planner: small refactor for index join inner range building (#38100)

ref #37176

planner/core/exhaust_physical_plans.go

@@ -1326,20 +1326,17 @@ func (ijHelper *indexJoinBuildHelper) resetContextForIndex(innerKeys []*expressi
 
 // findUsefulEqAndInFilters analyzes the pushedDownConds held by inner child and split them to three parts.
 // usefulEqOrInFilters is the continuous eq/in conditions on current unused index columns.
-// uselessFilters is the conditions which cannot be used for building ranges.
+// remainedEqOrIn is part of usefulEqOrInFilters, which needs to be evaluated again in selection.
 // remainingRangeCandidates is the other conditions for future use.
-func (ijHelper *indexJoinBuildHelper) findUsefulEqAndInFilters(innerPlan *DataSource) (usefulEqOrInFilters, uselessFilters, remainingRangeCandidates []expression.Expression, emptyRange bool) {
-	uselessFilters = make([]expression.Expression, 0, len(innerPlan.pushedDownConds))
-	var remainedEqOrIn []expression.Expression
+func (ijHelper *indexJoinBuildHelper) findUsefulEqAndInFilters(innerPlan *DataSource) (usefulEqOrInFilters, remainedEqOrIn, remainingRangeCandidates []expression.Expression, emptyRange bool) {
 	// Extract the eq/in functions of possible join key.
 	// you can see the comment of ExtractEqAndInCondition to get the meaning of the second return value.
 	usefulEqOrInFilters, remainedEqOrIn, remainingRangeCandidates, _, emptyRange = ranger.ExtractEqAndInCondition(
 		innerPlan.ctx, innerPlan.pushedDownConds,
 		ijHelper.curNotUsedIndexCols,
 		ijHelper.curNotUsedColLens,
 	)
-	uselessFilters = append(uselessFilters, remainedEqOrIn...)
-	return usefulEqOrInFilters, uselessFilters, remainingRangeCandidates, emptyRange
+	return usefulEqOrInFilters, remainedEqOrIn, remainingRangeCandidates, emptyRange
 }
 
 // buildLastColManager analyze the `OtherConditions` of join to see whether there're some filters can be used in manager.
@@ -1460,7 +1457,6 @@ func (ijHelper *indexJoinBuildHelper) analyzeLookUpFilters(path *util.AccessPath
 		return false, nil
 	}
 	accesses := make([]expression.Expression, 0, len(path.IdxCols))
-	relatedExprs := make([]expression.Expression, 0, len(path.IdxCols)) // all expressions related to the chosen range
 	ijHelper.resetContextForIndex(innerJoinKeys, path.IdxCols, path.IdxColLens, outerJoinKeys)
 	notKeyEqAndIn, remained, rangeFilterCandidates, emptyRange := ijHelper.findUsefulEqAndInFilters(innerPlan)
 	if emptyRange {
@@ -1474,7 +1470,6 @@ func (ijHelper *indexJoinBuildHelper) analyzeLookUpFilters(path *util.AccessPath
 		return false, nil
 	}
 	accesses = append(accesses, notKeyEqAndIn...)
-	relatedExprs = append(relatedExprs, notKeyEqAndIn...)
 	remained = append(remained, remainedEqAndIn...)
 	lastColPos := matchedKeyCnt + len(notKeyEqAndIn)
 	// There should be some equal conditions. But we don't need that there must be some join key in accesses here.
@@ -1498,7 +1493,7 @@ func (ijHelper *indexJoinBuildHelper) analyzeLookUpFilters(path *util.AccessPath
 		if emptyRange {
 			return true, nil
 		}
-		mutableRange := ijHelper.createMutableIndexJoinRange(relatedExprs, ranges, path, innerJoinKeys, outerJoinKeys)
+		mutableRange := ijHelper.createMutableIndexJoinRange(accesses, ranges, path, innerJoinKeys, outerJoinKeys)
 		ijHelper.updateBestChoice(mutableRange, path, accesses, remained, nil, lastColPos, rebuildMode)
 		return false, nil
 	}
@@ -1526,7 +1521,6 @@ func (ijHelper *indexJoinBuildHelper) analyzeLookUpFilters(path *util.AccessPath
 			if err != nil {
 				return false, err
 			}
-			relatedExprs = append(relatedExprs, colAccesses...)
 		}
 		ranges, emptyRange, err = ijHelper.buildTemplateRange(matchedKeyCnt, notKeyEqAndIn, nextColRange, false)
 		if err != nil {
@@ -1543,7 +1537,7 @@ func (ijHelper *indexJoinBuildHelper) analyzeLookUpFilters(path *util.AccessPath
 		if len(colAccesses) > 0 {
 			lastColPos = lastColPos + 1
 		}
-		mutableRange := ijHelper.createMutableIndexJoinRange(relatedExprs, ranges, path, innerJoinKeys, outerJoinKeys)
+		mutableRange := ijHelper.createMutableIndexJoinRange(accesses, ranges, path, innerJoinKeys, outerJoinKeys)
 		ijHelper.updateBestChoice(mutableRange, path, accesses, remained, nil, lastColPos, rebuildMode)
 		return false, nil
 	}
@@ -1556,7 +1550,7 @@ func (ijHelper *indexJoinBuildHelper) analyzeLookUpFilters(path *util.AccessPath
 	if emptyRange {
 		return true, nil
 	}
-	mutableRange := ijHelper.createMutableIndexJoinRange(relatedExprs, ranges, path, innerJoinKeys, outerJoinKeys)
+	mutableRange := ijHelper.createMutableIndexJoinRange(accesses, ranges, path, innerJoinKeys, outerJoinKeys)
 	ijHelper.updateBestChoice(mutableRange, path, accesses, remained, lastColManager, lastColPos+1, rebuildMode)
 	return false, nil
 }

util/ranger/detacher.go

@@ -542,7 +542,7 @@ func extractValueInfo(expr expression.Expression) *valueInfo {
 
 // ExtractEqAndInCondition will split the given condition into three parts by the information of index columns and their lengths.
 // accesses: The condition will be used to build range.
-// filters: filters is the part that some access conditions need to be evaluate again since it's only the prefix part of char column.
+// filters: filters is the part that some access conditions need to be evaluated again since it's only the prefix part of char column.
 // newConditions: We'll simplify the given conditions if there're multiple in conditions or eq conditions on the same column.
 //
 //	e.g. if there're a in (1, 2, 3) and a in (2, 3, 4). This two will be combined to a in (2, 3) and pushed to newConditions.