predicate.h

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/*-------------------------------------------------------------------------
 *
 * predicate.h
 *    POSTGRES public predicate locking definitions.
 *
 *
 * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/include/storage/predicate.h
 *
 *-------------------------------------------------------------------------
 */
#ifndef PREDICATE_H
#define PREDICATE_H
 
#include "storage/itemptr.h"
#include "storage/lock.h"
#include "utils/relcache.h"
#include "utils/snapshot.h"
 
 
/*
 * GUC variables
 */
extern PGDLLIMPORT int max_predicate_locks_per_xact;
extern PGDLLIMPORT int max_predicate_locks_per_relation;
extern PGDLLIMPORT int max_predicate_locks_per_page;
 
/*
 * A handle used for sharing SERIALIZABLEXACT objects between the participants
 * in a parallel query.
 */
typedef void *SerializableXactHandle;
 
/*
 * function prototypes
 */
 
/* housekeeping for shared memory predicate lock structures */
extern void PredicateLockShmemInit(void);
extern Size PredicateLockShmemSize(void);
 
extern void CheckPointPredicate(void);
 
/* predicate lock reporting */
extern bool PageIsPredicateLocked(Relation relation, BlockNumber blkno);
 
/* predicate lock maintenance */
extern Snapshot GetSerializableTransactionSnapshot(Snapshot snapshot);
extern void SetSerializableTransactionSnapshot(Snapshot snapshot,
                                               VirtualTransactionId *sourcevxid,
                                               int sourcepid);
extern void RegisterPredicateLockingXid(TransactionId xid);
extern void PredicateLockRelation(Relation relation, Snapshot snapshot);
extern void PredicateLockPage(Relation relation, BlockNumber blkno, Snapshot snapshot);
extern void PredicateLockTID(Relation relation, const ItemPointerData *tid, Snapshot snapshot,
                             TransactionId tuple_xid);
extern void PredicateLockPageSplit(Relation relation, BlockNumber oldblkno, BlockNumber newblkno);
extern void PredicateLockPageCombine(Relation relation, BlockNumber oldblkno, BlockNumber newblkno);
extern void TransferPredicateLocksToHeapRelation(Relation relation);
extern void ReleasePredicateLocks(bool isCommit, bool isReadOnlySafe);
 
/* conflict detection (may also trigger rollback) */
extern bool CheckForSerializableConflictOutNeeded(Relation relation, Snapshot snapshot);
extern void CheckForSerializableConflictOut(Relation relation, TransactionId xid, Snapshot snapshot);
extern void CheckForSerializableConflictIn(Relation relation, const ItemPointerData *tid, BlockNumber blkno);
extern void CheckTableForSerializableConflictIn(Relation relation);
 
/* final rollback checking */
extern void PreCommit_CheckForSerializationFailure(void);
 
/* two-phase commit support */
extern void AtPrepare_PredicateLocks(void);
extern void PostPrepare_PredicateLocks(FullTransactionId fxid);
extern void PredicateLockTwoPhaseFinish(FullTransactionId fxid, bool isCommit);
extern void predicatelock_twophase_recover(FullTransactionId fxid, uint16 info,
                                           void *recdata, uint32 len);
 
/* parallel query support */
extern SerializableXactHandle ShareSerializableXact(void);
extern void AttachSerializableXact(SerializableXactHandle handle);
 
#endif                          /* PREDICATE_H */