From bfb7727526b2081074325142b7a84426c89531fa Mon Sep 17 00:00:00 2001
From: Igor Babaev <igor@askmonty.org>
Date: Sat, 4 Dec 2010 19:19:55 -0800
Subject: [PATCH] Fixed LP bug #684117. A crash may happenin the cases when the
 range optimizer tried to OR two index merge such that the second one
 contained less range trees than the first one. The bug was introduced by the
 patch of MWL#24: "index_merge: fair choice between index_merge union and
 range access".

---
 mysql-test/r/range_vs_index_merge.result        | 12 ++++++++++++
 mysql-test/r/range_vs_index_merge_innodb.result | 12 ++++++++++++
 mysql-test/t/range_vs_index_merge.test          | 16 ++++++++++++++++
 sql/opt_range.cc                                |  3 ++-
 4 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/mysql-test/r/range_vs_index_merge.result b/mysql-test/r/range_vs_index_merge.result
index b616afc9578..1f5d2564be2 100644
--- a/mysql-test/r/range_vs_index_merge.result
+++ b/mysql-test/r/range_vs_index_merge.result
@@ -1314,4 +1314,16 @@ WHERE c  = 'i'  OR b IN ( 'Arkansas' , 'd' , 'pdib' , 'can' )  OR
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index_merge	PRIMARY,idx1,idx2,idx3	idx3,idx2,PRIMARY,idx1	67,13,4,3	NULL	8	Using sort_union(idx3,idx2,PRIMARY,idx1); Using where
 DROP TABLE t1;
+CREATE TABLE t1 (
+f1 int, f2 int, f3 int, f4 int, f5 int,
+PRIMARY KEY (f4), KEY (f1), KEY (f2), KEY (f3)
+) ;
+INSERT INTO t1 VALUES (0,0,NULL,9,5), (0,0,1,9425,NULL);
+SELECT f5 FROM t1
+WHERE f2 != 1 OR f1 IS NULL OR f4 = 4 OR
+f2 AND (f4 BETWEEN 6 AND 255 OR f3 IS NULL);
+f5
+5
+NULL
+DROP TABLE t1;
 set session optimizer_switch='index_merge_sort_intersection=default';
diff --git a/mysql-test/r/range_vs_index_merge_innodb.result b/mysql-test/r/range_vs_index_merge_innodb.result
index 037e23eae5d..8a373115522 100644
--- a/mysql-test/r/range_vs_index_merge_innodb.result
+++ b/mysql-test/r/range_vs_index_merge_innodb.result
@@ -1315,5 +1315,17 @@ WHERE c  = 'i'  OR b IN ( 'Arkansas' , 'd' , 'pdib' , 'can' )  OR
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index_merge	PRIMARY,idx1,idx2,idx3	idx3,idx2,idx1,PRIMARY	67,13,3,4	NULL	9	Using sort_union(idx3,idx2,idx1,PRIMARY); Using where
 DROP TABLE t1;
+CREATE TABLE t1 (
+f1 int, f2 int, f3 int, f4 int, f5 int,
+PRIMARY KEY (f4), KEY (f1), KEY (f2), KEY (f3)
+) ;
+INSERT INTO t1 VALUES (0,0,NULL,9,5), (0,0,1,9425,NULL);
+SELECT f5 FROM t1
+WHERE f2 != 1 OR f1 IS NULL OR f4 = 4 OR
+f2 AND (f4 BETWEEN 6 AND 255 OR f3 IS NULL);
+f5
+5
+NULL
+DROP TABLE t1;
 set session optimizer_switch='index_merge_sort_intersection=default';
 SET SESSION STORAGE_ENGINE=DEFAULT;
diff --git a/mysql-test/t/range_vs_index_merge.test b/mysql-test/t/range_vs_index_merge.test
index d63a88ebf74..036d8837d0b 100755
--- a/mysql-test/t/range_vs_index_merge.test
+++ b/mysql-test/t/range_vs_index_merge.test
@@ -925,6 +925,22 @@ SELECT COUNT(*) FROM t1
 
 DROP TABLE t1;
 
+#
+# Bug #637978: ORing of two index merge that caused a crash
+#
+
+CREATE TABLE t1 (
+  f1 int, f2 int, f3 int, f4 int, f5 int,
+  PRIMARY KEY (f4), KEY (f1), KEY (f2), KEY (f3)
+) ;
+INSERT INTO t1 VALUES (0,0,NULL,9,5), (0,0,1,9425,NULL);
+
+SELECT f5 FROM t1
+  WHERE f2 != 1 OR f1 IS NULL OR f4 = 4 OR
+        f2 AND (f4 BETWEEN 6 AND 255 OR f3 IS NULL);
+
+DROP TABLE t1;
+
 #the following command must be the last one in the file
 set session optimizer_switch='index_merge_sort_intersection=default';
 
diff --git a/sql/opt_range.cc b/sql/opt_range.cc
index 9c961a45164..7c293648d23 100644
--- a/sql/opt_range.cc
+++ b/sql/opt_range.cc
@@ -1195,7 +1195,8 @@ int SEL_IMERGE::or_sel_imerge_with_checks(RANGE_OPT_PARAM *param,
 {
   *is_last_check_pass= TRUE;
   SEL_TREE** tree= imerge->trees;
-  for (uint i= 0; i < n_trees; i++, tree++)
+  SEL_TREE** tree_end= imerge->trees_next;
+  for ( ; tree < tree_end; tree++)
   {
     uint rc;
     bool is_last= TRUE;