Merge fix for MDEV-376

mysql-test/r/index_merge_innodb.result

@@ -777,4 +777,19 @@ commit;
 select * from t1 where t1.zone_id=830 AND modified=9;
 pk	zone_id	modified
 drop table t0, t1;
+#
+# MDEV-376: Wrong result (missing rows) with index_merge+index_merge_intersection, join
+#
+CREATE TABLE t1 (
+a INT, b CHAR(1), c CHAR(1), KEY(a), KEY(b)
+) ENGINE=InnoDB;
+INSERT INTO t1 VALUES (8,'v','v'),(8,'m','m'),(9,'d','d');
+SELECT ta.* FROM t1 AS ta, t1 AS tb
+WHERE ( tb.b != ta.b OR tb.a = ta.a )
+AND ( tb.b = ta.c OR tb.b = ta.b );
+a	b	c
+8	v	v
+8	m	m
+9	d	d
+DROP TABLE t1;
 set optimizer_switch= @optimizer_switch_save;

mysql-test/t/index_merge_innodb.test

@@ -156,6 +156,21 @@ select * from t1 where t1.zone_id=830 AND modified=9;
 
 drop table t0, t1;
 
+--echo #
+--echo # MDEV-376: Wrong result (missing rows) with index_merge+index_merge_intersection, join
+--echo #
+CREATE TABLE t1 (
+  a INT, b CHAR(1), c CHAR(1), KEY(a), KEY(b)
+) ENGINE=InnoDB;
+
+INSERT INTO t1 VALUES (8,'v','v'),(8,'m','m'),(9,'d','d');
+
+
+SELECT ta.* FROM t1 AS ta, t1 AS tb
+WHERE ( tb.b != ta.b OR tb.a = ta.a )
+  AND ( tb.b = ta.c OR tb.b = ta.b );
+
+DROP TABLE t1;
 
 set optimizer_switch= @optimizer_switch_save;
 

sql/opt_range.cc

@@ -2008,7 +2008,7 @@ int QUICK_RANGE_SELECT::init_ror_merged_scan(bool reuse_handler)
   if (reuse_handler)
   {
     DBUG_PRINT("info", ("Reusing handler 0x%lx", (long) file));
-    if (init() || reset())
+    if (init())
     {
       DBUG_RETURN(1);
     }
@@ -2043,7 +2043,7 @@ int QUICK_RANGE_SELECT::init_ror_merged_scan(bool reuse_handler)
   if (file->ha_external_lock(thd, F_RDLCK))
     goto failure;
 
-  if (init() || reset())
+  if (init())
   {
     file->ha_external_lock(thd, F_UNLCK);
     file->ha_close();
@@ -2090,7 +2090,18 @@ int QUICK_RANGE_SELECT::init_ror_merged_scan(bool reuse_handler)
   head->key_read= org_key_read;
   bitmap_copy(&column_bitmap, head->read_set);
   head->column_bitmaps_set(&column_bitmap, &column_bitmap);
-
+ 
+  if (reset())
+  {
+    if (!reuse_handler)
+    {
+      file->ha_external_lock(thd, F_UNLCK);
+      file->ha_close();
+      goto failure;
+    }
+    else
+      DBUG_RETURN(1);
+  }
   DBUG_RETURN(0);
 
 failure: