AccumuloGraph

This is an implementation of the TinkerPop Blueprints 2.6 API using Apache Accumulo as the backend. This implementation provides easy to use, easy to write, and easy to read access to an arbitrarily large graph that is stored in Accumulo.

We implement the following Blueprints interfaces:
1. Graph
2. KeyIndexableGraph
3. IndexableGraph

Please feel free to submit issues for any bugs you find or features you want. We are open to pull requests from your forks also.

##Usage

The releases are currently stored in Maven Central.

<dependency>
	<groupId>edu.jhuapl.tinkerpop</groupId>
	<artifactId>blueprints-accumulo-graph</artifactId>
	<version>0.0.2</version>
</dependency>

For non-Maven users, the binaries can be found in the releases section in this GitHub repository, or you can get them from Maven Central. ##Code Examples ###Creating a new or connecting to an existing distributed graph

Configuration cfg = new AccumuloGraphConfiguration()
	.setInstanceName("accumulo").setUser("user").setZookeeperHosts("zk1")
    .setPassword("password".getBytes()).setGraphName("myGraph");
Graph graph = GraphFactory.open(cfg.getConfiguration());

###Creating a new Mock Graph

Setting the instance type to mock allows for in-memory processing with a MockAccumulo instance.
There is also support for Mini Accumulo.

Configuration cfg = new AccumuloGraphConfiguration().setInstanceType(InstanceType.Mock)
	.setGraphName("myGraph");
Graph graph = GraphFactory.open(cfg);

###Accessing a graph

Vertex v1 = graph.addVertex("1");
v1.setProperty("name", "Alice");
Vertex v2 = graph.addVertex("2");
v2.setProperty("name", "Bob");

Edge e1 = graph.addEdge("E1", v1, v2, "knows");
e1.setProperty("since", new Date());

###Creating indexes

((KeyIndexableGraph)graph)
	.createKeyIndex("name", Vertex.class);

###MapReduce Integration

####In the tool

AccumuloConfiguration cfg = new AccumuloGraphConfiguration()
	.setInstanceName("accumulo").setZookeeperHosts("zk1").setUser("root")
	.setPassword("secret".getBytes()).setGraphName("myGraph");

Job j = new Job();
j.setInputFormatClass(VertexInputFormat.class);
VertexInputFormat.setAccumuloGraphConfiguration(j,
	cfg.getConfiguration());

####In the mapper

public void map(Text k, Vertex v, Context c) {
    System.out.println(v.getId().toString());
}

##Table Design ###Vertex Table

Row ID	Column Family	Column Qualifier	Value
VertexID	Label Flag	Exists Flag	[empty]
VertexID	INVERTEX	OutVertexID_EdgeID	Edge Label
VertexID	OUTVERTEX	InVertexID_EdgeID	Edge Label
VertexID	Property Key	[empty]	Serialized Value
###Edge Table
Row ID	Column Family	Column Qualifier	Value
---	---	---	---
EdgeID	Label Flag	InVertexID_OutVertexID	Edge Label
EdgeID	Property Key	[empty]	Serialized Value
###Edge/Vertex Index
Row ID	Column Family	Column Qualifier	Value
---	---	---	---
Serialized Value	Property Key	VertexID/EdgeID	[empty]

###Metadata Table

Row ID	Column Family	Column Qualifier	Value
Index Name	Index Class	[empty]	[empty]
##Advanced Configuration
###Graph Configuration

• setGraphName(String name)
• setCreate(boolean create) - Sets if the backing graph tables should be created if they do not exist.
• setClear(boolean clear) - Sets if the backing graph tables should be reset if they exist.
• autoFlush(boolean autoFlush) - Sets if each graph element and property change will be flushed to the server.
• skipExistenceChecks(boolean skip) - Sets if you want to skip existance checks when creating graph elemenets.
• setAutoIndex(boolean ison) - Turns on/off automatic indexing.

###Accumulo Control

• setUser(String user) - Sets the user to use when connecting to Accumulo
• setPassword(byte[] password | String password) - Sets the password to use when connecting to Accumulo
• setZookeeperHosts(String zookeeperHosts) - Sets the Zookeepers to connect to.
• setInstanceName(String instance) - Sets the Instance name to use when connecting to Zookeeper
• setInstanceType(InstanceType type) - Sets the type of Instance to use : Distrubuted, Mini, or Mock. Defaults to Distrubuted
• setQueryThreads(int threads) - Specifies the number of threads to use in scanners. Defaults to 3
• setMaxWriteLatency(long latency) - Sets the latency to be used for all writes to Accumulo
• setMaxWriteTimeout(long timeout) - Sets the timeout to be used for all writes to Accumulo
• setMaxWriteMemory(long mem) - Sets the memory buffer to be used for all writes to Accumulo
• setMaxWriteThreads(int threads) - Sets the number of threads to be used for all writes to Accumulo
• setAuthorizations(Authorizations auths) - Sets the authorizations to use when accessing the graph
• setColumnVisibility(ColumnVisibility colVis) - TODO
• setSplits(String splits | String[] splits) - Sets the splits to use when creating tables. Can be a space sperated list or an array of splits
• setMiniClusterTempDir(String dir) - Sets directory to use as the temp directory for the Mini cluster

###Caching

• setLruMaxCapacity(int max) - TODO
• setVertexCacheTimeout(int millis) - Sets the vertex cache timeout. A value <=0 clears the value
• setEdgeCacheTimeout(int millis) - Sets the edge cache timeout. A value <=0 clears the value

###Preloading

• setPropertyCacheTimeout(int millis) - Sets the element property cache timeout. A value <=0 clears the value
• setPreloadedProperties(String[] propertyKeys) - Sets the property keys that should be preloaded. Requiers a positive timout.
• setPreloadedEdgeLabels(String[] edgeLabels) - TODO