MDEV-23634: Select query hanged the server and leads to OOM ...bb-10.4-mdev23634

Handle "col<>const" in the same way that MDEV-21958 did for
"col NOT IN(const-list)": do not use the condition for range/index_merge
accesses if there is a unique UNIQUE KEY(col).

The testcase is in main/range.test. The rest of test updates are
due to widespread use of 'pk<>1' in the testsuite. Changed the test
to use different but equivalent forms of the conditions.

1 files changed, 11 insertions, 0 deletions

diff --git a/mysql-test/main/range.result b/mysql-test/main/range.result
index 60c79c02c44..afd1571283f 100644
--- a/mysql-test/main/range.result
+++ b/mysql-test/main/range.result
@@ -3244,6 +3244,17 @@ SELECT * FROM t1 JOIN t2 ON (t2.code = t1.b) WHERE t1.a NOT IN ('baz', 'qux') OR
 id	a	b	code	num
 DROP TABLE t1, t2;
 #
+# MDEV-23634: Select query hanged the server and leads to OOM ...
+# (The fix is to add the same handling for "col!=const" as MDEV-21958 did for NOT IN)
+#
+create table t1 (pk int primary key, a int);
+insert into t1 (pk) values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
+# must not use range:
+explain select * from t1 force index (primary) where pk != 1 and pk!=2 ;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	PRIMARY	NULL	NULL	NULL	10	Using where
+drop table t1;
+#
 # MDEV-22251: get_key_scans_params: Conditional jump or move depends on uninitialised value
 #
 create table t1 (pk int, i int, v int, primary key (pk), key(v));