5 files changed, 138 insertions, 2 deletions
diff --git a/mysql-test/r/merge_mmap.result b/mysql-test/r/merge_mmap.result
new file mode 100644
index 00000000000..d975a1be377
--- /dev/null
+++ b/mysql-test/r/merge_mmap.result
@@ -0,0 +1,64 @@
+SET GLOBAL storage_engine = MyISAM;
+SET SESSION storage_engine = MyISAM;
+DROP TABLE IF EXISTS t1, t2, m1, m2;
+CREATE TABLE t1 (c1 INT);
+CREATE TABLE t2 (c1 INT);
+CREATE TABLE m1 (c1 INT) ENGINE=MRG_MyISAM UNION=(t1,t2)
+INSERT_METHOD=LAST;
+CREATE TABLE m2 (c1 INT) ENGINE=MRG_MyISAM UNION=(t1,t2)
+INSERT_METHOD=LAST;
+INSERT INTO t1 VALUES (1);
+INSERT INTO t2 VALUES (2), (3), (4);
+INSERT INTO m2 SELECT * FROM m1;
+SELECT * FROM m2;
+c1
+1
+2
+3
+4
+1
+2
+3
+4
+SELECT * FROM t2;
+c1
+2
+3
+4
+1
+2
+3
+4
+DROP TABLE m2, m1, t2, t1;
+CREATE TABLE t1 (c1 INT);
+CREATE TABLE t2 (c1 INT);
+CREATE TABLE m1 (c1 INT) ENGINE=MRG_MyISAM UNION=(t1,t2)
+INSERT_METHOD=LAST;
+CREATE TABLE m2 (c1 INT) ENGINE=MRG_MyISAM UNION=(t1,t2)
+INSERT_METHOD=LAST;
+LOCK TABLE m1 WRITE, m2 WRITE;
+INSERT INTO t1 VALUES (1);
+INSERT INTO t2 VALUES (2), (3), (4);
+INSERT INTO m2 SELECT * FROM m1;
+SELECT * FROM m2;
+c1
+1
+2
+3
+4
+1
+2
+3
+4
+SELECT * FROM t2;
+c1
+2
+3
+4
+1
+2
+3
+4
+UNLOCK TABLES;
+DROP TABLE m2, m1, t2, t1;
+End of 6.0 tests
diff --git a/mysql-test/t/merge_mmap-master.opt b/mysql-test/t/merge_mmap-master.opt
new file mode 100644
index 00000000000..9606fb57187
--- /dev/null
+++ b/mysql-test/t/merge_mmap-master.opt
@@ -0,0 +1 @@
+--myisam-use-mmap
diff --git a/mysql-test/t/merge_mmap.test b/mysql-test/t/merge_mmap.test
new file mode 100644
index 00000000000..3468702ca45
--- /dev/null
+++ b/mysql-test/t/merge_mmap.test
@@ -0,0 +1,60 @@
+#
+# Test of MERGE TABLES with MyISAM memory mapping enabled (--myisam-use-mmap)
+#
+
+# MERGE tables require MyISAM tables
+--let $default=`SELECT @@global.storage_engine`
+SET GLOBAL storage_engine = MyISAM;
+SET SESSION storage_engine = MyISAM;
+
+# Clean up resources used in this test case.
+--disable_warnings
+DROP TABLE IF EXISTS t1, t2, m1, m2;
+--enable_warnings
+
+####################
+## No locked tables.
+####################
+#
+# INSERT-SELECT with no TEMPORARY table.
+#
+CREATE TABLE t1 (c1 INT);
+CREATE TABLE t2 (c1 INT);
+CREATE TABLE m1 (c1 INT) ENGINE=MRG_MyISAM UNION=(t1,t2)
+  INSERT_METHOD=LAST;
+CREATE TABLE m2 (c1 INT) ENGINE=MRG_MyISAM UNION=(t1,t2)
+  INSERT_METHOD=LAST;
+INSERT INTO t1 VALUES (1);
+INSERT INTO t2 VALUES (2), (3), (4);
+INSERT INTO m2 SELECT * FROM m1;
+SELECT * FROM m2;
+SELECT * FROM t2;
+DROP TABLE m2, m1, t2, t1;
+
+####################
+## With LOCK TABLES.
+####################
+#
+# INSERT-SELECT with no TEMPORARY table.
+#
+CREATE TABLE t1 (c1 INT);
+CREATE TABLE t2 (c1 INT);
+CREATE TABLE m1 (c1 INT) ENGINE=MRG_MyISAM UNION=(t1,t2)
+  INSERT_METHOD=LAST;
+CREATE TABLE m2 (c1 INT) ENGINE=MRG_MyISAM UNION=(t1,t2)
+  INSERT_METHOD=LAST;
+LOCK TABLE m1 WRITE, m2 WRITE;
+INSERT INTO t1 VALUES (1);
+INSERT INTO t2 VALUES (2), (3), (4);
+INSERT INTO m2 SELECT * FROM m1;
+SELECT * FROM m2;
+SELECT * FROM t2;
+UNLOCK TABLES;
+DROP TABLE m2, m1, t2, t1;
+--echo End of 6.0 tests
+
+--disable_result_log
+--disable_query_log
+eval SET GLOBAL storage_engine = $default;
+--enable_result_log
+--enable_query_log
diff --git a/storage/myisam/mi_statrec.c b/storage/myisam/mi_statrec.c
index 7d595916d78..f83afa3c886 100644
--- a/storage/myisam/mi_statrec.c
+++ b/storage/myisam/mi_statrec.c
@@ -298,8 +298,17 @@ int _mi_read_rnd_static_record(MI_INFO *info, uchar *buf,
     info->update|= HA_STATE_AKTIV | HA_STATE_KEY_CHANGED;
     DBUG_RETURN(0);
   }
-  /* my_errno should be set if rec_cache.error == -1 */
+  /* error is TRUE. my_errno should be set if rec_cache.error == -1 */
   if (info->rec_cache.error != -1 || my_errno == 0)
-    my_errno=HA_ERR_WRONG_IN_RECORD;
+  {
+    /*
+      If we could not get a full record, we either have a broken record,
+      or are at end of file.
+    */
+    if (info->rec_cache.error == 0)
+      my_errno= HA_ERR_END_OF_FILE;
+    else
+      my_errno= HA_ERR_WRONG_IN_RECORD;
+  }
   DBUG_RETURN(my_errno);			/* Something wrong (EOF?) */
 }
diff --git a/storage/myisammrg/ha_myisammrg.cc b/storage/myisammrg/ha_myisammrg.cc
index 67b81225b13..1681f062117 100644
--- a/storage/myisammrg/ha_myisammrg.cc
+++ b/storage/myisammrg/ha_myisammrg.cc
@@ -1322,6 +1322,8 @@ int ha_myisammrg::extra(enum ha_extra_function operation)
   if (operation == HA_EXTRA_FORCE_REOPEN ||
       operation == HA_EXTRA_PREPARE_FOR_DROP)
     return 0;
+  if (operation == HA_EXTRA_MMAP && !opt_myisam_use_mmap)
+    return 0;
   return myrg_extra(file,operation,0);
 }