From 41dd7b6b92ce8e3c2ccb5aa9ebeef12be746793e Mon Sep 17 00:00:00 2001
From: Davi Arnaut <Davi.Arnaut@Sun.COM>
Date: Tue, 21 Oct 2008 16:07:31 -0200
Subject: Bug#28323: Server crashed in xid cache operations
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.
---
sql/sql_parse.cc | 78 +++++++++++++++++++++++++++++++++++++++++++++++++-------
1 file changed, 69 insertions(+), 9 deletions(-)
(limited to 'sql/sql_parse.cc')
diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index 713aca9de47..345f2d0420f 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -90,9 +90,57 @@ const char *command_name[]={
};
const char *xa_state_names[]={
- "NON-EXISTING", "ACTIVE", "IDLE", "PREPARED"
+ "NON-EXISTING", "ACTIVE", "IDLE", "PREPARED", "ROLLBACK ONLY"
};
+/**
+ Mark a XA transaction as rollback-only if the RM unilaterally
+ rolled back the transaction branch.
+
+ @note If a rollback was requested by the RM, this function sets
+ the appropriate rollback error code and transits the state
+ to XA_ROLLBACK_ONLY.
+
+ @return TRUE if transaction was rolled back or if the transaction
+ state is XA_ROLLBACK_ONLY. FALSE otherwise.
+*/
+static bool xa_trans_rolled_back(XID_STATE *xid_state)
+{
+ if (xid_state->rm_error)
+ {
+ switch (xid_state->rm_error) {
+ case ER_LOCK_WAIT_TIMEOUT:
+ my_error(ER_XA_RBTIMEOUT, MYF(0));
+ break;
+ case ER_LOCK_DEADLOCK:
+ my_error(ER_XA_RBDEADLOCK, MYF(0));
+ break;
+ default:
+ my_error(ER_XA_RBROLLBACK, MYF(0));
+ }
+ xid_state->xa_state= XA_ROLLBACK_ONLY;
+ }
+
+ return (xid_state->xa_state == XA_ROLLBACK_ONLY);
+}
+
+/**
+ Rollback work done on behalf of at ransaction branch.
+*/
+static bool xa_trans_rollback(THD *thd)
+{
+ bool status= test(ha_rollback(thd));
+
+ thd->options&= ~(ulong) OPTION_BEGIN;
+ thd->transaction.all.modified_non_trans_table= FALSE;
+ thd->server_status&= ~SERVER_STATUS_IN_TRANS;
+ xid_cache_delete(&thd->transaction.xid_state);
+ thd->transaction.xid_state.xa_state= XA_NOTR;
+ thd->transaction.xid_state.rm_error= 0;
+
+ return status;
+}
+
#ifndef EMBEDDED_LIBRARY
static bool do_command(THD *thd);
#endif // EMBEDDED_LIBRARY
@@ -5049,6 +5097,7 @@ create_sp_error:
}
DBUG_ASSERT(thd->transaction.xid_state.xid.is_null());
thd->transaction.xid_state.xa_state=XA_ACTIVE;
+ thd->transaction.xid_state.rm_error= 0;
thd->transaction.xid_state.xid.set(thd->lex->xid);
xid_cache_insert(&thd->transaction.xid_state);
thd->transaction.all.modified_non_trans_table= FALSE;
@@ -5074,6 +5123,8 @@ create_sp_error:
my_error(ER_XAER_NOTA, MYF(0));
break;
}
+ if (xa_trans_rolled_back(&thd->transaction.xid_state))
+ break;
thd->transaction.xid_state.xa_state=XA_IDLE;
send_ok(thd);
break;
@@ -5105,6 +5156,12 @@ create_sp_error:
XID_STATE *xs=xid_cache_search(thd->lex->xid);
if (!xs || xs->in_thd)
my_error(ER_XAER_NOTA, MYF(0));
+ else if (xa_trans_rolled_back(xs))
+ {
+ ha_commit_or_rollback_by_xid(thd->lex->xid, 0);
+ xid_cache_delete(xs);
+ break;
+ }
else
{
ha_commit_or_rollback_by_xid(thd->lex->xid, 1);
@@ -5113,6 +5170,11 @@ create_sp_error:
}
break;
}
+ if (xa_trans_rolled_back(&thd->transaction.xid_state))
+ {
+ xa_trans_rollback(thd);
+ break;
+ }
if (thd->transaction.xid_state.xa_state == XA_IDLE &&
thd->lex->xa_opt == XA_ONE_PHASE)
{
@@ -5159,28 +5221,26 @@ create_sp_error:
my_error(ER_XAER_NOTA, MYF(0));
else
{
+ bool ok= !xa_trans_rolled_back(xs);
ha_commit_or_rollback_by_xid(thd->lex->xid, 0);
xid_cache_delete(xs);
- send_ok(thd);
+ if (ok)
+ send_ok(thd);
}
break;
}
if (thd->transaction.xid_state.xa_state != XA_IDLE &&
- thd->transaction.xid_state.xa_state != XA_PREPARED)
+ thd->transaction.xid_state.xa_state != XA_PREPARED &&
+ thd->transaction.xid_state.xa_state != XA_ROLLBACK_ONLY)
{
my_error(ER_XAER_RMFAIL, MYF(0),
xa_state_names[thd->transaction.xid_state.xa_state]);
break;
}
- if (ha_rollback(thd))
+ if (xa_trans_rollback(thd))
my_error(ER_XAER_RMERR, MYF(0));
else
send_ok(thd);
- thd->options&= ~(ulong) OPTION_BEGIN;
- thd->transaction.all.modified_non_trans_table= FALSE;
- thd->server_status&= ~SERVER_STATUS_IN_TRANS;
- xid_cache_delete(&thd->transaction.xid_state);
- thd->transaction.xid_state.xa_state=XA_NOTR;
break;
case SQLCOM_XA_RECOVER:
res= mysql_xa_recover(thd);
--
cgit v1.2.1