WL#3567 - MERGE engine: a check for underlying table conformance

When a merge table is opened compare column and key definition of
underlying tables against column and key definition of merge table.

If any of underlying tables have different column/key definition
refuse to open merge table.


mysql-test/r/merge.result:
  A test case for WL#3456.
mysql-test/t/merge.test:
  A test case for WL#3456.
sql/ha_myisam.cc:
  Moved a part of code that converts TABLE object to MyISAM key and column
  definition to a separate function.
  
  Added check_definition() function that compares MyISAM table definitions.
sql/ha_myisammrg.cc:
  Check if underlying table definition conforms to merge table definition,
  and in case underlying table definition differs, refuse to open merge
  table.

1 files changed, 28 insertions, 1 deletions

diff --git a/mysql-test/t/merge.test b/mysql-test/t/merge.test
index bb03b7b8d62..700a807e62c 100644
--- a/mysql-test/t/merge.test
+++ b/mysql-test/t/merge.test
@@ -383,7 +383,7 @@ drop table t1, t2, t3;
 CREATE TABLE t1(a INT);
 INSERT INTO t1 VALUES(2),(1);
 CREATE TABLE t2(a INT, KEY(a)) ENGINE=MERGE UNION=(t1);
---error 1030
+--error 1168
 SELECT * FROM t2 WHERE a=2;
 DROP TABLE t1, t2;
 
@@ -401,4 +401,31 @@ CREATE TABLE t2(a INT) ENGINE=MERGE UNION=(t3);
 SELECT * FROM t2;
 DROP TABLE t2;
 
+#
+# Underlying table definition conformance tests.
+#
+CREATE TABLE t1(a INT, b TEXT);
+CREATE TABLE tm1(a TEXT, b INT) ENGINE=MERGE UNION=(t1);
+--error 1168
+SELECT * FROM tm1;
+DROP TABLE t1, tm1;
+
+CREATE TABLE t1(a SMALLINT, b SMALLINT);
+CREATE TABLE tm1(a INT) ENGINE=MERGE UNION=(t1);
+--error 1168
+SELECT * FROM tm1;
+DROP TABLE t1, tm1;
+
+CREATE TABLE t1(a SMALLINT, b SMALLINT, KEY(a, b));
+CREATE TABLE tm1(a SMALLINT, b SMALLINT, KEY(a)) ENGINE=MERGE UNION=(t1);
+--error 1168
+SELECT * FROM tm1;
+DROP TABLE t1, tm1;
+
+CREATE TABLE t1(a SMALLINT, b SMALLINT, KEY(b));
+CREATE TABLE tm1(a SMALLINT, b SMALLINT, KEY(a)) ENGINE=MERGE UNION=(t1);
+--error 1168
+SELECT * FROM tm1;
+DROP TABLE t1, tm1;
+
 # End of 4.1 tests