greenplumn transam 源码
greenplumn transam 代码
文件路径:/src/include/access/transam.h
/*-------------------------------------------------------------------------
*
* transam.h
* postgres transaction access method support code
*
*
* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/access/transam.h
*
*-------------------------------------------------------------------------
*/
#ifndef TRANSAM_H
#define TRANSAM_H
#include "catalog/pg_magic_oid.h"
#include "access/xlogdefs.h"
/* ----------------
* Special transaction ID values
*
* BootstrapTransactionId is the XID for "bootstrap" operations, and
* FrozenTransactionId is used for very old tuples. Both should
* always be considered valid.
*
* FirstNormalTransactionId is the first "normal" transaction id.
* Note: if you need to change it, you must change pg_class.h as well.
* ----------------
*/
#define InvalidTransactionId ((TransactionId) 0)
#define BootstrapTransactionId ((TransactionId) 1)
#define FrozenTransactionId ((TransactionId) 2)
#define FirstNormalTransactionId ((TransactionId) 3)
#define MaxTransactionId ((TransactionId) 0xFFFFFFFF)
/* ----------------
* transaction ID manipulation macros
* ----------------
*/
#define TransactionIdIsValid(xid) ((xid) != InvalidTransactionId)
#define TransactionIdIsNormal(xid) ((xid) >= FirstNormalTransactionId)
#define TransactionIdEquals(id1, id2) ((id1) == (id2))
#define TransactionIdStore(xid, dest) (*(dest) = (xid))
#define StoreInvalidTransactionId(dest) (*(dest) = InvalidTransactionId)
#define EpochFromFullTransactionId(x) ((uint32) ((x).value >> 32))
#define XidFromFullTransactionId(x) ((uint32) (x).value)
#define U64FromFullTransactionId(x) ((x).value)
#define FullTransactionIdPrecedes(a, b) ((a).value < (b).value)
#define FullTransactionIdIsValid(x) TransactionIdIsValid(XidFromFullTransactionId(x))
#define InvalidFullTransactionId FullTransactionIdFromEpochAndXid(0, InvalidTransactionId)
/*
* A 64 bit value that contains an epoch and a TransactionId. This is
* wrapped in a struct to prevent implicit conversion to/from TransactionId.
* Not all values represent valid normal XIDs.
*/
typedef struct FullTransactionId
{
uint64 value;
} FullTransactionId;
static inline FullTransactionId
FullTransactionIdFromEpochAndXid(uint32 epoch, TransactionId xid)
{
FullTransactionId result;
result.value = ((uint64) epoch) << 32 | xid;
return result;
}
/* advance a transaction ID variable, handling wraparound correctly */
#define TransactionIdAdvance(dest) \
do { \
(dest)++; \
if ((dest) < FirstNormalTransactionId) \
(dest) = FirstNormalTransactionId; \
} while(0)
/* advance a FullTransactionId variable, stepping over special XIDs */
static inline void
FullTransactionIdAdvance(FullTransactionId *dest)
{
dest->value++;
while (XidFromFullTransactionId(*dest) < FirstNormalTransactionId)
dest->value++;
}
/* back up a transaction ID variable, handling wraparound correctly */
#define TransactionIdRetreat(dest) \
do { \
(dest)--; \
} while ((dest) < FirstNormalTransactionId)
/* compare two XIDs already known to be normal; this is a macro for speed */
#define NormalTransactionIdPrecedes(id1, id2) \
(AssertMacro(TransactionIdIsNormal(id1) && TransactionIdIsNormal(id2)), \
(int32) ((id1) - (id2)) < 0)
/* compare two XIDs already known to be normal; this is a macro for speed */
#define NormalTransactionIdFollows(id1, id2) \
(AssertMacro(TransactionIdIsNormal(id1) && TransactionIdIsNormal(id2)), \
(int32) ((id1) - (id2)) > 0)
/*
* VariableCache is a data structure in shared memory that is used to track
* OID and XID assignment state. For largely historical reasons, there is
* just one struct with different fields that are protected by different
* LWLocks.
*
* Note: xidWrapLimit and oldestXidDB are not "active" values, but are
* used just to generate useful messages when xidWarnLimit or xidStopLimit
* are exceeded.
*/
typedef struct VariableCacheData
{
/*
* These fields are protected by OidGenLock.
*/
Oid nextOid; /* next OID to assign */
uint32 oidCount; /* OIDs available before must do XLOG work */
/*
* These fields are protected by RelfilenodeGenLock.
*/
Oid nextRelfilenode; /* next relfilenode to assign */
uint32 relfilenodeCount; /* relfilenodes available before we must do XLOG work */
/*
* These fields are protected by XidGenLock.
*/
FullTransactionId nextFullXid; /* next full XID to assign */
TransactionId oldestXid; /* cluster-wide minimum datfrozenxid */
TransactionId xidVacLimit; /* start forcing autovacuums here */
TransactionId xidWarnLimit; /* start complaining here */
TransactionId xidStopLimit; /* refuse to advance nextFullXid beyond here */
TransactionId xidWrapLimit; /* where the world ends */
Oid oldestXidDB; /* database with minimum datfrozenxid */
/*
* These fields are protected by CommitTsLock
*/
TransactionId oldestCommitTsXid;
TransactionId newestCommitTsXid;
/*
* These fields are protected by ProcArrayLock.
*/
TransactionId latestCompletedXid; /* newest XID that has committed or
* aborted */
TransactionId latestCompletedGxid; /* newest distributed XID that has
committed or aborted */
/*
* The two variables are protected by shmGxidGenLock. Note nextGxid won't
* be accurate after crash recovery. When crash recovery happens, we bump
* them to the next batch on the coordinator, while on the primary, it is
* not accurate until the next query with an assigned gxid is dispatched.
*/
DistributedTransactionId nextGxid; /* next full XID to assign */
uint32 GxidCount; /* Gxids available before must do XLOG work */
/*
* These fields are protected by CLogTruncationLock
*/
TransactionId oldestClogXid; /* oldest it's safe to look up in clog */
} VariableCacheData;
typedef VariableCacheData *VariableCache;
/* ----------------
* extern declarations
* ----------------
*/
/* in transam/xact.c */
extern bool TransactionStartedDuringRecovery(void);
/* in transam/varsup.c */
extern PGDLLIMPORT VariableCache ShmemVariableCache;
extern int xid_stop_limit;
extern int xid_warn_limit;
/* GPDB-specific */
extern bool gp_pause_on_restore_point_replay;
/*
* prototypes for functions in transam/transam.c
*/
extern bool TransactionIdDidCommit(TransactionId transactionId);
extern bool TransactionIdDidAbort(TransactionId transactionId);
extern bool TransactionIdDidAbortForReader(TransactionId transactionId);
extern bool TransactionIdIsKnownCompleted(TransactionId transactionId);
extern void TransactionIdCommitTree(TransactionId xid, int nxids, TransactionId *xids);
extern void TransactionIdAsyncCommitTree(TransactionId xid, int nxids, TransactionId *xids, XLogRecPtr lsn);
extern void TransactionIdAbortTree(TransactionId xid, int nxids, TransactionId *xids);
extern bool TransactionIdPrecedes(TransactionId id1, TransactionId id2);
extern bool TransactionIdPrecedesOrEquals(TransactionId id1, TransactionId id2);
extern bool TransactionIdFollows(TransactionId id1, TransactionId id2);
extern bool TransactionIdFollowsOrEquals(TransactionId id1, TransactionId id2);
extern TransactionId TransactionIdLatest(TransactionId mainxid,
int nxids, const TransactionId *xids);
extern XLogRecPtr TransactionIdGetCommitLSN(TransactionId xid);
/* in transam/varsup.c */
extern FullTransactionId GetNewTransactionId(bool isSubXact);
extern void AdvanceNextFullTransactionIdPastXid(TransactionId xid);
extern FullTransactionId ReadNextFullTransactionId(void);
extern void SetTransactionIdLimit(TransactionId oldest_datfrozenxid,
Oid oldest_datoid);
extern void AdvanceOldestClogXid(TransactionId oldest_datfrozenxid);
extern bool ForceTransactionIdLimitUpdate(void);
extern Oid GetNewObjectId(void);
extern void AdvanceObjectId(Oid newOid);
extern Oid GetNewSegRelfilenode(void);
extern bool OidFollowsNextOid(Oid id);
/*
* Some frontend programs include this header. For compilers that emit static
* inline functions even when they're unused, that leads to unsatisfied
* external references; hence hide them with #ifndef FRONTEND.
*/
#ifndef FRONTEND
/*
* For callers that just need the XID part of the next transaction ID.
*/
static inline TransactionId
ReadNewTransactionId(void)
{
return XidFromFullTransactionId(ReadNextFullTransactionId());
}
#endif /* FRONTEND */
#endif /* TRANSAM_H */
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