func fetchStatDatabase(db *sqlx.DB) (map[string]interface{}, error) {
	db = db.Unsafe()
	rows, err := db.Queryx(`SELECT * FROM pg_stat_database`)
	if err != nil {
		logger.Errorf("Failed to select pg_stat_database. %s", err)
		return nil, err
	}

	type pgStat struct {
		XactCommit   uint64   `db:"xact_commit"`
		XactRollback uint64   `db:"xact_rollback"`
		BlksRead     uint64   `db:"blks_read"`
		BlksHit      uint64   `db:"blks_hit"`
		BlkReadTime  *float64 `db:"blk_read_time"`
		BlkWriteTime *float64 `db:"blk_write_time"`
		TupReturned  uint64   `db:"tup_returned"`
		TupFetched   uint64   `db:"tup_fetched"`
		TupInserted  uint64   `db:"tup_inserted"`
		TupUpdated   uint64   `db:"tup_updated"`
		TupDeleted   uint64   `db:"tup_deleted"`
		Deadlocks    *uint64  `db:"deadlocks"`
		TempBytes    *uint64  `db:"temp_bytes"`
	}

	totalStat := pgStat{}
	for rows.Next() {
		p := pgStat{}
		if err := rows.StructScan(&p); err != nil {
			logger.Warningf("Failed to scan. %s", err)
			continue
		}
		totalStat.XactCommit += p.XactCommit
		totalStat.XactRollback += p.XactRollback
		totalStat.BlksRead += p.BlksRead
		totalStat.BlksHit += p.BlksHit
		if p.BlkReadTime != nil {
			if totalStat.BlkReadTime == nil {
				totalStat.BlkReadTime = p.BlkReadTime
			} else {
				*totalStat.BlkReadTime += *p.BlkReadTime
			}
		}
		if p.BlkWriteTime != nil {
			if totalStat.BlkWriteTime == nil {
				totalStat.BlkWriteTime = p.BlkWriteTime
			} else {
				*totalStat.BlkWriteTime += *p.BlkWriteTime
			}
		}
		totalStat.TupReturned += p.TupReturned
		totalStat.TupFetched += p.TupFetched
		totalStat.TupInserted += p.TupInserted
		totalStat.TupUpdated += p.TupUpdated
		totalStat.TupDeleted += p.TupDeleted
		if p.Deadlocks != nil {
			if totalStat.Deadlocks == nil {
				totalStat.Deadlocks = p.Deadlocks
			} else {
				*totalStat.Deadlocks += *p.Deadlocks
			}
		}
		if p.TempBytes != nil {
			if totalStat.TempBytes == nil {
				totalStat.TempBytes = p.TempBytes
			} else {
				*totalStat.TempBytes += *p.TempBytes
			}
		}
	}
	stat := make(map[string]interface{})
	stat["xact_commit"] = totalStat.XactCommit
	stat["xact_rollback"] = totalStat.XactRollback
	stat["blks_read"] = totalStat.BlksRead
	stat["blks_hit"] = totalStat.BlksHit
	if totalStat.BlkReadTime != nil {
		stat["blk_read_time"] = *totalStat.BlkReadTime
	}
	if totalStat.BlkWriteTime != nil {
		stat["blk_write_time"] = *totalStat.BlkWriteTime
	}
	stat["tup_returned"] = totalStat.TupReturned
	stat["tup_fetched"] = totalStat.TupFetched
	stat["tup_inserted"] = totalStat.TupInserted
	stat["tup_updated"] = totalStat.TupUpdated
	stat["tup_deleted"] = totalStat.TupDeleted
	if totalStat.Deadlocks != nil {
		stat["deadlocks"] = *totalStat.Deadlocks
	}
	if totalStat.TempBytes != nil {
		stat["temp_bytes"] = *totalStat.TempBytes
	}
	return stat, nil
}