backend_progress.c

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/* ----------
 * backend_progress.c
 *
 *  Command progress reporting infrastructure.
 *
 *  Copyright (c) 2001-2024, PostgreSQL Global Development Group
 *
 *  src/backend/utils/activity/backend_progress.c
 * ----------
 */
#include "postgres.h"
 
#include "access/parallel.h"
#include "libpq/pqformat.h"
#include "port/atomics.h"       /* for memory barriers */
#include "utils/backend_progress.h"
#include "utils/backend_status.h"
 
 
/*-----------
 * pgstat_progress_start_command() -
 *
 * Set st_progress_command (and st_progress_command_target) in own backend
 * entry.  Also, zero-initialize st_progress_param array.
 *-----------
 */
void
pgstat_progress_start_command(ProgressCommandType cmdtype, Oid relid)
{
    volatile PgBackendStatus *beentry = MyBEEntry;
 
    if (!beentry || !pgstat_track_activities)
        return;
 
    PGSTAT_BEGIN_WRITE_ACTIVITY(beentry);
    beentry->st_progress_command = cmdtype;
    beentry->st_progress_command_target = relid;
    MemSet(&beentry->st_progress_param, 0, sizeof(beentry->st_progress_param));
    PGSTAT_END_WRITE_ACTIVITY(beentry);
}
 
/*-----------
 * pgstat_progress_update_param() -
 *
 * Update index'th member in st_progress_param[] of own backend entry.
 *-----------
 */
void
pgstat_progress_update_param(int index, int64 val)
{
    volatile PgBackendStatus *beentry = MyBEEntry;
 
    Assert(index >= 0 && index < PGSTAT_NUM_PROGRESS_PARAM);
 
    if (!beentry || !pgstat_track_activities)
        return;
 
    PGSTAT_BEGIN_WRITE_ACTIVITY(beentry);
    beentry->st_progress_param[index] = val;
    PGSTAT_END_WRITE_ACTIVITY(beentry);
}
 
/*-----------
 * pgstat_progress_incr_param() -
 *
 * Increment index'th member in st_progress_param[] of own backend entry.
 *-----------
 */
void
pgstat_progress_incr_param(int index, int64 incr)
{
    volatile PgBackendStatus *beentry = MyBEEntry;
 
    Assert(index >= 0 && index < PGSTAT_NUM_PROGRESS_PARAM);
 
    if (!beentry || !pgstat_track_activities)
        return;
 
    PGSTAT_BEGIN_WRITE_ACTIVITY(beentry);
    beentry->st_progress_param[index] += incr;
    PGSTAT_END_WRITE_ACTIVITY(beentry);
}
 
/*-----------
 * pgstat_progress_parallel_incr_param() -
 *
 * A variant of pgstat_progress_incr_param to allow a worker to poke at
 * a leader to do an incremental progress update.
 *-----------
 */
void
pgstat_progress_parallel_incr_param(int index, int64 incr)
{
    /*
     * Parallel workers notify a leader through a 'P' protocol message to
     * update progress, passing the progress index and incremented value.
     * Leaders can just call pgstat_progress_incr_param directly.
     */
    if (IsParallelWorker())
    {
        static StringInfoData progress_message;
 
        initStringInfo(&progress_message);
 
        pq_beginmessage(&progress_message, 'P');
        pq_sendint32(&progress_message, index);
        pq_sendint64(&progress_message, incr);
        pq_endmessage(&progress_message);
    }
    else
        pgstat_progress_incr_param(index, incr);
}
 
/*-----------
 * pgstat_progress_update_multi_param() -
 *
 * Update multiple members in st_progress_param[] of own backend entry.
 * This is atomic; readers won't see intermediate states.
 *-----------
 */
void
pgstat_progress_update_multi_param(int nparam, const int *index,
                                   const int64 *val)
{
    volatile PgBackendStatus *beentry = MyBEEntry;
    int         i;
 
    if (!beentry || !pgstat_track_activities || nparam == 0)
        return;
 
    PGSTAT_BEGIN_WRITE_ACTIVITY(beentry);
 
    for (i = 0; i < nparam; ++i)
    {
        Assert(index[i] >= 0 && index[i] < PGSTAT_NUM_PROGRESS_PARAM);
 
        beentry->st_progress_param[index[i]] = val[i];
    }
 
    PGSTAT_END_WRITE_ACTIVITY(beentry);
}
 
/*-----------
 * pgstat_progress_end_command() -
 *
 * Reset st_progress_command (and st_progress_command_target) in own backend
 * entry.  This signals the end of the command.
 *-----------
 */
void
pgstat_progress_end_command(void)
{
    volatile PgBackendStatus *beentry = MyBEEntry;
 
    if (!beentry || !pgstat_track_activities)
        return;
 
    if (beentry->st_progress_command == PROGRESS_COMMAND_INVALID)
        return;
 
    PGSTAT_BEGIN_WRITE_ACTIVITY(beentry);
    beentry->st_progress_command = PROGRESS_COMMAND_INVALID;
    beentry->st_progress_command_target = InvalidOid;
    PGSTAT_END_WRITE_ACTIVITY(beentry);
}