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https://issues.apache.org/jira/browse/HIVE-24087?focusedWorklogId=475841&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-475841
]
ASF GitHub Bot logged work on HIVE-24087:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 28/Aug/20 14:32
Start Date: 28/Aug/20 14:32
Worklog Time Spent: 10m
Work Description: kgyrtkirk commented on a change in pull request #1440:
URL: https://github.com/apache/hive/pull/1440#discussion_r479342835
##########
File path:
ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/rules/HiveJoinConstraintsRule.java
##########
@@ -213,61 +218,137 @@ public void onMatch(RelOptRuleCall call) {
// 2) Check whether this join can be rewritten or removed
RewritablePKFKJoinInfo r = HiveRelOptUtil.isRewritablePKFKJoin(
- join, leftInput == fkInput, call.getMetadataQuery());
+ join, fkInput, nonFkInput, call.getMetadataQuery());
// 3) If it is the only condition, we can trigger the rewriting
if (r.rewritable) {
- List<RexNode> nullableNodes = r.nullableNodes;
- // If we reach here, we trigger the transform
- if (mode == Mode.REMOVE) {
- if (rightInputPotentialFK) {
- // First, if FK is the right input, we need to shift
- nullableNodes = nullableNodes.stream()
- .map(node -> RexUtil.shift(node, 0,
-leftInput.getRowType().getFieldCount()))
- .collect(Collectors.toList());
- topProjExprs = topProjExprs.stream()
- .map(node -> RexUtil.shift(node, 0,
-leftInput.getRowType().getFieldCount()))
- .collect(Collectors.toList());
- }
- // Fix nullability in references to the input node
- topProjExprs = HiveCalciteUtil.fixNullability(rexBuilder,
topProjExprs, RelOptUtil.getFieldTypeList(fkInput.getRowType()));
- // Trigger transformation
- if (nullableNodes.isEmpty()) {
- call.transformTo(call.builder()
- .push(fkInput)
- .project(topProjExprs)
- .convert(project.getRowType(), false)
- .build());
+ rewrite(mode, fkInput, nonFkInput, join, topProjExprs, call, project,
r.nullableNodes);
+ } else {
+ // check if FK side could be removed instead
+
+ // Possibly this could be enhanced to take other join type into
consideration.
+ if (joinType != JoinRelType.INNER) {
+ return;
+ }
+
+ //first swap fk and non-fk input and see if we can rewrite them
+ RewritablePKFKJoinInfo fkRemoval = HiveRelOptUtil.isRewritablePKFKJoin(
+ join, nonFkInput, fkInput, call.getMetadataQuery());
+
+ if (fkRemoval.rewritable) {
+ // we have established that nonFkInput is FK, and fkInput is PK
+ // and there is no row filtering on FK side
+
+ // check that FK side join column is distinct (i.e. have a group by)
+ ImmutableBitSet fkSideBitSet;
+ if (nonFkInput == leftInput) {
+ fkSideBitSet = leftBits;
} else {
- RexNode newFilterCond;
- if (nullableNodes.size() == 1) {
- newFilterCond =
rexBuilder.makeCall(SqlStdOperatorTable.IS_NOT_NULL, nullableNodes.get(0));
- } else {
- List<RexNode> isNotNullConds = new ArrayList<>();
- for (RexNode nullableNode : nullableNodes) {
-
isNotNullConds.add(rexBuilder.makeCall(SqlStdOperatorTable.IS_NOT_NULL,
nullableNode));
+ fkSideBitSet = rightBits;
+ }
+
+ ImmutableBitSet.Builder fkJoinColBuilder = ImmutableBitSet.builder();
+ for (RexNode conj : RelOptUtil.conjunctions(cond)) {
+ if (!conj.isA(SqlKind.EQUALS)) {
+ continue;
Review comment:
why do we skip all other kinds which are not `EQUALS`?
I think instead there should be a return here instead of a continue
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Issue Time Tracking
-------------------
Worklog Id: (was: 475841)
Time Spent: 20m (was: 10m)
> FK side join elimination in presence of PK-FK constraint
> --------------------------------------------------------
>
> Key: HIVE-24087
> URL: https://issues.apache.org/jira/browse/HIVE-24087
> Project: Hive
> Issue Type: Improvement
> Components: Query Planning
> Reporter: Vineet Garg
> Assignee: Vineet Garg
> Priority: Major
> Labels: pull-request-available
> Time Spent: 20m
> Remaining Estimate: 0h
>
> If there is PK-FK join FK join could be eliminated by removing FK side if
> following conditions are met
> * There is no row filtering on FK side.
> * No columns from FK side is required after JOIN.
> * FK join columns are guranteed to be unique (have group by)
> * FK join columns are guranteed to be NOT NULL (either IS NOT NULL filter or
> constraint)
> *Example*
> {code:sql}
> EXPLAIN
> SELECT customer_removal_n0.*
> FROM customer_removal_n0
> JOIN
> (SELECT lo_custkey
> FROM lineorder_removal_n0
> WHERE lo_custkey IS NOT NULL
> GROUP BY lo_custkey) fkSide ON fkSide.lo_custkey =
> customer_removal_n0.c_custkey;
> {code}
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