Bug#60196 / Bug#11831040

Setting lowercase_table_names to 2 on Windows causing Foreign Key problems

This problem was exposed by the fix for Bug#55222.  There was a codepath in dict0load.c,
dict_load_foreigns() that made sure the table name matched case sensitive in order to
load a referenced table into the dictionary as needed.  If an engine is rebooted which
accesses a table with foreign keys, and lower_case_table_names=2, then the table with
foreign keys will get an error when it is changed (insert/updated/delete).
Once the referenced tables are loaded into the dictionary cache by a select statement
on those tables, the same change would succeed because the affected code path would
not get followed.

mysql-test/suite/innodb/r/innodb_bug60196.result

+DROP TABLE IF EXISTS Bug_60196_FK1 ;
+DROP TABLE IF EXISTS Bug_60196_FK2 ;
+DROP TABLE IF EXISTS Bug_60196 ;
+CREATE TABLE `Bug_60196_FK1` (Primary_Key INT PRIMARY KEY) ENGINE=InnoDB;
+CREATE TABLE `Bug_60196_FK2` (Primary_Key INT PRIMARY KEY) ENGINE=InnoDB;
+CREATE TABLE `Bug_60196` (
+FK1_Key INT NOT NULL,
+FK2_Key INT NOT NULL,
+PRIMARY KEY (FK2_Key, FK1_Key),
+KEY FK1_Key (FK1_Key),
+KEY FK2_Key (FK2_Key),
+CONSTRAINT FK_FK1 FOREIGN KEY (FK1_Key)
+REFERENCES Bug_60196_FK1 (Primary_Key)
+ON DELETE CASCADE
+ON UPDATE CASCADE,
+CONSTRAINT FK_FK2 FOREIGN KEY (FK2_Key)
+REFERENCES Bug_60196_FK2 (Primary_Key)
+ON DELETE CASCADE
+ON UPDATE CASCADE
+) ENGINE=InnoDB;
+INSERT INTO Bug_60196_FK1 VALUES (1), (2), (3), (4), (5);
+INSERT INTO Bug_60196_FK2 VALUES (1), (2), (3), (4), (5);
+INSERT INTO Bug_60196 VALUES (1, 1);
+INSERT INTO Bug_60196 VALUES (1, 2);
+INSERT INTO Bug_60196 VALUES (1, 3);
+INSERT INTO Bug_60196 VALUES (1, 99);
+ERROR 23000: Cannot add or update a child row: a foreign key constraint fails (`test`.`bug_60196`, CONSTRAINT `FK_FK2` FOREIGN KEY (`FK2_Key`) REFERENCES `Bug_60196_FK2` (`Primary_Key`) ON DELETE CASCADE ON UPDATE CASCADE)
+INSERT INTO Bug_60196 VALUES (99, 1);
+ERROR 23000: Cannot add or update a child row: a foreign key constraint fails (`test`.`bug_60196`, CONSTRAINT `FK_FK1` FOREIGN KEY (`FK1_Key`) REFERENCES `Bug_60196_FK1` (`Primary_Key`) ON DELETE CASCADE ON UPDATE CASCADE)
+SELECT * FROM bug_60196_FK1;
+Primary_Key
+1
+2
+3
+4
+5
+SELECT * FROM bug_60196_FK2;
+Primary_Key
+1
+2
+3
+4
+5
+SELECT * FROM bug_60196;
+FK1_Key	FK2_Key
+1	1
+1	2
+1	3
+# Stop master server
+# Restart server.
+#
+# Try to insert more to the example table with foreign keys.
+# Bug60196 causes the foreign key file not to be found after
+# the resstart above.
+#
+SELECT * FROM Bug_60196;
+FK1_Key	FK2_Key
+1	1
+1	2
+1	3
+INSERT INTO Bug_60196 VALUES (2, 1);
+INSERT INTO Bug_60196 VALUES (2, 2);
+INSERT INTO Bug_60196 VALUES (2, 3);
+SELECT * FROM Bug_60196;
+FK1_Key	FK2_Key
+1	1
+1	2
+1	3
+2	1
+2	2
+2	3
+
+# Clean up.
+DROP TABLE Bug_60196;
+DROP TABLE Bug_60196_FK1;
+DROP TABLE Bug_60196_FK2;

mysql-test/suite/innodb/t/innodb_bug60196-master.opt

+--lower-case-table-names=2

mysql-test/suite/innodb/t/innodb_bug60196.test

+# Bug#60196 - Setting lowercase_table_names to 2 on Windows causing
+# Foreign Key problems after an engine is restarted.
+
+# This test case needs InnoDB.
+-- source include/have_innodb.inc
+
+#
+# Precautionary clean up.
+#
+--disable_warnings
+DROP TABLE IF EXISTS Bug_60196_FK1 ;
+DROP TABLE IF EXISTS Bug_60196_FK2 ;
+DROP TABLE IF EXISTS Bug_60196 ;
+--enable_warnings
+
+#
+# Create test data.
+#
+CREATE TABLE `Bug_60196_FK1` (Primary_Key INT PRIMARY KEY) ENGINE=InnoDB;
+CREATE TABLE `Bug_60196_FK2` (Primary_Key INT PRIMARY KEY) ENGINE=InnoDB;
+CREATE TABLE `Bug_60196` (
+  FK1_Key INT NOT NULL,
+  FK2_Key INT NOT NULL,
+  PRIMARY KEY (FK2_Key, FK1_Key),
+  KEY FK1_Key (FK1_Key),
+  KEY FK2_Key (FK2_Key),
+  CONSTRAINT FK_FK1 FOREIGN KEY (FK1_Key)
+    REFERENCES Bug_60196_FK1 (Primary_Key)
+    ON DELETE CASCADE
+    ON UPDATE CASCADE,
+  CONSTRAINT FK_FK2 FOREIGN KEY (FK2_Key)
+    REFERENCES Bug_60196_FK2 (Primary_Key)
+    ON DELETE CASCADE
+    ON UPDATE CASCADE
+) ENGINE=InnoDB;
+INSERT INTO Bug_60196_FK1 VALUES (1), (2), (3), (4), (5);
+INSERT INTO Bug_60196_FK2 VALUES (1), (2), (3), (4), (5);
+INSERT INTO Bug_60196 VALUES (1, 1);
+INSERT INTO Bug_60196 VALUES (1, 2);
+INSERT INTO Bug_60196 VALUES (1, 3);
+--error ER_NO_REFERENCED_ROW_2
+INSERT INTO Bug_60196 VALUES (1, 99);
+--error ER_NO_REFERENCED_ROW_2
+INSERT INTO Bug_60196 VALUES (99, 1);
+
+SELECT * FROM bug_60196_FK1;
+SELECT * FROM bug_60196_FK2;
+SELECT * FROM bug_60196;
+
+--echo # Stop master server
+
+# Write file to make mysql-test-run.pl wait for the server to stop
+-- exec echo "wait" > $MYSQLTEST_VARDIR/tmp/mysqld.1.expect
+
+# Send a shutdown request to the server
+-- shutdown_server 10
+
+# Call script that will poll the server waiting for it to disapear
+-- source include/wait_until_disconnected.inc
+
+--echo # Restart server.
+
+# Write file to make mysql-test-run.pl start up the server again
+--exec echo "restart" > $MYSQLTEST_VARDIR/tmp/mysqld.1.expect
+
+# Turn on reconnect
+--enable_reconnect
+
+# Call script that will poll the server waiting for it to be back online again
+--source include/wait_until_connected_again.inc
+
+# Turn off reconnect again
+--disable_reconnect
+
+--echo #
+--echo # Try to insert more to the example table with foreign keys.
+--echo # Bug60196 causes the foreign key file not to be found after
+--echo # the resstart above.
+--echo #
+SELECT * FROM Bug_60196;
+INSERT INTO Bug_60196 VALUES (2, 1);
+INSERT INTO Bug_60196 VALUES (2, 2);
+INSERT INTO Bug_60196 VALUES (2, 3);
+SELECT * FROM Bug_60196;
+
+--echo
+--echo # Clean up.
+DROP TABLE Bug_60196;
+DROP TABLE Bug_60196_FK1;
+DROP TABLE Bug_60196_FK2;
+

storage/innobase/dict/dict0load.c

@@ -2258,10 +2258,12 @@ loop:
 	/* Since table names in SYS_FOREIGN are stored in a case-insensitive
 	order, we have to check that the table name matches also in a binary
 	string comparison. On Unix, MySQL allows table names that only differ
-	in character case. */
-
-	if (0 != ut_memcmp(field, table_name, len)) {
+	in character case.  If lower_case_table_names=2 then what is stored
+	may not be the same case, but the previous comparison showed that they
+	match with no-case.  */
 
+	if ((srv_lower_case_table_names != 2)
+	    && (0 != ut_memcmp(field, table_name, len))) {
 		goto next_rec;
 	}