szehon-ho commented on code in PR #58153: URL: https://github.com/apache/spark/pull/58153#discussion_r4066704999
########## sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/util/WriteDistributionAndOrdering.scala: ########## @@ -0,0 +1,73 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.spark.sql.catalyst.util + +import org.apache.spark.sql.connector.catalog.{Identifier, TableCatalog, TableCatalogCapability} +import org.apache.spark.sql.connector.expressions.SortOrder +import org.apache.spark.sql.errors.QueryCompilationErrors + +/** + * This object contains utility methods for the create-time write distribution and ordering + * requested by `CREATE`/`REPLACE TABLE ... DISTRIBUTED BY PARTITION / [LOCALLY] ORDERED BY`. + */ +object WriteDistributionAndOrdering { + + /** + * True when a CREATE/REPLACE TABLE statement asked for a write distribution or ordering. + * + * `UNORDERED` counts: it asks for no distribution, which is not the same as saying nothing. Only + * the catalog knows what it would otherwise have defaulted to, so Spark cannot treat the request + * as a no-op without guessing. + */ + def isRequested(writeDistributionMode: String, writeOrdering: Seq[SortOrder]): Boolean = { + writeDistributionMode != null || writeOrdering.nonEmpty + } + + /** + * Rejects a create-time write distribution or ordering that the catalog has not advertised + * support for, before anything is created or dropped. + * + * `TableInfo` carries the request as plain metadata, so a catalog that does not know about it + * would ignore it and hand back a table with none of the requested layout, and no indication of + * it. This is the only thing standing between the user and that silent drop. + */ + def validateCatalogForWriteDistributionAndOrdering( + catalog: TableCatalog, + ident: Identifier, + operation: String, + writeDistributionMode: String, + writeOrdering: Seq[SortOrder]): Unit = { + if (isRequested(writeDistributionMode, writeOrdering) && + !catalog.capabilities().contains( + TableCatalogCapability.SUPPORTS_CREATE_TABLE_WITH_WRITE_DISTRIBUTION_AND_ORDERING)) { + throw QueryCompilationErrors.unsupportedTableOperationError( + catalog, ident, s"$operation ... DISTRIBUTED BY/ORDERED BY") + } + } + + /** + * Renders a requested sort key the way SQL spells it, for SHOW CREATE TABLE and DESCRIBE. + * + * This deliberately uses the expression's `describe` rather than the `SortOrder`'s own + * `toString`: the latter renders an identity transform as `identity(col)`, which the parser + * would read back as a transform *named* `identity` rather than as a plain column reference. + */ + def describeSortOrder(sortOrder: SortOrder): String = { + s"${sortOrder.expression().describe()} ${sortOrder.direction()} ${sortOrder.nullOrdering()}" Review Comment: [P2] `describe()` does not preserve literal types. For example, the parser stores `DATE '1970-01-01'` as `LiteralValue(0, DateType)`, whose description is `0`. Consequently, an ordering such as `f(id, DATE '1970-01-01')` passes `isSpellable` but becomes `f(id, 0)` in `SHOW CREATE TABLE`. Replaying that DDL changes the argument to `IntegerType`, potentially changing or invalidating the ordering. Could we render type-preserving SQL literals and add a round-trip test comparing the reconstructed ordering expressions? -- 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: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
