This is a native graph storage/database library implemented in C++. Main goal of this graph storage is to support streaming graph data and high performance graph operations. To cater the these requirement, We(JasmineGraph team) build this native streaming graph storage system. And with all we try to make the implementation simple as possible.
This repository contains only the C++ modules for graph storage system (core Graph store) and there is a Graph Storage system implemented using this core modules in this repository
We treat fundamental graph structural elements as first class citizens in the storage system. The Nodes/Vertices, Relations/Edges and their properties have their own storage implementations. Each of those storage engines are optimized to have low storage fragmentation and fast data insertion/retrieval.
Nodes or Vertices in the graph are stored in
<ROOT>/streamStore/nodes.db
A node should have an identifier, and in the implementation it can be any string value with not exceeding the length of a value in properties store. example for node IDs:
- e-mail address ([email protected])
- UUID (abb086aa-8010-420c-8987-a07ba185df12)
- account number (778205432131)
- and more . . .
A record in this storage has following data structure
A Node Block records is a reference holder for a node/vertex record. It has two references for Node properties and Node relations. These references are pointing to a block address in the respective Relations and Properties store.
And also, A Node Block record contains node_label attribute. But this will hold a value iff the length of the label is less than 6 characters. If it's larger than 6 characters, It gets stored in the properties store.
Both Node/Vertex properties and Relation/Edge properties are stored in
<ROOT>/streamStore/properties.db
file in binary format.
A PropertyBlock has following data structure in the disk.
A property link has a reference from a NodeBlock as below.
Following is a sample graphical view of the properties single link list.
Relations in the graph are stored in
<ROOT>/streamStore/relations.db
A Relation Block has following data structure in the disk.
Node index is a lookup table for locating node id and it's relevent block index in the nodes DB
Node index of the graph is stored in
<ROOT>/streamStore/relations.db
We have defined a NodeManager.h to integrate and manage all the above Nodes,Properties and Relation data stores. You need to initialize a NodeManager instance to do any interactions with Graph storage.
Basic implementation was inspired by the Neo4J storage architecture1. But there are some extensions and additions we have made to support handling streaming graph data.