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617fffee8a
GlobalVisIsRemovableFullXid() is now GlobalVisCheckRemovableFullXid(). This is consistent with the general convention for FullTransactionId equivalents of functions that deal with TransactionId values. It now matches the nearby GlobalVisCheckRemovableXid() function, which performs the same check for callers that use TransactionId values. Oversight in commit dc7420c2c92. Discussion: https://postgr.es/m/CAH2-Wzmes12jFNDcVgpU89Vp=r6uLFrE-MT0fjSWGsE70UiNaA@mail.gmail.com
178 lines
6.6 KiB
C
178 lines
6.6 KiB
C
/*-------------------------------------------------------------------------
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*
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* snapmgr.h
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* POSTGRES snapshot manager
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*
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* Portions Copyright (c) 1996-2021, 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/snapmgr.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef SNAPMGR_H
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#define SNAPMGR_H
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#include "access/transam.h"
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#include "utils/relcache.h"
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#include "utils/resowner.h"
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#include "utils/snapshot.h"
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/*
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* The structure used to map times to TransactionId values for the "snapshot
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* too old" feature must have a few entries at the tail to hold old values;
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* otherwise the lookup will often fail and the expected early pruning or
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* vacuum will not usually occur. It is best if this padding is for a number
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* of minutes greater than a thread would normally be stalled, but it's OK if
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* early vacuum opportunities are occasionally missed, so there's no need to
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* use an extreme value or get too fancy. 10 minutes seems plenty.
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*/
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#define OLD_SNAPSHOT_PADDING_ENTRIES 10
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#define OLD_SNAPSHOT_TIME_MAP_ENTRIES (old_snapshot_threshold + OLD_SNAPSHOT_PADDING_ENTRIES)
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/*
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* Common definition of relation properties that allow early pruning/vacuuming
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* when old_snapshot_threshold >= 0.
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*/
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#define RelationAllowsEarlyPruning(rel) \
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( \
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(rel)->rd_rel->relpersistence == RELPERSISTENCE_PERMANENT \
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&& !IsCatalogRelation(rel) \
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&& !RelationIsAccessibleInLogicalDecoding(rel) \
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)
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#define EarlyPruningEnabled(rel) (old_snapshot_threshold >= 0 && RelationAllowsEarlyPruning(rel))
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/* GUC variables */
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extern PGDLLIMPORT int old_snapshot_threshold;
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extern Size SnapMgrShmemSize(void);
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extern void SnapMgrInit(void);
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extern TimestampTz GetSnapshotCurrentTimestamp(void);
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extern TimestampTz GetOldSnapshotThresholdTimestamp(void);
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extern void SnapshotTooOldMagicForTest(void);
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extern bool FirstSnapshotSet;
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extern PGDLLIMPORT TransactionId TransactionXmin;
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extern PGDLLIMPORT TransactionId RecentXmin;
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/* Variables representing various special snapshot semantics */
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extern PGDLLIMPORT SnapshotData SnapshotSelfData;
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extern PGDLLIMPORT SnapshotData SnapshotAnyData;
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extern PGDLLIMPORT SnapshotData CatalogSnapshotData;
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#define SnapshotSelf (&SnapshotSelfData)
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#define SnapshotAny (&SnapshotAnyData)
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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).snapshot_type = SNAPSHOT_DIRTY)
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/*
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* Similarly, some initialization is required for a NonVacuumable snapshot.
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* The caller must supply the visibility cutoff state to use (c.f.
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* GlobalVisTestFor()).
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*/
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#define InitNonVacuumableSnapshot(snapshotdata, vistestp) \
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((snapshotdata).snapshot_type = SNAPSHOT_NON_VACUUMABLE, \
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(snapshotdata).vistest = (vistestp))
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/*
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* Similarly, some initialization is required for SnapshotToast. We need
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* to set lsn and whenTaken correctly to support snapshot_too_old.
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*/
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#define InitToastSnapshot(snapshotdata, l, w) \
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((snapshotdata).snapshot_type = SNAPSHOT_TOAST, \
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(snapshotdata).lsn = (l), \
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(snapshotdata).whenTaken = (w))
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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)->snapshot_type == SNAPSHOT_MVCC || \
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(snapshot)->snapshot_type == SNAPSHOT_HISTORIC_MVCC)
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static inline bool
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OldSnapshotThresholdActive(void)
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{
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return old_snapshot_threshold >= 0;
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}
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extern Snapshot GetTransactionSnapshot(void);
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extern Snapshot GetLatestSnapshot(void);
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extern void SnapshotSetCommandId(CommandId curcid);
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extern Snapshot GetOldestSnapshot(void);
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extern Snapshot GetCatalogSnapshot(Oid relid);
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extern Snapshot GetNonHistoricCatalogSnapshot(Oid relid);
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extern void InvalidateCatalogSnapshot(void);
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extern void InvalidateCatalogSnapshotConditionally(void);
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extern void PushActiveSnapshot(Snapshot snapshot);
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extern void PushCopiedSnapshot(Snapshot snapshot);
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extern void UpdateActiveSnapshotCommandId(void);
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extern void PopActiveSnapshot(void);
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extern Snapshot GetActiveSnapshot(void);
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extern bool ActiveSnapshotSet(void);
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extern Snapshot RegisterSnapshot(Snapshot snapshot);
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extern void UnregisterSnapshot(Snapshot snapshot);
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extern Snapshot RegisterSnapshotOnOwner(Snapshot snapshot, ResourceOwner owner);
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extern void UnregisterSnapshotFromOwner(Snapshot snapshot, ResourceOwner owner);
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extern void AtSubCommit_Snapshot(int level);
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extern void AtSubAbort_Snapshot(int level);
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extern void AtEOXact_Snapshot(bool isCommit, bool resetXmin);
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extern void ImportSnapshot(const char *idstr);
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extern bool XactHasExportedSnapshots(void);
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extern void DeleteAllExportedSnapshotFiles(void);
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extern bool ThereAreNoPriorRegisteredSnapshots(void);
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extern bool TransactionIdLimitedForOldSnapshots(TransactionId recentXmin,
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Relation relation,
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TransactionId *limit_xid,
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TimestampTz *limit_ts);
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extern void SetOldSnapshotThresholdTimestamp(TimestampTz ts, TransactionId xlimit);
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extern void MaintainOldSnapshotTimeMapping(TimestampTz whenTaken,
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TransactionId xmin);
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extern char *ExportSnapshot(Snapshot snapshot);
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/*
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* These live in procarray.c because they're intimately linked to the
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* procarray contents, but thematically they better fit into snapmgr.h.
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*/
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typedef struct GlobalVisState GlobalVisState;
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extern GlobalVisState *GlobalVisTestFor(Relation rel);
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extern bool GlobalVisTestIsRemovableXid(GlobalVisState *state, TransactionId xid);
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extern bool GlobalVisTestIsRemovableFullXid(GlobalVisState *state, FullTransactionId fxid);
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extern FullTransactionId GlobalVisTestNonRemovableFullHorizon(GlobalVisState *state);
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extern TransactionId GlobalVisTestNonRemovableHorizon(GlobalVisState *state);
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extern bool GlobalVisCheckRemovableXid(Relation rel, TransactionId xid);
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extern bool GlobalVisCheckRemovableFullXid(Relation rel, FullTransactionId fxid);
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/*
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* Utility functions for implementing visibility routines in table AMs.
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*/
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extern bool XidInMVCCSnapshot(TransactionId xid, Snapshot snapshot);
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/* Support for catalog timetravel for logical decoding */
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struct HTAB;
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extern struct HTAB *HistoricSnapshotGetTupleCids(void);
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extern void SetupHistoricSnapshot(Snapshot snapshot_now, struct HTAB *tuplecids);
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extern void TeardownHistoricSnapshot(bool is_error);
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extern bool HistoricSnapshotActive(void);
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extern Size EstimateSnapshotSpace(Snapshot snapshot);
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extern void SerializeSnapshot(Snapshot snapshot, char *start_address);
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extern Snapshot RestoreSnapshot(char *start_address);
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extern void RestoreTransactionSnapshot(Snapshot snapshot, void *source_pgproc);
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#endif /* SNAPMGR_H */
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