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6c6f395a8a
a frozen (copied) snapshot too. Move execMain's snapshot copying code out into a subroutine in case we find other places that need it.
119 lines
3.8 KiB
C
119 lines
3.8 KiB
C
/*-------------------------------------------------------------------------
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*
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* tqual.h
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* POSTGRES "time" qualification definitions, ie, tuple visibility rules.
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*
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* Should be moved/renamed... - vadim 07/28/98
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*
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* Portions Copyright (c) 1996-2001, 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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* $Id: tqual.h,v 1.40 2002/05/21 22:59:01 tgl 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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#include "access/xact.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 ids in xip[] */
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TransactionId *xip; /* array of xact IDs in progress */
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/* note: all ids in xip[] satisfy xmin <= xip[i] < xmax */
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CommandId curcid; /* in my xact, CID < curcid are visible */
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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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#define SnapshotAny ((Snapshot) 0x2)
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#define SnapshotToast ((Snapshot) 0x3)
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extern DLLIMPORT Snapshot SnapshotDirty;
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extern DLLIMPORT Snapshot QuerySnapshot;
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extern DLLIMPORT Snapshot SerializableSnapshot;
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extern bool ReferentialIntegritySnapshotOverride;
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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 IsSnapshotAny(snapshot) ((Snapshot) (snapshot) == SnapshotAny)
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#define IsSnapshotToast(snapshot) ((Snapshot) (snapshot) == SnapshotToast)
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#define IsSnapshotDirty(snapshot) ((Snapshot) (snapshot) == SnapshotDirty)
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/*
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* HeapTupleSatisfiesVisibility
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* True iff heap tuple satisfies a time qual.
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*
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* Notes:
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* Assumes heap tuple is valid.
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* Beware of multiple evaluations of snapshot argument.
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*/
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#define HeapTupleSatisfiesVisibility(tuple, snapshot) \
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(IsSnapshotNow(snapshot) ? \
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HeapTupleSatisfiesNow((tuple)->t_data) \
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: \
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(IsSnapshotSelf(snapshot) ? \
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HeapTupleSatisfiesItself((tuple)->t_data) \
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: \
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(IsSnapshotAny(snapshot) ? \
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true \
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: \
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(IsSnapshotToast(snapshot) ? \
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HeapTupleSatisfiesToast((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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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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)
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/* Result codes for HeapTupleSatisfiesUpdate */
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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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/* Result codes for HeapTupleSatisfiesVacuum */
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typedef enum
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{
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HEAPTUPLE_DEAD, /* tuple is dead and deletable */
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HEAPTUPLE_LIVE, /* tuple is live (committed, no deleter) */
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HEAPTUPLE_RECENTLY_DEAD, /* tuple is dead, but not deletable yet */
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HEAPTUPLE_INSERT_IN_PROGRESS, /* inserting xact is still in
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* progress */
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HEAPTUPLE_DELETE_IN_PROGRESS /* deleting xact is still in progress */
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} HTSV_Result;
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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 HeapTupleSatisfiesToast(HeapTupleHeader tuple);
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extern bool HeapTupleSatisfiesSnapshot(HeapTupleHeader tuple,
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Snapshot snapshot);
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extern int HeapTupleSatisfiesUpdate(HeapTuple tuple,
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CommandId curcid);
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extern HTSV_Result HeapTupleSatisfiesVacuum(HeapTupleHeader tuple,
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TransactionId OldestXmin);
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extern Snapshot GetSnapshotData(bool serializable);
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extern void SetQuerySnapshot(void);
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extern Snapshot CopyQuerySnapshot(void);
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extern void FreeXactSnapshot(void);
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#endif /* TQUAL_H */
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