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Bug#28323: Server crashed in xid cache operations

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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.
This commit is contained in:
Davi Arnaut
2008-10-21 15:45:43 -02:00
parent 41f139bbc1
commit ca53651d40
6 changed files with 145 additions and 11 deletions
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78
sql/sql_parse.cc
View File

@ -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
@ -5070,6 +5118,7 @@ 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;
@ -5095,6 +5144,8 @@ 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;
@ -5126,6 +5177,12 @@ 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);
@ -5134,6 +5191,11 @@ 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)
{
@ -5180,28 +5242,26 @@ 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);