Backport of:

------------------------------------------------------------
 2599.161.3 Ingo Struewing      2009-07-21
 Bug#20667 - Truncate table fails for a write locked table

 TRUNCATE TABLE was not allowed under LOCK TABLES.

 The patch removes this restriction. mysql_truncate()
 does now handle that case.


mysql-test/r/merge.result:
  Bug#20667 - Truncate table fails for a write locked table
  Updated test result.
mysql-test/r/truncate.result:
  Bug#20667 - Truncate table fails for a write locked table
  Updated test result.
mysql-test/r/truncate_coverage.result:
  Bug#20667 - Truncate table fails for a write locked table
  New test result.
mysql-test/t/merge.test:
  Bug#20667 - Truncate table fails for a write locked table
  Updated test case due to now working TRUNCATE under LOCK TABLES.
  Added some SELECTs to show that child tables are truncated.
mysql-test/t/truncate.test:
  Bug#20667 - Truncate table fails for a write locked table
  Added test cases for TRUNCATE under LOCK TABLE.
mysql-test/t/truncate_coverage.test:
  Bug#20667 - Truncate table fails for a write locked table
  New test file. Coverage tests for TRUNCATE.
sql/sql_delete.cc:
  Bug#20667 - Truncate table fails for a write locked table
  Added branches for thd->locked_tables_mode.
sql/sql_parse.cc:
  Bug#20667 - Truncate table fails for a write locked table
  Deleted rejection of TRUNCATE in case of LOCK TABLES.

1 files changed, 155 insertions, 0 deletions

diff --git a/mysql-test/t/truncate_coverage.test b/mysql-test/t/truncate_coverage.test
new file mode 100644
index 00000000000..9870fbb5ebf
--- /dev/null
+++ b/mysql-test/t/truncate_coverage.test
@@ -0,0 +1,155 @@
+#
+# Code coverage testing of TRUNCATE TABLE.
+#
+# Ingo Struewing, 2009-07-20
+#
+
+--source include/have_debug_sync.inc
+SET DEBUG_SYNC='RESET';
+
+--let $MYSQLD_DATADIR= `SELECT @@datadir`
+
+--disable_warnings
+DROP TABLE IF EXISTS t1;
+--enable_warnings
+
+--echo #
+--echo # Bug#20667 - Truncate table fails for a write locked table
+--echo #
+########
+# Attack wait_while_table_is_used(). Kill query while trying to
+# upgrade MDL.
+#
+CREATE TABLE t1 (c1 INT);
+INSERT INTO t1 VALUES (1);
+#
+# Start a transaction and execute a DML in it. Since 5.4.4 this leaves
+# a shared meta data lock (MDL) behind. TRUNCATE shall block on it.
+#
+--echo #
+--echo # connection con1
+--connect (con1, localhost, root,,)
+START TRANSACTION;
+INSERT INTO t1 VALUES (2);
+#
+# Get connection id of default connection.
+# Lock the table and start TRUNCATE, which will block on MDL upgrade.
+#
+--echo #
+--echo # connection default
+--connection default
+let $ID= `SELECT @id := CONNECTION_ID()`;
+LOCK TABLE t1 WRITE;
+SET DEBUG_SYNC='mdl_upgrade_shared_lock_to_exclusive SIGNAL waiting';
+send TRUNCATE TABLE t1;
+#
+# Get the default connection ID into a variable in an invisible statement.
+# Kill the TRUNCATE query. This shall result in an error return
+# from wait_while_table_is_used().
+#
+--echo #
+--echo # connection con1
+--connection con1
+SET DEBUG_SYNC='now WAIT_FOR waiting';
+let $invisible_assignment_in_select = `SELECT @id := $ID`;
+KILL QUERY @id;
+COMMIT;
+--disconnect con1
+--echo #
+--echo # connection default
+--connection default
+--error ER_QUERY_INTERRUPTED
+reap;
+UNLOCK TABLES;
+DROP TABLE t1;
+SET DEBUG_SYNC='RESET';
+########
+# Attack reopen_tables(). Remove form file.
+#
+CREATE TABLE t1 (c1 INT);
+INSERT INTO t1 VALUES (1);
+#
+# Start a transaction and execute a DML in it. Since 5.4.4 this leaves
+# a shared meta data lock (MDL) behind. TRUNCATE shall block on it.
+#
+--echo #
+--echo # connection con1
+--connect (con1, localhost, root,,)
+START TRANSACTION;
+INSERT INTO t1 VALUES (2);
+#
+# Lock the table and start TRUNCATE, which will block on MDL upgrade.
+#
+--echo #
+--echo # connection default
+--connection default
+LOCK TABLE t1 WRITE;
+SET DEBUG_SYNC='mdl_upgrade_shared_lock_to_exclusive SIGNAL waiting';
+send TRUNCATE TABLE t1;
+#
+# Remove datafile.
+# Commit to let TRUNCATE continue.
+#
+--echo #
+--echo # connection con1
+--connection con1
+SET DEBUG_SYNC='now WAIT_FOR waiting';
+--remove_file $MYSQLD_DATADIR/test/t1.frm
+COMMIT;
+--disconnect con1
+--echo #
+--echo # connection default
+--connection default
+--error ER_NO_SUCH_TABLE
+reap;
+UNLOCK TABLES;
+--error ER_BAD_TABLE_ERROR
+DROP TABLE t1;
+SET DEBUG_SYNC='RESET';
+########
+# Attack acquire_exclusive_locks(). Hold a global read lock.
+# Non-LOCK TABLE case.
+#
+CREATE TABLE t1 (c1 INT);
+INSERT INTO t1 VALUES (1);
+#
+# Start a transaction and execute a DML in it. Since 5.4.4 this leaves
+# a shared meta data lock (MDL) behind. TRUNCATE shall block on it.
+#
+--echo #
+--echo # connection con1
+--connect (con1, localhost, root,,)
+START TRANSACTION;
+INSERT INTO t1 VALUES (2);
+#
+# Get connection id of default connection.
+# Start TRUNCATE, which will block on acquire_exclusive_locks().
+#
+--echo #
+--echo # connection default
+--connection default
+let $ID= `SELECT @id := CONNECTION_ID()`;
+SET DEBUG_SYNC='mdl_acquire_exclusive_locks_wait SIGNAL waiting';
+send TRUNCATE TABLE t1;
+#
+# Get the default connection ID into a variable in an invisible statement.
+# Kill the TRUNCATE query. This shall result in an error return
+# from wait_while_table_is_used().
+#
+--echo #
+--echo # connection con1
+--connection con1
+SET DEBUG_SYNC='now WAIT_FOR waiting';
+let $invisible_assignment_in_select = `SELECT @id := $ID`;
+KILL QUERY @id;
+COMMIT;
+--disconnect con1
+--echo #
+--echo # connection default
+--connection default
+--error ER_QUERY_INTERRUPTED
+reap;
+UNLOCK TABLES;
+DROP TABLE t1;
+SET DEBUG_SYNC='RESET';
+