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MDL_lock encapsulation: final

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All MDL_lock objects and types are private now. Along with a set
of methods which are not used outside.

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 2025-05-04 01:32:04 +04:00 committed by Sergei Golubchik
parent 0a9234fa8f
commit 42336cedd2
1 changed files with 29 additions and 34 deletions
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63
sql/mdl.cc
View File

@ -388,7 +388,6 @@ Deadlock_detection_visitor::opt_change_victim_to(MDL_context *new_victim)
class MDL_lock
{
public:
typedef mdl_bitmap_t bitmap_t;
class Ticket_list
@ -552,9 +551,10 @@ public:
static const bitmap_t m_waiting_incompatible[MDL_BACKUP_END];
};
public:
/** The key of the object (data) being protected. */
MDL_key key;
/**
Read-write lock protecting this lock context.
@ -590,18 +590,28 @@ public:
*/
mutable mysql_prlock_t m_rwlock;
/** List of granted tickets for this lock. */
Ticket_list m_granted;
/** Tickets for contexts waiting to acquire a lock. */
Ticket_list m_waiting;
/**
Number of times high priority lock requests have been granted while
low priority lock requests were waiting.
*/
ulong m_hog_lock_count;
const MDL_lock_strategy *m_strategy;
static const MDL_backup_lock m_backup_lock_strategy;
static const MDL_scoped_lock m_scoped_lock_strategy;
static const MDL_object_lock m_object_lock_strategy;
bool is_empty() const
{
return (m_granted.is_empty() && m_waiting.is_empty());
}
const bitmap_t *incompatible_granted_types_bitmap() const
{ return m_strategy->incompatible_granted_types_bitmap(); }
const bitmap_t *incompatible_waiting_types_bitmap() const
{ return m_strategy->incompatible_waiting_types_bitmap(); }
bool has_pending_conflicting_lock(enum_mdl_type type);
bool can_grant_lock(enum_mdl_type type, MDL_context *requstor_ctx,
bool ignore_lock_priority) const;
@ -610,9 +620,6 @@ public:
void remove_ticket(LF_PINS *pins, Ticket_list MDL_lock::*queue,
MDL_ticket *ticket);
bool visit_subgraph(MDL_ticket *waiting_ticket,
MDL_wait_for_graph_visitor *gvisitor);
bool needs_notification(const MDL_ticket *ticket) const
{ return m_strategy->needs_notification(ticket); }
void notify_conflicting_locks(MDL_context *ctx, bool abort_blocking)
@ -639,18 +646,16 @@ public:
bool check_if_conflicting_replication_locks(MDL_context *ctx);
#endif
/** List of granted tickets for this lock. */
Ticket_list m_granted;
/** Tickets for contexts waiting to acquire a lock. */
Ticket_list m_waiting;
/**
Number of times high priority lock requests have been granted while
low priority lock requests were waiting.
*/
ulong m_hog_lock_count;
public:
const bitmap_t *incompatible_granted_types_bitmap() const
{ return m_strategy->incompatible_granted_types_bitmap(); }
const bitmap_t *incompatible_waiting_types_bitmap() const
{ return m_strategy->incompatible_waiting_types_bitmap(); }
bool has_pending_conflicting_lock(enum_mdl_type type);
bool visit_subgraph(MDL_ticket *waiting_ticket,
MDL_wait_for_graph_visitor *gvisitor);
MDL_lock()
: m_hog_lock_count(0),
@ -893,13 +898,6 @@ end:
const MDL_key *get_key() const { return &key; }
const MDL_lock_strategy *m_strategy;
private:
static const MDL_backup_lock m_backup_lock_strategy;
static const MDL_scoped_lock m_scoped_lock_strategy;
static const MDL_object_lock m_object_lock_strategy;
};
@ -1049,7 +1047,6 @@ enum tal_status MDL_map::try_acquire_lock(LF_PINS *pins, MDL_key *mdl_key,
for them look like '<namespace-id>\0\0'.
*/
DBUG_ASSERT(mdl_key->length() == 3);
DBUG_ASSERT(m_backup_lock->m_strategy);
return m_backup_lock->try_acquire_lock(ticket, wait);
}
@ -2033,9 +2030,7 @@ MDL_wait_for_subgraph::~MDL_wait_for_subgraph()
bool MDL_ticket::has_stronger_or_equal_type(enum_mdl_type type) const
{
const MDL_lock::bitmap_t *
granted_incompat_map= m_lock->incompatible_granted_types_bitmap();
const auto *granted_incompat_map= m_lock->incompatible_granted_types_bitmap();
return ! (granted_incompat_map[type] & ~(granted_incompat_map[m_type]));
}