4a78cdeb6b
before reporting a transaction committed. Data consistency is still guaranteed (unlike setting fsync = off), but a crash may lose the effects of the last few transactions. Patch by Simon, some editorialization by Tom.
188 lines
5.9 KiB
C
188 lines
5.9 KiB
C
/*-------------------------------------------------------------------------
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*
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* xact.h
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* postgres transaction system definitions
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*
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*
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* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $PostgreSQL: pgsql/src/include/access/xact.h,v 1.88 2007/08/01 22:45:09 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef XACT_H
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#define XACT_H
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#include "access/xlog.h"
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#include "nodes/pg_list.h"
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#include "storage/relfilenode.h"
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#include "utils/timestamp.h"
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/*
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* Xact isolation levels
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*/
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#define XACT_READ_UNCOMMITTED 0
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#define XACT_READ_COMMITTED 1
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#define XACT_REPEATABLE_READ 2
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#define XACT_SERIALIZABLE 3
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extern int DefaultXactIsoLevel;
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extern int XactIsoLevel;
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/*
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* We only implement two isolation levels internally. This macro should
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* be used to check which one is selected.
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*/
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#define IsXactIsoLevelSerializable (XactIsoLevel >= XACT_REPEATABLE_READ)
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/* Xact read-only state */
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extern bool DefaultXactReadOnly;
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extern bool XactReadOnly;
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/* Asynchronous commits */
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extern bool XactSyncCommit;
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/*
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* start- and end-of-transaction callbacks for dynamically loaded modules
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*/
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typedef enum
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{
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XACT_EVENT_COMMIT,
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XACT_EVENT_ABORT,
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XACT_EVENT_PREPARE
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} XactEvent;
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typedef void (*XactCallback) (XactEvent event, void *arg);
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typedef enum
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{
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SUBXACT_EVENT_START_SUB,
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SUBXACT_EVENT_COMMIT_SUB,
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SUBXACT_EVENT_ABORT_SUB
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} SubXactEvent;
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typedef void (*SubXactCallback) (SubXactEvent event, SubTransactionId mySubid,
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SubTransactionId parentSubid, void *arg);
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/* ----------------
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* transaction-related XLOG entries
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* ----------------
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*/
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/*
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* XLOG allows to store some information in high 4 bits of log
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* record xl_info field
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*/
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#define XLOG_XACT_COMMIT 0x00
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#define XLOG_XACT_PREPARE 0x10
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#define XLOG_XACT_ABORT 0x20
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#define XLOG_XACT_COMMIT_PREPARED 0x30
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#define XLOG_XACT_ABORT_PREPARED 0x40
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typedef struct xl_xact_commit
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{
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TimestampTz xact_time; /* time of commit */
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int nrels; /* number of RelFileNodes */
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int nsubxacts; /* number of subtransaction XIDs */
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/* Array of RelFileNode(s) to drop at commit */
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RelFileNode xnodes[1]; /* VARIABLE LENGTH ARRAY */
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/* ARRAY OF COMMITTED SUBTRANSACTION XIDs FOLLOWS */
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} xl_xact_commit;
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#define MinSizeOfXactCommit offsetof(xl_xact_commit, xnodes)
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typedef struct xl_xact_abort
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{
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TimestampTz xact_time; /* time of abort */
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int nrels; /* number of RelFileNodes */
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int nsubxacts; /* number of subtransaction XIDs */
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/* Array of RelFileNode(s) to drop at abort */
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RelFileNode xnodes[1]; /* VARIABLE LENGTH ARRAY */
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/* ARRAY OF ABORTED SUBTRANSACTION XIDs FOLLOWS */
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} xl_xact_abort;
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#define MinSizeOfXactAbort offsetof(xl_xact_abort, xnodes)
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/*
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* COMMIT_PREPARED and ABORT_PREPARED are identical to COMMIT/ABORT records
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* except that we have to store the XID of the prepared transaction explicitly
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* --- the XID in the record header will be for the transaction doing the
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* COMMIT PREPARED or ABORT PREPARED command.
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*/
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typedef struct xl_xact_commit_prepared
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{
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TransactionId xid; /* XID of prepared xact */
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xl_xact_commit crec; /* COMMIT record */
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/* MORE DATA FOLLOWS AT END OF STRUCT */
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} xl_xact_commit_prepared;
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#define MinSizeOfXactCommitPrepared offsetof(xl_xact_commit_prepared, crec.xnodes)
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typedef struct xl_xact_abort_prepared
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{
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TransactionId xid; /* XID of prepared xact */
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xl_xact_abort arec; /* ABORT record */
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/* MORE DATA FOLLOWS AT END OF STRUCT */
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} xl_xact_abort_prepared;
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#define MinSizeOfXactAbortPrepared offsetof(xl_xact_abort_prepared, arec.xnodes)
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/* ----------------
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* extern definitions
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* ----------------
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*/
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extern bool IsTransactionState(void);
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extern bool IsAbortedTransactionBlockState(void);
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extern TransactionId GetTopTransactionId(void);
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extern TransactionId GetCurrentTransactionId(void);
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extern TransactionId GetCurrentTransactionIdIfAny(void);
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extern SubTransactionId GetCurrentSubTransactionId(void);
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extern CommandId GetCurrentCommandId(void);
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extern TimestampTz GetCurrentTransactionStartTimestamp(void);
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extern TimestampTz GetCurrentStatementStartTimestamp(void);
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extern TimestampTz GetCurrentTransactionStopTimestamp(void);
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extern void SetCurrentStatementStartTimestamp(void);
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extern int GetCurrentTransactionNestLevel(void);
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extern bool TransactionIdIsCurrentTransactionId(TransactionId xid);
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extern void CommandCounterIncrement(void);
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extern void ForceSyncCommit(void);
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extern void StartTransactionCommand(void);
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extern void CommitTransactionCommand(void);
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extern void AbortCurrentTransaction(void);
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extern void BeginTransactionBlock(void);
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extern bool EndTransactionBlock(void);
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extern bool PrepareTransactionBlock(char *gid);
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extern void UserAbortTransactionBlock(void);
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extern void ReleaseSavepoint(List *options);
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extern void DefineSavepoint(char *name);
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extern void RollbackToSavepoint(List *options);
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extern void BeginInternalSubTransaction(char *name);
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extern void ReleaseCurrentSubTransaction(void);
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extern void RollbackAndReleaseCurrentSubTransaction(void);
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extern bool IsSubTransaction(void);
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extern bool IsTransactionBlock(void);
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extern bool IsTransactionOrTransactionBlock(void);
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extern char TransactionBlockStatusCode(void);
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extern void AbortOutOfAnyTransaction(void);
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extern void PreventTransactionChain(bool isTopLevel, const char *stmtType);
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extern void RequireTransactionChain(bool isTopLevel, const char *stmtType);
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extern bool IsInTransactionChain(bool isTopLevel);
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extern void RegisterXactCallback(XactCallback callback, void *arg);
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extern void UnregisterXactCallback(XactCallback callback, void *arg);
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extern void RegisterSubXactCallback(SubXactCallback callback, void *arg);
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extern void UnregisterSubXactCallback(SubXactCallback callback, void *arg);
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extern void RecordTransactionCommit(void);
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extern int xactGetCommittedChildren(TransactionId **ptr);
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extern void xact_redo(XLogRecPtr lsn, XLogRecord *record);
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extern void xact_desc(StringInfo buf, uint8 xl_info, char *rec);
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#endif /* XACT_H */
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