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Previously, these functions took a HeapTupleHeader, but upcoming patches for logical replication will introduce new a new snapshot type under which the tuple's TID will be used to lookup (CMIN, CMAX) for visibility determination purposes. This makes that information available. Code churn is minimal since HeapTupleSatisfiesVisibility took the HeapTuple anyway, and deferenced it before calling the satisfies function. Independently of logical replication, this allows t_tableOid and t_self to be cross-checked via assertions in tqual.c. This seems like a useful way to make sure that all callers are setting these values properly, which has been previously put forward as desirable. Andres Freund, reviewed by Álvaro Herrera
93 lines
3.4 KiB
C
93 lines
3.4 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) 1996-2013, 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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* src/include/utils/tqual.h
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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 "utils/snapshot.h"
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/* Static variables representing various special snapshot semantics */
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extern PGDLLIMPORT SnapshotData SnapshotNowData;
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extern PGDLLIMPORT SnapshotData SnapshotSelfData;
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extern PGDLLIMPORT SnapshotData SnapshotAnyData;
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extern PGDLLIMPORT SnapshotData SnapshotToastData;
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#define SnapshotNow (&SnapshotNowData)
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#define SnapshotSelf (&SnapshotSelfData)
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#define SnapshotAny (&SnapshotAnyData)
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#define SnapshotToast (&SnapshotToastData)
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/*
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* We don't provide a static SnapshotDirty variable because it would be
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* non-reentrant. Instead, users of that snapshot type should declare a
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* local variable of type SnapshotData, and initialize it with this macro.
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*/
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#define InitDirtySnapshot(snapshotdata) \
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((snapshotdata).satisfies = HeapTupleSatisfiesDirty)
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/* This macro encodes the knowledge of which snapshots are MVCC-safe */
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#define IsMVCCSnapshot(snapshot) \
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((snapshot)->satisfies == HeapTupleSatisfiesMVCC)
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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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* Hint bits in the HeapTuple's t_infomask may be updated as a side effect;
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* if so, the indicated buffer is marked dirty.
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*/
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#define HeapTupleSatisfiesVisibility(tuple, snapshot, buffer) \
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((*(snapshot)->satisfies) (tuple, snapshot, buffer))
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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 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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/* These are the "satisfies" test routines for the various snapshot types */
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extern bool HeapTupleSatisfiesMVCC(HeapTuple htup,
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Snapshot snapshot, Buffer buffer);
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extern bool HeapTupleSatisfiesNow(HeapTuple htup,
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Snapshot snapshot, Buffer buffer);
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extern bool HeapTupleSatisfiesSelf(HeapTuple htup,
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Snapshot snapshot, Buffer buffer);
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extern bool HeapTupleSatisfiesAny(HeapTuple htup,
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Snapshot snapshot, Buffer buffer);
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extern bool HeapTupleSatisfiesToast(HeapTuple htup,
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Snapshot snapshot, Buffer buffer);
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extern bool HeapTupleSatisfiesDirty(HeapTuple htup,
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Snapshot snapshot, Buffer buffer);
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/* Special "satisfies" routines with different APIs */
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extern HTSU_Result HeapTupleSatisfiesUpdate(HeapTuple htup,
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CommandId curcid, Buffer buffer);
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extern HTSV_Result HeapTupleSatisfiesVacuum(HeapTuple htup,
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TransactionId OldestXmin, Buffer buffer);
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extern bool HeapTupleIsSurelyDead(HeapTuple htup,
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TransactionId OldestXmin);
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extern void HeapTupleSetHintBits(HeapTupleHeader tuple, Buffer buffer,
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uint16 infomask, TransactionId xid);
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extern bool HeapTupleHeaderIsOnlyLocked(HeapTupleHeader tuple);
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#endif /* TQUAL_H */
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