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/*-------------------------------------------------------------------------
*
* xact.h
* postgres transaction system definitions
*
*
* Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/access/xact.h
*
*-------------------------------------------------------------------------
*/
#ifndef XACT_H
#define XACT_H
#include "access/xlog.h"
#include "nodes/pg_list.h"
#include "storage/relfilenode.h"
/*
* Xact isolation levels
*/
#define XACT_READ_UNCOMMITTED 0
#define XACT_READ_COMMITTED 1
#define XACT_REPEATABLE_READ 2
#define XACT_SERIALIZABLE 3
extern int DefaultXactIsoLevel;
extern int XactIsoLevel;
/*
* We implement three isolation levels internally.
* The two stronger ones use one snapshot per database transaction;
* the others use one snapshot per statement.
* Serializable uses predicate locks in addition to snapshots.
* These macros should be used to check which isolation level is selected.
*/
#define IsolationUsesXactSnapshot() (XactIsoLevel >= XACT_REPEATABLE_READ)
#define IsolationIsSerializable() (XactIsoLevel == XACT_SERIALIZABLE)
/* Xact read-only state */
extern bool DefaultXactReadOnly;
extern bool XactReadOnly;
/*
* Xact is deferrable -- only meaningful (currently) for read only
* SERIALIZABLE transactions
*/
extern bool DefaultXactDeferrable;
extern bool XactDeferrable;
typedef enum
{
SYNCHRONOUS_COMMIT_OFF, /* asynchronous commit */
SYNCHRONOUS_COMMIT_LOCAL_FLUSH, /* wait for local flush only */
SYNCHRONOUS_COMMIT_REMOTE_WRITE, /* wait for local flush and remote
* write */
SYNCHRONOUS_COMMIT_REMOTE_FLUSH /* wait for local and remote flush */
} SyncCommitLevel;
/* Define the default setting for synchronous_commit */
#define SYNCHRONOUS_COMMIT_ON SYNCHRONOUS_COMMIT_REMOTE_FLUSH
/* Synchronous commit level */
extern int synchronous_commit;
/* Kluge for 2PC support */
extern bool MyXactAccessedTempRel;
/*
* start- and end-of-transaction callbacks for dynamically loaded modules
*/
typedef enum
{
XACT_EVENT_COMMIT,
XACT_EVENT_ABORT,
XACT_EVENT_PREPARE
} XactEvent;
typedef void (*XactCallback) (XactEvent event, void *arg);
typedef enum
{
SUBXACT_EVENT_START_SUB,
SUBXACT_EVENT_COMMIT_SUB,
SUBXACT_EVENT_ABORT_SUB
} SubXactEvent;
typedef void (*SubXactCallback) (SubXactEvent event, SubTransactionId mySubid,
SubTransactionId parentSubid, void *arg);
/* ----------------
* transaction-related XLOG entries
* ----------------
*/
/*
* XLOG allows to store some information in high 4 bits of log
* record xl_info field
*/
#define XLOG_XACT_COMMIT 0x00
#define XLOG_XACT_PREPARE 0x10
#define XLOG_XACT_ABORT 0x20
#define XLOG_XACT_COMMIT_PREPARED 0x30
#define XLOG_XACT_ABORT_PREPARED 0x40
#define XLOG_XACT_ASSIGNMENT 0x50
#define XLOG_XACT_COMMIT_COMPACT 0x60
typedef struct xl_xact_assignment
{
TransactionId xtop; /* assigned XID's top-level XID */
int nsubxacts; /* number of subtransaction XIDs */
TransactionId xsub[1]; /* assigned subxids */
} xl_xact_assignment;
#define MinSizeOfXactAssignment offsetof(xl_xact_assignment, xsub)
typedef struct xl_xact_commit_compact
{
TimestampTz xact_time; /* time of commit */
int nsubxacts; /* number of subtransaction XIDs */
/* ARRAY OF COMMITTED SUBTRANSACTION XIDs FOLLOWS */
TransactionId subxacts[1]; /* VARIABLE LENGTH ARRAY */
} xl_xact_commit_compact;
#define MinSizeOfXactCommitCompact offsetof(xl_xact_commit_compact, subxacts)
typedef struct xl_xact_commit
{
TimestampTz xact_time; /* time of commit */
uint32 xinfo; /* info flags */
int nrels; /* number of RelFileNodes */
int nsubxacts; /* number of subtransaction XIDs */
int nmsgs; /* number of shared inval msgs */
Oid dbId; /* MyDatabaseId */
Oid tsId; /* MyDatabaseTableSpace */
/* Array of RelFileNode(s) to drop at commit */
RelFileNode xnodes[1]; /* VARIABLE LENGTH ARRAY */
/* ARRAY OF COMMITTED SUBTRANSACTION XIDs FOLLOWS */
/* ARRAY OF SHARED INVALIDATION MESSAGES FOLLOWS */
} xl_xact_commit;
#define MinSizeOfXactCommit offsetof(xl_xact_commit, xnodes)
/*
* These flags are set in the xinfo fields of WAL commit records,
* indicating a variety of additional actions that need to occur
* when emulating transaction effects during recovery.
* They are named XactCompletion... to differentiate them from
* EOXact... routines which run at the end of the original
* transaction completion.
*/
#define XACT_COMPLETION_UPDATE_RELCACHE_FILE 0x01
#define XACT_COMPLETION_FORCE_SYNC_COMMIT 0x02
/* Access macros for above flags */
#define XactCompletionRelcacheInitFileInval(xinfo) (xinfo & XACT_COMPLETION_UPDATE_RELCACHE_FILE)
#define XactCompletionForceSyncCommit(xinfo) (xinfo & XACT_COMPLETION_FORCE_SYNC_COMMIT)
typedef struct xl_xact_abort
{
TimestampTz xact_time; /* time of abort */
int nrels; /* number of RelFileNodes */
int nsubxacts; /* number of subtransaction XIDs */
/* Array of RelFileNode(s) to drop at abort */
RelFileNode xnodes[1]; /* VARIABLE LENGTH ARRAY */
/* ARRAY OF ABORTED SUBTRANSACTION XIDs FOLLOWS */
} xl_xact_abort;
/* Note the intentional lack of an invalidation message array c.f. commit */
#define MinSizeOfXactAbort offsetof(xl_xact_abort, xnodes)
/*
* COMMIT_PREPARED and ABORT_PREPARED are identical to COMMIT/ABORT records
* except that we have to store the XID of the prepared transaction explicitly
* --- the XID in the record header will be invalid.
*/
typedef struct xl_xact_commit_prepared
{
TransactionId xid; /* XID of prepared xact */
xl_xact_commit crec; /* COMMIT record */
/* MORE DATA FOLLOWS AT END OF STRUCT */
} xl_xact_commit_prepared;
#define MinSizeOfXactCommitPrepared offsetof(xl_xact_commit_prepared, crec.xnodes)
typedef struct xl_xact_abort_prepared
{
TransactionId xid; /* XID of prepared xact */
xl_xact_abort arec; /* ABORT record */
/* MORE DATA FOLLOWS AT END OF STRUCT */
} xl_xact_abort_prepared;
#define MinSizeOfXactAbortPrepared offsetof(xl_xact_abort_prepared, arec.xnodes)
/* ----------------
* extern definitions
* ----------------
*/
extern bool IsTransactionState(void);
extern bool IsAbortedTransactionBlockState(void);
extern TransactionId GetTopTransactionId(void);
extern TransactionId GetTopTransactionIdIfAny(void);
extern TransactionId GetCurrentTransactionId(void);
extern TransactionId GetCurrentTransactionIdIfAny(void);
extern TransactionId GetStableLatestTransactionId(void);
extern SubTransactionId GetCurrentSubTransactionId(void);
extern bool SubTransactionIsActive(SubTransactionId subxid);
extern CommandId GetCurrentCommandId(bool used);
extern TimestampTz GetCurrentTransactionStartTimestamp(void);
extern TimestampTz GetCurrentStatementStartTimestamp(void);
extern TimestampTz GetCurrentTransactionStopTimestamp(void);
extern void SetCurrentStatementStartTimestamp(void);
extern int GetCurrentTransactionNestLevel(void);
extern bool TransactionIdIsCurrentTransactionId(TransactionId xid);
extern void CommandCounterIncrement(void);
extern void ForceSyncCommit(void);
extern void StartTransactionCommand(void);
extern void CommitTransactionCommand(void);
extern void AbortCurrentTransaction(void);
extern void BeginTransactionBlock(void);
extern bool EndTransactionBlock(void);
extern bool PrepareTransactionBlock(char *gid);
extern void UserAbortTransactionBlock(void);
extern void ReleaseSavepoint(List *options);
extern void DefineSavepoint(char *name);
extern void RollbackToSavepoint(List *options);
extern void BeginInternalSubTransaction(char *name);
extern void ReleaseCurrentSubTransaction(void);
extern void RollbackAndReleaseCurrentSubTransaction(void);
extern bool IsSubTransaction(void);
extern bool IsTransactionBlock(void);
extern bool IsTransactionOrTransactionBlock(void);
extern char TransactionBlockStatusCode(void);
extern void AbortOutOfAnyTransaction(void);
extern void PreventTransactionChain(bool isTopLevel, const char *stmtType);
extern void RequireTransactionChain(bool isTopLevel, const char *stmtType);
extern bool IsInTransactionChain(bool isTopLevel);
extern void RegisterXactCallback(XactCallback callback, void *arg);
extern void UnregisterXactCallback(XactCallback callback, void *arg);
extern void RegisterSubXactCallback(SubXactCallback callback, void *arg);
extern void UnregisterSubXactCallback(SubXactCallback callback, void *arg);
extern int xactGetCommittedChildren(TransactionId **ptr);
extern void xact_redo(XLogRecPtr lsn, XLogRecord *record);
extern void xact_desc(StringInfo buf, uint8 xl_info, char *rec);
#endif /* XACT_H */
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