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lock.h
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1 /*-------------------------------------------------------------------------
2  *
3  * lock.h
4  * POSTGRES low-level lock mechanism
5  *
6  *
7  * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
8  * Portions Copyright (c) 1994, Regents of the University of California
9  *
10  * src/include/storage/lock.h
11  *
12  *-------------------------------------------------------------------------
13  */
14 #ifndef LOCK_H_
15 #define LOCK_H_
16 
17 #ifdef FRONTEND
18 #error "lock.h may not be included from frontend code"
19 #endif
20 
21 #include "storage/lockdefs.h"
22 #include "storage/backendid.h"
23 #include "storage/lwlock.h"
24 #include "storage/shmem.h"
25 
26 
27 /* struct PGPROC is declared in proc.h, but must forward-reference it */
28 typedef struct PGPROC PGPROC;
29 
30 typedef struct PROC_QUEUE
31 {
32  SHM_QUEUE links; /* head of list of PGPROC objects */
33  int size; /* number of entries in list */
34 } PROC_QUEUE;
35 
36 /* GUC variables */
37 extern int max_locks_per_xact;
38 
39 #ifdef LOCK_DEBUG
40 extern int Trace_lock_oidmin;
41 extern bool Trace_locks;
42 extern bool Trace_userlocks;
43 extern int Trace_lock_table;
44 extern bool Debug_deadlocks;
45 #endif /* LOCK_DEBUG */
46 
47 
48 /*
49  * Top-level transactions are identified by VirtualTransactionIDs comprising
50  * the BackendId of the backend running the xact, plus a locally-assigned
51  * LocalTransactionId. These are guaranteed unique over the short term,
52  * but will be reused after a database restart; hence they should never
53  * be stored on disk.
54  *
55  * Note that struct VirtualTransactionId can not be assumed to be atomically
56  * assignable as a whole. However, type LocalTransactionId is assumed to
57  * be atomically assignable, and the backend ID doesn't change often enough
58  * to be a problem, so we can fetch or assign the two fields separately.
59  * We deliberately refrain from using the struct within PGPROC, to prevent
60  * coding errors from trying to use struct assignment with it; instead use
61  * GET_VXID_FROM_PGPROC().
62  */
63 typedef struct
64 {
65  BackendId backendId; /* determined at backend startup */
66  LocalTransactionId localTransactionId; /* backend-local transaction id */
68 
69 #define InvalidLocalTransactionId 0
70 #define LocalTransactionIdIsValid(lxid) ((lxid) != InvalidLocalTransactionId)
71 #define VirtualTransactionIdIsValid(vxid) \
72  (((vxid).backendId != InvalidBackendId) && \
73  LocalTransactionIdIsValid((vxid).localTransactionId))
74 #define VirtualTransactionIdEquals(vxid1, vxid2) \
75  ((vxid1).backendId == (vxid2).backendId && \
76  (vxid1).localTransactionId == (vxid2).localTransactionId)
77 #define SetInvalidVirtualTransactionId(vxid) \
78  ((vxid).backendId = InvalidBackendId, \
79  (vxid).localTransactionId = InvalidLocalTransactionId)
80 #define GET_VXID_FROM_PGPROC(vxid, proc) \
81  ((vxid).backendId = (proc).backendId, \
82  (vxid).localTransactionId = (proc).lxid)
83 
84 /* MAX_LOCKMODES cannot be larger than the # of bits in LOCKMASK */
85 #define MAX_LOCKMODES 10
86 
87 #define LOCKBIT_ON(lockmode) (1 << (lockmode))
88 #define LOCKBIT_OFF(lockmode) (~(1 << (lockmode)))
89 
90 
91 /*
92  * This data structure defines the locking semantics associated with a
93  * "lock method". The semantics specify the meaning of each lock mode
94  * (by defining which lock modes it conflicts with).
95  * All of this data is constant and is kept in const tables.
96  *
97  * numLockModes -- number of lock modes (READ,WRITE,etc) that
98  * are defined in this lock method. Must be less than MAX_LOCKMODES.
99  *
100  * conflictTab -- this is an array of bitmasks showing lock
101  * mode conflicts. conflictTab[i] is a mask with the j-th bit
102  * turned on if lock modes i and j conflict. Lock modes are
103  * numbered 1..numLockModes; conflictTab[0] is unused.
104  *
105  * lockModeNames -- ID strings for debug printouts.
106  *
107  * trace_flag -- pointer to GUC trace flag for this lock method. (The
108  * GUC variable is not constant, but we use "const" here to denote that
109  * it can't be changed through this reference.)
110  */
111 typedef struct LockMethodData
112 {
115  const char *const *lockModeNames;
116  const bool *trace_flag;
118 
119 typedef const LockMethodData *LockMethod;
120 
121 /*
122  * Lock methods are identified by LOCKMETHODID. (Despite the declaration as
123  * uint16, we are constrained to 256 lockmethods by the layout of LOCKTAG.)
124  */
126 
127 /* These identify the known lock methods */
128 #define DEFAULT_LOCKMETHOD 1
129 #define USER_LOCKMETHOD 2
130 
131 /*
132  * LOCKTAG is the key information needed to look up a LOCK item in the
133  * lock hashtable. A LOCKTAG value uniquely identifies a lockable object.
134  *
135  * The LockTagType enum defines the different kinds of objects we can lock.
136  * We can handle up to 256 different LockTagTypes.
137  */
138 typedef enum LockTagType
139 {
140  LOCKTAG_RELATION, /* whole relation */
141  /* ID info for a relation is DB OID + REL OID; DB OID = 0 if shared */
142  LOCKTAG_RELATION_EXTEND, /* the right to extend a relation */
143  /* same ID info as RELATION */
144  LOCKTAG_PAGE, /* one page of a relation */
145  /* ID info for a page is RELATION info + BlockNumber */
146  LOCKTAG_TUPLE, /* one physical tuple */
147  /* ID info for a tuple is PAGE info + OffsetNumber */
148  LOCKTAG_TRANSACTION, /* transaction (for waiting for xact done) */
149  /* ID info for a transaction is its TransactionId */
150  LOCKTAG_VIRTUALTRANSACTION, /* virtual transaction (ditto) */
151  /* ID info for a virtual transaction is its VirtualTransactionId */
152  LOCKTAG_SPECULATIVE_TOKEN, /* speculative insertion Xid and token */
153  /* ID info for a transaction is its TransactionId */
154  LOCKTAG_OBJECT, /* non-relation database object */
155  /* ID info for an object is DB OID + CLASS OID + OBJECT OID + SUBID */
156 
157  /*
158  * Note: object ID has same representation as in pg_depend and
159  * pg_description, but notice that we are constraining SUBID to 16 bits.
160  * Also, we use DB OID = 0 for shared objects such as tablespaces.
161  */
162  LOCKTAG_USERLOCK, /* reserved for old contrib/userlock code */
163  LOCKTAG_ADVISORY /* advisory user locks */
164 } LockTagType;
165 
166 #define LOCKTAG_LAST_TYPE LOCKTAG_ADVISORY
167 
168 extern const char *const LockTagTypeNames[];
169 
170 /*
171  * The LOCKTAG struct is defined with malice aforethought to fit into 16
172  * bytes with no padding. Note that this would need adjustment if we were
173  * to widen Oid, BlockNumber, or TransactionId to more than 32 bits.
174  *
175  * We include lockmethodid in the locktag so that a single hash table in
176  * shared memory can store locks of different lockmethods.
177  */
178 typedef struct LOCKTAG
179 {
180  uint32 locktag_field1; /* a 32-bit ID field */
181  uint32 locktag_field2; /* a 32-bit ID field */
182  uint32 locktag_field3; /* a 32-bit ID field */
183  uint16 locktag_field4; /* a 16-bit ID field */
184  uint8 locktag_type; /* see enum LockTagType */
185  uint8 locktag_lockmethodid; /* lockmethod indicator */
186 } LOCKTAG;
187 
188 /*
189  * These macros define how we map logical IDs of lockable objects into
190  * the physical fields of LOCKTAG. Use these to set up LOCKTAG values,
191  * rather than accessing the fields directly. Note multiple eval of target!
192  */
193 #define SET_LOCKTAG_RELATION(locktag,dboid,reloid) \
194  ((locktag).locktag_field1 = (dboid), \
195  (locktag).locktag_field2 = (reloid), \
196  (locktag).locktag_field3 = 0, \
197  (locktag).locktag_field4 = 0, \
198  (locktag).locktag_type = LOCKTAG_RELATION, \
199  (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
200 
201 #define SET_LOCKTAG_RELATION_EXTEND(locktag,dboid,reloid) \
202  ((locktag).locktag_field1 = (dboid), \
203  (locktag).locktag_field2 = (reloid), \
204  (locktag).locktag_field3 = 0, \
205  (locktag).locktag_field4 = 0, \
206  (locktag).locktag_type = LOCKTAG_RELATION_EXTEND, \
207  (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
208 
209 #define SET_LOCKTAG_PAGE(locktag,dboid,reloid,blocknum) \
210  ((locktag).locktag_field1 = (dboid), \
211  (locktag).locktag_field2 = (reloid), \
212  (locktag).locktag_field3 = (blocknum), \
213  (locktag).locktag_field4 = 0, \
214  (locktag).locktag_type = LOCKTAG_PAGE, \
215  (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
216 
217 #define SET_LOCKTAG_TUPLE(locktag,dboid,reloid,blocknum,offnum) \
218  ((locktag).locktag_field1 = (dboid), \
219  (locktag).locktag_field2 = (reloid), \
220  (locktag).locktag_field3 = (blocknum), \
221  (locktag).locktag_field4 = (offnum), \
222  (locktag).locktag_type = LOCKTAG_TUPLE, \
223  (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
224 
225 #define SET_LOCKTAG_TRANSACTION(locktag,xid) \
226  ((locktag).locktag_field1 = (xid), \
227  (locktag).locktag_field2 = 0, \
228  (locktag).locktag_field3 = 0, \
229  (locktag).locktag_field4 = 0, \
230  (locktag).locktag_type = LOCKTAG_TRANSACTION, \
231  (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
232 
233 #define SET_LOCKTAG_VIRTUALTRANSACTION(locktag,vxid) \
234  ((locktag).locktag_field1 = (vxid).backendId, \
235  (locktag).locktag_field2 = (vxid).localTransactionId, \
236  (locktag).locktag_field3 = 0, \
237  (locktag).locktag_field4 = 0, \
238  (locktag).locktag_type = LOCKTAG_VIRTUALTRANSACTION, \
239  (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
240 
241 #define SET_LOCKTAG_SPECULATIVE_INSERTION(locktag,xid,token) \
242  ((locktag).locktag_field1 = (xid), \
243  (locktag).locktag_field2 = (token), \
244  (locktag).locktag_field3 = 0, \
245  (locktag).locktag_field4 = 0, \
246  (locktag).locktag_type = LOCKTAG_SPECULATIVE_TOKEN, \
247  (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
248 
249 #define SET_LOCKTAG_OBJECT(locktag,dboid,classoid,objoid,objsubid) \
250  ((locktag).locktag_field1 = (dboid), \
251  (locktag).locktag_field2 = (classoid), \
252  (locktag).locktag_field3 = (objoid), \
253  (locktag).locktag_field4 = (objsubid), \
254  (locktag).locktag_type = LOCKTAG_OBJECT, \
255  (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
256 
257 #define SET_LOCKTAG_ADVISORY(locktag,id1,id2,id3,id4) \
258  ((locktag).locktag_field1 = (id1), \
259  (locktag).locktag_field2 = (id2), \
260  (locktag).locktag_field3 = (id3), \
261  (locktag).locktag_field4 = (id4), \
262  (locktag).locktag_type = LOCKTAG_ADVISORY, \
263  (locktag).locktag_lockmethodid = USER_LOCKMETHOD)
264 
265 
266 /*
267  * Per-locked-object lock information:
268  *
269  * tag -- uniquely identifies the object being locked
270  * grantMask -- bitmask for all lock types currently granted on this object.
271  * waitMask -- bitmask for all lock types currently awaited on this object.
272  * procLocks -- list of PROCLOCK objects for this lock.
273  * waitProcs -- queue of processes waiting for this lock.
274  * requested -- count of each lock type currently requested on the lock
275  * (includes requests already granted!!).
276  * nRequested -- total requested locks of all types.
277  * granted -- count of each lock type currently granted on the lock.
278  * nGranted -- total granted locks of all types.
279  *
280  * Note: these counts count 1 for each backend. Internally to a backend,
281  * there may be multiple grabs on a particular lock, but this is not reflected
282  * into shared memory.
283  */
284 typedef struct LOCK
285 {
286  /* hash key */
287  LOCKTAG tag; /* unique identifier of lockable object */
288 
289  /* data */
290  LOCKMASK grantMask; /* bitmask for lock types already granted */
291  LOCKMASK waitMask; /* bitmask for lock types awaited */
292  SHM_QUEUE procLocks; /* list of PROCLOCK objects assoc. with lock */
293  PROC_QUEUE waitProcs; /* list of PGPROC objects waiting on lock */
294  int requested[MAX_LOCKMODES]; /* counts of requested locks */
295  int nRequested; /* total of requested[] array */
296  int granted[MAX_LOCKMODES]; /* counts of granted locks */
297  int nGranted; /* total of granted[] array */
298 } LOCK;
299 
300 #define LOCK_LOCKMETHOD(lock) ((LOCKMETHODID) (lock).tag.locktag_lockmethodid)
301 
302 
303 /*
304  * We may have several different backends holding or awaiting locks
305  * on the same lockable object. We need to store some per-holder/waiter
306  * information for each such holder (or would-be holder). This is kept in
307  * a PROCLOCK struct.
308  *
309  * PROCLOCKTAG is the key information needed to look up a PROCLOCK item in the
310  * proclock hashtable. A PROCLOCKTAG value uniquely identifies the combination
311  * of a lockable object and a holder/waiter for that object. (We can use
312  * pointers here because the PROCLOCKTAG need only be unique for the lifespan
313  * of the PROCLOCK, and it will never outlive the lock or the proc.)
314  *
315  * Internally to a backend, it is possible for the same lock to be held
316  * for different purposes: the backend tracks transaction locks separately
317  * from session locks. However, this is not reflected in the shared-memory
318  * state: we only track which backend(s) hold the lock. This is OK since a
319  * backend can never block itself.
320  *
321  * The holdMask field shows the already-granted locks represented by this
322  * proclock. Note that there will be a proclock object, possibly with
323  * zero holdMask, for any lock that the process is currently waiting on.
324  * Otherwise, proclock objects whose holdMasks are zero are recycled
325  * as soon as convenient.
326  *
327  * releaseMask is workspace for LockReleaseAll(): it shows the locks due
328  * to be released during the current call. This must only be examined or
329  * set by the backend owning the PROCLOCK.
330  *
331  * Each PROCLOCK object is linked into lists for both the associated LOCK
332  * object and the owning PGPROC object. Note that the PROCLOCK is entered
333  * into these lists as soon as it is created, even if no lock has yet been
334  * granted. A PGPROC that is waiting for a lock to be granted will also be
335  * linked into the lock's waitProcs queue.
336  */
337 typedef struct PROCLOCKTAG
338 {
339  /* NB: we assume this struct contains no padding! */
340  LOCK *myLock; /* link to per-lockable-object information */
341  PGPROC *myProc; /* link to PGPROC of owning backend */
342 } PROCLOCKTAG;
343 
344 typedef struct PROCLOCK
345 {
346  /* tag */
347  PROCLOCKTAG tag; /* unique identifier of proclock object */
348 
349  /* data */
350  PGPROC *groupLeader; /* proc's lock group leader, or proc itself */
351  LOCKMASK holdMask; /* bitmask for lock types currently held */
352  LOCKMASK releaseMask; /* bitmask for lock types to be released */
353  SHM_QUEUE lockLink; /* list link in LOCK's list of proclocks */
354  SHM_QUEUE procLink; /* list link in PGPROC's list of proclocks */
355 } PROCLOCK;
356 
357 #define PROCLOCK_LOCKMETHOD(proclock) \
358  LOCK_LOCKMETHOD(*((proclock).tag.myLock))
359 
360 /*
361  * Each backend also maintains a local hash table with information about each
362  * lock it is currently interested in. In particular the local table counts
363  * the number of times that lock has been acquired. This allows multiple
364  * requests for the same lock to be executed without additional accesses to
365  * shared memory. We also track the number of lock acquisitions per
366  * ResourceOwner, so that we can release just those locks belonging to a
367  * particular ResourceOwner.
368  *
369  * When holding a lock taken "normally", the lock and proclock fields always
370  * point to the associated objects in shared memory. However, if we acquired
371  * the lock via the fast-path mechanism, the lock and proclock fields are set
372  * to NULL, since there probably aren't any such objects in shared memory.
373  * (If the lock later gets promoted to normal representation, we may eventually
374  * update our locallock's lock/proclock fields after finding the shared
375  * objects.)
376  *
377  * Caution: a locallock object can be left over from a failed lock acquisition
378  * attempt. In this case its lock/proclock fields are untrustworthy, since
379  * the shared lock object is neither held nor awaited, and hence is available
380  * to be reclaimed. If nLocks > 0 then these pointers must either be valid or
381  * NULL, but when nLocks == 0 they should be considered garbage.
382  */
383 typedef struct LOCALLOCKTAG
384 {
385  LOCKTAG lock; /* identifies the lockable object */
386  LOCKMODE mode; /* lock mode for this table entry */
387 } LOCALLOCKTAG;
388 
389 typedef struct LOCALLOCKOWNER
390 {
391  /*
392  * Note: if owner is NULL then the lock is held on behalf of the session;
393  * otherwise it is held on behalf of my current transaction.
394  *
395  * Must use a forward struct reference to avoid circularity.
396  */
398  int64 nLocks; /* # of times held by this owner */
400 
401 typedef struct LOCALLOCK
402 {
403  /* tag */
404  LOCALLOCKTAG tag; /* unique identifier of locallock entry */
405 
406  /* data */
407  LOCK *lock; /* associated LOCK object, if any */
408  PROCLOCK *proclock; /* associated PROCLOCK object, if any */
409  uint32 hashcode; /* copy of LOCKTAG's hash value */
410  int64 nLocks; /* total number of times lock is held */
411  int numLockOwners; /* # of relevant ResourceOwners */
412  int maxLockOwners; /* allocated size of array */
413  bool holdsStrongLockCount; /* bumped FastPathStrongRelationLocks */
414  LOCALLOCKOWNER *lockOwners; /* dynamically resizable array */
415 } LOCALLOCK;
416 
417 #define LOCALLOCK_LOCKMETHOD(llock) ((llock).tag.lock.locktag_lockmethodid)
418 
419 
420 /*
421  * These structures hold information passed from lmgr internals to the lock
422  * listing user-level functions (in lockfuncs.c).
423  */
424 
425 typedef struct LockInstanceData
426 {
427  LOCKTAG locktag; /* tag for locked object */
428  LOCKMASK holdMask; /* locks held by this PGPROC */
429  LOCKMODE waitLockMode; /* lock awaited by this PGPROC, if any */
430  BackendId backend; /* backend ID of this PGPROC */
431  LocalTransactionId lxid; /* local transaction ID of this PGPROC */
432  int pid; /* pid of this PGPROC */
433  int leaderPid; /* pid of group leader; = pid if no group */
434  bool fastpath; /* taken via fastpath? */
436 
437 typedef struct LockData
438 {
439  int nelements; /* The length of the array */
440  LockInstanceData *locks; /* Array of per-PROCLOCK information */
441 } LockData;
442 
443 typedef struct BlockedProcData
444 {
445  int pid; /* pid of a blocked PGPROC */
446  /* Per-PROCLOCK information about PROCLOCKs of the lock the pid awaits */
447  /* (these fields refer to indexes in BlockedProcsData.locks[]) */
448  int first_lock; /* index of first relevant LockInstanceData */
449  int num_locks; /* number of relevant LockInstanceDatas */
450  /* PIDs of PGPROCs that are ahead of "pid" in the lock's wait queue */
451  /* (these fields refer to indexes in BlockedProcsData.waiter_pids[]) */
452  int first_waiter; /* index of first preceding waiter */
453  int num_waiters; /* number of preceding waiters */
455 
456 typedef struct BlockedProcsData
457 {
458  BlockedProcData *procs; /* Array of per-blocked-proc information */
459  LockInstanceData *locks; /* Array of per-PROCLOCK information */
460  int *waiter_pids; /* Array of PIDs of other blocked PGPROCs */
461  int nprocs; /* # of valid entries in procs[] array */
462  int maxprocs; /* Allocated length of procs[] array */
463  int nlocks; /* # of valid entries in locks[] array */
464  int maxlocks; /* Allocated length of locks[] array */
465  int npids; /* # of valid entries in waiter_pids[] array */
466  int maxpids; /* Allocated length of waiter_pids[] array */
468 
469 
470 /* Result codes for LockAcquire() */
471 typedef enum
472 {
473  LOCKACQUIRE_NOT_AVAIL, /* lock not available, and dontWait=true */
474  LOCKACQUIRE_OK, /* lock successfully acquired */
475  LOCKACQUIRE_ALREADY_HELD /* incremented count for lock already held */
477 
478 /* Deadlock states identified by DeadLockCheck() */
479 typedef enum
480 {
481  DS_NOT_YET_CHECKED, /* no deadlock check has run yet */
482  DS_NO_DEADLOCK, /* no deadlock detected */
483  DS_SOFT_DEADLOCK, /* deadlock avoided by queue rearrangement */
484  DS_HARD_DEADLOCK, /* deadlock, no way out but ERROR */
485  DS_BLOCKED_BY_AUTOVACUUM /* no deadlock; queue blocked by autovacuum
486  * worker */
487 } DeadLockState;
488 
489 /*
490  * The lockmgr's shared hash tables are partitioned to reduce contention.
491  * To determine which partition a given locktag belongs to, compute the tag's
492  * hash code with LockTagHashCode(), then apply one of these macros.
493  * NB: NUM_LOCK_PARTITIONS must be a power of 2!
494  */
495 #define LockHashPartition(hashcode) \
496  ((hashcode) % NUM_LOCK_PARTITIONS)
497 #define LockHashPartitionLock(hashcode) \
498  (&MainLWLockArray[LOCK_MANAGER_LWLOCK_OFFSET + \
499  LockHashPartition(hashcode)].lock)
500 #define LockHashPartitionLockByIndex(i) \
501  (&MainLWLockArray[LOCK_MANAGER_LWLOCK_OFFSET + (i)].lock)
502 
503 /*
504  * The deadlock detector needs to be able to access lockGroupLeader and
505  * related fields in the PGPROC, so we arrange for those fields to be protected
506  * by one of the lock hash partition locks. Since the deadlock detector
507  * acquires all such locks anyway, this makes it safe for it to access these
508  * fields without doing anything extra. To avoid contention as much as
509  * possible, we map different PGPROCs to different partition locks. The lock
510  * used for a given lock group is determined by the group leader's pgprocno.
511  */
512 #define LockHashPartitionLockByProc(leader_pgproc) \
513  LockHashPartitionLock((leader_pgproc)->pgprocno)
514 
515 /*
516  * function prototypes
517  */
518 extern void InitLocks(void);
519 extern LockMethod GetLocksMethodTable(const LOCK *lock);
520 extern LockMethod GetLockTagsMethodTable(const LOCKTAG *locktag);
521 extern uint32 LockTagHashCode(const LOCKTAG *locktag);
522 extern bool DoLockModesConflict(LOCKMODE mode1, LOCKMODE mode2);
523 extern LockAcquireResult LockAcquire(const LOCKTAG *locktag,
524  LOCKMODE lockmode,
525  bool sessionLock,
526  bool dontWait);
527 extern LockAcquireResult LockAcquireExtended(const LOCKTAG *locktag,
528  LOCKMODE lockmode,
529  bool sessionLock,
530  bool dontWait,
531  bool report_memory_error);
532 extern void AbortStrongLockAcquire(void);
533 extern bool LockRelease(const LOCKTAG *locktag,
534  LOCKMODE lockmode, bool sessionLock);
535 extern void LockReleaseAll(LOCKMETHODID lockmethodid, bool allLocks);
536 extern void LockReleaseSession(LOCKMETHODID lockmethodid);
537 extern void LockReleaseCurrentOwner(LOCALLOCK **locallocks, int nlocks);
538 extern void LockReassignCurrentOwner(LOCALLOCK **locallocks, int nlocks);
539 extern bool LockHasWaiters(const LOCKTAG *locktag,
540  LOCKMODE lockmode, bool sessionLock);
541 extern VirtualTransactionId *GetLockConflicts(const LOCKTAG *locktag,
542  LOCKMODE lockmode);
543 extern void AtPrepare_Locks(void);
544 extern void PostPrepare_Locks(TransactionId xid);
545 extern int LockCheckConflicts(LockMethod lockMethodTable,
546  LOCKMODE lockmode,
547  LOCK *lock, PROCLOCK *proclock);
548 extern void GrantLock(LOCK *lock, PROCLOCK *proclock, LOCKMODE lockmode);
549 extern void GrantAwaitedLock(void);
550 extern void RemoveFromWaitQueue(PGPROC *proc, uint32 hashcode);
551 extern Size LockShmemSize(void);
552 extern LockData *GetLockStatusData(void);
553 extern BlockedProcsData *GetBlockerStatusData(int blocked_pid);
554 
555 extern xl_standby_lock *GetRunningTransactionLocks(int *nlocks);
556 extern const char *GetLockmodeName(LOCKMETHODID lockmethodid, LOCKMODE mode);
557 
558 extern void lock_twophase_recover(TransactionId xid, uint16 info,
559  void *recdata, uint32 len);
560 extern void lock_twophase_postcommit(TransactionId xid, uint16 info,
561  void *recdata, uint32 len);
562 extern void lock_twophase_postabort(TransactionId xid, uint16 info,
563  void *recdata, uint32 len);
565  void *recdata, uint32 len);
566 
567 extern DeadLockState DeadLockCheck(PGPROC *proc);
568 extern PGPROC *GetBlockingAutoVacuumPgproc(void);
569 extern void DeadLockReport(void) pg_attribute_noreturn();
570 extern void RememberSimpleDeadLock(PGPROC *proc1,
571  LOCKMODE lockmode,
572  LOCK *lock,
573  PGPROC *proc2);
574 extern void InitDeadLockChecking(void);
575 
576 extern int LockWaiterCount(const LOCKTAG *locktag);
577 
578 #ifdef LOCK_DEBUG
579 extern void DumpLocks(PGPROC *proc);
580 extern void DumpAllLocks(void);
581 #endif
582 
583 /* Lock a VXID (used to wait for a transaction to finish) */
585 extern void VirtualXactLockTableCleanup(void);
586 extern bool VirtualXactLock(VirtualTransactionId vxid, bool wait);
587 
588 #endif /* LOCK_H */
struct BlockedProcData BlockedProcData
const char *const LockTagTypeNames[]
Definition: lockfuncs.c:26
PROCLOCKTAG tag
Definition: lock.h:347
uint32 hashcode
Definition: lock.h:409
Size LockShmemSize(void)
Definition: lock.c:3361
void VirtualXactLockTableInsert(VirtualTransactionId vxid)
Definition: lock.c:4221
LOCALLOCKTAG tag
Definition: lock.h:404
VirtualTransactionId * GetLockConflicts(const LOCKTAG *locktag, LOCKMODE lockmode)
Definition: lock.c:2745
bool holdsStrongLockCount
Definition: lock.h:413
void RemoveFromWaitQueue(PGPROC *proc, uint32 hashcode)
Definition: lock.c:1761
int * waiter_pids
Definition: lock.h:460
void AbortStrongLockAcquire(void)
Definition: lock.c:1614
int numLockOwners
Definition: lock.h:411
LockInstanceData * locks
Definition: lock.h:440
LOCKTAG lock
Definition: lock.h:385
uint32 TransactionId
Definition: c.h:397
void lock_twophase_postcommit(TransactionId xid, uint16 info, void *recdata, uint32 len)
Definition: lock.c:4171
int LOCKMODE
Definition: lockdefs.h:26
int first_lock
Definition: lock.h:448
LOCKMODE mode
Definition: lock.h:386
void LockReleaseCurrentOwner(LOCALLOCK **locallocks, int nlocks)
Definition: lock.c:2318
PROCLOCK * proclock
Definition: lock.h:408
int nRequested
Definition: lock.h:295
SHM_QUEUE links
Definition: lock.h:32
int num_waiters
Definition: lock.h:453
LOCKMASK holdMask
Definition: lock.h:351
int64 nLocks
Definition: lock.h:398
bool fastpath
Definition: lock.h:434
LockMethod GetLocksMethodTable(const LOCK *lock)
Definition: lock.c:460
struct LOCALLOCKOWNER LOCALLOCKOWNER
LOCKTAG tag
Definition: lock.h:287
void PostPrepare_Locks(TransactionId xid)
Definition: lock.c:3169
unsigned char uint8
Definition: c.h:266
Definition: lock.h:178
const LOCKMASK * conflictTab
Definition: lock.h:114
int LockWaiterCount(const LOCKTAG *locktag)
Definition: lock.c:4387
SHM_QUEUE lockLink
Definition: lock.h:353
void LockReassignCurrentOwner(LOCALLOCK **locallocks, int nlocks)
Definition: lock.c:2413
LockMethod GetLockTagsMethodTable(const LOCKTAG *locktag)
Definition: lock.c:472
BlockedProcData * procs
Definition: lock.h:458
Definition: lock.h:437
LocalTransactionId localTransactionId
Definition: lock.h:66
struct LOCALLOCKTAG LOCALLOCKTAG
LOCKTAG locktag
Definition: lock.h:427
LOCKMODE waitLockMode
Definition: lock.h:429
int maxLockOwners
Definition: lock.h:412
int nGranted
Definition: lock.h:297
void LockReleaseAll(LOCKMETHODID lockmethodid, bool allLocks)
Definition: lock.c:2014
void DeadLockReport(void) pg_attribute_noreturn()
Definition: deadlock.c:1077
int num_locks
Definition: lock.h:449
int max_locks_per_xact
Definition: lock.c:54
PROC_QUEUE waitProcs
Definition: lock.h:293
void InitLocks(void)
Definition: lock.c:377
uint16 locktag_field4
Definition: lock.h:183
BlockedProcsData * GetBlockerStatusData(int blocked_pid)
Definition: lock.c:3582
int leaderPid
Definition: lock.h:433
LockAcquireResult LockAcquireExtended(const LOCKTAG *locktag, LOCKMODE lockmode, bool sessionLock, bool dontWait, bool report_memory_error)
Definition: lock.c:701
struct LOCALLOCK LOCALLOCK
unsigned short uint16
Definition: c.h:267
struct BlockedProcsData BlockedProcsData
void lock_twophase_postabort(TransactionId xid, uint16 info, void *recdata, uint32 len)
Definition: lock.c:4197
LockAcquireResult LockAcquire(const LOCKTAG *locktag, LOCKMODE lockmode, bool sessionLock, bool dontWait)
Definition: lock.c:683
void VirtualXactLockTableCleanup(void)
Definition: lock.c:4244
const char * GetLockmodeName(LOCKMETHODID lockmethodid, LOCKMODE mode)
Definition: lock.c:3845
uint32 locktag_field2
Definition: lock.h:181
unsigned int uint32
Definition: c.h:268
int granted[MAX_LOCKMODES]
Definition: lock.h:296
Definition: lock.h:284
uint32 LocalTransactionId
Definition: c.h:399
xl_standby_lock * GetRunningTransactionLocks(int *nlocks)
Definition: lock.c:3762
struct PROCLOCK PROCLOCK
LOCKMASK waitMask
Definition: lock.h:291
int maxlocks
Definition: lock.h:464
uint16 LOCKMETHODID
Definition: lock.h:125
SHM_QUEUE procLocks
Definition: lock.h:292
struct LOCKTAG LOCKTAG
int requested[MAX_LOCKMODES]
Definition: lock.h:294
int nelements
Definition: lock.h:439
#define MAX_LOCKMODES
Definition: lock.h:85
SHM_QUEUE procLink
Definition: lock.h:354
LockInstanceData * locks
Definition: lock.h:459
struct PROCLOCKTAG PROCLOCKTAG
const LockMethodData * LockMethod
Definition: lock.h:119
BackendId backend
Definition: lock.h:430
int BackendId
Definition: backendid.h:21
bool LockRelease(const LOCKTAG *locktag, LOCKMODE lockmode, bool sessionLock)
Definition: lock.c:1818
bool LockHasWaiters(const LOCKTAG *locktag, LOCKMODE lockmode, bool sessionLock)
Definition: lock.c:571
void RememberSimpleDeadLock(PGPROC *proc1, LOCKMODE lockmode, LOCK *lock, PGPROC *proc2)
Definition: deadlock.c:1149
DeadLockState DeadLockCheck(PGPROC *proc)
Definition: deadlock.c:217
struct LOCK LOCK
void lock_twophase_recover(TransactionId xid, uint16 info, void *recdata, uint32 len)
Definition: lock.c:3958
int first_waiter
Definition: lock.h:452
void GrantAwaitedLock(void)
Definition: lock.c:1643
bool DoLockModesConflict(LOCKMODE mode1, LOCKMODE mode2)
Definition: lock.c:556
uint8 locktag_type
Definition: lock.h:184
DeadLockState
Definition: lock.h:479
LocalTransactionId lxid
Definition: lock.h:431
BackendId backendId
Definition: lock.h:65
size_t Size
Definition: c.h:356
bool VirtualXactLock(VirtualTransactionId vxid, bool wait)
Definition: lock.c:4291
LOCALLOCKOWNER * lockOwners
Definition: lock.h:414
LOCK * lock
Definition: lock.h:407
int LOCKMASK
Definition: lockdefs.h:25
struct LockMethodData LockMethodData
LOCKMASK holdMask
Definition: lock.h:428
uint8 locktag_lockmethodid
Definition: lock.h:185
PGPROC * myProc
Definition: lock.h:341
#define pg_attribute_noreturn()
Definition: c.h:653
int LockCheckConflicts(LockMethod lockMethodTable, LOCKMODE lockmode, LOCK *lock, PROCLOCK *proclock)
Definition: lock.c:1292
LOCKMASK grantMask
Definition: lock.h:290
Definition: lock.h:344
int64 nLocks
Definition: lock.h:410
struct PROC_QUEUE PROC_QUEUE
LockAcquireResult
Definition: lock.h:471
void InitDeadLockChecking(void)
Definition: deadlock.c:143
struct LockInstanceData LockInstanceData
const bool * trace_flag
Definition: lock.h:116
LockData * GetLockStatusData(void)
Definition: lock.c:3398
int size
Definition: lock.h:33
LOCK * myLock
Definition: lock.h:340
LockTagType
Definition: lock.h:138
struct ResourceOwnerData * owner
Definition: lock.h:397
void lock_twophase_standby_recover(TransactionId xid, uint16 info, void *recdata, uint32 len)
Definition: lock.c:4139
struct LockData LockData
PGPROC * GetBlockingAutoVacuumPgproc(void)
Definition: deadlock.c:293
void GrantLock(LOCK *lock, PROCLOCK *proclock, LOCKMODE lockmode)
Definition: lock.c:1415
uint32 locktag_field1
Definition: lock.h:180
Definition: proc.h:94
uint32 LockTagHashCode(const LOCKTAG *locktag)
Definition: lock.c:490
uint32 locktag_field3
Definition: lock.h:182
void AtPrepare_Locks(void)
Definition: lock.c:3059
const char *const * lockModeNames
Definition: lock.h:115
PGPROC * groupLeader
Definition: lock.h:350
void LockReleaseSession(LOCKMETHODID lockmethodid)
Definition: lock.c:2288
int numLockModes
Definition: lock.h:113
int maxprocs
Definition: lock.h:462
LOCKMASK releaseMask
Definition: lock.h:352