43 lines
1.3 KiB
C++
43 lines
1.3 KiB
C++
/**
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* Copyright (c) 2021 OceanBase
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* OceanBase CE is licensed under Mulan PubL v2.
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* You can use this software according to the terms and conditions of the Mulan PubL v2.
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* You may obtain a copy of Mulan PubL v2 at:
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* http://license.coscl.org.cn/MulanPubL-2.0
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* THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
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* EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
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* MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
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* See the Mulan PubL v2 for more details.
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*/
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#include "storage/ob_i_sample_iterator.h"
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namespace oceanbase {
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using namespace common;
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namespace storage {
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ObISampleIterator::ObISampleIterator(const SampleInfo& sample_info) : sample_info_(&sample_info)
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{}
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ObISampleIterator::~ObISampleIterator()
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{
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sample_info_ = nullptr;
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}
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bool ObISampleIterator::return_this_sample(const int64_t num) const
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{
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bool bret = false;
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int64_t seed = sample_info_->seed_;
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if (seed == -1) {
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// seed is not specified, generate random seed
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seed = ObTimeUtility::current_time();
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}
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uint64_t hash_value = murmurhash(&num, sizeof(num), static_cast<uint64_t>(seed));
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uint64_t cut_off = static_cast<uint64_t>(static_cast<double>(UINT64_MAX) * sample_info_->percent_ / 100.0);
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bret = hash_value <= cut_off;
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return bret;
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}
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} // namespace storage
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} // namespace oceanbase
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