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/*-------------------------------------------------------------------------
*
* transam.h
* postgres transaction access method support code
*
*
* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Id: transam.h,v 1.36 2001/07/12 04:11:13 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#ifndef TRANSAM_H
#define TRANSAM_H
#include "storage/bufmgr.h"
/* ----------------
* Special transaction ID values
*
* We do not use any transaction IDs less than 512 --- this leaves the first
* 128 bytes of pg_log available for special purposes such as version number
* storage. (Currently, we do not actually use them for anything.)
*
* AmiTransactionId is the XID for "bootstrap" operations. It should always
* be considered valid.
*
* FirstTransactionId is the first "normal" transaction id.
* ----------------
*/
#define NullTransactionId ((TransactionId) 0)
#define DisabledTransactionId ((TransactionId) 1)
#define AmiTransactionId ((TransactionId) 512)
#define FirstTransactionId ((TransactionId) 514)
/* ----------------
* transaction ID manipulation macros
* ----------------
*/
#define TransactionIdIsValid(xid) ((bool) ((xid) != NullTransactionId))
#define TransactionIdIsSpecial(xid) ((bool) ((xid) < FirstTransactionId))
#define TransactionIdEquals(id1, id2) ((bool) ((id1) == (id2)))
#define TransactionIdPrecedes(id1, id2) ((bool) ((id1) < (id2)))
#define TransactionIdStore(xid, dest) \
(*((TransactionId*) (dest)) = (TransactionId) (xid))
#define StoreInvalidTransactionId(dest) \
(*((TransactionId*) (dest)) = NullTransactionId)
/* ----------------
* transaction status values
*
* someday we will use "11" = 3 = XID_COMMIT_CHILD to mean the
* commiting of child xactions.
* ----------------
*/
#define XID_INPROGRESS 0 /* transaction in progress */
#define XID_ABORT 1 /* transaction aborted */
#define XID_COMMIT 2 /* transaction commited */
#define XID_COMMIT_CHILD 3 /* child xact commited */
typedef unsigned char XidStatus; /* (2 bits) */
/* ----------
* We reserve the first 16384 object ids for manual assignment.
* oid's less than this appear in the .bki files. the choice of
* 16384 is completely arbitrary.
* ----------
*/
#define BootstrapObjectIdData 16384
/*
* VariableCache is placed in shmem and used by
* backends to get next available XID & OID.
*/
typedef struct VariableCacheData
{
TransactionId nextXid; /* next XID to assign */
Oid nextOid; /* next OID to assign */
uint32 oidCount; /* OIDs available before must do XLOG work */
} VariableCacheData;
typedef VariableCacheData *VariableCache;
/* ----------------
* extern declarations
* ----------------
*/
/*
* prototypes for functions in transam/transam.c
*/
extern void InitializeTransactionLog(void);
extern bool TransactionIdDidCommit(TransactionId transactionId);
extern bool TransactionIdDidAbort(TransactionId transactionId);
extern void TransactionIdCommit(TransactionId transactionId);
extern void TransactionIdAbort(TransactionId transactionId);
/* in transam/transsup.c */
extern void AmiTransactionOverride(bool flag);
extern void TransComputeBlockNumber(Relation relation,
TransactionId transactionId, BlockNumber *blockNumberOutP);
extern XidStatus TransBlockNumberGetXidStatus(Relation relation,
BlockNumber blockNumber, TransactionId xid, bool *failP);
extern void TransBlockNumberSetXidStatus(Relation relation,
BlockNumber blockNumber, TransactionId xid, XidStatus xstatus,
bool *failP);
/* in transam/varsup.c */
extern void GetNewTransactionId(TransactionId *xid);
extern void ReadNewTransactionId(TransactionId *xid);
extern void GetNewObjectId(Oid *oid_return);
extern void CheckMaxObjectId(Oid assigned_oid);
/* ----------------
* global variable extern declarations
* ----------------
*/
/* in transam.c */
extern Relation LogRelation;
/* in xact.c */
extern bool AMI_OVERRIDE;
/* in varsup.c */
extern SPINLOCK OidGenLockId;
extern SPINLOCK XidGenLockId;
extern VariableCache ShmemVariableCache;
#endif /* TRAMSAM_H */
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