefined) {
- CatalogTableType.EXTERNAL
- } else {
- CatalogTableType.MANAGED
+ val catalog = df.sparkSession.sessionState.catalog
+ val db = tableIdent.database.getOrElse(catalog.getCurrentDatabase)
+ val tableIdentWithDB = tableIdent.copy(database = Some(db))
+ val tableName = tableIdent.unquotedString
+
+ catalog.getTableMetadataOption(tableIdent) match {
+ // If the table already exists...
+ case Some(tableMeta) =>
+ mode match {
+ case SaveMode.Ignore => // Do nothing
+
+ case SaveMode.ErrorIfExists =>
+ throw new AnalysisException(s"Table $tableName already exists.
You can set SaveMode " +
+ "to SaveMode.Append to insert data into the table or set
SaveMode to " +
+ "SaveMode.Overwrite to overwrite the existing data.")
+
+ case SaveMode.Append =>
+ // Check if the specified data source match the data source of
the existing table.
+ val specifiedProvider = DataSource.lookupDataSource(source)
+ // TODO: Check that options from the resolved relation match
the relation that we are
+ // inserting into (i.e. using the same compression).
+
+ // Pass a table identifier with database part, so that
`lookupRelation` won't get temp
+ // views unexpectedly.
+
EliminateSubqueryAliases(catalog.lookupRelation(tableIdentWithDB)) match {
+ case l @ LogicalRelation(_: InsertableRelation | _:
HadoopFsRelation, _, _) =>
+ // check if the file formats match
+ l.relation match {
+ case r: HadoopFsRelation if r.fileFormat.getClass !=
specifiedProvider =>
+ throw new AnalysisException(
+ s"The file format of the existing table $tableName
is " +
+ s"`${r.fileFormat.getClass.getName}`. It doesn't
match the specified " +
+ s"format `$source`")
+ case _ =>
+ }
+ case s: SimpleCatalogRelation if
DDLUtils.isDatasourceTable(s.metadata) => // OK.
+ case c: CatalogRelation if c.catalogTable.provider ==
Some(DDLUtils.HIVE_PROVIDER) =>
+ throw new AnalysisException(s"Saving data in the Hive
serde table $tableName " +
+ s"is not supported yet. Please use the insertInto() API
as an alternative.")
+ case o =>
+ throw new AnalysisException(s"Saving data in ${o.toString}
is not supported.")
+ }
+
+ val existingSchema = tableMeta.schema
+ if (df.logicalPlan.schema.size != existingSchema.size) {
+ throw new AnalysisException(
+ s"The column number of the existing table $tableName" +
+ s"(${existingSchema.catalogString}) doesn't match the
data schema" +
+ s"(${df.logicalPlan.schema.catalogString})")
+ }
+
+ if (partitioningColumns.isDefined) {
+ logWarning("append to an existing table, the specified
partition columns " +
+ s"[${partitioningColumns.get.mkString(", ")}] will be
ignored.")
+ }
+
+ val specifiedBucketSpec = getBucketSpec
+ if (specifiedBucketSpec.isDefined) {
+ logWarning("append to an existing table, the specified
bucketing " +
+ s"(${specifiedBucketSpec.get}) will be ignored.")
+ }
+
+ // Because we are inserting into an existing table, we should
respect the existing
+ // schema and adjust columns order of the given dataframe
according to it.
+ val adjustedColumns = existingSchema.map(f =>
Column(df.resolve(f.name)))
+ df.select(adjustedColumns:
_*).write.insertInto(tableIdentWithDB)
+
+ case SaveMode.Overwrite =>
+
EliminateSubqueryAliases(catalog.lookupRelation(tableIdentWithDB)) match {
+ // Only do the check if the table is a data source table
+ // (the relation is a BaseRelation).
+ case LogicalRelation(dest: BaseRelation, _, _) =>
+ // Get all input data source relations of the query.
+ val srcRelations = df.logicalPlan.collect {
+ case LogicalRelation(src: BaseRelation, _, _) => src
+ }
+ if (srcRelations.contains(dest)) {
+ throw new AnalysisException(
+ s"Cannot overwrite table $tableName that is also being
read from")
+ }
+ case _ => // OK
+ }
+
+ // Drop the existing table and create it again.
+ catalog.dropTable(tableIdentWithDB, ignoreIfNotExists = true,
purge = false)
+ createTable(tableIdentWithDB)
+
+ // Refresh the cache of the table in the catalog.
+ catalog.refreshTable(tableIdentWithDB)
}
- val tableDesc = CatalogTable(
- identifier = tableIdent,
- tableType = tableType,
- storage = storage,
- schema = new StructType,
- provider = Some(source),
- partitionColumnNames = partitioningColumns.getOrElse(Nil),
- bucketSpec = getBucketSpec
- )
- df.sparkSession.sessionState.executePlan(
- CreateTable(tableDesc, mode, Some(df.logicalPlan))).toRdd
+ // If the table doesn't exist...
+ case None => createTable(tableIdentWithDB)
}
}
+ private def createTable(tableIdent: TableIdentifier): Unit = {
+ val storage =
DataSource.buildStorageFormatFromOptions(extraOptions.toMap)
+ val tableType = if (storage.locationUri.isDefined) {
--- End diff --
all of it, except the test
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