aokolnychyi commented on a change in pull request #35395: URL: https://github.com/apache/spark/pull/35395#discussion_r807424289
########## File path: sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/v2/RowLevelCommandScanRelationPushDown.scala ########## @@ -0,0 +1,81 @@ +/* + * 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.execution.datasources.v2 + +import org.apache.spark.sql.catalyst.expressions.{AttributeReference, AttributeSet, Expression, PredicateHelper, SubqueryExpression} +import org.apache.spark.sql.catalyst.planning.RewrittenRowLevelCommand +import org.apache.spark.sql.catalyst.plans.logical.LogicalPlan +import org.apache.spark.sql.catalyst.rules.Rule +import org.apache.spark.sql.connector.expressions.filter.{Filter => V2Filter} +import org.apache.spark.sql.connector.read.ScanBuilder +import org.apache.spark.sql.execution.datasources.DataSourceStrategy +import org.apache.spark.sql.sources.Filter + +object RowLevelCommandScanRelationPushDown extends Rule[LogicalPlan] with PredicateHelper { + import DataSourceV2Implicits._ + + override def apply(plan: LogicalPlan): LogicalPlan = plan transformDown { + // push down the filter from the command condition instead of the filter in the rewrite plan, + // which may be negated for sources that only support replacing groups of data (e.g. files) Review comment: We actually have to prevent that (added the new rule to the list of rules that cannot be excluded). Here is how a DELETE command may look like. ``` == Analyzed Logical Plan == DeleteFromTable (id#88 <= 1) :- RelationV2[id#88, dep#89] cat.ns1.test_table +- ReplaceData RelationV2[id#88, dep#89] cat.ns1.test_table +- Filter NOT ((id#88 <= 1) <=> true) +- RelationV2[id#88, dep#89, _partition#91] cat.ns1.test_table ``` The condition we should push down to the source is the DELETE condition `(id < 1)` (not the condition in the filter on top of the scan). Suppose we have a data source that can replace files. We have two files: File A contains IDs 1, 2, 3 and File B contains IDs 5, 6, 7. If we want to delete the record with ID = 1, we should push down the actual delete condition (ID = 1) for correct file pruning. Once the data source determines that only File A contains records to delete, we need to read the entire file and determine what records did not match the condition (that's what that filter on top of the scan is doing). Those records (IDs 2, 3 in our example) have to be written back to the data source as it can only replace files. That's why pushing the filter condition would actually be wrong and we have to prevent it. -- 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]
