diff options
Diffstat (limited to 'src/backend/access/transam.h')
| -rw-r--r-- | src/backend/access/transam.h | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/src/backend/access/transam.h b/src/backend/access/transam.h new file mode 100644 index 00000000000..0f5a9724dc0 --- /dev/null +++ b/src/backend/access/transam.h @@ -0,0 +1,213 @@ +/*------------------------------------------------------------------------- + * + * transam.h-- + * postgres transaction access method support code header + * + * + * Copyright (c) 1994, Regents of the University of California + * + * $Id: transam.h,v 1.1.1.1 1996/07/09 06:21:09 scrappy Exp $ + * + * NOTES + * Transaction System Version 101 now support proper oid + * generation and recording in the variable relation. + * + *------------------------------------------------------------------------- + */ +#ifndef TRANSAM_H +#define TRANSAM_H + +/* ---------------- + * transaction system version id + * + * 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. + * + * 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. + * ---------------- + */ +#define TRANS_SYSTEM_VERSION 101 + +/* ---------------- + * transaction id status values + * + * someday we will use "11" = 3 = XID_INVALID to mean the + * starting of run-length encoded log data. + * ---------------- + */ +#define XID_COMMIT 2 /* transaction commited */ +#define XID_ABORT 1 /* transaction aborted */ +#define XID_INPROGRESS 0 /* transaction in progress */ +#define XID_INVALID 3 /* other */ + +typedef unsigned char XidStatus; /* (2 bits) */ + +/* ---------------- + * BitIndexOf computes the index of the Nth xid on a given block + * ---------------- + */ +#define BitIndexOf(N) ((N) * 2) + +/* ---------------- + * transaction page definitions + * ---------------- + */ +#define TP_DataSize BLCKSZ +#define TP_NumXidStatusPerBlock (TP_DataSize * 4) +#define TP_NumTimePerBlock (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 transction system. + * ---------------- + */ +typedef struct LogRelationContentsData { + int TransSystemVersion; +} LogRelationContentsData; + +typedef LogRelationContentsData *LogRelationContents; + +/* ---------------- + * TimeRelationContents structure + * + * This structure describes the storage of the data in the + * first 2048 bytes of the time relation. This storage is never + * used for transaction commit times because transaction id's begin + * their numbering at 512. + * + * The first 4 bytes of this relation store the version + * number of the transction system. + * ---------------- + */ +typedef struct TimeRelationContentsData { + int TransSystemVersion; +} TimeRelationContentsData; + +typedef TimeRelationContentsData *TimeRelationContents; + +/* ---------------- + * VariableRelationContents structure + * + * The variable relation is a special "relation" which + * is used to store various system "variables" persistantly. + * Unlike other relations in the system, this relation + * is updated in place whenever the variables change. + * + * The first 4 bytes of this relation store the version + * number of the transction system. + * + * Currently, the relation has only one page and the next + * available xid, the last committed xid and the next + * available oid are stored there. + * ---------------- + */ +typedef struct VariableRelationContentsData { + int TransSystemVersion; + TransactionId nextXidData; + TransactionId lastXidData; + Oid nextOid; +} VariableRelationContentsData; + +typedef VariableRelationContentsData *VariableRelationContents; + +/* ---------------- + * extern declarations + * ---------------- + */ + +/* + * prototypes for functions in transam/transam.c + */ +extern int RecoveryCheckingEnabled(); +extern void SetRecoveryCheckingEnabled(bool state); +extern bool TransactionLogTest(TransactionId transactionId, XidStatus status); +extern void TransactionLogUpdate(TransactionId transactionId, + XidStatus status); +extern AbsoluteTime TransactionIdGetCommitTime(TransactionId transactionId); +extern void TransRecover(Relation logRelation); +extern void InitializeTransactionLog(); +extern bool TransactionIdDidCommit(TransactionId transactionId); +extern bool TransactionIdDidAbort(TransactionId transactionId); +extern bool TransactionIdIsInProgress(TransactionId transactionId); +extern void TransactionIdCommit(TransactionId transactionId); +extern void TransactionIdAbort(TransactionId transactionId); +extern void TransactionIdSetInProgress(TransactionId transactionId); + +/* in transam/transsup.c */ +extern void AmiTransactionOverride(bool flag); +extern void TransComputeBlockNumber(Relation relation, + TransactionId transactionId, BlockNumber *blockNumberOutP); +extern XidStatus TransBlockGetLastTransactionIdStatus(Block tblock, + TransactionId baseXid, TransactionId *returnXidP); +extern XidStatus TransBlockGetXidStatus(Block tblock, + TransactionId transactionId); +extern void TransBlockSetXidStatus(Block tblock, + TransactionId transactionId, XidStatus xstatus); +extern AbsoluteTime TransBlockGetCommitTime(Block tblock, + TransactionId transactionId); +extern void TransBlockSetCommitTime(Block tblock, + TransactionId transactionId, AbsoluteTime commitTime); +extern XidStatus TransBlockNumberGetXidStatus(Relation relation, + BlockNumber blockNumber, TransactionId xid, bool *failP); +extern void TransBlockNumberSetXidStatus(Relation relation, + BlockNumber blockNumber, TransactionId xid, XidStatus xstatus, + bool *failP); +extern AbsoluteTime TransBlockNumberGetCommitTime(Relation relation, + BlockNumber blockNumber, TransactionId xid, bool *failP); +extern void TransBlockNumberSetCommitTime(Relation relation, + BlockNumber blockNumber, TransactionId xid, AbsoluteTime xtime, + bool *failP); +extern void TransGetLastRecordedTransaction(Relation relation, + TransactionId xid, bool *failP); + +/* in transam/varsup.c */ +extern void VariableRelationGetNextXid(TransactionId *xidP); +extern void VariableRelationGetLastXid(TransactionId *xidP); +extern void VariableRelationPutNextXid(TransactionId xid); +extern void VariableRelationPutLastXid(TransactionId xid); +extern void VariableRelationGetNextOid(Oid *oid_return); +extern void VariableRelationPutNextOid(Oid *oidP); +extern void GetNewTransactionId(TransactionId *xid); +extern void UpdateLastCommittedXid(TransactionId xid); +extern void GetNewObjectIdBlock(Oid *oid_return, int oid_block_size); +extern void GetNewObjectId(Oid *oid_return); + +/* ---------------- + * global variable extern declarations + * ---------------- + */ + +/* in transam.c */ +extern Relation LogRelation; +extern Relation TimeRelation; +extern Relation VariableRelation; + +extern TransactionId cachedGetCommitTimeXid; +extern AbsoluteTime cachedGetCommitTime; +extern TransactionId cachedTestXid; +extern XidStatus cachedTestXidStatus; + +extern TransactionId NullTransactionId; +extern TransactionId AmiTransactionId; +extern TransactionId FirstTransactionId; + +extern int RecoveryCheckingEnableState; + +/* in transsup.c */ +extern bool AMI_OVERRIDE; + +/* in varsup.c */ +extern int OidGenLockId; + +#endif /* TRAMSAM_H */ |