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doris/be/src/exec/scan_node.h

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// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the License for the
// specific language governing permissions and limitations
// under the License.
// This file is copied from
// https://github.com/apache/impala/blob/branch-2.9.0/be/src/exec/scan-node.h
// and modified by Doris
#pragma once
#include <functional>
#include <string>
#include <vector>
#include "common/status.h"
#include "exec/exec_node.h"
#include "util/runtime_profile.h"
namespace doris {
class DescriptorTbl;
class ObjectPool;
class RuntimeState;
class TPlanNode;
class TScanRangeParams;
// Abstract base class of all scan nodes; introduces set_scan_range().
//
// Includes ScanNode common counters:
// BytesRead - total bytes read by this scan node
//
// TotalRawHdfsReadTime - it measures the total time spent in the disk-io-mgr's reading
// threads for this node. For example, if we have 3 reading threads and each spent
// 1 sec, this counter will report 3 sec.
//
// TotalReadThroughput - BytesRead divided by the total time spent in this node
// (from Open to Close). For IO bounded queries, this should be very close to the
// total throughput of all the disks.
//
// PerDiskRawHdfsThroughput - the read throughput for each disk. If all the data reside
// on disk, this should be the read throughput the disk, regardless of whether the
// query is IO bounded or not.
//
// NumDisksAccessed - number of disks accessed.
//
// AverageIoMgrQueueCapcity - the average queue capacity in the io mgr for this node.
// AverageIoMgrQueueSize - the average queue size (for ready buffers) in the io mgr
// for this node.
//
// AverageScannerThreadConcurrency - the average number of active scanner threads. A
// scanner thread is considered active if it is not blocked by IO. This number would
// be low (less than 1) for IO bounded queries. For cpu bounded queries, this number
// would be close to the max scanner threads allowed.
//
// AverageHdfsReadThreadConcurrency - the average number of active hdfs reading threads
// reading for this scan node. For IO bound queries, this should be close to the
// number of disk.
//
// HdfsReadThreadConcurrencyCount=<i> - the number of samples taken when the hdfs read
// thread concurrency is <i>.
//
// ScanRangesComplete - number of scan ranges completed
//
class ScanNode : public ExecNode {
public:
ScanNode(ObjectPool* pool, const TPlanNode& tnode, const DescriptorTbl& descs)
: ExecNode(pool, tnode, descs) {}
// Set up counters
Status prepare(RuntimeState* state) override;
// Convert scan_ranges into node-specific scan restrictions. This should be
// called after prepare()
virtual Status set_scan_ranges(RuntimeState* state,
const std::vector<TScanRangeParams>& scan_ranges) = 0;
bool is_scan_node() const override { return true; }
RuntimeProfile::Counter* bytes_read_counter() const { return _bytes_read_counter; }
RuntimeProfile::Counter* rows_read_counter() const { return _rows_read_counter; }
RuntimeProfile::Counter* total_throughput_counter() const { return _total_throughput_counter; }
// names of ScanNode common counters
static const std::string _s_bytes_read_counter;
static const std::string _s_rows_read_counter;
static const std::string _s_total_throughput_counter;
static const std::string _s_num_disks_accessed_counter;
protected:
RuntimeProfile::Counter* _bytes_read_counter = nullptr; // # bytes read from the scanner
RuntimeProfile::Counter* _rows_read_counter = nullptr;
// Wall based aggregate read throughput [bytes/sec]
RuntimeProfile::Counter* _total_throughput_counter = nullptr;
RuntimeProfile::Counter* _num_disks_accessed_counter = nullptr;
};
} // namespace doris