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109 lines
2.9 KiB
C
109 lines
2.9 KiB
C
/*-------------------------------------------------------------------------
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*
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* tqual.h
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* POSTGRES "time" qualification definitions.
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*
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* Should be moved/renamed... - vadim 07/28/98
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*
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* Copyright (c) 1994, Regents of the University of California
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*
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* $Id: tqual.h,v 1.22 1999/05/25 22:43:39 momjian Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef TQUAL_H
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#define TQUAL_H
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#include <access/htup.h>
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typedef struct SnapshotData
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{
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TransactionId xmin; /* XID < xmin are visible to me */
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TransactionId xmax; /* XID >= xmax are invisible to me */
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uint32 xcnt; /* # of xact below */
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TransactionId *xip; /* array of xacts in progress */
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ItemPointerData tid; /* required for Dirty snapshot -:( */
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} SnapshotData;
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typedef SnapshotData *Snapshot;
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#define SnapshotNow ((Snapshot) 0x0)
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#define SnapshotSelf ((Snapshot) 0x1)
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extern Snapshot SnapshotDirty;
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extern Snapshot QuerySnapshot;
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extern Snapshot SerializableSnapshot;
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#define IsSnapshotNow(snapshot) ((Snapshot) snapshot == SnapshotNow)
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#define IsSnapshotSelf(snapshot) ((Snapshot) snapshot == SnapshotSelf)
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#define IsSnapshotDirty(snapshot) ((Snapshot) snapshot == SnapshotDirty)
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extern TransactionId HeapSpecialTransactionId;
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extern CommandId HeapSpecialCommandId;
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/*
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* HeapTupleSatisfiesVisibility
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* True iff heap tuple satsifies a time qual.
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*
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* Note:
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* Assumes heap tuple is valid.
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*/
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#define HeapTupleSatisfiesVisibility(tuple, snapshot) \
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( \
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TransactionIdEquals((tuple)->t_data->t_xmax, AmiTransactionId) ? \
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false \
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: \
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( \
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(IsSnapshotSelf(snapshot) || heapisoverride()) ? \
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HeapTupleSatisfiesItself((tuple)->t_data) \
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: \
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((IsSnapshotDirty(snapshot)) ? \
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HeapTupleSatisfiesDirty((tuple)->t_data) \
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: \
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((IsSnapshotNow(snapshot)) ? \
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HeapTupleSatisfiesNow((tuple)->t_data) \
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: \
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HeapTupleSatisfiesSnapshot((tuple)->t_data, snapshot) \
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) \
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) \
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) \
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)
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#define heapisoverride() \
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( \
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(!TransactionIdIsValid(HeapSpecialTransactionId)) ? \
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false \
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: \
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( \
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(!TransactionIdEquals(GetCurrentTransactionId(), \
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HeapSpecialTransactionId) || \
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GetCurrentCommandId() != HeapSpecialCommandId) ? \
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( \
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HeapSpecialTransactionId = InvalidTransactionId, \
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false \
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) \
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: \
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true \
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) \
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)
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#define HeapTupleMayBeUpdated 0
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#define HeapTupleInvisible 1
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#define HeapTupleSelfUpdated 2
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#define HeapTupleUpdated 3
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#define HeapTupleBeingUpdated 4
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extern bool HeapTupleSatisfiesItself(HeapTupleHeader tuple);
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extern bool HeapTupleSatisfiesNow(HeapTupleHeader tuple);
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extern bool HeapTupleSatisfiesDirty(HeapTupleHeader tuple);
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extern bool HeapTupleSatisfiesSnapshot(HeapTupleHeader tuple, Snapshot snapshot);
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extern int HeapTupleSatisfiesUpdate(HeapTuple tuple);
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extern void setheapoverride(bool on);
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extern Snapshot GetSnapshotData(bool serializable);
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extern void SetQuerySnapshot(void);
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extern void FreeXactSnapshot(void);
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#endif /* TQUAL_H */
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