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 */ 67 } VirtualTransactionId; 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 { 113 int numLockModes; 114 const LOCKMASK *conflictTab; 115 const char *const *lockModeNames; 116 const bool *trace_flag; 117 } LockMethodData; 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 */ 125 typedef uint16 LOCKMETHODID; 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 */ 397 struct ResourceOwnerData *owner; 398 int64 nLocks; /* # of times held by this owner */ 399 } LOCALLOCKOWNER; 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? */ 435 } LockInstanceData; 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 */ 454 } BlockedProcData; 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 */ 467 } BlockedProcsData; 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 */ 476 } LockAcquireResult; 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); 564 extern void lock_twophase_standby_recover(TransactionId xid, uint16 info, 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) */ 584 extern void VirtualXactLockTableInsert(VirtualTransactionId vxid); 585 extern void VirtualXactLockTableCleanup(void); 586 extern bool VirtualXactLock(VirtualTransactionId vxid, bool wait); 587 588 #endif /* LOCK_H */ 589