ClickHouse/dbms/Storages/tests/merge_selector.cpp
Ivan 97f2a2213e
Move all folders inside /dbms one level up (#9974)
* Move some code outside dbms/src folder
* Fix paths
2020-04-02 02:51:21 +03:00

118 lines
3.2 KiB
C++

#include <iostream>
#include <IO/ReadBufferFromFileDescriptor.h>
#include <IO/ReadHelpers.h>
#include <Storages/MergeTree/SimpleMergeSelector.h>
#include <Storages/MergeTree/LevelMergeSelector.h>
/** This program tests merge-selecting algorithm.
* Usage:
* ./merge_selector <<< "1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20"
* clickhouse-client --query="SELECT 100 + round(10 * rand() / 0xFFFFFFFF) FROM system.numbers LIMIT 105" | tr '\n' ' ' | ./merge_selector
*/
int main(int, char **)
{
using namespace DB;
IMergeSelector::Partitions partitions(1);
IMergeSelector::PartsInPartition & parts = partitions.back();
SimpleMergeSelector::Settings settings;
// settings.base = 2;
// settings.max_parts_to_merge_at_once = 10;
SimpleMergeSelector selector(settings);
/* LevelMergeSelector::Settings settings;
settings.min_parts_to_merge = 8;
settings.max_parts_to_merge = 16;
LevelMergeSelector selector(settings);*/
ReadBufferFromFileDescriptor in(STDIN_FILENO);
size_t sum_parts_size = 0;
while (!in.eof())
{
size_t size = 0;
readText(size, in);
skipWhitespaceIfAny(in);
IMergeSelector::Part part;
part.size = size;
part.age = 0;
part.level = 0;
part.data = reinterpret_cast<const void *>(parts.size());
parts.emplace_back(part);
sum_parts_size += size;
}
size_t sum_size_written = sum_parts_size;
size_t num_merges = 1;
while (parts.size() > 1)
{
IMergeSelector::PartsInPartition selected_parts = selector.select(partitions, 0);
if (selected_parts.empty())
{
std::cout << '.';
for (auto & part : parts)
++part.age;
continue;
}
std::cout << '\n';
size_t sum_merged_size = 0;
size_t start_index = 0;
size_t max_level = 0;
bool in_range = false;
for (size_t i = 0, size = parts.size(); i < size; ++i)
{
if (parts[i].data == selected_parts.front().data)
{
std::cout << "\033[1;31m";
in_range = true;
start_index = i;
}
std::cout << parts[i].size;
if (in_range)
{
sum_merged_size += parts[i].size;
if (parts[i].level > max_level)
max_level = parts[i].level;
}
if (parts[i].data == selected_parts.back().data)
{
in_range = false;
std::cout << "\033[0m";
}
std::cout << " ";
}
parts[start_index].size = sum_merged_size;
parts[start_index].level = max_level + 1;
parts[start_index].age = 0;
parts.erase(parts.begin() + start_index + 1, parts.begin() + start_index + selected_parts.size());
std::cout << '\n';
sum_size_written += sum_merged_size;
++num_merges;
}
std::cout << std::fixed << std::setprecision(2)
<< "Write amplification: " << static_cast<double>(sum_size_written) / sum_parts_size << "\n"
<< "Num merges: " << num_merges << "\n"
<< "Tree depth: " << parts.front().level << "\n"
;
return 0;
}