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Posted to commits@doris.apache.org by GitBox <gi...@apache.org> on 2021/08/12 07:53:15 UTC
[GitHub] [incubator-doris] HappenLee commented on a change in pull request #6410: [Feature] Support exact percentile aggregate function
HappenLee commented on a change in pull request #6410:
URL: https://github.com/apache/incubator-doris/pull/6410#discussion_r687472932
##########
File path: be/src/util/counts.h
##########
@@ -0,0 +1,128 @@
+// 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.
+
+#ifndef DORIS_BE_SRC_UTIL_COUNTS_H_
+#define DORIS_BE_SRC_UTIL_COUNTS_H_
+
+#include <map>
+#include <cmath>
+#include "udf/udf.h"
+
+namespace doris {
+
+class Counts {
+public:
+ Counts() = default;
+
+ inline void merge(const Counts* other) {
+ if (other == nullptr || other->_counts.empty()) {
+ return;
+ }
+
+ for (auto& cell : other->_counts) {
+ increment(cell.first, cell.second);
+ }
+ }
+
+ void increment(int64_t key, int i) {
+ auto item = _counts.find(key);
+ if (item != _counts.end()) {
+ item->second += i;
+ } else {
+ _counts.emplace(std::make_pair(key, i));
+ }
+ }
+
+ uint32_t serialized_size() {
+ return sizeof(uint32_t) + sizeof(int64_t) * _counts.size() + sizeof(int) * _counts.size();
+ }
+
+ void serialize(uint8_t* writer) {
+ uint32_t size = _counts.size();
+ memcpy(writer, &size, sizeof(uint32_t));
+ writer += sizeof(uint32_t);
+ for (auto& cell : _counts) {
+ memcpy(writer, &cell.first, sizeof(int64_t));
+ writer += sizeof(int64_t);
+ memcpy(writer, &cell.second, sizeof(int));
+ writer += sizeof(int);
+ }
+ }
+
+ void unserialize(const uint8_t* type_reader) {
+ uint32_t size;
+ memcpy(&size, type_reader, sizeof(uint32_t));
+ type_reader += sizeof(uint32_t);
+ for (uint32_t i = 0; i < size; ++i) {
+ int64_t key;
+ int count;
+ memcpy(&key, type_reader, sizeof(int64_t));
+ type_reader += sizeof(int64_t);
+ memcpy(&count, type_reader, sizeof(int));
+ type_reader += sizeof(int);
+ _counts.emplace(std::make_pair(key, count));
+ }
+ }
+
+ double get_percentile(std::map<int64_t, int>& copy_counts, double position) {
+ long lower = std::floor(position);
+ long higher = std::ceil(position);
+
+ auto iter = copy_counts.begin();
+ for (; iter != copy_counts.end() && iter->second < lower + 1; ++iter);
+
+ int64_t lower_key = iter->first;
+ if (higher == lower) {
+ return lower_key;
+ }
+
+ if (iter->second < higher + 1) {
+ iter++;
+ }
+
+ int64_t higher_key = iter->first;
Review comment:
code format
##########
File path: be/src/util/counts.h
##########
@@ -0,0 +1,128 @@
+// 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.
+
+#ifndef DORIS_BE_SRC_UTIL_COUNTS_H_
+#define DORIS_BE_SRC_UTIL_COUNTS_H_
+
+#include <map>
+#include <cmath>
+#include "udf/udf.h"
+
+namespace doris {
+
+class Counts {
+public:
+ Counts() = default;
+
+ inline void merge(const Counts* other) {
+ if (other == nullptr || other->_counts.empty()) {
+ return;
+ }
+
+ for (auto& cell : other->_counts) {
+ increment(cell.first, cell.second);
+ }
+ }
+
+ void increment(int64_t key, int i) {
+ auto item = _counts.find(key);
+ if (item != _counts.end()) {
+ item->second += i;
+ } else {
+ _counts.emplace(std::make_pair(key, i));
+ }
+ }
+
+ uint32_t serialized_size() {
+ return sizeof(uint32_t) + sizeof(int64_t) * _counts.size() + sizeof(int) * _counts.size();
+ }
+
+ void serialize(uint8_t* writer) {
+ uint32_t size = _counts.size();
+ memcpy(writer, &size, sizeof(uint32_t));
+ writer += sizeof(uint32_t);
+ for (auto& cell : _counts) {
+ memcpy(writer, &cell.first, sizeof(int64_t));
+ writer += sizeof(int64_t);
+ memcpy(writer, &cell.second, sizeof(int));
+ writer += sizeof(int);
+ }
+ }
+
+ void unserialize(const uint8_t* type_reader) {
+ uint32_t size;
+ memcpy(&size, type_reader, sizeof(uint32_t));
+ type_reader += sizeof(uint32_t);
+ for (uint32_t i = 0; i < size; ++i) {
+ int64_t key;
+ int count;
+ memcpy(&key, type_reader, sizeof(int64_t));
+ type_reader += sizeof(int64_t);
+ memcpy(&count, type_reader, sizeof(int));
+ type_reader += sizeof(int);
+ _counts.emplace(std::make_pair(key, count));
+ }
+ }
+
+ double get_percentile(std::map<int64_t, int>& copy_counts, double position) {
+ long lower = std::floor(position);
+ long higher = std::ceil(position);
+
+ auto iter = copy_counts.begin();
+ for (; iter != copy_counts.end() && iter->second < lower + 1; ++iter);
+
+ int64_t lower_key = iter->first;
+ if (higher == lower) {
+ return lower_key;
+ }
+
+ if (iter->second < higher + 1) {
+ iter++;
+ }
+
+ int64_t higher_key = iter->first;
+ if (lower_key == higher_key) {
+ return lower_key;
+ }
+
+ return (higher - position) * lower_key + (position - lower) * higher_key;
+ }
+
+ doris_udf::DoubleVal terminate(double quantile) {
+ if (_counts.empty()) {
+ return doris_udf::DoubleVal();
+ }
+
+ std::map<int64_t, int> copy_counts(_counts);
+ long total = 0;
+ for (auto& cell : copy_counts) {
+ total += cell.second;
+ cell.second = total;
+ }
+
+ long max_position = total - 1;
+ double position = max_position * quantile;
+ return doris_udf::DoubleVal(get_percentile(copy_counts, position));
+ }
+
+private:
+ std::map<int64_t, int> _counts;
Review comment:
It doesn't look like there will be a negative number here, so you should use uint32_t instead of int
##########
File path: be/src/exprs/aggregate_functions.cpp
##########
@@ -172,6 +173,79 @@ void AggregateFunctions::count_remove(FunctionContext*, const AnyVal& src, BigIn
}
}
+struct PercentileState {
+ PercentileState() : counts(new Counts()) {}
+ ~PercentileState() { delete counts; }
+
+ Counts* counts = nullptr;
Review comment:
Why can't it be a member variable here, instead it needs to be a pointer
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