diff options
Diffstat (limited to 'src/include/access/transam.h')
| -rw-r--r-- | src/include/access/transam.h | 99 |
1 files changed, 35 insertions, 64 deletions
diff --git a/src/include/access/transam.h b/src/include/access/transam.h index 90d1f359839..5d328b3c714 100644 --- a/src/include/access/transam.h +++ b/src/include/access/transam.h @@ -1,17 +1,13 @@ /*------------------------------------------------------------------------- * * transam.h - * postgres transaction access method support code header + * 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 1.35 2001/05/25 15:45:33 momjian Exp $ - * - * NOTES - * Transaction System Version 101 now support proper oid - * generation and recording in the variable relation. + * $Id: transam.h,v 1.36 2001/07/12 04:11:13 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -20,77 +16,60 @@ #include "storage/bufmgr.h" + /* ---------------- - * transaction system version id + * Special transaction ID values * - * this is stored on the first page of the log, time and variable - * relations on the first 4 bytes. This is so that if we improve - * the format of the transaction log after postgres version 2, then - * people won't have to rebuild their databases. + * 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.) * - * TRANS_SYSTEM_VERSION 100 means major version 1 minor version 0. - * Two databases with the same major version should be compatible, - * even if their minor versions differ. + * 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 TRANS_SYSTEM_VERSION 200 +#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 id status values + * transaction status values * * someday we will use "11" = 3 = XID_COMMIT_CHILD to mean the * commiting of child xactions. * ---------------- */ -#define XID_COMMIT 2 /* transaction commited */ -#define XID_ABORT 1 /* transaction aborted */ #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) */ +typedef unsigned char XidStatus; /* (2 bits) */ /* ---------- - * note: we reserve the first 16384 object ids for internal use. + * 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 -/* ---------------- - * BitIndexOf computes the index of the Nth xid on a given block - * ---------------- - */ -#define BitIndexOf(N) ((N) * 2) - -/* ---------------- - * transaction page definitions - * ---------------- - */ -#define TP_DataSize (BLCKSZ - sizeof(XLogRecPtr)) -#define TP_NumXidStatusPerBlock (TP_DataSize * 4) - -/* ---------------- - * LogRelationContents structure - * - * This structure describes the storage of the data in the - * first 128 bytes of the log relation. This storage is never - * used for transaction status because transaction id's begin - * their numbering at 512. - * - * The first 4 bytes of this relation store the version - * number of the transaction system. - * ---------------- - */ -typedef struct LogRelationContentsData -{ - XLogRecPtr LSN; /* temp hack: LSN is member of any block */ - /* so should be described in bufmgr */ - int TransSystemVersion; -} LogRelationContentsData; - -typedef LogRelationContentsData *LogRelationContents; - /* * VariableCache is placed in shmem and used by * backends to get next available XID & OID. @@ -104,6 +83,7 @@ typedef struct VariableCacheData typedef VariableCacheData *VariableCache; + /* ---------------- * extern declarations * ---------------- @@ -142,16 +122,7 @@ extern void CheckMaxObjectId(Oid assigned_oid); /* in transam.c */ extern Relation LogRelation; -extern TransactionId cachedTestXid; -extern XidStatus cachedTestXidStatus; - -extern TransactionId NullTransactionId; -extern TransactionId AmiTransactionId; -extern TransactionId FirstTransactionId; - -extern int RecoveryCheckingEnableState; - -/* in transsup.c */ +/* in xact.c */ extern bool AMI_OVERRIDE; /* in varsup.c */ |