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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/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  LOCKTAG_RELATION_EXTEND, /* the right to extend a relation */
142  LOCKTAG_PAGE, /* one page of a relation */
143  LOCKTAG_TUPLE, /* one physical tuple */
144  LOCKTAG_TRANSACTION, /* transaction (for waiting for xact done) */
145  LOCKTAG_VIRTUALTRANSACTION, /* virtual transaction (ditto) */
146  LOCKTAG_SPECULATIVE_TOKEN, /* speculative insertion Xid and token */
147  LOCKTAG_OBJECT, /* non-relation database object */
148  LOCKTAG_USERLOCK, /* reserved for old contrib/userlock code */
149  LOCKTAG_ADVISORY /* advisory user locks */
150 } LockTagType;
151 
152 #define LOCKTAG_LAST_TYPE LOCKTAG_ADVISORY
153 
154 extern const char *const LockTagTypeNames[];
155 
156 /*
157  * The LOCKTAG struct is defined with malice aforethought to fit into 16
158  * bytes with no padding. Note that this would need adjustment if we were
159  * to widen Oid, BlockNumber, or TransactionId to more than 32 bits.
160  *
161  * We include lockmethodid in the locktag so that a single hash table in
162  * shared memory can store locks of different lockmethods.
163  */
164 typedef struct LOCKTAG
165 {
166  uint32 locktag_field1; /* a 32-bit ID field */
167  uint32 locktag_field2; /* a 32-bit ID field */
168  uint32 locktag_field3; /* a 32-bit ID field */
169  uint16 locktag_field4; /* a 16-bit ID field */
170  uint8 locktag_type; /* see enum LockTagType */
171  uint8 locktag_lockmethodid; /* lockmethod indicator */
172 } LOCKTAG;
173 
174 /*
175  * These macros define how we map logical IDs of lockable objects into
176  * the physical fields of LOCKTAG. Use these to set up LOCKTAG values,
177  * rather than accessing the fields directly. Note multiple eval of target!
178  */
179 
180 /* ID info for a relation is DB OID + REL OID; DB OID = 0 if shared */
181 #define SET_LOCKTAG_RELATION(locktag,dboid,reloid) \
182  ((locktag).locktag_field1 = (dboid), \
183  (locktag).locktag_field2 = (reloid), \
184  (locktag).locktag_field3 = 0, \
185  (locktag).locktag_field4 = 0, \
186  (locktag).locktag_type = LOCKTAG_RELATION, \
187  (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
188 
189 /* same ID info as RELATION */
190 #define SET_LOCKTAG_RELATION_EXTEND(locktag,dboid,reloid) \
191  ((locktag).locktag_field1 = (dboid), \
192  (locktag).locktag_field2 = (reloid), \
193  (locktag).locktag_field3 = 0, \
194  (locktag).locktag_field4 = 0, \
195  (locktag).locktag_type = LOCKTAG_RELATION_EXTEND, \
196  (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
197 
198 /* ID info for a page is RELATION info + BlockNumber */
199 #define SET_LOCKTAG_PAGE(locktag,dboid,reloid,blocknum) \
200  ((locktag).locktag_field1 = (dboid), \
201  (locktag).locktag_field2 = (reloid), \
202  (locktag).locktag_field3 = (blocknum), \
203  (locktag).locktag_field4 = 0, \
204  (locktag).locktag_type = LOCKTAG_PAGE, \
205  (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
206 
207 /* ID info for a tuple is PAGE info + OffsetNumber */
208 #define SET_LOCKTAG_TUPLE(locktag,dboid,reloid,blocknum,offnum) \
209  ((locktag).locktag_field1 = (dboid), \
210  (locktag).locktag_field2 = (reloid), \
211  (locktag).locktag_field3 = (blocknum), \
212  (locktag).locktag_field4 = (offnum), \
213  (locktag).locktag_type = LOCKTAG_TUPLE, \
214  (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
215 
216 /* ID info for a transaction is its TransactionId */
217 #define SET_LOCKTAG_TRANSACTION(locktag,xid) \
218  ((locktag).locktag_field1 = (xid), \
219  (locktag).locktag_field2 = 0, \
220  (locktag).locktag_field3 = 0, \
221  (locktag).locktag_field4 = 0, \
222  (locktag).locktag_type = LOCKTAG_TRANSACTION, \
223  (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
224 
225 /* ID info for a virtual transaction is its VirtualTransactionId */
226 #define SET_LOCKTAG_VIRTUALTRANSACTION(locktag,vxid) \
227  ((locktag).locktag_field1 = (vxid).backendId, \
228  (locktag).locktag_field2 = (vxid).localTransactionId, \
229  (locktag).locktag_field3 = 0, \
230  (locktag).locktag_field4 = 0, \
231  (locktag).locktag_type = LOCKTAG_VIRTUALTRANSACTION, \
232  (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
233 
234 /*
235  * ID info for a speculative insert is TRANSACTION info +
236  * its speculative insert counter.
237  */
238 #define SET_LOCKTAG_SPECULATIVE_INSERTION(locktag,xid,token) \
239  ((locktag).locktag_field1 = (xid), \
240  (locktag).locktag_field2 = (token), \
241  (locktag).locktag_field3 = 0, \
242  (locktag).locktag_field4 = 0, \
243  (locktag).locktag_type = LOCKTAG_SPECULATIVE_TOKEN, \
244  (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
245 
246 /*
247  * ID info for an object is DB OID + CLASS OID + OBJECT OID + SUBID
248  *
249  * Note: object ID has same representation as in pg_depend and
250  * pg_description, but notice that we are constraining SUBID to 16 bits.
251  * Also, we use DB OID = 0 for shared objects such as tablespaces.
252  */
253 #define SET_LOCKTAG_OBJECT(locktag,dboid,classoid,objoid,objsubid) \
254  ((locktag).locktag_field1 = (dboid), \
255  (locktag).locktag_field2 = (classoid), \
256  (locktag).locktag_field3 = (objoid), \
257  (locktag).locktag_field4 = (objsubid), \
258  (locktag).locktag_type = LOCKTAG_OBJECT, \
259  (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD)
260 
261 #define SET_LOCKTAG_ADVISORY(locktag,id1,id2,id3,id4) \
262  ((locktag).locktag_field1 = (id1), \
263  (locktag).locktag_field2 = (id2), \
264  (locktag).locktag_field3 = (id3), \
265  (locktag).locktag_field4 = (id4), \
266  (locktag).locktag_type = LOCKTAG_ADVISORY, \
267  (locktag).locktag_lockmethodid = USER_LOCKMETHOD)
268 
269 
270 /*
271  * Per-locked-object lock information:
272  *
273  * tag -- uniquely identifies the object being locked
274  * grantMask -- bitmask for all lock types currently granted on this object.
275  * waitMask -- bitmask for all lock types currently awaited on this object.
276  * procLocks -- list of PROCLOCK objects for this lock.
277  * waitProcs -- queue of processes waiting for this lock.
278  * requested -- count of each lock type currently requested on the lock
279  * (includes requests already granted!!).
280  * nRequested -- total requested locks of all types.
281  * granted -- count of each lock type currently granted on the lock.
282  * nGranted -- total granted locks of all types.
283  *
284  * Note: these counts count 1 for each backend. Internally to a backend,
285  * there may be multiple grabs on a particular lock, but this is not reflected
286  * into shared memory.
287  */
288 typedef struct LOCK
289 {
290  /* hash key */
291  LOCKTAG tag; /* unique identifier of lockable object */
292 
293  /* data */
294  LOCKMASK grantMask; /* bitmask for lock types already granted */
295  LOCKMASK waitMask; /* bitmask for lock types awaited */
296  SHM_QUEUE procLocks; /* list of PROCLOCK objects assoc. with lock */
297  PROC_QUEUE waitProcs; /* list of PGPROC objects waiting on lock */
298  int requested[MAX_LOCKMODES]; /* counts of requested locks */
299  int nRequested; /* total of requested[] array */
300  int granted[MAX_LOCKMODES]; /* counts of granted locks */
301  int nGranted; /* total of granted[] array */
302 } LOCK;
303 
304 #define LOCK_LOCKMETHOD(lock) ((LOCKMETHODID) (lock).tag.locktag_lockmethodid)
305 
306 
307 /*
308  * We may have several different backends holding or awaiting locks
309  * on the same lockable object. We need to store some per-holder/waiter
310  * information for each such holder (or would-be holder). This is kept in
311  * a PROCLOCK struct.
312  *
313  * PROCLOCKTAG is the key information needed to look up a PROCLOCK item in the
314  * proclock hashtable. A PROCLOCKTAG value uniquely identifies the combination
315  * of a lockable object and a holder/waiter for that object. (We can use
316  * pointers here because the PROCLOCKTAG need only be unique for the lifespan
317  * of the PROCLOCK, and it will never outlive the lock or the proc.)
318  *
319  * Internally to a backend, it is possible for the same lock to be held
320  * for different purposes: the backend tracks transaction locks separately
321  * from session locks. However, this is not reflected in the shared-memory
322  * state: we only track which backend(s) hold the lock. This is OK since a
323  * backend can never block itself.
324  *
325  * The holdMask field shows the already-granted locks represented by this
326  * proclock. Note that there will be a proclock object, possibly with
327  * zero holdMask, for any lock that the process is currently waiting on.
328  * Otherwise, proclock objects whose holdMasks are zero are recycled
329  * as soon as convenient.
330  *
331  * releaseMask is workspace for LockReleaseAll(): it shows the locks due
332  * to be released during the current call. This must only be examined or
333  * set by the backend owning the PROCLOCK.
334  *
335  * Each PROCLOCK object is linked into lists for both the associated LOCK
336  * object and the owning PGPROC object. Note that the PROCLOCK is entered
337  * into these lists as soon as it is created, even if no lock has yet been
338  * granted. A PGPROC that is waiting for a lock to be granted will also be
339  * linked into the lock's waitProcs queue.
340  */
341 typedef struct PROCLOCKTAG
342 {
343  /* NB: we assume this struct contains no padding! */
344  LOCK *myLock; /* link to per-lockable-object information */
345  PGPROC *myProc; /* link to PGPROC of owning backend */
346 } PROCLOCKTAG;
347 
348 typedef struct PROCLOCK
349 {
350  /* tag */
351  PROCLOCKTAG tag; /* unique identifier of proclock object */
352 
353  /* data */
354  PGPROC *groupLeader; /* proc's lock group leader, or proc itself */
355  LOCKMASK holdMask; /* bitmask for lock types currently held */
356  LOCKMASK releaseMask; /* bitmask for lock types to be released */
357  SHM_QUEUE lockLink; /* list link in LOCK's list of proclocks */
358  SHM_QUEUE procLink; /* list link in PGPROC's list of proclocks */
359 } PROCLOCK;
360 
361 #define PROCLOCK_LOCKMETHOD(proclock) \
362  LOCK_LOCKMETHOD(*((proclock).tag.myLock))
363 
364 /*
365  * Each backend also maintains a local hash table with information about each
366  * lock it is currently interested in. In particular the local table counts
367  * the number of times that lock has been acquired. This allows multiple
368  * requests for the same lock to be executed without additional accesses to
369  * shared memory. We also track the number of lock acquisitions per
370  * ResourceOwner, so that we can release just those locks belonging to a
371  * particular ResourceOwner.
372  *
373  * When holding a lock taken "normally", the lock and proclock fields always
374  * point to the associated objects in shared memory. However, if we acquired
375  * the lock via the fast-path mechanism, the lock and proclock fields are set
376  * to NULL, since there probably aren't any such objects in shared memory.
377  * (If the lock later gets promoted to normal representation, we may eventually
378  * update our locallock's lock/proclock fields after finding the shared
379  * objects.)
380  *
381  * Caution: a locallock object can be left over from a failed lock acquisition
382  * attempt. In this case its lock/proclock fields are untrustworthy, since
383  * the shared lock object is neither held nor awaited, and hence is available
384  * to be reclaimed. If nLocks > 0 then these pointers must either be valid or
385  * NULL, but when nLocks == 0 they should be considered garbage.
386  */
387 typedef struct LOCALLOCKTAG
388 {
389  LOCKTAG lock; /* identifies the lockable object */
390  LOCKMODE mode; /* lock mode for this table entry */
391 } LOCALLOCKTAG;
392 
393 typedef struct LOCALLOCKOWNER
394 {
395  /*
396  * Note: if owner is NULL then the lock is held on behalf of the session;
397  * otherwise it is held on behalf of my current transaction.
398  *
399  * Must use a forward struct reference to avoid circularity.
400  */
402  int64 nLocks; /* # of times held by this owner */
404 
405 typedef struct LOCALLOCK
406 {
407  /* tag */
408  LOCALLOCKTAG tag; /* unique identifier of locallock entry */
409 
410  /* data */
411  uint32 hashcode; /* copy of LOCKTAG's hash value */
412  LOCK *lock; /* associated LOCK object, if any */
413  PROCLOCK *proclock; /* associated PROCLOCK object, if any */
414  int64 nLocks; /* total number of times lock is held */
415  int numLockOwners; /* # of relevant ResourceOwners */
416  int maxLockOwners; /* allocated size of array */
417  LOCALLOCKOWNER *lockOwners; /* dynamically resizable array */
418  bool holdsStrongLockCount; /* bumped FastPathStrongRelationLocks */
419  bool lockCleared; /* we read all sinval msgs for lock */
420 } LOCALLOCK;
421 
422 #define LOCALLOCK_LOCKMETHOD(llock) ((llock).tag.lock.locktag_lockmethodid)
423 
424 
425 /*
426  * These structures hold information passed from lmgr internals to the lock
427  * listing user-level functions (in lockfuncs.c).
428  */
429 
430 typedef struct LockInstanceData
431 {
432  LOCKTAG locktag; /* tag for locked object */
433  LOCKMASK holdMask; /* locks held by this PGPROC */
434  LOCKMODE waitLockMode; /* lock awaited by this PGPROC, if any */
435  BackendId backend; /* backend ID of this PGPROC */
436  LocalTransactionId lxid; /* local transaction ID of this PGPROC */
437  int pid; /* pid of this PGPROC */
438  int leaderPid; /* pid of group leader; = pid if no group */
439  bool fastpath; /* taken via fastpath? */
441 
442 typedef struct LockData
443 {
444  int nelements; /* The length of the array */
445  LockInstanceData *locks; /* Array of per-PROCLOCK information */
446 } LockData;
447 
448 typedef struct BlockedProcData
449 {
450  int pid; /* pid of a blocked PGPROC */
451  /* Per-PROCLOCK information about PROCLOCKs of the lock the pid awaits */
452  /* (these fields refer to indexes in BlockedProcsData.locks[]) */
453  int first_lock; /* index of first relevant LockInstanceData */
454  int num_locks; /* number of relevant LockInstanceDatas */
455  /* PIDs of PGPROCs that are ahead of "pid" in the lock's wait queue */
456  /* (these fields refer to indexes in BlockedProcsData.waiter_pids[]) */
457  int first_waiter; /* index of first preceding waiter */
458  int num_waiters; /* number of preceding waiters */
460 
461 typedef struct BlockedProcsData
462 {
463  BlockedProcData *procs; /* Array of per-blocked-proc information */
464  LockInstanceData *locks; /* Array of per-PROCLOCK information */
465  int *waiter_pids; /* Array of PIDs of other blocked PGPROCs */
466  int nprocs; /* # of valid entries in procs[] array */
467  int maxprocs; /* Allocated length of procs[] array */
468  int nlocks; /* # of valid entries in locks[] array */
469  int maxlocks; /* Allocated length of locks[] array */
470  int npids; /* # of valid entries in waiter_pids[] array */
471  int maxpids; /* Allocated length of waiter_pids[] array */
473 
474 
475 /* Result codes for LockAcquire() */
476 typedef enum
477 {
478  LOCKACQUIRE_NOT_AVAIL, /* lock not available, and dontWait=true */
479  LOCKACQUIRE_OK, /* lock successfully acquired */
480  LOCKACQUIRE_ALREADY_HELD, /* incremented count for lock already held */
481  LOCKACQUIRE_ALREADY_CLEAR /* incremented count for lock already clear */
483 
484 /* Deadlock states identified by DeadLockCheck() */
485 typedef enum
486 {
487  DS_NOT_YET_CHECKED, /* no deadlock check has run yet */
488  DS_NO_DEADLOCK, /* no deadlock detected */
489  DS_SOFT_DEADLOCK, /* deadlock avoided by queue rearrangement */
490  DS_HARD_DEADLOCK, /* deadlock, no way out but ERROR */
491  DS_BLOCKED_BY_AUTOVACUUM /* no deadlock; queue blocked by autovacuum
492  * worker */
493 } DeadLockState;
494 
495 /*
496  * The lockmgr's shared hash tables are partitioned to reduce contention.
497  * To determine which partition a given locktag belongs to, compute the tag's
498  * hash code with LockTagHashCode(), then apply one of these macros.
499  * NB: NUM_LOCK_PARTITIONS must be a power of 2!
500  */
501 #define LockHashPartition(hashcode) \
502  ((hashcode) % NUM_LOCK_PARTITIONS)
503 #define LockHashPartitionLock(hashcode) \
504  (&MainLWLockArray[LOCK_MANAGER_LWLOCK_OFFSET + \
505  LockHashPartition(hashcode)].lock)
506 #define LockHashPartitionLockByIndex(i) \
507  (&MainLWLockArray[LOCK_MANAGER_LWLOCK_OFFSET + (i)].lock)
508 
509 /*
510  * The deadlock detector needs to be able to access lockGroupLeader and
511  * related fields in the PGPROC, so we arrange for those fields to be protected
512  * by one of the lock hash partition locks. Since the deadlock detector
513  * acquires all such locks anyway, this makes it safe for it to access these
514  * fields without doing anything extra. To avoid contention as much as
515  * possible, we map different PGPROCs to different partition locks. The lock
516  * used for a given lock group is determined by the group leader's pgprocno.
517  */
518 #define LockHashPartitionLockByProc(leader_pgproc) \
519  LockHashPartitionLock((leader_pgproc)->pgprocno)
520 
521 /*
522  * function prototypes
523  */
524 extern void InitLocks(void);
525 extern LockMethod GetLocksMethodTable(const LOCK *lock);
526 extern LockMethod GetLockTagsMethodTable(const LOCKTAG *locktag);
527 extern uint32 LockTagHashCode(const LOCKTAG *locktag);
528 extern bool DoLockModesConflict(LOCKMODE mode1, LOCKMODE mode2);
529 extern LockAcquireResult LockAcquire(const LOCKTAG *locktag,
530  LOCKMODE lockmode,
531  bool sessionLock,
532  bool dontWait);
533 extern LockAcquireResult LockAcquireExtended(const LOCKTAG *locktag,
534  LOCKMODE lockmode,
535  bool sessionLock,
536  bool dontWait,
537  bool reportMemoryError,
538  LOCALLOCK **locallockp);
539 extern void AbortStrongLockAcquire(void);
540 extern void MarkLockClear(LOCALLOCK *locallock);
541 extern bool LockRelease(const LOCKTAG *locktag,
542  LOCKMODE lockmode, bool sessionLock);
543 extern void LockReleaseAll(LOCKMETHODID lockmethodid, bool allLocks);
544 extern void LockReleaseSession(LOCKMETHODID lockmethodid);
545 extern void LockReleaseCurrentOwner(LOCALLOCK **locallocks, int nlocks);
546 extern void LockReassignCurrentOwner(LOCALLOCK **locallocks, int nlocks);
547 extern bool LockHeldByMe(const LOCKTAG *locktag, LOCKMODE lockmode);
548 extern bool LockHasWaiters(const LOCKTAG *locktag,
549  LOCKMODE lockmode, bool sessionLock);
550 extern VirtualTransactionId *GetLockConflicts(const LOCKTAG *locktag,
551  LOCKMODE lockmode, int *countp);
552 extern void AtPrepare_Locks(void);
553 extern void PostPrepare_Locks(TransactionId xid);
554 extern int LockCheckConflicts(LockMethod lockMethodTable,
555  LOCKMODE lockmode,
556  LOCK *lock, PROCLOCK *proclock);
557 extern void GrantLock(LOCK *lock, PROCLOCK *proclock, LOCKMODE lockmode);
558 extern void GrantAwaitedLock(void);
559 extern void RemoveFromWaitQueue(PGPROC *proc, uint32 hashcode);
560 extern Size LockShmemSize(void);
561 extern LockData *GetLockStatusData(void);
562 extern BlockedProcsData *GetBlockerStatusData(int blocked_pid);
563 
564 extern xl_standby_lock *GetRunningTransactionLocks(int *nlocks);
565 extern const char *GetLockmodeName(LOCKMETHODID lockmethodid, LOCKMODE mode);
566 
567 extern void lock_twophase_recover(TransactionId xid, uint16 info,
568  void *recdata, uint32 len);
569 extern void lock_twophase_postcommit(TransactionId xid, uint16 info,
570  void *recdata, uint32 len);
571 extern void lock_twophase_postabort(TransactionId xid, uint16 info,
572  void *recdata, uint32 len);
574  void *recdata, uint32 len);
575 
576 extern DeadLockState DeadLockCheck(PGPROC *proc);
577 extern PGPROC *GetBlockingAutoVacuumPgproc(void);
578 extern void DeadLockReport(void) pg_attribute_noreturn();
579 extern void RememberSimpleDeadLock(PGPROC *proc1,
580  LOCKMODE lockmode,
581  LOCK *lock,
582  PGPROC *proc2);
583 extern void InitDeadLockChecking(void);
584 
585 extern int LockWaiterCount(const LOCKTAG *locktag);
586 
587 #ifdef LOCK_DEBUG
588 extern void DumpLocks(PGPROC *proc);
589 extern void DumpAllLocks(void);
590 #endif
591 
592 /* Lock a VXID (used to wait for a transaction to finish) */
594 extern void VirtualXactLockTableCleanup(void);
595 extern bool VirtualXactLock(VirtualTransactionId vxid, bool wait);
596 
597 #endif /* LOCK_H_ */
struct BlockedProcData BlockedProcData
const char *const LockTagTypeNames[]
Definition: lockfuncs.c:26
PROCLOCKTAG tag
Definition: lock.h:351
static PgChecksumMode mode
Definition: pg_checksums.c:61
uint32 hashcode
Definition: lock.h:411
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:408
bool holdsStrongLockCount
Definition: lock.h:418
void RemoveFromWaitQueue(PGPROC *proc, uint32 hashcode)
Definition: lock.c:1827
int * waiter_pids
Definition: lock.h:465
void AbortStrongLockAcquire(void)
Definition: lock.c:1666
int numLockOwners
Definition: lock.h:415
LockInstanceData * locks
Definition: lock.h:445
LOCKTAG lock
Definition: lock.h:389
uint32 TransactionId
Definition: c.h:507
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:453
LOCKMODE mode
Definition: lock.h:390
void LockReleaseCurrentOwner(LOCALLOCK **locallocks, int nlocks)
Definition: lock.c:2393
PROCLOCK * proclock
Definition: lock.h:413
int nRequested
Definition: lock.h:299
SHM_QUEUE links
Definition: lock.h:32
int num_waiters
Definition: lock.h:458
LOCKMASK holdMask
Definition: lock.h:355
int64 nLocks
Definition: lock.h:402
LockAcquireResult LockAcquireExtended(const LOCKTAG *locktag, LOCKMODE lockmode, bool sessionLock, bool dontWait, bool reportMemoryError, LOCALLOCK **locallockp)
Definition: lock.c:732
bool fastpath
Definition: lock.h:439
LockMethod GetLocksMethodTable(const LOCK *lock)
Definition: lock.c:460
struct LOCALLOCKOWNER LOCALLOCKOWNER
LOCKTAG tag
Definition: lock.h:291
void PostPrepare_Locks(TransactionId xid)
Definition: lock.c:3249
unsigned char uint8
Definition: c.h:356
Definition: lock.h:164
const LOCKMASK * conflictTab
Definition: lock.h:114
int LockWaiterCount(const LOCKTAG *locktag)
Definition: lock.c:4467
SHM_QUEUE lockLink
Definition: lock.h:357
void LockReassignCurrentOwner(LOCALLOCK **locallocks, int nlocks)
Definition: lock.c:2488
LockMethod GetLockTagsMethodTable(const LOCKTAG *locktag)
Definition: lock.c:472
BlockedProcData * procs
Definition: lock.h:463
Definition: lock.h:442
LocalTransactionId localTransactionId
Definition: lock.h:66
struct LOCALLOCKTAG LOCALLOCKTAG
LOCKTAG locktag
Definition: lock.h:432
LOCKMODE waitLockMode
Definition: lock.h:434
int maxLockOwners
Definition: lock.h:416
int nGranted
Definition: lock.h:301
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:454
int max_locks_per_xact
Definition: lock.c:54
PROC_QUEUE waitProcs
Definition: lock.h:297
void InitLocks(void)
Definition: lock.c:377
uint16 locktag_field4
Definition: lock.h:169
BlockedProcsData * GetBlockerStatusData(int blocked_pid)
Definition: lock.c:3662
int leaderPid
Definition: lock.h:438
struct LOCALLOCK LOCALLOCK
unsigned short uint16
Definition: c.h:357
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:167
unsigned int uint32
Definition: c.h:358
bool LockHeldByMe(const LOCKTAG *locktag, LOCKMODE lockmode)
Definition: lock.c:571
Definition: lock.h:288
uint32 LocalTransactionId
Definition: c.h:509
xl_standby_lock * GetRunningTransactionLocks(int *nlocks)
Definition: lock.c:3842
struct PROCLOCK PROCLOCK
LOCKMASK waitMask
Definition: lock.h:295
int maxlocks
Definition: lock.h:469
uint16 LOCKMETHODID
Definition: lock.h:125
SHM_QUEUE procLocks
Definition: lock.h:296
struct LOCKTAG LOCKTAG
int nelements
Definition: lock.h:444
#define MAX_LOCKMODES
Definition: lock.h:85
SHM_QUEUE procLink
Definition: lock.h:358
LockInstanceData * locks
Definition: lock.h:464
struct PROCLOCKTAG PROCLOCKTAG
const LockMethodData * LockMethod
Definition: lock.h:119
BackendId backend
Definition: lock.h:435
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:457
void GrantAwaitedLock(void)
Definition: lock.c:1695
bool DoLockModesConflict(LOCKMODE mode1, LOCKMODE mode2)
Definition: lock.c:556
uint8 locktag_type
Definition: lock.h:170
DeadLockState
Definition: lock.h:485
LocalTransactionId lxid
Definition: lock.h:436
BackendId backendId
Definition: lock.h:65
size_t Size
Definition: c.h:466
bool VirtualXactLock(VirtualTransactionId vxid, bool wait)
Definition: lock.c:4371
LOCALLOCKOWNER * lockOwners
Definition: lock.h:417
LOCK * lock
Definition: lock.h:412
int LOCKMASK
Definition: lockdefs.h:25
struct LockMethodData LockMethodData
LOCKMASK holdMask
Definition: lock.h:433
uint8 locktag_lockmethodid
Definition: lock.h:171
PGPROC * myProc
Definition: lock.h:345
#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:294
Definition: lock.h:348
int64 nLocks
Definition: lock.h:414
struct PROC_QUEUE PROC_QUEUE
LockAcquireResult
Definition: lock.h:476
void InitDeadLockChecking(void)
Definition: deadlock.c:143
struct LockInstanceData LockInstanceData
const bool * trace_flag
Definition: lock.h:116
LockData * GetLockStatusData(void)
Definition: lock.c:3478
int size
Definition: lock.h:33
LOCK * myLock
Definition: lock.h:344
LockTagType
Definition: lock.h:138
struct ResourceOwnerData * owner
Definition: lock.h:401
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:166
Definition: proc.h:95
uint32 LockTagHashCode(const LOCKTAG *locktag)
Definition: lock.c:490
uint32 locktag_field3
Definition: lock.h:168
void AtPrepare_Locks(void)
Definition: lock.c:3139
bool lockCleared
Definition: lock.h:419
const char *const * lockModeNames
Definition: lock.h:115
PGPROC * groupLeader
Definition: lock.h:354
void LockReleaseSession(LOCKMETHODID lockmethodid)
Definition: lock.c:2363
int numLockModes
Definition: lock.h:113
int maxprocs
Definition: lock.h:467
LOCKMASK releaseMask
Definition: lock.h:356