From 3c58e9bac919ffa3b7131a5c9b3ceec879b50c0e Mon Sep 17 00:00:00 2001
From: LiBinfeng <46676950+LiBinfeng-01@users.noreply.github.com>
Date: Tue, 25 Jul 2023 10:05:00 +0800
Subject: [PATCH] [Fix](Nereids) Fix problem of infer predicates not completely
 (#22145)

Problem:
When inferring predicate in nereids, new inferred predicates can not be the source of next round. For example:

create table tt1(c1 int, c2 int) distributed by hash(c1) properties('replication_num'='1');
create table tt2(c1 int, c2 int) distributed by hash(c1) properties('replication_num'='1');
create table tt3(c1 int, c2 int) distributed by hash(c1) properties('replication_num'='1');
explain select * from tt1 left join tt2 on tt1.c1 = tt2.c1 left join tt3 on tt2.c1 = tt3.c1 where tt1.c1 = 123;

we expect to get t33.c1 = 123, but we can just get t22.c1 = 123. Because when infer tt1.c1 = 123 and tt2.c1 = tt3.c1, we can
not get any relationship of these two predicates.

Solution:
We need to cache middle results of source predicates like t22.c1 = 123 in example.
---
 .../nereids/rules/rewrite/PredicatePropagation.java      | 9 +++++++++
 .../nereids_p0/infer_predicate/infer_predicate.groovy    | 7 +++++++
 2 files changed, 16 insertions(+)

diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/rules/rewrite/PredicatePropagation.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/rules/rewrite/PredicatePropagation.java
index cc45952817a845..f6f04e899bc2f3 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/nereids/rules/rewrite/PredicatePropagation.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/nereids/rules/rewrite/PredicatePropagation.java
@@ -40,11 +40,17 @@
  */
 public class PredicatePropagation {
 
+    /**
+     * equal predicate with literal in one side would be chosen to be source predicates and used to infer all predicates
+     */
+    private Set<Expression> sourcePredicates = Sets.newHashSet();
+
     /**
      * infer additional predicates.
      */
     public Set<Expression> infer(Set<Expression> predicates) {
         Set<Expression> inferred = Sets.newHashSet();
+        predicates.addAll(sourcePredicates);
         for (Expression predicate : predicates) {
             if (canEquivalentInfer(predicate)) {
                 List<Expression> newInferred = predicates.stream()
@@ -55,6 +61,7 @@ public Set<Expression> infer(Set<Expression> predicates) {
             }
         }
         inferred.removeAll(predicates);
+        sourcePredicates.addAll(inferred);
         return inferred;
     }
 
@@ -76,8 +83,10 @@ public Expression visit(Expression expr, Void context) {
             public Expression visitComparisonPredicate(ComparisonPredicate cp, Void context) {
                 // we need to get expression covered by cast, because we want to infer different datatype
                 if (ExpressionUtils.isExpressionSlotCoveredByCast(cp.left()) && (cp.right().isConstant())) {
+                    sourcePredicates.add(cp);
                     return replaceSlot(cp, ExpressionUtils.getDatatypeCoveredByCast(cp.left()));
                 } else if (ExpressionUtils.isExpressionSlotCoveredByCast(cp.right()) && cp.left().isConstant()) {
+                    sourcePredicates.add(cp);
                     return replaceSlot(cp, ExpressionUtils.getDatatypeCoveredByCast(cp.right()));
                 }
                 return super.visit(cp, context);
diff --git a/regression-test/suites/nereids_p0/infer_predicate/infer_predicate.groovy b/regression-test/suites/nereids_p0/infer_predicate/infer_predicate.groovy
index f93de7273b9f45..2ad1c250cabc09 100644
--- a/regression-test/suites/nereids_p0/infer_predicate/infer_predicate.groovy
+++ b/regression-test/suites/nereids_p0/infer_predicate/infer_predicate.groovy
@@ -21,6 +21,7 @@ suite("test_infer_predicate") {
 
     sql 'drop table if exists infer_tb1;'
     sql 'drop table if exists infer_tb2;'
+    sql 'drop table if exists infer_tb3;'
 
     sql '''create table infer_tb1 (k1 int, k2 int) distributed by hash(k1) buckets 3 properties('replication_num' = '1');'''
 
@@ -47,4 +48,10 @@ suite("test_infer_predicate") {
         sql "select * from infer_tb1 inner join infer_tb3 where infer_tb3.k1 = infer_tb1.k2  and infer_tb3.k1 = '123';"
         notContains "PREDICATES: k2[#6] = '123'"
     }
+
+    explain {
+        sql "select * from infer_tb1 left join infer_tb2 on infer_tb1.k1 = infer_tb2.k3 left join infer_tb3 on " +
+                "infer_tb2.k3 = infer_tb3.k2 where infer_tb1.k1 = 1;"
+        contains "PREDICATES: k3[#4] = 1"
+    }
 }