1 /*------------------------------------------------------------------------- 2 * 3 * lock.h 4 * POSTGRES low-level lock mechanism 5 * 6 * 7 * Portions Copyright (c) 1996-2020, 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 * PGPROC fields backendId and lxid. For recovered prepared transactions, the 50 * LocalTransactionId is an ordinary XID; LOCKTAG_VIRTUALTRANSACTION never 51 * refers to that kind. These are guaranteed unique over the short term, but 52 * will be reused after a database restart or XID wraparound; hence they 53 * should never 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; /* backendId from PGPROC */ 66 LocalTransactionId localTransactionId; /* lxid from PGPROC */ 67 } VirtualTransactionId; 68 69 #define InvalidLocalTransactionId 0 70 #define LocalTransactionIdIsValid(lxid) ((lxid) != InvalidLocalTransactionId) 71 #define VirtualTransactionIdIsValid(vxid) \ 72 (LocalTransactionIdIsValid((vxid).localTransactionId)) 73 #define VirtualTransactionIdIsRecoveredPreparedXact(vxid) \ 74 ((vxid).backendId == InvalidBackendId) 75 #define VirtualTransactionIdEquals(vxid1, vxid2) \ 76 ((vxid1).backendId == (vxid2).backendId && \ 77 (vxid1).localTransactionId == (vxid2).localTransactionId) 78 #define SetInvalidVirtualTransactionId(vxid) \ 79 ((vxid).backendId = InvalidBackendId, \ 80 (vxid).localTransactionId = InvalidLocalTransactionId) 81 #define GET_VXID_FROM_PGPROC(vxid, proc) \ 82 ((vxid).backendId = (proc).backendId, \ 83 (vxid).localTransactionId = (proc).lxid) 84 85 /* MAX_LOCKMODES cannot be larger than the # of bits in LOCKMASK */ 86 #define MAX_LOCKMODES 10 87 88 #define LOCKBIT_ON(lockmode) (1 << (lockmode)) 89 #define LOCKBIT_OFF(lockmode) (~(1 << (lockmode))) 90 91 92 /* 93 * This data structure defines the locking semantics associated with a 94 * "lock method". The semantics specify the meaning of each lock mode 95 * (by defining which lock modes it conflicts with). 96 * All of this data is constant and is kept in const tables. 97 * 98 * numLockModes -- number of lock modes (READ,WRITE,etc) that 99 * are defined in this lock method. Must be less than MAX_LOCKMODES. 100 * 101 * conflictTab -- this is an array of bitmasks showing lock 102 * mode conflicts. conflictTab[i] is a mask with the j-th bit 103 * turned on if lock modes i and j conflict. Lock modes are 104 * numbered 1..numLockModes; conflictTab[0] is unused. 105 * 106 * lockModeNames -- ID strings for debug printouts. 107 * 108 * trace_flag -- pointer to GUC trace flag for this lock method. (The 109 * GUC variable is not constant, but we use "const" here to denote that 110 * it can't be changed through this reference.) 111 */ 112 typedef struct LockMethodData 113 { 114 int numLockModes; 115 const LOCKMASK *conflictTab; 116 const char *const *lockModeNames; 117 const bool *trace_flag; 118 } LockMethodData; 119 120 typedef const LockMethodData *LockMethod; 121 122 /* 123 * Lock methods are identified by LOCKMETHODID. (Despite the declaration as 124 * uint16, we are constrained to 256 lockmethods by the layout of LOCKTAG.) 125 */ 126 typedef uint16 LOCKMETHODID; 127 128 /* These identify the known lock methods */ 129 #define DEFAULT_LOCKMETHOD 1 130 #define USER_LOCKMETHOD 2 131 132 /* 133 * LOCKTAG is the key information needed to look up a LOCK item in the 134 * lock hashtable. A LOCKTAG value uniquely identifies a lockable object. 135 * 136 * The LockTagType enum defines the different kinds of objects we can lock. 137 * We can handle up to 256 different LockTagTypes. 138 */ 139 typedef enum LockTagType 140 { 141 LOCKTAG_RELATION, /* whole relation */ 142 LOCKTAG_RELATION_EXTEND, /* the right to extend a relation */ 143 LOCKTAG_DATABASE_FROZEN_IDS, /* pg_database.datfrozenxid */ 144 LOCKTAG_PAGE, /* one page of a relation */ 145 LOCKTAG_TUPLE, /* one physical tuple */ 146 LOCKTAG_TRANSACTION, /* transaction (for waiting for xact done) */ 147 LOCKTAG_VIRTUALTRANSACTION, /* virtual transaction (ditto) */ 148 LOCKTAG_SPECULATIVE_TOKEN, /* speculative insertion Xid and token */ 149 LOCKTAG_OBJECT, /* non-relation database object */ 150 LOCKTAG_USERLOCK, /* reserved for old contrib/userlock code */ 151 LOCKTAG_ADVISORY /* advisory user locks */ 152 } LockTagType; 153 154 #define LOCKTAG_LAST_TYPE LOCKTAG_ADVISORY 155 156 extern const char *const LockTagTypeNames[]; 157 158 /* 159 * The LOCKTAG struct is defined with malice aforethought to fit into 16 160 * bytes with no padding. Note that this would need adjustment if we were 161 * to widen Oid, BlockNumber, or TransactionId to more than 32 bits. 162 * 163 * We include lockmethodid in the locktag so that a single hash table in 164 * shared memory can store locks of different lockmethods. 165 */ 166 typedef struct LOCKTAG 167 { 168 uint32 locktag_field1; /* a 32-bit ID field */ 169 uint32 locktag_field2; /* a 32-bit ID field */ 170 uint32 locktag_field3; /* a 32-bit ID field */ 171 uint16 locktag_field4; /* a 16-bit ID field */ 172 uint8 locktag_type; /* see enum LockTagType */ 173 uint8 locktag_lockmethodid; /* lockmethod indicator */ 174 } LOCKTAG; 175 176 /* 177 * These macros define how we map logical IDs of lockable objects into 178 * the physical fields of LOCKTAG. Use these to set up LOCKTAG values, 179 * rather than accessing the fields directly. Note multiple eval of target! 180 */ 181 182 /* ID info for a relation is DB OID + REL OID; DB OID = 0 if shared */ 183 #define SET_LOCKTAG_RELATION(locktag,dboid,reloid) \ 184 ((locktag).locktag_field1 = (dboid), \ 185 (locktag).locktag_field2 = (reloid), \ 186 (locktag).locktag_field3 = 0, \ 187 (locktag).locktag_field4 = 0, \ 188 (locktag).locktag_type = LOCKTAG_RELATION, \ 189 (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD) 190 191 /* same ID info as RELATION */ 192 #define SET_LOCKTAG_RELATION_EXTEND(locktag,dboid,reloid) \ 193 ((locktag).locktag_field1 = (dboid), \ 194 (locktag).locktag_field2 = (reloid), \ 195 (locktag).locktag_field3 = 0, \ 196 (locktag).locktag_field4 = 0, \ 197 (locktag).locktag_type = LOCKTAG_RELATION_EXTEND, \ 198 (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD) 199 200 /* ID info for frozen IDs is DB OID */ 201 #define SET_LOCKTAG_DATABASE_FROZEN_IDS(locktag,dboid) \ 202 ((locktag).locktag_field1 = (dboid), \ 203 (locktag).locktag_field2 = 0, \ 204 (locktag).locktag_field3 = 0, \ 205 (locktag).locktag_field4 = 0, \ 206 (locktag).locktag_type = LOCKTAG_DATABASE_FROZEN_IDS, \ 207 (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD) 208 209 /* ID info for a page is RELATION info + BlockNumber */ 210 #define SET_LOCKTAG_PAGE(locktag,dboid,reloid,blocknum) \ 211 ((locktag).locktag_field1 = (dboid), \ 212 (locktag).locktag_field2 = (reloid), \ 213 (locktag).locktag_field3 = (blocknum), \ 214 (locktag).locktag_field4 = 0, \ 215 (locktag).locktag_type = LOCKTAG_PAGE, \ 216 (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD) 217 218 /* ID info for a tuple is PAGE info + OffsetNumber */ 219 #define SET_LOCKTAG_TUPLE(locktag,dboid,reloid,blocknum,offnum) \ 220 ((locktag).locktag_field1 = (dboid), \ 221 (locktag).locktag_field2 = (reloid), \ 222 (locktag).locktag_field3 = (blocknum), \ 223 (locktag).locktag_field4 = (offnum), \ 224 (locktag).locktag_type = LOCKTAG_TUPLE, \ 225 (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD) 226 227 /* ID info for a transaction is its TransactionId */ 228 #define SET_LOCKTAG_TRANSACTION(locktag,xid) \ 229 ((locktag).locktag_field1 = (xid), \ 230 (locktag).locktag_field2 = 0, \ 231 (locktag).locktag_field3 = 0, \ 232 (locktag).locktag_field4 = 0, \ 233 (locktag).locktag_type = LOCKTAG_TRANSACTION, \ 234 (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD) 235 236 /* ID info for a virtual transaction is its VirtualTransactionId */ 237 #define SET_LOCKTAG_VIRTUALTRANSACTION(locktag,vxid) \ 238 ((locktag).locktag_field1 = (vxid).backendId, \ 239 (locktag).locktag_field2 = (vxid).localTransactionId, \ 240 (locktag).locktag_field3 = 0, \ 241 (locktag).locktag_field4 = 0, \ 242 (locktag).locktag_type = LOCKTAG_VIRTUALTRANSACTION, \ 243 (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD) 244 245 /* 246 * ID info for a speculative insert is TRANSACTION info + 247 * its speculative insert counter. 248 */ 249 #define SET_LOCKTAG_SPECULATIVE_INSERTION(locktag,xid,token) \ 250 ((locktag).locktag_field1 = (xid), \ 251 (locktag).locktag_field2 = (token), \ 252 (locktag).locktag_field3 = 0, \ 253 (locktag).locktag_field4 = 0, \ 254 (locktag).locktag_type = LOCKTAG_SPECULATIVE_TOKEN, \ 255 (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD) 256 257 /* 258 * ID info for an object is DB OID + CLASS OID + OBJECT OID + SUBID 259 * 260 * Note: object ID has same representation as in pg_depend and 261 * pg_description, but notice that we are constraining SUBID to 16 bits. 262 * Also, we use DB OID = 0 for shared objects such as tablespaces. 263 */ 264 #define SET_LOCKTAG_OBJECT(locktag,dboid,classoid,objoid,objsubid) \ 265 ((locktag).locktag_field1 = (dboid), \ 266 (locktag).locktag_field2 = (classoid), \ 267 (locktag).locktag_field3 = (objoid), \ 268 (locktag).locktag_field4 = (objsubid), \ 269 (locktag).locktag_type = LOCKTAG_OBJECT, \ 270 (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD) 271 272 #define SET_LOCKTAG_ADVISORY(locktag,id1,id2,id3,id4) \ 273 ((locktag).locktag_field1 = (id1), \ 274 (locktag).locktag_field2 = (id2), \ 275 (locktag).locktag_field3 = (id3), \ 276 (locktag).locktag_field4 = (id4), \ 277 (locktag).locktag_type = LOCKTAG_ADVISORY, \ 278 (locktag).locktag_lockmethodid = USER_LOCKMETHOD) 279 280 281 /* 282 * Per-locked-object lock information: 283 * 284 * tag -- uniquely identifies the object being locked 285 * grantMask -- bitmask for all lock types currently granted on this object. 286 * waitMask -- bitmask for all lock types currently awaited on this object. 287 * procLocks -- list of PROCLOCK objects for this lock. 288 * waitProcs -- queue of processes waiting for this lock. 289 * requested -- count of each lock type currently requested on the lock 290 * (includes requests already granted!!). 291 * nRequested -- total requested locks of all types. 292 * granted -- count of each lock type currently granted on the lock. 293 * nGranted -- total granted locks of all types. 294 * 295 * Note: these counts count 1 for each backend. Internally to a backend, 296 * there may be multiple grabs on a particular lock, but this is not reflected 297 * into shared memory. 298 */ 299 typedef struct LOCK 300 { 301 /* hash key */ 302 LOCKTAG tag; /* unique identifier of lockable object */ 303 304 /* data */ 305 LOCKMASK grantMask; /* bitmask for lock types already granted */ 306 LOCKMASK waitMask; /* bitmask for lock types awaited */ 307 SHM_QUEUE procLocks; /* list of PROCLOCK objects assoc. with lock */ 308 PROC_QUEUE waitProcs; /* list of PGPROC objects waiting on lock */ 309 int requested[MAX_LOCKMODES]; /* counts of requested locks */ 310 int nRequested; /* total of requested[] array */ 311 int granted[MAX_LOCKMODES]; /* counts of granted locks */ 312 int nGranted; /* total of granted[] array */ 313 } LOCK; 314 315 #define LOCK_LOCKMETHOD(lock) ((LOCKMETHODID) (lock).tag.locktag_lockmethodid) 316 #define LOCK_LOCKTAG(lock) ((LockTagType) (lock).tag.locktag_type) 317 318 319 /* 320 * We may have several different backends holding or awaiting locks 321 * on the same lockable object. We need to store some per-holder/waiter 322 * information for each such holder (or would-be holder). This is kept in 323 * a PROCLOCK struct. 324 * 325 * PROCLOCKTAG is the key information needed to look up a PROCLOCK item in the 326 * proclock hashtable. A PROCLOCKTAG value uniquely identifies the combination 327 * of a lockable object and a holder/waiter for that object. (We can use 328 * pointers here because the PROCLOCKTAG need only be unique for the lifespan 329 * of the PROCLOCK, and it will never outlive the lock or the proc.) 330 * 331 * Internally to a backend, it is possible for the same lock to be held 332 * for different purposes: the backend tracks transaction locks separately 333 * from session locks. However, this is not reflected in the shared-memory 334 * state: we only track which backend(s) hold the lock. This is OK since a 335 * backend can never block itself. 336 * 337 * The holdMask field shows the already-granted locks represented by this 338 * proclock. Note that there will be a proclock object, possibly with 339 * zero holdMask, for any lock that the process is currently waiting on. 340 * Otherwise, proclock objects whose holdMasks are zero are recycled 341 * as soon as convenient. 342 * 343 * releaseMask is workspace for LockReleaseAll(): it shows the locks due 344 * to be released during the current call. This must only be examined or 345 * set by the backend owning the PROCLOCK. 346 * 347 * Each PROCLOCK object is linked into lists for both the associated LOCK 348 * object and the owning PGPROC object. Note that the PROCLOCK is entered 349 * into these lists as soon as it is created, even if no lock has yet been 350 * granted. A PGPROC that is waiting for a lock to be granted will also be 351 * linked into the lock's waitProcs queue. 352 */ 353 typedef struct PROCLOCKTAG 354 { 355 /* NB: we assume this struct contains no padding! */ 356 LOCK *myLock; /* link to per-lockable-object information */ 357 PGPROC *myProc; /* link to PGPROC of owning backend */ 358 } PROCLOCKTAG; 359 360 typedef struct PROCLOCK 361 { 362 /* tag */ 363 PROCLOCKTAG tag; /* unique identifier of proclock object */ 364 365 /* data */ 366 PGPROC *groupLeader; /* proc's lock group leader, or proc itself */ 367 LOCKMASK holdMask; /* bitmask for lock types currently held */ 368 LOCKMASK releaseMask; /* bitmask for lock types to be released */ 369 SHM_QUEUE lockLink; /* list link in LOCK's list of proclocks */ 370 SHM_QUEUE procLink; /* list link in PGPROC's list of proclocks */ 371 } PROCLOCK; 372 373 #define PROCLOCK_LOCKMETHOD(proclock) \ 374 LOCK_LOCKMETHOD(*((proclock).tag.myLock)) 375 376 /* 377 * Each backend also maintains a local hash table with information about each 378 * lock it is currently interested in. In particular the local table counts 379 * the number of times that lock has been acquired. This allows multiple 380 * requests for the same lock to be executed without additional accesses to 381 * shared memory. We also track the number of lock acquisitions per 382 * ResourceOwner, so that we can release just those locks belonging to a 383 * particular ResourceOwner. 384 * 385 * When holding a lock taken "normally", the lock and proclock fields always 386 * point to the associated objects in shared memory. However, if we acquired 387 * the lock via the fast-path mechanism, the lock and proclock fields are set 388 * to NULL, since there probably aren't any such objects in shared memory. 389 * (If the lock later gets promoted to normal representation, we may eventually 390 * update our locallock's lock/proclock fields after finding the shared 391 * objects.) 392 * 393 * Caution: a locallock object can be left over from a failed lock acquisition 394 * attempt. In this case its lock/proclock fields are untrustworthy, since 395 * the shared lock object is neither held nor awaited, and hence is available 396 * to be reclaimed. If nLocks > 0 then these pointers must either be valid or 397 * NULL, but when nLocks == 0 they should be considered garbage. 398 */ 399 typedef struct LOCALLOCKTAG 400 { 401 LOCKTAG lock; /* identifies the lockable object */ 402 LOCKMODE mode; /* lock mode for this table entry */ 403 } LOCALLOCKTAG; 404 405 typedef struct LOCALLOCKOWNER 406 { 407 /* 408 * Note: if owner is NULL then the lock is held on behalf of the session; 409 * otherwise it is held on behalf of my current transaction. 410 * 411 * Must use a forward struct reference to avoid circularity. 412 */ 413 struct ResourceOwnerData *owner; 414 int64 nLocks; /* # of times held by this owner */ 415 } LOCALLOCKOWNER; 416 417 typedef struct LOCALLOCK 418 { 419 /* tag */ 420 LOCALLOCKTAG tag; /* unique identifier of locallock entry */ 421 422 /* data */ 423 uint32 hashcode; /* copy of LOCKTAG's hash value */ 424 LOCK *lock; /* associated LOCK object, if any */ 425 PROCLOCK *proclock; /* associated PROCLOCK object, if any */ 426 int64 nLocks; /* total number of times lock is held */ 427 int numLockOwners; /* # of relevant ResourceOwners */ 428 int maxLockOwners; /* allocated size of array */ 429 LOCALLOCKOWNER *lockOwners; /* dynamically resizable array */ 430 bool holdsStrongLockCount; /* bumped FastPathStrongRelationLocks */ 431 bool lockCleared; /* we read all sinval msgs for lock */ 432 } LOCALLOCK; 433 434 #define LOCALLOCK_LOCKMETHOD(llock) ((llock).tag.lock.locktag_lockmethodid) 435 #define LOCALLOCK_LOCKTAG(llock) ((LockTagType) (llock).tag.lock.locktag_type) 436 437 438 /* 439 * These structures hold information passed from lmgr internals to the lock 440 * listing user-level functions (in lockfuncs.c). 441 */ 442 443 typedef struct LockInstanceData 444 { 445 LOCKTAG locktag; /* tag for locked object */ 446 LOCKMASK holdMask; /* locks held by this PGPROC */ 447 LOCKMODE waitLockMode; /* lock awaited by this PGPROC, if any */ 448 BackendId backend; /* backend ID of this PGPROC */ 449 LocalTransactionId lxid; /* local transaction ID of this PGPROC */ 450 int pid; /* pid of this PGPROC */ 451 int leaderPid; /* pid of group leader; = pid if no group */ 452 bool fastpath; /* taken via fastpath? */ 453 } LockInstanceData; 454 455 typedef struct LockData 456 { 457 int nelements; /* The length of the array */ 458 LockInstanceData *locks; /* Array of per-PROCLOCK information */ 459 } LockData; 460 461 typedef struct BlockedProcData 462 { 463 int pid; /* pid of a blocked PGPROC */ 464 /* Per-PROCLOCK information about PROCLOCKs of the lock the pid awaits */ 465 /* (these fields refer to indexes in BlockedProcsData.locks[]) */ 466 int first_lock; /* index of first relevant LockInstanceData */ 467 int num_locks; /* number of relevant LockInstanceDatas */ 468 /* PIDs of PGPROCs that are ahead of "pid" in the lock's wait queue */ 469 /* (these fields refer to indexes in BlockedProcsData.waiter_pids[]) */ 470 int first_waiter; /* index of first preceding waiter */ 471 int num_waiters; /* number of preceding waiters */ 472 } BlockedProcData; 473 474 typedef struct BlockedProcsData 475 { 476 BlockedProcData *procs; /* Array of per-blocked-proc information */ 477 LockInstanceData *locks; /* Array of per-PROCLOCK information */ 478 int *waiter_pids; /* Array of PIDs of other blocked PGPROCs */ 479 int nprocs; /* # of valid entries in procs[] array */ 480 int maxprocs; /* Allocated length of procs[] array */ 481 int nlocks; /* # of valid entries in locks[] array */ 482 int maxlocks; /* Allocated length of locks[] array */ 483 int npids; /* # of valid entries in waiter_pids[] array */ 484 int maxpids; /* Allocated length of waiter_pids[] array */ 485 } BlockedProcsData; 486 487 488 /* Result codes for LockAcquire() */ 489 typedef enum 490 { 491 LOCKACQUIRE_NOT_AVAIL, /* lock not available, and dontWait=true */ 492 LOCKACQUIRE_OK, /* lock successfully acquired */ 493 LOCKACQUIRE_ALREADY_HELD, /* incremented count for lock already held */ 494 LOCKACQUIRE_ALREADY_CLEAR /* incremented count for lock already clear */ 495 } LockAcquireResult; 496 497 /* Deadlock states identified by DeadLockCheck() */ 498 typedef enum 499 { 500 DS_NOT_YET_CHECKED, /* no deadlock check has run yet */ 501 DS_NO_DEADLOCK, /* no deadlock detected */ 502 DS_SOFT_DEADLOCK, /* deadlock avoided by queue rearrangement */ 503 DS_HARD_DEADLOCK, /* deadlock, no way out but ERROR */ 504 DS_BLOCKED_BY_AUTOVACUUM /* no deadlock; queue blocked by autovacuum 505 * worker */ 506 } DeadLockState; 507 508 /* 509 * The lockmgr's shared hash tables are partitioned to reduce contention. 510 * To determine which partition a given locktag belongs to, compute the tag's 511 * hash code with LockTagHashCode(), then apply one of these macros. 512 * NB: NUM_LOCK_PARTITIONS must be a power of 2! 513 */ 514 #define LockHashPartition(hashcode) \ 515 ((hashcode) % NUM_LOCK_PARTITIONS) 516 #define LockHashPartitionLock(hashcode) \ 517 (&MainLWLockArray[LOCK_MANAGER_LWLOCK_OFFSET + \ 518 LockHashPartition(hashcode)].lock) 519 #define LockHashPartitionLockByIndex(i) \ 520 (&MainLWLockArray[LOCK_MANAGER_LWLOCK_OFFSET + (i)].lock) 521 522 /* 523 * The deadlock detector needs to be able to access lockGroupLeader and 524 * related fields in the PGPROC, so we arrange for those fields to be protected 525 * by one of the lock hash partition locks. Since the deadlock detector 526 * acquires all such locks anyway, this makes it safe for it to access these 527 * fields without doing anything extra. To avoid contention as much as 528 * possible, we map different PGPROCs to different partition locks. The lock 529 * used for a given lock group is determined by the group leader's pgprocno. 530 */ 531 #define LockHashPartitionLockByProc(leader_pgproc) \ 532 LockHashPartitionLock((leader_pgproc)->pgprocno) 533 534 /* 535 * function prototypes 536 */ 537 extern void InitLocks(void); 538 extern LockMethod GetLocksMethodTable(const LOCK *lock); 539 extern LockMethod GetLockTagsMethodTable(const LOCKTAG *locktag); 540 extern uint32 LockTagHashCode(const LOCKTAG *locktag); 541 extern bool DoLockModesConflict(LOCKMODE mode1, LOCKMODE mode2); 542 extern LockAcquireResult LockAcquire(const LOCKTAG *locktag, 543 LOCKMODE lockmode, 544 bool sessionLock, 545 bool dontWait); 546 extern LockAcquireResult LockAcquireExtended(const LOCKTAG *locktag, 547 LOCKMODE lockmode, 548 bool sessionLock, 549 bool dontWait, 550 bool reportMemoryError, 551 LOCALLOCK **locallockp); 552 extern void AbortStrongLockAcquire(void); 553 extern void MarkLockClear(LOCALLOCK *locallock); 554 extern bool LockRelease(const LOCKTAG *locktag, 555 LOCKMODE lockmode, bool sessionLock); 556 extern void LockReleaseAll(LOCKMETHODID lockmethodid, bool allLocks); 557 extern void LockReleaseSession(LOCKMETHODID lockmethodid); 558 extern void LockReleaseCurrentOwner(LOCALLOCK **locallocks, int nlocks); 559 extern void LockReassignCurrentOwner(LOCALLOCK **locallocks, int nlocks); 560 extern bool LockHeldByMe(const LOCKTAG *locktag, LOCKMODE lockmode); 561 #ifdef USE_ASSERT_CHECKING 562 extern HTAB *GetLockMethodLocalHash(void); 563 #endif 564 extern bool LockHasWaiters(const LOCKTAG *locktag, 565 LOCKMODE lockmode, bool sessionLock); 566 extern VirtualTransactionId *GetLockConflicts(const LOCKTAG *locktag, 567 LOCKMODE lockmode, int *countp); 568 extern void AtPrepare_Locks(void); 569 extern void PostPrepare_Locks(TransactionId xid); 570 extern bool LockCheckConflicts(LockMethod lockMethodTable, 571 LOCKMODE lockmode, 572 LOCK *lock, PROCLOCK *proclock); 573 extern void GrantLock(LOCK *lock, PROCLOCK *proclock, LOCKMODE lockmode); 574 extern void GrantAwaitedLock(void); 575 extern void RemoveFromWaitQueue(PGPROC *proc, uint32 hashcode); 576 extern Size LockShmemSize(void); 577 extern LockData *GetLockStatusData(void); 578 extern BlockedProcsData *GetBlockerStatusData(int blocked_pid); 579 580 extern xl_standby_lock *GetRunningTransactionLocks(int *nlocks); 581 extern const char *GetLockmodeName(LOCKMETHODID lockmethodid, LOCKMODE mode); 582 583 extern void lock_twophase_recover(TransactionId xid, uint16 info, 584 void *recdata, uint32 len); 585 extern void lock_twophase_postcommit(TransactionId xid, uint16 info, 586 void *recdata, uint32 len); 587 extern void lock_twophase_postabort(TransactionId xid, uint16 info, 588 void *recdata, uint32 len); 589 extern void lock_twophase_standby_recover(TransactionId xid, uint16 info, 590 void *recdata, uint32 len); 591 592 extern DeadLockState DeadLockCheck(PGPROC *proc); 593 extern PGPROC *GetBlockingAutoVacuumPgproc(void); 594 extern void DeadLockReport(void) pg_attribute_noreturn(); 595 extern void RememberSimpleDeadLock(PGPROC *proc1, 596 LOCKMODE lockmode, 597 LOCK *lock, 598 PGPROC *proc2); 599 extern void InitDeadLockChecking(void); 600 601 extern int LockWaiterCount(const LOCKTAG *locktag); 602 603 #ifdef LOCK_DEBUG 604 extern void DumpLocks(PGPROC *proc); 605 extern void DumpAllLocks(void); 606 #endif 607 608 /* Lock a VXID (used to wait for a transaction to finish) */ 609 extern void VirtualXactLockTableInsert(VirtualTransactionId vxid); 610 extern void VirtualXactLockTableCleanup(void); 611 extern bool VirtualXactLock(VirtualTransactionId vxid, bool wait); 612 613 #endif /* LOCK_H_ */ 614