SET autocommit=1 while XA transaction is active may
cause various side effects, including memory corruption
and server crash.
The problem is that SET autocommit=1 and further queries
attempt to commit local transaction, whereas XA transaction
is still active.
As local and XA transactions are mutually exclusive, this
patch forbids enabling autocommit mode while XA transaction
is active.
mysql-test/r/xa.result:
A test case for BUG#51342.
mysql-test/t/xa.test:
A test case for BUG#51342.
sql/set_var.cc:
Forbid enabling autocommit mode while XA transaction is
active.
XA START may cause assertion failure/server crash when it is called
after unilateral roll back issued by the Resource Manager (both
in regular transaction and after XA transaction).
The problem was that rm_error variable wasn't set/reset properly.
mysql-test/r/xa.result:
A test case for BUG#43171.
mysql-test/t/xa.test:
A test case for BUG#43171.
sql/handler.cc:
Setting rm_error when we're out of XA transaction has no
special meaning. But it blocks reset of thd->transaction.xid
structure later.
sql/sql_parse.cc:
Reset rm_error before we enter ha_rollback(), so
thd->transaction.xid strucure is reinitialized.
The problem is that the one phase commit function failed to
properly end a empty transaction. The solution is to ensure
that the transaction cleanup procedure is invoked even for
empty transactions.
mysql-test/r/xa.result:
Add test case result for Bug#45548
mysql-test/t/xa.test:
Add test case for Bug#45548
sql/handler.cc:
Invoke transaction cleanup function whenever a transaction is ended.
The problem is that when a optimization of read-only transactions
(bypass 2-phase commit) was implemented, it removed the code that
reseted the XID once a transaction wasn't active anymore:
sql/sql_parse.cc:
- bzero(&thd->transaction.stmt, sizeof(thd->transaction.stmt));
- if (!thd->active_transaction())
- thd->transaction.xid_state.xid.null();
+ thd->transaction.stmt.reset();
This mostly worked fine as the transaction commit and rollback
functions (in handler.cc) reset the XID once the transaction is
ended. But those functions wouldn't reset the XID in case of
a empty transaction, leading to a assertion when a new starting
a new XA transaction.
The solution is to ensure that the XID state is reset when empty
transactions are ended (by either commit or rollback). This is
achieved by reorganizing the code so that the transaction cleanup
routine is invoked whenever a transaction is ended.
mysql-test/r/xa.result:
Add test case result for Bug#44672
mysql-test/t/xa.test:
Add test case for Bug#44672
sql/handler.cc:
Invoke transaction cleanup function whenever a transaction is
ended. Move XID state reset logic to the transaction cleanup
function.
sql/sql_class.h:
Add XID state reset logic.
The problem was that the server did not robustly handle a
unilateral roll back issued by the Resource Manager (RM)
due to a resource deadlock within the transaction branch.
By not acknowledging the roll back, the server (TM) would
eventually corrupt the XA transaction state and crash.
The solution is to mark the transaction as rollback-only
if the RM indicates that it rolled back its branch of the
transaction.
mysql-test/r/xa.result:
Add test case result for Bug#28323
mysql-test/t/xa.test:
Add test case for Bug#28323
sql/handler.cc:
Reset XID only at the end of the global transaction.
sql/share/errmsg.txt:
Add new error codes.
sql/sql_class.h:
Remember the error reported by the Resource Manager.
sql/sql_parse.cc:
Rollback the transaction if the Resource Manager reported
a error and rolled back its branch of the transaction.
