instrument.h

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/*-------------------------------------------------------------------------
 *
 * instrument.h
 *    definitions for run-time statistics collection
 *
 *
 * Copyright (c) 2001-2025, PostgreSQL Global Development Group
 *
 * src/include/executor/instrument.h
 *
 *-------------------------------------------------------------------------
 */
#ifndef INSTRUMENT_H
#define INSTRUMENT_H
 
#include "portability/instr_time.h"
 
 
/*
 * BufferUsage and WalUsage counters keep being incremented infinitely,
 * i.e., must never be reset to zero, so that we can calculate how much
 * the counters are incremented in an arbitrary period.
 */
typedef struct BufferUsage
{
    int64       shared_blks_hit;    /* # of shared buffer hits */
    int64       shared_blks_read;   /* # of shared disk blocks read */
    int64       shared_blks_dirtied;    /* # of shared blocks dirtied */
    int64       shared_blks_written;    /* # of shared disk blocks written */
    int64       local_blks_hit; /* # of local buffer hits */
    int64       local_blks_read;    /* # of local disk blocks read */
    int64       local_blks_dirtied; /* # of local blocks dirtied */
    int64       local_blks_written; /* # of local disk blocks written */
    int64       temp_blks_read; /* # of temp blocks read */
    int64       temp_blks_written;  /* # of temp blocks written */
    instr_time  shared_blk_read_time;   /* time spent reading shared blocks */
    instr_time  shared_blk_write_time;  /* time spent writing shared blocks */
    instr_time  local_blk_read_time;    /* time spent reading local blocks */
    instr_time  local_blk_write_time;   /* time spent writing local blocks */
    instr_time  temp_blk_read_time; /* time spent reading temp blocks */
    instr_time  temp_blk_write_time;    /* time spent writing temp blocks */
} BufferUsage;
 
/*
 * WalUsage tracks only WAL activity like WAL records generation that
 * can be measured per query and is displayed by EXPLAIN command,
 * pg_stat_statements extension, etc. It does not track other WAL activity
 * like WAL writes that it's not worth measuring per query. That's tracked
 * by WAL global statistics counters in WalStats, instead.
 */
typedef struct WalUsage
{
    int64       wal_records;    /* # of WAL records produced */
    int64       wal_fpi;        /* # of WAL full page images produced */
    uint64      wal_bytes;      /* size of WAL records produced */
} WalUsage;
 
/* Flag bits included in InstrAlloc's instrument_options bitmask */
typedef enum InstrumentOption
{
    INSTRUMENT_TIMER = 1 << 0,  /* needs timer (and row counts) */
    INSTRUMENT_BUFFERS = 1 << 1,    /* needs buffer usage */
    INSTRUMENT_ROWS = 1 << 2,   /* needs row count */
    INSTRUMENT_WAL = 1 << 3,    /* needs WAL usage */
    INSTRUMENT_ALL = PG_INT32_MAX
} InstrumentOption;
 
typedef struct Instrumentation
{
    /* Parameters set at node creation: */
    bool        need_timer;     /* true if we need timer data */
    bool        need_bufusage;  /* true if we need buffer usage data */
    bool        need_walusage;  /* true if we need WAL usage data */
    bool        async_mode;     /* true if node is in async mode */
    /* Info about current plan cycle: */
    bool        running;        /* true if we've completed first tuple */
    instr_time  starttime;      /* start time of current iteration of node */
    instr_time  counter;        /* accumulated runtime for this node */
    double      firsttuple;     /* time for first tuple of this cycle */
    double      tuplecount;     /* # of tuples emitted so far this cycle */
    BufferUsage bufusage_start; /* buffer usage at start */
    WalUsage    walusage_start; /* WAL usage at start */
    /* Accumulated statistics across all completed cycles: */
    double      startup;        /* total startup time (in seconds) */
    double      total;          /* total time (in seconds) */
    double      ntuples;        /* total tuples produced */
    double      ntuples2;       /* secondary node-specific tuple counter */
    double      nloops;         /* # of run cycles for this node */
    double      nfiltered1;     /* # of tuples removed by scanqual or joinqual */
    double      nfiltered2;     /* # of tuples removed by "other" quals */
    BufferUsage bufusage;       /* total buffer usage */
    WalUsage    walusage;       /* total WAL usage */
} Instrumentation;
 
typedef struct WorkerInstrumentation
{
    int         num_workers;    /* # of structures that follow */
    Instrumentation instrument[FLEXIBLE_ARRAY_MEMBER];
} WorkerInstrumentation;
 
extern PGDLLIMPORT BufferUsage pgBufferUsage;
extern PGDLLIMPORT WalUsage pgWalUsage;
 
extern Instrumentation *InstrAlloc(int n, int instrument_options,
                                   bool async_mode);
extern void InstrInit(Instrumentation *instr, int instrument_options);
extern void InstrStartNode(Instrumentation *instr);
extern void InstrStopNode(Instrumentation *instr, double nTuples);
extern void InstrUpdateTupleCount(Instrumentation *instr, double nTuples);
extern void InstrEndLoop(Instrumentation *instr);
extern void InstrAggNode(Instrumentation *dst, Instrumentation *add);
extern void InstrStartParallelQuery(void);
extern void InstrEndParallelQuery(BufferUsage *bufusage, WalUsage *walusage);
extern void InstrAccumParallelQuery(BufferUsage *bufusage, WalUsage *walusage);
extern void BufferUsageAccumDiff(BufferUsage *dst,
                                 const BufferUsage *add, const BufferUsage *sub);
extern void WalUsageAccumDiff(WalUsage *dst, const WalUsage *add,
                              const WalUsage *sub);
 
#endif                          /* INSTRUMENT_H */