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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) 1996-2019, 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/backendid.h"
22 #include "storage/lockdefs.h"
23 #include "storage/lwlock.h"
24 #include "storage/shmem.h"
25 
26 /* struct PGPROC is declared in proc.h, but must forward-reference it */
27 typedef struct PGPROC PGPROC;
28 
29 typedef struct PROC_QUEUE
30 {
31  SHM_QUEUE links; /* head of list of PGPROC objects */
32  int size; /* number of entries in list */
33 } PROC_QUEUE;
34 
35 /* GUC variables */
36 extern int max_locks_per_xact;
37 
38 #ifdef LOCK_DEBUG
39 extern int Trace_lock_oidmin;
40 extern bool Trace_locks;
41 extern bool Trace_userlocks;
42 extern int Trace_lock_table;
43 extern bool Debug_deadlocks;
44 #endif /* LOCK_DEBUG */
45 
46 
47 /*
48  * Top-level transactions are identified by VirtualTransactionIDs comprising
49  * the BackendId of the backend running the xact, plus a locally-assigned
50  * LocalTransactionId. These are guaranteed unique over the short term,
51  * but will be reused after a database restart; hence they should never
52  * be stored on disk.
53  *
54  * Note that struct VirtualTransactionId can not be assumed to be atomically
55  * assignable as a whole. However, type LocalTransactionId is assumed to
56  * be atomically assignable, and the backend ID doesn't change often enough
57  * to be a problem, so we can fetch or assign the two fields separately.
58  * We deliberately refrain from using the struct within PGPROC, to prevent
59  * coding errors from trying to use struct assignment with it; instead use
60  * GET_VXID_FROM_PGPROC().
61  */
62 typedef struct
63 {
64  BackendId backendId; /* determined at backend startup */
65  LocalTransactionId localTransactionId; /* backend-local transaction id */
67 
68 #define InvalidLocalTransactionId 0
69 #define LocalTransactionIdIsValid(lxid) ((lxid) != InvalidLocalTransactionId)
70 #define VirtualTransactionIdIsValid(vxid) \
71  (((vxid).backendId != InvalidBackendId) && \
72  LocalTransactionIdIsValid((vxid).localTransactionId))
73 #define VirtualTransactionIdEquals(vxid1, vxid2) \
74  ((vxid1).backendId == (vxid2).backendId && \
75  (vxid1).localTransactionId == (vxid2).localTransactionId)
76 #define SetInvalidVirtualTransactionId(vxid) \
77  ((vxid).backendId = InvalidBackendId, \
78  (vxid).localTransactionId = InvalidLocalTransactionId)
79 #define GET_VXID_FROM_PGPROC(vxid, proc) \
80  ((vxid).backendId = (proc).backendId, \
81  (vxid).localTransactionId = (proc).lxid)
82 
83 /* MAX_LOCKMODES cannot be larger than the # of bits in LOCKMASK */
84 #define MAX_LOCKMODES 10
85 
86 #define LOCKBIT_ON(lockmode) (1 << (lockmode))
87 #define LOCKBIT_OFF(lockmode) (~(1 << (lockmode)))
88 
89 
90 /*
91  * This data structure defines the locking semantics associated with a
92  * "lock method". The semantics specify the meaning of each lock mode
93  * (by defining which lock modes it conflicts with).
94  * All of this data is constant and is kept in const tables.
95  *
96  * numLockModes -- number of lock modes (READ,WRITE,etc) that
97  * are defined in this lock method. Must be less than MAX_LOCKMODES.
98  *
99  * conflictTab -- this is an array of bitmasks showing lock
100  * mode conflicts. conflictTab[i] is a mask with the j-th bit
101  * turned on if lock modes i and j conflict. Lock modes are
102  * numbered 1..numLockModes; conflictTab[0] is unused.
103  *
104  * lockModeNames -- ID strings for debug printouts.
105  *
106  * trace_flag -- pointer to GUC trace flag for this lock method. (The
107  * GUC variable is not constant, but we use "const" here to denote that
108  * it can't be changed through this reference.)
109  */
110 typedef struct LockMethodData
111 {
114  const char *const *lockModeNames;
115  const bool *trace_flag;
117 
118 typedef const LockMethodData *LockMethod;
119 
120 /*
121  * Lock methods are identified by LOCKMETHODID. (Despite the declaration as
122  * uint16, we are constrained to 256 lockmethods by the layout of LOCKTAG.)
123  */
125 
126 /* These identify the known lock methods */
127 #define DEFAULT_LOCKMETHOD 1
128 #define USER_LOCKMETHOD 2
129 
130 /*
131  * LOCKTAG is the key information needed to look up a LOCK item in the
132  * lock hashtable. A LOCKTAG value uniquely identifies a lockable object.
133  *
134  * The LockTagType enum defines the different kinds of objects we can lock.
135  * We can handle up to 256 different LockTagTypes.
136  */
137 typedef enum LockTagType
138 {
139  LOCKTAG_RELATION, /* whole relation */
140  LOCKTAG_RELATION_EXTEND, /* the right to extend a relation */
141  LOCKTAG_PAGE, /* one page of a relation */
142  LOCKTAG_TUPLE, /* one physical tuple */
143  LOCKTAG_TRANSACTION, /* transaction (for waiting for xact done) */
144  LOCKTAG_VIRTUALTRANSACTION, /* virtual transaction (ditto) */
145  LOCKTAG_SPECULATIVE_TOKEN, /* speculative insertion Xid and token */
146  LOCKTAG_OBJECT, /* non-relation database object */
147  LOCKTAG_USERLOCK, /* reserved for old contrib/userlock code */
148  LOCKTAG_ADVISORY /* advisory user locks */
149 } LockTagType;
150 
151 #define LOCKTAG_LAST_TYPE LOCKTAG_ADVISORY
152 
153 extern const char *const LockTagTypeNames[];
154 
155 /*
156  * The LOCKTAG struct is defined with malice aforethought to fit into 16
157  * bytes with no padding. Note that this would need adjustment if we were
158  * to widen Oid, BlockNumber, or TransactionId to more than 32 bits.
159  *
160  * We include lockmethodid in the locktag so that a single hash table in
161  * shared memory can store locks of different lockmethods.
162  */
163 typedef struct LOCKTAG
164 {
165  uint32 locktag_field1; /* a 32-bit ID field */
166  uint32 locktag_field2; /* a 32-bit ID field */
167  uint32 locktag_field3; /* a 32-bit ID field */
168  uint16 locktag_field4; /* a 16-bit ID field */
169  uint8 locktag_type; /* see enum LockTagType */
170  uint8 locktag_lockmethodid; /* lockmethod indicator */
171 } LOCKTAG;
172 
173 /*
174  * These macros define how we map logical IDs of lockable objects into
175  * the physical fields of LOCKTAG. Use these to set up LOCKTAG values,
176  * rather than accessing the fields directly. Note multiple eval of target!
177  */
178 
179 /* ID info for a relation is DB OID + REL OID; DB OID = 0 if shared */
180 #define SET_LOCKTAG_RELATION(locktag,dboid,reloid) \
181  ((locktag).locktag_field1 = (dboid), \
182  (locktag).locktag_field2 = (reloid), \
183  (locktag).locktag_field3 = 0, \
184  (locktag).locktag_field4 = 0, \
185  (locktag).locktag_type = LOCKTAG_RELATION, \
186  (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
187 
188 /* same ID info as RELATION */
189 #define SET_LOCKTAG_RELATION_EXTEND(locktag,dboid,reloid) \
190  ((locktag).locktag_field1 = (dboid), \
191  (locktag).locktag_field2 = (reloid), \
192  (locktag).locktag_field3 = 0, \
193  (locktag).locktag_field4 = 0, \
194  (locktag).locktag_type = LOCKTAG_RELATION_EXTEND, \
195  (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
196 
197 /* ID info for a page is RELATION info + BlockNumber */
198 #define SET_LOCKTAG_PAGE(locktag,dboid,reloid,blocknum) \
199  ((locktag).locktag_field1 = (dboid), \
200  (locktag).locktag_field2 = (reloid), \
201  (locktag).locktag_field3 = (blocknum), \
202  (locktag).locktag_field4 = 0, \
203  (locktag).locktag_type = LOCKTAG_PAGE, \
204  (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
205 
206 /* ID info for a tuple is PAGE info + OffsetNumber */
207 #define SET_LOCKTAG_TUPLE(locktag,dboid,reloid,blocknum,offnum) \
208  ((locktag).locktag_field1 = (dboid), \
209  (locktag).locktag_field2 = (reloid), \
210  (locktag).locktag_field3 = (blocknum), \
211  (locktag).locktag_field4 = (offnum), \
212  (locktag).locktag_type = LOCKTAG_TUPLE, \
213  (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
214 
215 /* ID info for a transaction is its TransactionId */
216 #define SET_LOCKTAG_TRANSACTION(locktag,xid) \
217  ((locktag).locktag_field1 = (xid), \
218  (locktag).locktag_field2 = 0, \
219  (locktag).locktag_field3 = 0, \
220  (locktag).locktag_field4 = 0, \
221  (locktag).locktag_type = LOCKTAG_TRANSACTION, \
222  (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
223 
224 /* ID info for a virtual transaction is its VirtualTransactionId */
225 #define SET_LOCKTAG_VIRTUALTRANSACTION(locktag,vxid) \
226  ((locktag).locktag_field1 = (vxid).backendId, \
227  (locktag).locktag_field2 = (vxid).localTransactionId, \
228  (locktag).locktag_field3 = 0, \
229  (locktag).locktag_field4 = 0, \
230  (locktag).locktag_type = LOCKTAG_VIRTUALTRANSACTION, \
231  (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
232 
233 /*
234  * ID info for a speculative insert is TRANSACTION info +
235  * its speculative insert counter.
236  */
237 #define SET_LOCKTAG_SPECULATIVE_INSERTION(locktag,xid,token) \
238  ((locktag).locktag_field1 = (xid), \
239  (locktag).locktag_field2 = (token), \
240  (locktag).locktag_field3 = 0, \
241  (locktag).locktag_field4 = 0, \
242  (locktag).locktag_type = LOCKTAG_SPECULATIVE_TOKEN, \
243  (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
244 
245 /*
246  * ID info for an object is DB OID + CLASS OID + OBJECT OID + SUBID
247  *
248  * Note: object ID has same representation as in pg_depend and
249  * pg_description, but notice that we are constraining SUBID to 16 bits.
250  * Also, we use DB OID = 0 for shared objects such as tablespaces.
251  */
252 #define SET_LOCKTAG_OBJECT(locktag,dboid,classoid,objoid,objsubid) \
253  ((locktag).locktag_field1 = (dboid), \
254  (locktag).locktag_field2 = (classoid), \
255  (locktag).locktag_field3 = (objoid), \
256  (locktag).locktag_field4 = (objsubid), \
257  (locktag).locktag_type = LOCKTAG_OBJECT, \
258  (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
259 
260 #define SET_LOCKTAG_ADVISORY(locktag,id1,id2,id3,id4) \
261  ((locktag).locktag_field1 = (id1), \
262  (locktag).locktag_field2 = (id2), \
263  (locktag).locktag_field3 = (id3), \
264  (locktag).locktag_field4 = (id4), \
265  (locktag).locktag_type = LOCKTAG_ADVISORY, \
266  (locktag).locktag_lockmethodid = USER_LOCKMETHOD)
267 
268 
269 /*
270  * Per-locked-object lock information:
271  *
272  * tag -- uniquely identifies the object being locked
273  * grantMask -- bitmask for all lock types currently granted on this object.
274  * waitMask -- bitmask for all lock types currently awaited on this object.
275  * procLocks -- list of PROCLOCK objects for this lock.
276  * waitProcs -- queue of processes waiting for this lock.
277  * requested -- count of each lock type currently requested on the lock
278  * (includes requests already granted!!).
279  * nRequested -- total requested locks of all types.
280  * granted -- count of each lock type currently granted on the lock.
281  * nGranted -- total granted locks of all types.
282  *
283  * Note: these counts count 1 for each backend. Internally to a backend,
284  * there may be multiple grabs on a particular lock, but this is not reflected
285  * into shared memory.
286  */
287 typedef struct LOCK
288 {
289  /* hash key */
290  LOCKTAG tag; /* unique identifier of lockable object */
291 
292  /* data */
293  LOCKMASK grantMask; /* bitmask for lock types already granted */
294  LOCKMASK waitMask; /* bitmask for lock types awaited */
295  SHM_QUEUE procLocks; /* list of PROCLOCK objects assoc. with lock */
296  PROC_QUEUE waitProcs; /* list of PGPROC objects waiting on lock */
297  int requested[MAX_LOCKMODES]; /* counts of requested locks */
298  int nRequested; /* total of requested[] array */
299  int granted[MAX_LOCKMODES]; /* counts of granted locks */
300  int nGranted; /* total of granted[] array */
301 } LOCK;
302 
303 #define LOCK_LOCKMETHOD(lock) ((LOCKMETHODID) (lock).tag.locktag_lockmethodid)
304 
305 
306 /*
307  * We may have several different backends holding or awaiting locks
308  * on the same lockable object. We need to store some per-holder/waiter
309  * information for each such holder (or would-be holder). This is kept in
310  * a PROCLOCK struct.
311  *
312  * PROCLOCKTAG is the key information needed to look up a PROCLOCK item in the
313  * proclock hashtable. A PROCLOCKTAG value uniquely identifies the combination
314  * of a lockable object and a holder/waiter for that object. (We can use
315  * pointers here because the PROCLOCKTAG need only be unique for the lifespan
316  * of the PROCLOCK, and it will never outlive the lock or the proc.)
317  *
318  * Internally to a backend, it is possible for the same lock to be held
319  * for different purposes: the backend tracks transaction locks separately
320  * from session locks. However, this is not reflected in the shared-memory
321  * state: we only track which backend(s) hold the lock. This is OK since a
322  * backend can never block itself.
323  *
324  * The holdMask field shows the already-granted locks represented by this
325  * proclock. Note that there will be a proclock object, possibly with
326  * zero holdMask, for any lock that the process is currently waiting on.
327  * Otherwise, proclock objects whose holdMasks are zero are recycled
328  * as soon as convenient.
329  *
330  * releaseMask is workspace for LockReleaseAll(): it shows the locks due
331  * to be released during the current call. This must only be examined or
332  * set by the backend owning the PROCLOCK.
333  *
334  * Each PROCLOCK object is linked into lists for both the associated LOCK
335  * object and the owning PGPROC object. Note that the PROCLOCK is entered
336  * into these lists as soon as it is created, even if no lock has yet been
337  * granted. A PGPROC that is waiting for a lock to be granted will also be
338  * linked into the lock's waitProcs queue.
339  */
340 typedef struct PROCLOCKTAG
341 {
342  /* NB: we assume this struct contains no padding! */
343  LOCK *myLock; /* link to per-lockable-object information */
344  PGPROC *myProc; /* link to PGPROC of owning backend */
345 } PROCLOCKTAG;
346 
347 typedef struct PROCLOCK
348 {
349  /* tag */
350  PROCLOCKTAG tag; /* unique identifier of proclock object */
351 
352  /* data */
353  PGPROC *groupLeader; /* proc's lock group leader, or proc itself */
354  LOCKMASK holdMask; /* bitmask for lock types currently held */
355  LOCKMASK releaseMask; /* bitmask for lock types to be released */
356  SHM_QUEUE lockLink; /* list link in LOCK's list of proclocks */
357  SHM_QUEUE procLink; /* list link in PGPROC's list of proclocks */
358 } PROCLOCK;
359 
360 #define PROCLOCK_LOCKMETHOD(proclock) \
361  LOCK_LOCKMETHOD(*((proclock).tag.myLock))
362 
363 /*
364  * Each backend also maintains a local hash table with information about each
365  * lock it is currently interested in. In particular the local table counts
366  * the number of times that lock has been acquired. This allows multiple
367  * requests for the same lock to be executed without additional accesses to
368  * shared memory. We also track the number of lock acquisitions per
369  * ResourceOwner, so that we can release just those locks belonging to a
370  * particular ResourceOwner.
371  *
372  * When holding a lock taken "normally", the lock and proclock fields always
373  * point to the associated objects in shared memory. However, if we acquired
374  * the lock via the fast-path mechanism, the lock and proclock fields are set
375  * to NULL, since there probably aren't any such objects in shared memory.
376  * (If the lock later gets promoted to normal representation, we may eventually
377  * update our locallock's lock/proclock fields after finding the shared
378  * objects.)
379  *
380  * Caution: a locallock object can be left over from a failed lock acquisition
381  * attempt. In this case its lock/proclock fields are untrustworthy, since
382  * the shared lock object is neither held nor awaited, and hence is available
383  * to be reclaimed. If nLocks > 0 then these pointers must either be valid or
384  * NULL, but when nLocks == 0 they should be considered garbage.
385  */
386 typedef struct LOCALLOCKTAG
387 {
388  LOCKTAG lock; /* identifies the lockable object */
389  LOCKMODE mode; /* lock mode for this table entry */
390 } LOCALLOCKTAG;
391 
392 typedef struct LOCALLOCKOWNER
393 {
394  /*
395  * Note: if owner is NULL then the lock is held on behalf of the session;
396  * otherwise it is held on behalf of my current transaction.
397  *
398  * Must use a forward struct reference to avoid circularity.
399  */
401  int64 nLocks; /* # of times held by this owner */
403 
404 typedef struct LOCALLOCK
405 {
406  /* tag */
407  LOCALLOCKTAG tag; /* unique identifier of locallock entry */
408 
409  /* data */
410  uint32 hashcode; /* copy of LOCKTAG's hash value */
411  LOCK *lock; /* associated LOCK object, if any */
412  PROCLOCK *proclock; /* associated PROCLOCK object, if any */
413  int64 nLocks; /* total number of times lock is held */
414  int numLockOwners; /* # of relevant ResourceOwners */
415  int maxLockOwners; /* allocated size of array */
416  LOCALLOCKOWNER *lockOwners; /* dynamically resizable array */
417  bool holdsStrongLockCount; /* bumped FastPathStrongRelationLocks */
418  bool lockCleared; /* we read all sinval msgs for lock */
419 } LOCALLOCK;
420 
421 #define LOCALLOCK_LOCKMETHOD(llock) ((llock).tag.lock.locktag_lockmethodid)
422 
423 
424 /*
425  * These structures hold information passed from lmgr internals to the lock
426  * listing user-level functions (in lockfuncs.c).
427  */
428 
429 typedef struct LockInstanceData
430 {
431  LOCKTAG locktag; /* tag for locked object */
432  LOCKMASK holdMask; /* locks held by this PGPROC */
433  LOCKMODE waitLockMode; /* lock awaited by this PGPROC, if any */
434  BackendId backend; /* backend ID of this PGPROC */
435  LocalTransactionId lxid; /* local transaction ID of this PGPROC */
436  int pid; /* pid of this PGPROC */
437  int leaderPid; /* pid of group leader; = pid if no group */
438  bool fastpath; /* taken via fastpath? */
440 
441 typedef struct LockData
442 {
443  int nelements; /* The length of the array */
444  LockInstanceData *locks; /* Array of per-PROCLOCK information */
445 } LockData;
446 
447 typedef struct BlockedProcData
448 {
449  int pid; /* pid of a blocked PGPROC */
450  /* Per-PROCLOCK information about PROCLOCKs of the lock the pid awaits */
451  /* (these fields refer to indexes in BlockedProcsData.locks[]) */
452  int first_lock; /* index of first relevant LockInstanceData */
453  int num_locks; /* number of relevant LockInstanceDatas */
454  /* PIDs of PGPROCs that are ahead of "pid" in the lock's wait queue */
455  /* (these fields refer to indexes in BlockedProcsData.waiter_pids[]) */
456  int first_waiter; /* index of first preceding waiter */
457  int num_waiters; /* number of preceding waiters */
459 
460 typedef struct BlockedProcsData
461 {
462  BlockedProcData *procs; /* Array of per-blocked-proc information */
463  LockInstanceData *locks; /* Array of per-PROCLOCK information */
464  int *waiter_pids; /* Array of PIDs of other blocked PGPROCs */
465  int nprocs; /* # of valid entries in procs[] array */
466  int maxprocs; /* Allocated length of procs[] array */
467  int nlocks; /* # of valid entries in locks[] array */
468  int maxlocks; /* Allocated length of locks[] array */
469  int npids; /* # of valid entries in waiter_pids[] array */
470  int maxpids; /* Allocated length of waiter_pids[] array */
472 
473 
474 /* Result codes for LockAcquire() */
475 typedef enum
476 {
477  LOCKACQUIRE_NOT_AVAIL, /* lock not available, and dontWait=true */
478  LOCKACQUIRE_OK, /* lock successfully acquired */
479  LOCKACQUIRE_ALREADY_HELD, /* incremented count for lock already held */
480  LOCKACQUIRE_ALREADY_CLEAR /* incremented count for lock already clear */
482 
483 /* Deadlock states identified by DeadLockCheck() */
484 typedef enum
485 {
486  DS_NOT_YET_CHECKED, /* no deadlock check has run yet */
487  DS_NO_DEADLOCK, /* no deadlock detected */
488  DS_SOFT_DEADLOCK, /* deadlock avoided by queue rearrangement */
489  DS_HARD_DEADLOCK, /* deadlock, no way out but ERROR */
490  DS_BLOCKED_BY_AUTOVACUUM /* no deadlock; queue blocked by autovacuum
491  * worker */
492 } DeadLockState;
493 
494 /*
495  * The lockmgr's shared hash tables are partitioned to reduce contention.
496  * To determine which partition a given locktag belongs to, compute the tag's
497  * hash code with LockTagHashCode(), then apply one of these macros.
498  * NB: NUM_LOCK_PARTITIONS must be a power of 2!
499  */
500 #define LockHashPartition(hashcode) \
501  ((hashcode) % NUM_LOCK_PARTITIONS)
502 #define LockHashPartitionLock(hashcode) \
503  (&MainLWLockArray[LOCK_MANAGER_LWLOCK_OFFSET + \
504  LockHashPartition(hashcode)].lock)
505 #define LockHashPartitionLockByIndex(i) \
506  (&MainLWLockArray[LOCK_MANAGER_LWLOCK_OFFSET + (i)].lock)
507 
508 /*
509  * The deadlock detector needs to be able to access lockGroupLeader and
510  * related fields in the PGPROC, so we arrange for those fields to be protected
511  * by one of the lock hash partition locks. Since the deadlock detector
512  * acquires all such locks anyway, this makes it safe for it to access these
513  * fields without doing anything extra. To avoid contention as much as
514  * possible, we map different PGPROCs to different partition locks. The lock
515  * used for a given lock group is determined by the group leader's pgprocno.
516  */
517 #define LockHashPartitionLockByProc(leader_pgproc) \
518  LockHashPartitionLock((leader_pgproc)->pgprocno)
519 
520 /*
521  * function prototypes
522  */
523 extern void InitLocks(void);
524 extern LockMethod GetLocksMethodTable(const LOCK *lock);
525 extern LockMethod GetLockTagsMethodTable(const LOCKTAG *locktag);
526 extern uint32 LockTagHashCode(const LOCKTAG *locktag);
527 extern bool DoLockModesConflict(LOCKMODE mode1, LOCKMODE mode2);
528 extern LockAcquireResult LockAcquire(const LOCKTAG *locktag,
529  LOCKMODE lockmode,
530  bool sessionLock,
531  bool dontWait);
532 extern LockAcquireResult LockAcquireExtended(const LOCKTAG *locktag,
533  LOCKMODE lockmode,
534  bool sessionLock,
535  bool dontWait,
536  bool reportMemoryError,
537  LOCALLOCK **locallockp);
538 extern void AbortStrongLockAcquire(void);
539 extern void MarkLockClear(LOCALLOCK *locallock);
540 extern bool LockRelease(const LOCKTAG *locktag,
541  LOCKMODE lockmode, bool sessionLock);
542 extern void LockReleaseAll(LOCKMETHODID lockmethodid, bool allLocks);
543 extern void LockReleaseSession(LOCKMETHODID lockmethodid);
544 extern void LockReleaseCurrentOwner(LOCALLOCK **locallocks, int nlocks);
545 extern void LockReassignCurrentOwner(LOCALLOCK **locallocks, int nlocks);
546 extern bool LockHeldByMe(const LOCKTAG *locktag, LOCKMODE lockmode);
547 extern bool LockHasWaiters(const LOCKTAG *locktag,
548  LOCKMODE lockmode, bool sessionLock);
549 extern VirtualTransactionId *GetLockConflicts(const LOCKTAG *locktag,
550  LOCKMODE lockmode, int *countp);
551 extern void AtPrepare_Locks(void);
552 extern void PostPrepare_Locks(TransactionId xid);
553 extern int LockCheckConflicts(LockMethod lockMethodTable,
554  LOCKMODE lockmode,
555  LOCK *lock, PROCLOCK *proclock);
556 extern void GrantLock(LOCK *lock, PROCLOCK *proclock, LOCKMODE lockmode);
557 extern void GrantAwaitedLock(void);
558 extern void RemoveFromWaitQueue(PGPROC *proc, uint32 hashcode);
559 extern Size LockShmemSize(void);
560 extern LockData *GetLockStatusData(void);
561 extern BlockedProcsData *GetBlockerStatusData(int blocked_pid);
562 
563 extern xl_standby_lock *GetRunningTransactionLocks(int *nlocks);
564 extern const char *GetLockmodeName(LOCKMETHODID lockmethodid, LOCKMODE mode);
565 
566 extern void lock_twophase_recover(TransactionId xid, uint16 info,
567  void *recdata, uint32 len);
568 extern void lock_twophase_postcommit(TransactionId xid, uint16 info,
569  void *recdata, uint32 len);
570 extern void lock_twophase_postabort(TransactionId xid, uint16 info,
571  void *recdata, uint32 len);
573  void *recdata, uint32 len);
574 
575 extern DeadLockState DeadLockCheck(PGPROC *proc);
576 extern PGPROC *GetBlockingAutoVacuumPgproc(void);
577 extern void DeadLockReport(void) pg_attribute_noreturn();
578 extern void RememberSimpleDeadLock(PGPROC *proc1,
579  LOCKMODE lockmode,
580  LOCK *lock,
581  PGPROC *proc2);
582 extern void InitDeadLockChecking(void);
583 
584 extern int LockWaiterCount(const LOCKTAG *locktag);
585 
586 #ifdef LOCK_DEBUG
587 extern void DumpLocks(PGPROC *proc);
588 extern void DumpAllLocks(void);
589 #endif
590 
591 /* Lock a VXID (used to wait for a transaction to finish) */
593 extern void VirtualXactLockTableCleanup(void);
594 extern bool VirtualXactLock(VirtualTransactionId vxid, bool wait);
595 
596 #endif /* LOCK_H_ */
struct BlockedProcData BlockedProcData
const char *const LockTagTypeNames[]
Definition: lockfuncs.c:26
PROCLOCKTAG tag
Definition: lock.h:350
static PgChecksumMode mode
Definition: pg_checksums.c:61
uint32 hashcode
Definition: lock.h:410
void MarkLockClear(LOCALLOCK *locallock)
Definition: lock.c:1708
Size LockShmemSize(void)
Definition: lock.c:3441
void VirtualXactLockTableInsert(VirtualTransactionId vxid)
Definition: lock.c:4301
LOCALLOCKTAG tag
Definition: lock.h:407
bool holdsStrongLockCount
Definition: lock.h:417
void RemoveFromWaitQueue(PGPROC *proc, uint32 hashcode)
Definition: lock.c:1827
int * waiter_pids
Definition: lock.h:464
void AbortStrongLockAcquire(void)
Definition: lock.c:1666
int numLockOwners
Definition: lock.h:414
LockInstanceData * locks
Definition: lock.h:444
LOCKTAG lock
Definition: lock.h:388
uint32 TransactionId
Definition: c.h:514
void lock_twophase_postcommit(TransactionId xid, uint16 info, void *recdata, uint32 len)
Definition: lock.c:4251
int LOCKMODE
Definition: lockdefs.h:26
int first_lock
Definition: lock.h:452
LOCKMODE mode
Definition: lock.h:389
void LockReleaseCurrentOwner(LOCALLOCK **locallocks, int nlocks)
Definition: lock.c:2393
PROCLOCK * proclock
Definition: lock.h:412
int nRequested
Definition: lock.h:298
SHM_QUEUE links
Definition: lock.h:31
int num_waiters
Definition: lock.h:457
LOCKMASK holdMask
Definition: lock.h:354
int64 nLocks
Definition: lock.h:401
LockAcquireResult LockAcquireExtended(const LOCKTAG *locktag, LOCKMODE lockmode, bool sessionLock, bool dontWait, bool reportMemoryError, LOCALLOCK **locallockp)
Definition: lock.c:732
bool fastpath
Definition: lock.h:438
LockMethod GetLocksMethodTable(const LOCK *lock)
Definition: lock.c:460
struct LOCALLOCKOWNER LOCALLOCKOWNER
LOCKTAG tag
Definition: lock.h:290
void PostPrepare_Locks(TransactionId xid)
Definition: lock.c:3249
unsigned char uint8
Definition: c.h:357
Definition: lock.h:163
const LOCKMASK * conflictTab
Definition: lock.h:113
int LockWaiterCount(const LOCKTAG *locktag)
Definition: lock.c:4467
SHM_QUEUE lockLink
Definition: lock.h:356
void LockReassignCurrentOwner(LOCALLOCK **locallocks, int nlocks)
Definition: lock.c:2488
LockMethod GetLockTagsMethodTable(const LOCKTAG *locktag)
Definition: lock.c:472
BlockedProcData * procs
Definition: lock.h:462
Definition: lock.h:441
LocalTransactionId localTransactionId
Definition: lock.h:65
struct LOCALLOCKTAG LOCALLOCKTAG
LOCKTAG locktag
Definition: lock.h:431
LOCKMODE waitLockMode
Definition: lock.h:433
int maxLockOwners
Definition: lock.h:415
int nGranted
Definition: lock.h:300
void LockReleaseAll(LOCKMETHODID lockmethodid, bool allLocks)
Definition: lock.c:2089
void DeadLockReport(void) pg_attribute_noreturn()
Definition: deadlock.c:1083
int num_locks
Definition: lock.h:453
int max_locks_per_xact
Definition: lock.c:54
PROC_QUEUE waitProcs
Definition: lock.h:296
void InitLocks(void)
Definition: lock.c:377
uint16 locktag_field4
Definition: lock.h:168
BlockedProcsData * GetBlockerStatusData(int blocked_pid)
Definition: lock.c:3662
int leaderPid
Definition: lock.h:437
struct LOCALLOCK LOCALLOCK
unsigned short uint16
Definition: c.h:358
struct BlockedProcsData BlockedProcsData
void lock_twophase_postabort(TransactionId xid, uint16 info, void *recdata, uint32 len)
Definition: lock.c:4277
LockAcquireResult LockAcquire(const LOCKTAG *locktag, LOCKMODE lockmode, bool sessionLock, bool dontWait)
Definition: lock.c:708
void VirtualXactLockTableCleanup(void)
Definition: lock.c:4324
const char * GetLockmodeName(LOCKMETHODID lockmethodid, LOCKMODE mode)
Definition: lock.c:3925
uint32 locktag_field2
Definition: lock.h:166
unsigned int uint32
Definition: c.h:359
bool LockHeldByMe(const LOCKTAG *locktag, LOCKMODE lockmode)
Definition: lock.c:571
Definition: lock.h:287
uint32 LocalTransactionId
Definition: c.h:516
xl_standby_lock * GetRunningTransactionLocks(int *nlocks)
Definition: lock.c:3842
struct PROCLOCK PROCLOCK
LOCKMASK waitMask
Definition: lock.h:294
int maxlocks
Definition: lock.h:468
uint16 LOCKMETHODID
Definition: lock.h:124
SHM_QUEUE procLocks
Definition: lock.h:295
struct LOCKTAG LOCKTAG
int nelements
Definition: lock.h:443
#define MAX_LOCKMODES
Definition: lock.h:84
SHM_QUEUE procLink
Definition: lock.h:357
LockInstanceData * locks
Definition: lock.h:463
struct PROCLOCKTAG PROCLOCKTAG
const LockMethodData * LockMethod
Definition: lock.h:118
BackendId backend
Definition: lock.h:434
int BackendId
Definition: backendid.h:21
bool LockRelease(const LOCKTAG *locktag, LOCKMODE lockmode, bool sessionLock)
Definition: lock.c:1884
bool LockHasWaiters(const LOCKTAG *locktag, LOCKMODE lockmode, bool sessionLock)
Definition: lock.c:595
void RememberSimpleDeadLock(PGPROC *proc1, LOCKMODE lockmode, LOCK *lock, PGPROC *proc2)
Definition: deadlock.c:1155
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:4038
int first_waiter
Definition: lock.h:456
void GrantAwaitedLock(void)
Definition: lock.c:1695
bool DoLockModesConflict(LOCKMODE mode1, LOCKMODE mode2)
Definition: lock.c:556
uint8 locktag_type
Definition: lock.h:169
DeadLockState
Definition: lock.h:484
LocalTransactionId lxid
Definition: lock.h:435
BackendId backendId
Definition: lock.h:64
size_t Size
Definition: c.h:467
bool VirtualXactLock(VirtualTransactionId vxid, bool wait)
Definition: lock.c:4371
LOCALLOCKOWNER * lockOwners
Definition: lock.h:416
LOCK * lock
Definition: lock.h:411
int LOCKMASK
Definition: lockdefs.h:25
struct LockMethodData LockMethodData
LOCKMASK holdMask
Definition: lock.h:432
uint8 locktag_lockmethodid
Definition: lock.h:170
PGPROC * myProc
Definition: lock.h:344
#define pg_attribute_noreturn()
Definition: c.h:147
int LockCheckConflicts(LockMethod lockMethodTable, LOCKMODE lockmode, LOCK *lock, PROCLOCK *proclock)
Definition: lock.c:1344
LOCKMASK grantMask
Definition: lock.h:293
Definition: lock.h:347
int64 nLocks
Definition: lock.h:413
struct PROC_QUEUE PROC_QUEUE
LockAcquireResult
Definition: lock.h:475
void InitDeadLockChecking(void)
Definition: deadlock.c:143
struct LockInstanceData LockInstanceData
const bool * trace_flag
Definition: lock.h:115
LockData * GetLockStatusData(void)
Definition: lock.c:3478
int size
Definition: lock.h:32
LOCK * myLock
Definition: lock.h:343
LockTagType
Definition: lock.h:137
struct ResourceOwnerData * owner
Definition: lock.h:400
void lock_twophase_standby_recover(TransactionId xid, uint16 info, void *recdata, uint32 len)
Definition: lock.c:4219
struct LockData LockData
VirtualTransactionId * GetLockConflicts(const LOCKTAG *locktag, LOCKMODE lockmode, int *countp)
Definition: lock.c:2821
PGPROC * GetBlockingAutoVacuumPgproc(void)
Definition: deadlock.c:293
void GrantLock(LOCK *lock, PROCLOCK *proclock, LOCKMODE lockmode)
Definition: lock.c:1467
uint32 locktag_field1
Definition: lock.h:165
Definition: proc.h:95
uint32 LockTagHashCode(const LOCKTAG *locktag)
Definition: lock.c:490
uint32 locktag_field3
Definition: lock.h:167
void AtPrepare_Locks(void)
Definition: lock.c:3139
bool lockCleared
Definition: lock.h:418
const char *const * lockModeNames
Definition: lock.h:114
PGPROC * groupLeader
Definition: lock.h:353
void LockReleaseSession(LOCKMETHODID lockmethodid)
Definition: lock.c:2363
int numLockModes
Definition: lock.h:112
int maxprocs
Definition: lock.h:466
LOCKMASK releaseMask
Definition: lock.h:355