Skip to content

Commit

Permalink
Cleanup around wsrep mdl exception.
Browse files Browse the repository at this point in the history
  • Loading branch information
Nirbhay Choubey committed Jul 30, 2016
1 parent fb07658 commit 355bf4f
Show file tree
Hide file tree
Showing 2 changed files with 98 additions and 58 deletions.
74 changes: 47 additions & 27 deletions sql/mdl.cc
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2929,34 +2929,54 @@ bool MDL_context::has_explicit_locks()
}

#ifdef WITH_WSREP
void MDL_ticket::wsrep_report(bool debug)
static
const char *wsrep_get_mdl_type_name(enum_mdl_type type)
{
if (debug)
switch (type)
{
const PSI_stage_info *psi_stage = m_lock->key.get_wait_state_name();

WSREP_DEBUG("MDL ticket: type: %s space: %s db: %s name: %s (%s)",
(get_type() == MDL_INTENTION_EXCLUSIVE) ? "intention exclusive" :
((get_type() == MDL_SHARED) ? "shared" :
((get_type() == MDL_SHARED_HIGH_PRIO ? "shared high prio" :
((get_type() == MDL_SHARED_READ) ? "shared read" :
((get_type() == MDL_SHARED_WRITE) ? "shared write" :
((get_type() == MDL_SHARED_NO_WRITE) ? "shared no write" :
((get_type() == MDL_SHARED_NO_READ_WRITE) ? "shared no read write" :
((get_type() == MDL_EXCLUSIVE) ? "exclusive" :
"UNKNOWN")))))))),
(m_lock->key.mdl_namespace() == MDL_key::GLOBAL) ? "GLOBAL" :
((m_lock->key.mdl_namespace() == MDL_key::SCHEMA) ? "SCHEMA" :
((m_lock->key.mdl_namespace() == MDL_key::TABLE) ? "TABLE" :
((m_lock->key.mdl_namespace() == MDL_key::TABLE) ? "FUNCTION" :
((m_lock->key.mdl_namespace() == MDL_key::TABLE) ? "PROCEDURE" :
((m_lock->key.mdl_namespace() == MDL_key::TABLE) ? "TRIGGER" :
((m_lock->key.mdl_namespace() == MDL_key::TABLE) ? "EVENT" :
((m_lock->key.mdl_namespace() == MDL_key::COMMIT) ? "COMMIT" :
(char *)"UNKNOWN"))))))),
m_lock->key.db_name(),
m_lock->key.name(),
psi_stage->m_name);
}
case MDL_INTENTION_EXCLUSIVE : return "intention exclusive";
case MDL_SHARED : return "shared";
case MDL_SHARED_HIGH_PRIO : return "shared high prio";
case MDL_SHARED_READ : return "shared read";
case MDL_SHARED_WRITE : return "shared write";
case MDL_SHARED_UPGRADABLE : return "shared upgradable";
case MDL_SHARED_NO_WRITE : return "shared no write";
case MDL_SHARED_NO_READ_WRITE : return "shared no read write";
case MDL_EXCLUSIVE : return "exclusive";
default: break;
}
return "UNKNOWN";
}

static
const char *wsrep_get_mdl_namespace_name(MDL_key::enum_mdl_namespace ns)
{
switch (ns)
{
case MDL_key::GLOBAL : return "GLOBAL";
case MDL_key::SCHEMA : return "SCHEMA";
case MDL_key::TABLE : return "TABLE";
case MDL_key::FUNCTION : return "FUNCTION";
case MDL_key::PROCEDURE : return "PROCEDURE";
case MDL_key::TRIGGER : return "TRIGGER";
case MDL_key::EVENT : return "EVENT";
case MDL_key::COMMIT : return "COMMIT";
case MDL_key::USER_LOCK : return "USER_LOCK";
default: break;
}
return "UNKNOWN";
}

void MDL_ticket::wsrep_report(bool debug)
{
if (!debug) return;

const PSI_stage_info *psi_stage= m_lock->key.get_wait_state_name();
WSREP_DEBUG("MDL ticket: type: %s space: %s db: %s name: %s (%s)",
wsrep_get_mdl_type_name(get_type()),
wsrep_get_mdl_namespace_name(m_lock->key.mdl_namespace()),
m_lock->key.db_name(),
m_lock->key.name(),
psi_stage->m_name);
}
#endif /* WITH_WSREP */
82 changes: 51 additions & 31 deletions sql/wsrep_mysqld.cc
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1684,22 +1684,41 @@ void wsrep_to_isolation_end(THD *thd)
@retval FALSE Lock request cannot be granted
*/

bool
wsrep_grant_mdl_exception(MDL_context *requestor_ctx,
MDL_ticket *ticket,
const MDL_key *key
) {
bool wsrep_grant_mdl_exception(MDL_context *requestor_ctx,
MDL_ticket *ticket,
const MDL_key *key)
{
/* Fallback to the non-wsrep behaviour */
if (!WSREP_ON) return FALSE;

THD *request_thd = requestor_ctx->get_thd();
THD *granted_thd = ticket->get_ctx()->get_thd();
bool ret = FALSE;
THD *request_thd= requestor_ctx->get_thd();
THD *granted_thd= ticket->get_ctx()->get_thd();
bool ret= false;

const char* schema= key->db_name();
int schema_len= key->db_name_length();

mysql_mutex_lock(&request_thd->LOCK_wsrep_thd);

/*
We consider granting MDL exceptions only for appliers (BF THD) and ones
executing under TOI mode.
Rules:
1. If granted/owner THD is also an applier (BF THD) or one executing
under TOI mode, then we grant the requested lock to the requester
THD.
@return true
2. If granted/owner THD is executing a FLUSH command or already has an
explicit lock, then do not grant the requested lock to the requester
THD and it has to wait.
@return false
3. In all other cases the granted/owner THD is aborted and the requested
lock is not granted to the requester THD, thus it has to wait.
@return false
*/
if (request_thd->wsrep_exec_mode == TOTAL_ORDER ||
request_thd->wsrep_exec_mode == REPL_RECV)
{
Expand All @@ -1716,46 +1735,47 @@ wsrep_grant_mdl_exception(MDL_context *requestor_ctx,
request_thd, granted_thd);
ticket->wsrep_report(true);
mysql_mutex_unlock(&granted_thd->LOCK_wsrep_thd);
ret = TRUE;
ret= true;
}
else if (granted_thd->lex->sql_command == SQLCOM_FLUSH ||
granted_thd->mdl_context.has_explicit_locks())
{
WSREP_DEBUG("BF thread waiting for FLUSH");
ticket->wsrep_report(wsrep_debug);
mysql_mutex_unlock(&granted_thd->LOCK_wsrep_thd);
ret = FALSE;
}
else if (request_thd->lex->sql_command == SQLCOM_DROP_TABLE)
{
WSREP_DEBUG("DROP caused BF abort");
ticket->wsrep_report(wsrep_debug);
mysql_mutex_unlock(&granted_thd->LOCK_wsrep_thd);
wsrep_abort_thd((void*)request_thd, (void*)granted_thd, 1);
ret = FALSE;
}
else if (granted_thd->wsrep_query_state == QUERY_COMMITTING)
{
WSREP_DEBUG("MDL granted, but committing thd abort scheduled");
ticket->wsrep_report(wsrep_debug);
mysql_mutex_unlock(&granted_thd->LOCK_wsrep_thd);
wsrep_abort_thd((void*)request_thd, (void*)granted_thd, 1);
ret = FALSE;
ret= false;
}
else
{
WSREP_MDL_LOG(DEBUG, "MDL conflict-> BF abort", schema, schema_len,
request_thd, granted_thd);
ticket->wsrep_report(wsrep_debug);
/* Print some debug information. */
if (wsrep_debug)
{
if ((request_thd->lex->sql_command == SQLCOM_DROP_TABLE))
{
WSREP_DEBUG("DROP caused BF abort");
}
else if ((granted_thd->wsrep_query_state == QUERY_COMMITTING))
{
WSREP_DEBUG("MDL granted, but committing thd abort scheduled");
}
else
{
WSREP_MDL_LOG(DEBUG, "MDL conflict-> BF abort", schema, schema_len,
request_thd, granted_thd);
}
ticket->wsrep_report(true);
}

mysql_mutex_unlock(&granted_thd->LOCK_wsrep_thd);
wsrep_abort_thd((void*)request_thd, (void*)granted_thd, 1);
ret = FALSE;
wsrep_abort_thd((void *) request_thd, (void *) granted_thd, 1);
ret= false;
}
}
else
{
mysql_mutex_unlock(&request_thd->LOCK_wsrep_thd);
}

return ret;
}

Expand Down

0 comments on commit 355bf4f

Please sign in to comment.