parallel.h

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/*-------------------------------------------------------------------------
 *
 * parallel.h
 *
 *  Parallel support for pg_dump and pg_restore
 *
 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
 *      src/bin/pg_dump/parallel.h
 *
 *-------------------------------------------------------------------------
 */
 
#ifndef PG_DUMP_PARALLEL_H
#define PG_DUMP_PARALLEL_H
 
#include <limits.h>
 
#include "pg_backup_archiver.h"
 
/* Function to call in leader process on completion of a worker task */
typedef void (*ParallelCompletionPtr) (ArchiveHandle *AH,
                                       TocEntry *te,
                                       int status,
                                       void *callback_data);
 
/* Wait options for WaitForWorkers */
typedef enum
{
    WFW_NO_WAIT,
    WFW_GOT_STATUS,
    WFW_ONE_IDLE,
    WFW_ALL_IDLE,
} WFW_WaitOption;
 
/*
 * Maximum number of parallel jobs allowed.
 *
 * On Windows we can only have at most MAXIMUM_WAIT_OBJECTS (= 64 usually)
 * parallel jobs because that's the maximum limit for the
 * WaitForMultipleObjects() call.
 */
#ifdef WIN32
#define PG_MAX_JOBS MAXIMUM_WAIT_OBJECTS
#else
#define PG_MAX_JOBS INT_MAX
#endif
 
/* ParallelSlot is an opaque struct known only within parallel.c */
typedef struct ParallelSlot ParallelSlot;
 
/* Overall state for parallel.c */
typedef struct ParallelState
{
    int         numWorkers;     /* allowed number of workers */
    /* these arrays have numWorkers entries, one per worker: */
    TocEntry  **te;             /* item being worked on, or NULL */
    ParallelSlot *parallelSlot; /* private info about each worker */
} ParallelState;
 
#ifdef WIN32
extern bool parallel_init_done;
extern DWORD mainThreadId;
#endif
 
extern void init_parallel_dump_utils(void);
 
extern bool IsEveryWorkerIdle(ParallelState *pstate);
extern void WaitForWorkers(ArchiveHandle *AH, ParallelState *pstate,
                           WFW_WaitOption mode);
 
extern ParallelState *ParallelBackupStart(ArchiveHandle *AH);
extern void DispatchJobForTocEntry(ArchiveHandle *AH,
                                   ParallelState *pstate,
                                   TocEntry *te,
                                   T_Action act,
                                   ParallelCompletionPtr callback,
                                   void *callback_data);
extern void ParallelBackupEnd(ArchiveHandle *AH, ParallelState *pstate);
 
extern void set_archive_cancel_info(ArchiveHandle *AH, PGconn *conn);
 
#endif                          /* PG_DUMP_PARALLEL_H */