Levin - A Quick Way to Bulk Loading

Description

Levin provides a highly efficient solution in bulk loading scenario. A collection of STL-like containers are implemented with high performance and memory efficiency. Levin containers arrange memory layout SEQUENTIALLY, allocated at share memory region for inter-process reuse. In which case, we can extend the lifetime of data resources, and prevent unnecessary time-consuming reload.

Loading with levin is fast, let's get started.

Getting Started

Brief Intro for Levin Container

STD Container	Levin Container	Notes	Suggestion
vector<T>	SharedVector<T>	T is POD type
set<K, Compare>	SharedSet<K, Compare>	K is POD type	use SharedHashSet if no comparison
map<K, V, Compare>	SharedMap<K, V, Compare>	K/V is POD type	use SharedHashMap if no comparison
unordered_set<K, Hash, Pred>	SharedHashSet<K, Hash, Pred>	K is POD type
unordered_map<K, V, Hash, Pred>	SharedHashMap<K, V, Hash>	K/V is POD type
vector<vector<T> >	SharedNestedVector<T, SizeType>	T is POD type; SizeType is unsigned integral type	specified SizeType for memory space efficiency
unordered_map<K, vector<V> >	SharedNestedHashMap<K, V>	K/V is POD type
vector<map<K, V, Compare> >	SharedNestedMap<K, V, Compare, SizeType>	K/V is POD type; SizeType is unsigned integral type

How to Dump Container Data to A File

// vector dump demo
std::vector<int> vec_data = {1, 2, 3, 4, 5};
levin::SharedVector<int>::Dump("./vec_demo.dat", vec_data);

// map/hashmap dump demo
std::unordered_map<int64_t, int32_t> map_data = { {1, 100}, {2, 200}, {3, 300} };
// or std::map<int64_t, int32_t> map_data = { {1, 100}, {2, 200}, {3, 300} };
levin::SharedHashMap<int64_t, int32_t>::Dump("./map_demo.dat", map_data);

How to Use Container

Tips: Levin container SHOULD be immutable, NOT suggest to modify or reallocate.

// shared vector use demo
levin::SharedVector<int> vec("./vec_demo.dat");
if (vec.Init() == levin::SC_RET_OK && vec.Load() == levin::SC_RET_OK) {
    ...
}
vec.Destroy();

// shared hashmap use demo
auto map_ptr = new levin::SharedHashMap<int64_t, int32_t>("./map_demo.dat");
if (map_ptr->Init() == levin::SC_RET_OK && map_ptr->Load() == levin::SC_RET_OK) {
    ...
}
map_ptr->Destroy();
delete map_ptr;

How to Manage a set of Containers

example code of container manager usage

Dependencies

Levin depends on following packages, required deps:

gcc >= 4.8.5
cmake >= 2.6.0
boost >= 1.56.0
openssl
gtest

Compile

create directory build, cd build
compile: cmake .. && make

Documentation

About the details, please see Wiki.

Contributing

Welcome to contribute by creating issues or sending pull requests. See Contributing Guide for guidelines.

Communication

License

Levin is licensed under the Apache License 2.0. See the LICENSE file.

didi/levin