From b3cd40e0d2aeafa64a1fa8b81a1d3905c67f4726 Mon Sep 17 00:00:00 2001
From: Igor Babaev <igor@askmonty.org>
Date: Thu, 9 Sep 2010 21:16:01 -0700
Subject: [PATCH] Fixed bug #49322. When not-exists optimization was applied to
 a table that happened to be an inner table of two outer joins, one embedded
 into another, then setting the match flag for the embedding outer join on
 could be skipped. This caused generation of extra null complemented rows.
 Made sure that the match flags are set correctly in all cases when not-exists
 optimization is used.

---
 mysql-test/r/join_nested.result | 58 +++++++++++++++++++++++++++++++++
 mysql-test/t/join_nested.test   | 40 +++++++++++++++++++++++
 sql/sql_select.cc               |  6 +++-
 3 files changed, 103 insertions(+), 1 deletion(-)

diff --git a/mysql-test/r/join_nested.result b/mysql-test/r/join_nested.result
index 2bdac08e7fd..9033e2b2252 100644
--- a/mysql-test/r/join_nested.result
+++ b/mysql-test/r/join_nested.result
@@ -1743,4 +1743,62 @@ ON t4.carrier = t1.carrier;
 COUNT(*)
 6
 DROP TABLE t1,t2,t3,t4,t5;
+CREATE TABLE t1 (
+pk int NOT NULL AUTO_INCREMENT PRIMARY KEY,
+a int DEFAULT NULL,
+KEY idx(a)
+);
+CREATE TABLE t2 (
+pk int  NOT NULL AUTO_INCREMENT PRIMARY KEY,
+a int DEFAULT NULL,
+KEY idx(a)
+);
+CREATE TABLE t3 (
+pk int NOT NULL AUTO_INCREMENT PRIMARY KEY,
+a int DEFAULT NULL,
+KEY idx(a)
+);
+INSERT INTO t1 VALUES 
+(1,2), (2,7), (3,5), (4,7), (5,5), (6,NULL), (7,NULL), (8,9);
+INSERT INTO t2 VALUES 
+(1,NULL), (4,2), (5,2), (3,4), (2,8);
+INSERT INTO t3 VALUES
+(1,9), (2,2), (3,5), (4,2), (5,7), (6,0), (7,5);
+SELECT t1.pk, t1.a, t2.pk, t2.a,t3.pk, t3.a 
+FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON t3.a=t2.a) ON t2.a=t1.a;
+pk	a	pk	a	pk	a
+1	2	4	2	2	2
+1	2	4	2	4	2
+1	2	5	2	2	2
+1	2	5	2	4	2
+2	7	NULL	NULL	NULL	NULL
+3	5	NULL	NULL	NULL	NULL
+4	7	NULL	NULL	NULL	NULL
+5	5	NULL	NULL	NULL	NULL
+6	NULL	NULL	NULL	NULL	NULL
+7	NULL	NULL	NULL	NULL	NULL
+8	9	NULL	NULL	NULL	NULL
+SELECT t1.pk, t1.a, t2.pk, t2.a,t3.pk, t3.a 
+FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON t3.a=t2.a) ON t2.a=t1.a
+WHERE t2.pk IS NULL;
+pk	a	pk	a	pk	a
+2	7	NULL	NULL	NULL	NULL
+3	5	NULL	NULL	NULL	NULL
+4	7	NULL	NULL	NULL	NULL
+5	5	NULL	NULL	NULL	NULL
+6	NULL	NULL	NULL	NULL	NULL
+7	NULL	NULL	NULL	NULL	NULL
+8	9	NULL	NULL	NULL	NULL
+SELECT t1.pk, t1.a, t2.pk, t2.a,t3.pk, t3.a 
+FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON t3.a=t2.a) ON t2.a=t1.a
+WHERE t3.pk IS NULL;
+pk	a	pk	a	pk	a
+2	7	NULL	NULL	NULL	NULL
+3	5	NULL	NULL	NULL	NULL
+4	7	NULL	NULL	NULL	NULL
+5	5	NULL	NULL	NULL	NULL
+6	NULL	NULL	NULL	NULL	NULL
+7	NULL	NULL	NULL	NULL	NULL
+8	9	NULL	NULL	NULL	NULL
+DROP TABLE t1, t2, t3;
 End of 5.0 tests
diff --git a/mysql-test/t/join_nested.test b/mysql-test/t/join_nested.test
index 5b07d8966f1..6ae7fb6dfee 100644
--- a/mysql-test/t/join_nested.test
+++ b/mysql-test/t/join_nested.test
@@ -1196,5 +1196,45 @@ SELECT COUNT(*)
 
 DROP TABLE t1,t2,t3,t4,t5;
 
+#
+# BUG#49322: Nested left joins + not-exist optimization
+#
+
+CREATE TABLE t1 (
+  pk int NOT NULL AUTO_INCREMENT PRIMARY KEY,
+  a int DEFAULT NULL,
+  KEY idx(a)
+);
+CREATE TABLE t2 (
+  pk int  NOT NULL AUTO_INCREMENT PRIMARY KEY,
+  a int DEFAULT NULL,
+  KEY idx(a)
+);
+CREATE TABLE t3 (
+  pk int NOT NULL AUTO_INCREMENT PRIMARY KEY,
+  a int DEFAULT NULL,
+  KEY idx(a)
+);
+
+INSERT INTO t1 VALUES 
+  (1,2), (2,7), (3,5), (4,7), (5,5), (6,NULL), (7,NULL), (8,9);
+INSERT INTO t2 VALUES 
+  (1,NULL), (4,2), (5,2), (3,4), (2,8);
+INSERT INTO t3 VALUES
+  (1,9), (2,2), (3,5), (4,2), (5,7), (6,0), (7,5);
+
+SELECT t1.pk, t1.a, t2.pk, t2.a,t3.pk, t3.a 
+  FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON t3.a=t2.a) ON t2.a=t1.a;
+
+SELECT t1.pk, t1.a, t2.pk, t2.a,t3.pk, t3.a 
+  FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON t3.a=t2.a) ON t2.a=t1.a
+  WHERE t2.pk IS NULL;
+
+SELECT t1.pk, t1.a, t2.pk, t2.a,t3.pk, t3.a 
+  FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON t3.a=t2.a) ON t2.a=t1.a
+  WHERE t3.pk IS NULL;
+
+DROP TABLE t1, t2, t3;
+
 --echo End of 5.0 tests
 
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 8381e257e26..a939213566e 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -11738,6 +11738,7 @@ evaluate_join_record(JOIN *join, JOIN_TAB *join_tab,
       condition is true => a match is found.
     */
     bool found= 1;
+    bool use_not_exists_opt= 0;
     while (join_tab->first_unmatched && found)
     {
       /*
@@ -11754,7 +11755,7 @@ evaluate_join_record(JOIN *join, JOIN_TAB *join_tab,
       for (JOIN_TAB *tab= first_unmatched; tab <= join_tab; tab++)
       {
         if (tab->table->reginfo.not_exists_optimize)
-          return NESTED_LOOP_NO_MORE_ROWS;
+          use_not_exists_opt= 1;
         /* Check all predicates that has just been activated. */
         /*
           Actually all predicates non-guarded by first_unmatched->found
@@ -11787,6 +11788,9 @@ evaluate_join_record(JOIN *join, JOIN_TAB *join_tab,
       join_tab->first_unmatched= first_unmatched;
     }
 
+    if (use_not_exists_opt)
+      return NESTED_LOOP_NO_MORE_ROWS;
+
     /*
       It was not just a return to lower loop level when one
       of the newly activated predicates is evaluated as false