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MDL_lock encapsulation: removed redundant methods

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Given that MDL_lock::m_strategy is only accessed by MDL_lock methods,
there is no point in having MDL_lock::needs_notification() and
MDL_lock::hog_lock_types_bitmap() getters anymore.

MDL_lock::has_pending_conflicting_lock() moved to MDL_lock class.

This is part of broader cleanup, which aims to make large part of
MDL_lock members private. It is needed to simplify further work on
MDEV-19749 - MDL scalability regression after backup locks.
This commit is contained in:
Sergey Vojtovich 2025-05-07 16:04:07 +04:00 committed by Sergei Golubchik
parent 42336cedd2
commit 73798620a8
2 changed files with 27 additions and 34 deletions
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55
sql/mdl.cc
View File

@ -370,11 +370,6 @@ Deadlock_detection_visitor::opt_change_victim_to(MDL_context *new_victim)
} }
/**
Get a bit corresponding to enum_mdl_type value in a granted/waiting bitmaps
and compatibility matrices.
*/
/** /**
The lock context. Created internally for an acquired lock. The lock context. Created internally for an acquired lock.
For a given name, there exists only one MDL_lock instance, For a given name, there exists only one MDL_lock instance,
@ -620,8 +615,6 @@ class MDL_lock
void remove_ticket(LF_PINS *pins, Ticket_list MDL_lock::*queue, void remove_ticket(LF_PINS *pins, Ticket_list MDL_lock::*queue,
MDL_ticket *ticket); MDL_ticket *ticket);
bool needs_notification(const MDL_ticket *ticket) const
{ return m_strategy->needs_notification(ticket); }
void notify_conflicting_locks(MDL_context *ctx, bool abort_blocking) void notify_conflicting_locks(MDL_context *ctx, bool abort_blocking)
{ {
for (const auto &conflicting_ticket : m_granted) for (const auto &conflicting_ticket : m_granted)
@ -639,9 +632,6 @@ class MDL_lock
} }
} }
bitmap_t hog_lock_types_bitmap() const
{ return m_strategy->hog_lock_types_bitmap(); }
#ifndef DBUG_OFF #ifndef DBUG_OFF
bool check_if_conflicting_replication_locks(MDL_context *ctx); bool check_if_conflicting_replication_locks(MDL_context *ctx);
#endif #endif
@ -652,7 +642,24 @@ public:
const bitmap_t *incompatible_waiting_types_bitmap() const const bitmap_t *incompatible_waiting_types_bitmap() const
{ return m_strategy->incompatible_waiting_types_bitmap(); } { return m_strategy->incompatible_waiting_types_bitmap(); }
bool has_pending_conflicting_lock(enum_mdl_type type);
/**
Check if we have any pending locks which conflict with existing
shared lock.
@pre The ticket must match an acquired lock.
@return TRUE if there is a conflicting lock request, FALSE otherwise.
*/
bool has_pending_conflicting_lock(enum_mdl_type type)
{
bool result;
mysql_prlock_rdlock(&m_rwlock);
result= (m_waiting.bitmap() & incompatible_granted_types_bitmap()[type]);
mysql_prlock_unlock(&m_rwlock);
return result;
}
bool visit_subgraph(MDL_ticket *waiting_ticket, bool visit_subgraph(MDL_ticket *waiting_ticket,
MDL_wait_for_graph_visitor *gvisitor); MDL_wait_for_graph_visitor *gvisitor);
@ -800,7 +807,7 @@ end:
void notify_conflicting_locks_if_needed(MDL_ticket *ticket, bool abort_blocking) void notify_conflicting_locks_if_needed(MDL_ticket *ticket, bool abort_blocking)
{ {
if (needs_notification(ticket)) if (m_strategy->needs_notification(ticket))
{ {
mysql_prlock_wrlock(&m_rwlock); mysql_prlock_wrlock(&m_rwlock);
notify_conflicting_locks(ticket->get_ctx(), abort_blocking); notify_conflicting_locks(ticket->get_ctx(), abort_blocking);
@ -867,7 +874,7 @@ end:
res= TAL_WAIT; res= TAL_WAIT;
m_waiting.add_ticket(ticket); m_waiting.add_ticket(ticket);
if (needs_notification(ticket)) if (m_strategy->needs_notification(ticket))
notify_conflicting_locks(mdl_context, false); notify_conflicting_locks(mdl_context, false);
DBUG_SLOW_ASSERT((ticket->get_type() != MDL_INTENTION_EXCLUSIVE && DBUG_SLOW_ASSERT((ticket->get_type() != MDL_INTENTION_EXCLUSIVE &&
@ -1449,7 +1456,7 @@ void MDL_lock::Ticket_list::remove_ticket(MDL_ticket *ticket)
void MDL_lock::reschedule_waiters() void MDL_lock::reschedule_waiters()
{ {
bool skip_high_priority= false; bool skip_high_priority= false;
bitmap_t hog_lock_types= hog_lock_types_bitmap(); bitmap_t hog_lock_types= m_strategy->hog_lock_types_bitmap();
if (m_hog_lock_count >= max_write_lock_count) if (m_hog_lock_count >= max_write_lock_count)
{ {
@ -1992,26 +1999,6 @@ void MDL_lock::remove_ticket(LF_PINS *pins, Ticket_list MDL_lock::*list,
} }
/**
Check if we have any pending locks which conflict with existing
shared lock.
@pre The ticket must match an acquired lock.
@return TRUE if there is a conflicting lock request, FALSE otherwise.
*/
bool MDL_lock::has_pending_conflicting_lock(enum_mdl_type type)
{
bool result;
mysql_prlock_rdlock(&m_rwlock);
result= (m_waiting.bitmap() & incompatible_granted_types_bitmap()[type]);
mysql_prlock_unlock(&m_rwlock);
return result;
}
MDL_wait_for_graph_visitor::~MDL_wait_for_graph_visitor() MDL_wait_for_graph_visitor::~MDL_wait_for_graph_visitor()
= default; = default;

6
sql/mdl.h
View File

@ -31,6 +31,12 @@ class MDL_lock;
class MDL_ticket; class MDL_ticket;
typedef unsigned short mdl_bitmap_t; typedef unsigned short mdl_bitmap_t;
/**
Get a bit corresponding to enum_mdl_type value in a granted/waiting bitmaps
and compatibility matrices.
*/
#define MDL_BIT(A) static_cast<mdl_bitmap_t>(1U << A) #define MDL_BIT(A) static_cast<mdl_bitmap_t>(1U << A)