[WIP][SPARK-55951][SPARK-55952][SPARK-55953][SQL] Add post-processing for CDC changelog tables #55426
There are no files selected for viewing
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,315 @@ | ||
| /* | ||
| * 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.analysis | ||
|
|
||
| import org.apache.spark.sql.catalyst.expressions._ | ||
| import org.apache.spark.sql.catalyst.expressions.aggregate.{Count, Max, Min} | ||
| import org.apache.spark.sql.catalyst.plans.logical._ | ||
| import org.apache.spark.sql.catalyst.rules.Rule | ||
| import org.apache.spark.sql.catalyst.streaming.StreamingRelationV2 | ||
| import org.apache.spark.sql.catalyst.trees.TreeNodeTag | ||
| import org.apache.spark.sql.connector.catalog.{Changelog, ChangelogInfo} | ||
| import org.apache.spark.sql.errors.QueryCompilationErrors | ||
| import org.apache.spark.sql.execution.datasources.v2.{ChangelogTable, DataSourceV2Relation} | ||
| import org.apache.spark.sql.types.{IntegerType, StringType} | ||
|
|
||
| /** | ||
| * Post-processes a resolved [[ChangelogTable]] read to apply CDC option semantics | ||
| * (carry-over removal, update detection) and to enforce supported option combinations. | ||
| * | ||
| * Fires after [[ResolveRelations]] has wrapped the connector's [[Changelog]] in a | ||
| * [[ChangelogTable]]. Both batch ([[DataSourceV2Relation]]) and streaming | ||
| * ([[StreamingRelationV2]]) reads are handled: | ||
| * - Batch: the requested post-processing passes are injected as logical operators on top | ||
| * of the relation. Carry-over removal and update detection are fused into a single | ||
| * pass over a (rowId, _commit_version)-partitioned Window: the Filter drops CoW | ||
| * carry-over pairs (same rowVersion on both sides) and the subsequent Project relabels | ||
| * real delete+insert pairs as update_preimage / update_postimage. | ||
| * - Streaming: post-processing is not yet supported. If the requested options would | ||
| * require any post-processing, the rule throws an explicit [[AnalysisException]] to | ||
| * prevent silent wrong results. Streams that don't require post-processing pass | ||
| * through unchanged. | ||
| * | ||
| * Net change computation (`deduplicationMode = netChanges`) is not yet implemented and | ||
| * is rejected up-front for both batch and streaming. | ||
| */ | ||
| object ResolveChangelogTable extends Rule[LogicalPlan] { | ||
|
|
||
| private val CHANGELOG_TRANSFORMED_TAG = | ||
| TreeNodeTag[Boolean]("changelog_transformed") | ||
|
|
||
| private object HelperColumn { | ||
| final val DelCnt = "_del_cnt" | ||
| final val InsCnt = "_ins_cnt" | ||
| final val MinRv = "_min_rv" | ||
| final val MaxRv = "_max_rv" | ||
|
|
||
| val all: Set[String] = Set(DelCnt, InsCnt, MinRv, MaxRv) | ||
| } | ||
|
|
||
| override def apply(plan: LogicalPlan): LogicalPlan = { | ||
| if (isAlreadyTransformed(plan)) return plan | ||
| var updatedPlan = plan | ||
| updatedPlan = plan.resolveOperatorsUp { | ||
| case rel @ DataSourceV2Relation(table: ChangelogTable, _, _, _, _, _) => | ||
| val changelog = table.changelog | ||
| val req = evaluateRequirements(changelog, table.changelogInfo) | ||
|
|
||
| var updatedRel: LogicalPlan = rel | ||
| if (req.requiresCarryOverRemoval || req.requiresUpdateDetection) { | ||
| updatedRel = addRowLevelPostProcessing( | ||
| rel, changelog, req.requiresCarryOverRemoval, req.requiresUpdateDetection) | ||
| } | ||
| if (req.requiresNetChanges) { | ||
| updatedRel = injectNetChangeComputation(updatedRel, changelog) | ||
| } | ||
| updatedRel | ||
|
|
||
| case rel @ StreamingRelationV2(_, _, table: ChangelogTable, _, _, _, _, _, _) => | ||
| // Streaming CDC reads do not yet apply post-processing. Run the same option / | ||
| // capability validation as the batch path so silent wrong results are impossible: | ||
| // either no post-processing would be required (fall through, return raw stream), | ||
| // or we throw an explicit AnalysisException. | ||
| val changelog = table.changelog | ||
| val req = evaluateRequirements(changelog, table.changelogInfo) | ||
| if (req.needsAny) { | ||
| throw QueryCompilationErrors.cdcStreamingPostProcessingNotSupported(changelog.name()) | ||
| } | ||
| rel | ||
| } | ||
| if (updatedPlan ne plan) { | ||
| updatedPlan.setTagValue(CHANGELOG_TRANSFORMED_TAG, true) | ||
| } | ||
| updatedPlan | ||
| } | ||
|
|
||
| // --------------------------------------------------------------------------- | ||
| // Option validation & Requirement Computation | ||
| // --------------------------------------------------------------------------- | ||
|
|
||
| /** | ||
| * Captures which post-processing passes a CDC query requires, derived from the | ||
| * user-provided [[ChangelogInfo]] options and the connector-declared [[Changelog]] | ||
| * capability flags. | ||
| */ | ||
| private case class PostProcessingRequirements( | ||
| requiresCarryOverRemoval: Boolean, | ||
| requiresUpdateDetection: Boolean, | ||
| requiresNetChanges: Boolean) { | ||
| def needsAny: Boolean = | ||
| requiresCarryOverRemoval || requiresUpdateDetection || requiresNetChanges | ||
| } | ||
|
|
||
| /** | ||
| * Validates CDC option/capability combinations and computes which post-processing | ||
| * passes are required. Throws an [[org.apache.spark.sql.AnalysisException]] for | ||
| * unsupported or contradictory combinations (currently: `netChanges` deduplication, | ||
| * and `computeUpdates` with surfaced carry-overs but no carry-over removal). | ||
| */ | ||
| private def evaluateRequirements( | ||
| changelog: Changelog, | ||
| options: ChangelogInfo): PostProcessingRequirements = { | ||
| // Net change computation is not yet implemented. | ||
| if (options.deduplicationMode() == ChangelogInfo.DeduplicationMode.NET_CHANGES) { | ||
| throw QueryCompilationErrors.cdcNetChangesNotYetSupported(changelog.name()) | ||
| } | ||
|
|
||
| val requiresCarryOverRemoval = | ||
| options.deduplicationMode() != ChangelogInfo.DeduplicationMode.NONE && | ||
| changelog.containsCarryoverRows() | ||
| val requiresUpdateDetection = | ||
| options.computeUpdates() && changelog.representsUpdateAsDeleteAndInsert() | ||
| val requiresNetChanges = | ||
| options.deduplicationMode() == ChangelogInfo.DeduplicationMode.NET_CHANGES && | ||
| changelog.containsIntermediateChanges() | ||
|
|
||
| // If carry-overs are surfaced and update detection is enabled without carry-over | ||
| // removal, carry-overs would be falsely classified as updates, leading to wrong | ||
| // results. Hence we throw. | ||
| if (requiresUpdateDetection && | ||
| changelog.containsCarryoverRows() && | ||
| options.deduplicationMode() == ChangelogInfo.DeduplicationMode.NONE) { | ||
| throw QueryCompilationErrors.cdcUpdateDetectionRequiresCarryOverRemoval( | ||
| changelog.name()) | ||
| } | ||
|
|
||
| PostProcessingRequirements( | ||
| requiresCarryOverRemoval, requiresUpdateDetection, requiresNetChanges) | ||
| } | ||
|
|
||
| // --------------------------------------------------------------------------- | ||
| // Row Level Post Processing (Update Detection & Carry-over Removal) | ||
| // --------------------------------------------------------------------------- | ||
|
|
||
| /** | ||
| * Adds row-level post-processing (carry-over removal and/or update detection) on top of | ||
| * the given plan: | ||
| * - both active -> Window(counts + rv bounds) -> Filter -> Project(relabel) -> Drop helpers | ||
| * - carry-over only -> Window(counts + rv bounds) -> Filter -> Drop helpers | ||
| * - update only -> Window(counts only) -> Project(relabel) -> Drop helpers | ||
| * - neither -> not invoked (caller guards this case) | ||
| */ | ||
| private def addRowLevelPostProcessing( | ||
| plan: LogicalPlan, | ||
| cl: Changelog, | ||
| requiresCarryOverRemoval: Boolean, | ||
| requiresUpdateDetection: Boolean): LogicalPlan = { | ||
| // Row-version bounds in the Window are needed iff we filter carry-over pairs. | ||
| var modifiedPlan = addPostProcessingWindow(plan, cl, | ||
| includeRowVersionBounds = requiresCarryOverRemoval) | ||
| if (requiresCarryOverRemoval) modifiedPlan = addCarryOverPairFilter(modifiedPlan) | ||
| if (requiresUpdateDetection) modifiedPlan = addUpdateRelabelProjection(modifiedPlan) | ||
| removeHelperColumns(modifiedPlan) | ||
| } | ||
|
|
||
| /** | ||
| * Adds a Window node partitioned by (rowId, _commit_version) that computes | ||
| * `_del_cnt` and `_ins_cnt` per partition, and, when `includeRowVersionBounds` | ||
| * is true, additionally `_min_rv` / `_max_rv` (min/max of `Changelog.rowVersion()`). | ||
| * | ||
| * `_del_cnt` / `_ins_cnt` drive update detection (1 each -> relabel as | ||
| * update_preimage / update_postimage). `_min_rv` / `_max_rv` drive carry-over | ||
| * detection (within a delete+insert pair, equal bounds signal a CoW carry-over). | ||
| */ | ||
| private def addPostProcessingWindow( | ||
| plan: LogicalPlan, | ||
| cl: Changelog, | ||
| includeRowVersionBounds: Boolean): LogicalPlan = { | ||
| val changeTypeAttr = getAttribute(plan, "_change_type") | ||
| val rowIdExprs = V2ExpressionUtils.resolveRefs[NamedExpression](cl.rowId().toSeq, plan) | ||
| val commitVersionAttr = getAttribute(plan, "_commit_version") | ||
| val partitionByCols = rowIdExprs ++ Seq(commitVersionAttr) | ||
| val windowSpec = WindowSpecDefinition(partitionByCols, Nil, UnspecifiedFrame) | ||
|
|
||
| val insertIf = If(EqualTo(changeTypeAttr, Literal("insert")), | ||
| Literal(1), Literal(null, IntegerType)) | ||
| val deleteIf = If(EqualTo(changeTypeAttr, Literal("delete")), | ||
| Literal(1), Literal(null, IntegerType)) | ||
|
|
||
| val insCntAlias = Alias(WindowExpression( | ||
| Count(Seq(insertIf)).toAggregateExpression(), windowSpec), HelperColumn.InsCnt)() | ||
| val delCntAlias = Alias(WindowExpression( | ||
| Count(Seq(deleteIf)).toAggregateExpression(), windowSpec), HelperColumn.DelCnt)() | ||
| val baseAliases = Seq(delCntAlias, insCntAlias) | ||
| val rowVersionAliases = if (includeRowVersionBounds) { | ||
| val rowVersionExpr = | ||
| V2ExpressionUtils.resolveRef[NamedExpression](cl.rowVersion(), plan) | ||
| Seq( | ||
| Alias(WindowExpression( | ||
| Min(rowVersionExpr).toAggregateExpression(), windowSpec), HelperColumn.MinRv)(), | ||
| Alias(WindowExpression( | ||
| Max(rowVersionExpr).toAggregateExpression(), windowSpec), HelperColumn.MaxRv)()) | ||
| } else { | ||
| Seq.empty | ||
| } | ||
| Window(baseAliases ++ rowVersionAliases, partitionByCols, Nil, plan) | ||
| } | ||
|
|
||
| /** | ||
| * Adds a Filter node that drops rows belonging to a CoW carry-over pair. | ||
| * Expects the input to expose `_del_cnt`, `_ins_cnt`, `_min_rv`, `_max_rv`. | ||
| * A pair is a carry-over iff `_del_cnt = 1 AND _ins_cnt = 1 AND _min_rv = _max_rv`. | ||
| */ | ||
| private def addCarryOverPairFilter(input: LogicalPlan): LogicalPlan = { | ||
| val delCnt = getAttribute(input, HelperColumn.DelCnt) | ||
| val insCnt = getAttribute(input, HelperColumn.InsCnt) | ||
| val minRv = getAttribute(input, HelperColumn.MinRv) | ||
| val maxRv = getAttribute(input, HelperColumn.MaxRv) | ||
|
|
||
| val isCarryoverPair = And( | ||
| And(EqualTo(delCnt, Literal(1L)), EqualTo(insCnt, Literal(1L))), | ||
| EqualTo(minRv, maxRv)) | ||
|
Member
There was a problem hiding this comment. NULL-safety concern on SQL equality with NULL is UNKNOWN, not TRUE:
Options:
Worth a test with NULL rowVersion on exactly one half of a pair.
Contributor
Author
There was a problem hiding this comment. Implemented option 1, added test cases
Member
There was a problem hiding this comment. updated doc in #55460 |
||
| Filter(Not(isCarryoverPair), input) | ||
| } | ||
|
|
||
| /** | ||
| * Adds a Project node that rewrites `_change_type` to `update_preimage` / | ||
| * `update_postimage` whenever a delete+insert pair is present in the partition. | ||
| * Expects the input to expose `_del_cnt` and `_ins_cnt`. | ||
| */ | ||
| private def addUpdateRelabelProjection(input: LogicalPlan): LogicalPlan = { | ||
| val changeTypeAttr = getAttribute(input, "_change_type") | ||
| val delCnt = getAttribute(input, HelperColumn.DelCnt) | ||
| val insCnt = getAttribute(input, HelperColumn.InsCnt) | ||
|
|
||
| val isUpdate = And( | ||
| EqualTo(delCnt, Literal(1L)), | ||
| EqualTo(insCnt, Literal(1L))) | ||
| val isInvalid = Or(GreaterThan(delCnt, Literal(1L)), GreaterThan(insCnt, Literal(1L))) | ||
| val updateType = If(EqualTo(changeTypeAttr, Literal("insert")), | ||
| Literal("update_postimage"), Literal("update_preimage")) | ||
|
|
||
| val raiseInvalid = RaiseError( | ||
| Literal("INVALID_CDC_OPTION.UNEXPECTED_MULTIPLE_CHANGES_PER_ROW_VERSION"), | ||
| CreateMap(Nil), | ||
| StringType) | ||
| val caseExpr = CaseWhen(Seq(isInvalid -> raiseInvalid, isUpdate -> updateType), changeTypeAttr) | ||
|
|
||
| val projectList = input.output.map { attr => | ||
| if (attr.name == "_change_type") Alias(caseExpr, "_change_type")() | ||
| else attr | ||
| } | ||
| Project(projectList, input) | ||
| } | ||
|
|
||
| // --------------------------------------------------------------------------- | ||
| // Net Change Computation | ||
| // --------------------------------------------------------------------------- | ||
|
|
||
| /** | ||
| * Collapses multiple changes per row identity into the net effect. | ||
| * Not yet implemented. | ||
| */ | ||
| private def injectNetChangeComputation( | ||
| plan: LogicalPlan, | ||
| cl: Changelog): LogicalPlan = { | ||
| plan | ||
| } | ||
|
|
||
| // --------------------------------------------------------------------------- | ||
| // Helpers | ||
| // --------------------------------------------------------------------------- | ||
|
|
||
| /** | ||
| * Returns true if this plan has already been transformed by this rule. | ||
| * Uses a plan-level tag to prevent re-processing on subsequent rule executor iterations. | ||
| */ | ||
| private def isAlreadyTransformed(plan: LogicalPlan): Boolean = { | ||
| plan.getTagValue(CHANGELOG_TRANSFORMED_TAG).getOrElse(false) | ||
| } | ||
|
|
||
| /** | ||
| * Removes any helper columns (see [[HelperColumn]]) that earlier steps added to the | ||
| * plan. Helper columns not present in the input are silently ignored, so this method | ||
| * can be applied unconditionally regardless of which post-processing steps ran. | ||
| */ | ||
| private def removeHelperColumns(input: LogicalPlan): LogicalPlan = { | ||
| Project(input.output.filterNot(a => HelperColumn.all.contains(a.name)), input) | ||
| } | ||
|
|
||
| /** | ||
| * Looks up an attribute by name in a plan's output. Throws a clear error if missing -- | ||
| * used for required columns like `_change_type` / `_commit_version` / helper columns | ||
| * added by earlier steps; a missing column is always a programming error. | ||
| */ | ||
| private def getAttribute(plan: LogicalPlan, name: String): Attribute = | ||
| plan.output.find(_.name == name).getOrElse( | ||
| throw new IllegalStateException( | ||
| s"Required column '$name' not found in plan output: " + | ||
| plan.output.map(_.name).mkString(", "))) | ||
| } | ||
Oops, something went wrong.
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
INVALID_CHANGELOG_SCHEMA.MISSING_ROW_IDandINVALID_CHANGELOG_SCHEMA.NESTED_ROW_IDare declared here but not raised anywhere: no helper inQueryCompilationErrors, no call sites, no tests reference them. The PR description lists them as shipped but the code never uses them.Either land the helpers + validation now (tying into the schema-validation relocation discussion on
ChangelogTable.scalaline 70), or remove these sub-classes until the follow-up that raises them. Dead error-class declarations surface in the generated docs and tend to drift once the real fix lands.There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
Covered with the first batch of PR feedback fixes