diff options
Diffstat (limited to 'src/include/storage/lock.h')
| -rw-r--r-- | src/include/storage/lock.h | 47 |
1 files changed, 45 insertions, 2 deletions
diff --git a/src/include/storage/lock.h b/src/include/storage/lock.h index e2a5bc7b6f..30c8a3fa2b 100644 --- a/src/include/storage/lock.h +++ b/src/include/storage/lock.h @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/storage/lock.h,v 1.106 2007/06/19 20:13:22 tgl Exp $ + * $PostgreSQL: pgsql/src/include/storage/lock.h,v 1.107 2007/09/05 18:10:48 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -15,6 +15,7 @@ #define LOCK_H_ #include "nodes/pg_list.h" +#include "storage/backendid.h" #include "storage/itemptr.h" #include "storage/lwlock.h" #include "storage/shmem.h" @@ -42,6 +43,37 @@ extern bool Debug_deadlocks; /* + * Top-level transactions are identified by VirtualTransactionIDs comprising + * the BackendId of the backend running the xact, plus a locally-assigned + * LocalTransactionId. These are guaranteed unique over the short term, + * but will be reused after a database restart; hence they should never + * be stored on disk. + * + * Note that struct VirtualTransactionId can not be assumed to be atomically + * assignable as a whole. However, type LocalTransactionId is assumed to + * be atomically assignable, and the backend ID doesn't change often enough + * to be a problem, so we can fetch or assign the two fields separately. + * We deliberately refrain from using the struct within PGPROC, to prevent + * coding errors from trying to use struct assignment with it; instead use + * GET_VXID_FROM_PGPROC(). + */ +typedef struct +{ + BackendId backendId; /* determined at backend startup */ + LocalTransactionId localTransactionId; /* backend-local transaction id */ +} VirtualTransactionId; + +#define InvalidLocalTransactionId 0 +#define LocalTransactionIdIsValid(lxid) ((lxid) != InvalidLocalTransactionId) +#define VirtualTransactionIdIsValid(vxid) \ + (((vxid).backendId != InvalidBackendId) && \ + LocalTransactionIdIsValid((vxid).localTransactionId)) +#define GET_VXID_FROM_PGPROC(vxid, proc) \ + ((vxid).backendId = (proc).backendId, \ + (vxid).localTransactionId = (proc).lxid) + + +/* * LOCKMODE is an integer (1..N) indicating a lock type. LOCKMASK is a bit * mask indicating a set of held or requested lock types (the bit 1<<mode * corresponds to a particular lock mode). @@ -139,6 +171,8 @@ typedef enum LockTagType /* ID info for a tuple is PAGE info + OffsetNumber */ LOCKTAG_TRANSACTION, /* transaction (for waiting for xact done) */ /* ID info for a transaction is its TransactionId */ + LOCKTAG_VIRTUALTRANSACTION, /* virtual transaction (ditto) */ + /* ID info for a virtual transaction is its VirtualTransactionId */ LOCKTAG_OBJECT, /* non-relation database object */ /* ID info for an object is DB OID + CLASS OID + OBJECT OID + SUBID */ @@ -214,6 +248,14 @@ typedef struct LOCKTAG (locktag).locktag_type = LOCKTAG_TRANSACTION, \ (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD) +#define SET_LOCKTAG_VIRTUALTRANSACTION(locktag,vxid) \ + ((locktag).locktag_field1 = (vxid).backendId, \ + (locktag).locktag_field2 = (vxid).localTransactionId, \ + (locktag).locktag_field3 = 0, \ + (locktag).locktag_field4 = 0, \ + (locktag).locktag_type = LOCKTAG_VIRTUALTRANSACTION, \ + (locktag).locktag_lockmethodid = DEFAULT_LOCKMETHOD) + #define SET_LOCKTAG_OBJECT(locktag,dboid,classoid,objoid,objsubid) \ ((locktag).locktag_field1 = (dboid), \ (locktag).locktag_field2 = (classoid), \ @@ -431,7 +473,8 @@ extern bool LockRelease(const LOCKTAG *locktag, extern void LockReleaseAll(LOCKMETHODID lockmethodid, bool allLocks); extern void LockReleaseCurrentOwner(void); extern void LockReassignCurrentOwner(void); -extern List *GetLockConflicts(const LOCKTAG *locktag, LOCKMODE lockmode); +extern VirtualTransactionId *GetLockConflicts(const LOCKTAG *locktag, + LOCKMODE lockmode); extern void AtPrepare_Locks(void); extern void PostPrepare_Locks(TransactionId xid); extern int LockCheckConflicts(LockMethod lockMethodTable, |