conflict.h

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/*-------------------------------------------------------------------------
 * conflict.h
 *     Exports for conflicts logging.
 *
 * Copyright (c) 2024-2026, PostgreSQL Global Development Group
 *
 *-------------------------------------------------------------------------
 */
#ifndef CONFLICT_H
#define CONFLICT_H
 
#include "access/xlogdefs.h"
#include "datatype/timestamp.h"
#include "nodes/pg_list.h"
 
/* Avoid including execnodes.h here */
typedef struct EState EState;
typedef struct ResultRelInfo ResultRelInfo;
typedef struct TupleTableSlot TupleTableSlot;
 
 
/*
 * Conflict types that could occur while applying remote changes.
 *
 * This enum is used in statistics collection (see
 * PgStat_StatSubEntry::conflict_count and
 * PgStat_BackendSubEntry::conflict_count) as well, therefore, when adding new
 * values or reordering existing ones, ensure to review and potentially adjust
 * the corresponding statistics collection codes.
 */
typedef enum
{
    /* The row to be inserted violates unique constraint */
    CT_INSERT_EXISTS,
 
    /* The row to be updated was modified by a different origin */
    CT_UPDATE_ORIGIN_DIFFERS,
 
    /* The updated row value violates unique constraint */
    CT_UPDATE_EXISTS,
 
    /* The row to be updated was concurrently deleted by a different origin */
    CT_UPDATE_DELETED,
 
    /* The row to be updated is missing */
    CT_UPDATE_MISSING,
 
    /* The row to be deleted was modified by a different origin */
    CT_DELETE_ORIGIN_DIFFERS,
 
    /* The row to be deleted is missing */
    CT_DELETE_MISSING,
 
    /* The row to be inserted/updated violates multiple unique constraint */
    CT_MULTIPLE_UNIQUE_CONFLICTS,
 
    /*
     * Other conflicts, such as exclusion constraint violations, involve more
     * complex rules than simple equality checks. These conflicts are left for
     * future improvements.
     */
} ConflictType;
 
#define CONFLICT_NUM_TYPES (CT_MULTIPLE_UNIQUE_CONFLICTS + 1)
 
/*
 * Information for the local row that caused the conflict.
 */
typedef struct ConflictTupleInfo
{
    TupleTableSlot *slot;       /* tuple slot holding the conflicting local
                                 * tuple */
    Oid         indexoid;       /* OID of the index where the conflict
                                 * occurred */
    TransactionId xmin;         /* transaction ID of the modification causing
                                 * the conflict */
    ReplOriginId origin;        /* origin identifier of the modification */
    TimestampTz ts;             /* timestamp of when the modification on the
                                 * conflicting local row occurred */
} ConflictTupleInfo;
 
/*
 * Defines where logical replication conflict details are recorded.
 *
 * While stored as a text-based array/string in
 * pg_subscription.subconflictlogdest for user readability and extensibility,
 * we map these to an internal enum to allow for efficient checks.
 */
typedef enum ConflictLogDest
{
    CONFLICT_LOG_DEST_LOG = 0,  /* Emit to server logs */
    CONFLICT_LOG_DEST_TABLE,    /* Insert into the conflict log table */
    CONFLICT_LOG_DEST_ALL       /* Both log and table */
} ConflictLogDest;
 
#define CONFLICTS_LOGGED_TO_TABLE(dest) \
    ((dest == CONFLICT_LOG_DEST_TABLE) || (dest == CONFLICT_LOG_DEST_ALL))
#define CONFLICTS_LOGGED_TO_LOG(dest) \
    ((dest == CONFLICT_LOG_DEST_LOG) || (dest == CONFLICT_LOG_DEST_ALL))
 
/*
 * Array mapping for converting internal enum to string.
 */
extern PGDLLIMPORT const char *const ConflictLogDestNames[];
 
extern Oid  create_conflict_log_table(Oid subid, char *subname, Oid subowner);
extern ConflictLogDest GetConflictLogDest(const char *dest);
extern bool GetTupleTransactionInfo(TupleTableSlot *localslot,
                                    TransactionId *xmin,
                                    ReplOriginId *localorigin,
                                    TimestampTz *localts);
extern void ReportApplyConflict(EState *estate, ResultRelInfo *relinfo,
                                int elevel, ConflictType type,
                                TupleTableSlot *searchslot,
                                TupleTableSlot *remoteslot,
                                List *conflicttuples);
extern void InitConflictIndexes(ResultRelInfo *relInfo);
#endif