We have two problems:
1- Why nlohmann use huge memory to parse data
2- After call parser in a function locally like below code it does not release memory. My JSON data size is about 8MB and the parser use more then 50MB for parsing. I parsed this JSON data 10 times and memory usage goes up to 600MB and after the function is finished memory did not released.
GenerateNlohmann() {
std::string filePath{FILE_ADDRESS};
std::ifstream iFile(filePath.c_str(), std::ios::in);
std::string data{};
if (iFile.is_open()) {
data = std::string((std::istreambuf_iterator<char>(iFile)),
std::istreambuf_iterator<char>()); // About 8MB size
iFile.close();
}
if (!data.empty()) {
nlohmann::json json = nlohmann::json::parse(data); // Use memory about 50MB
std::vector<nlohmann::json> jsons{};
for (int i = 0; i < 10; ++i) {
nlohmann::json j = nlohmann::json::parse(data);
jsons.emplace_back(j);
}
while (!jsons.empty()) {
jsons.pop_back();
}
}
}
int main() {
GenerateNlohmann();
// Now memory usage is about 600MB
std::cout << "Input a numberto exit" << std::endl;
int i;
std::cin >> i;
return 0;
}
Our platform is Ubuntu 18.04, CMake 3.15.3, g++ 7.4.0
We have two problems:
1- Why nlohmann use huge memory to parse data
2- After call parser in a function locally like below code it does not release memory. My JSON data size is about 8MB and the parser use more then 50MB for parsing. I parsed this JSON data 10 times and memory usage goes up to 600MB and after the function is finished memory did not released.
Our platform is Ubuntu 18.04, CMake 3.15.3, g++ 7.4.0