Ti-Client in Java [Under Construction]

A Java client for TiDB/TiKV. It is supposed to:

• Communicate via gRPC
• Talk to Placement Driver searching for a region
• Talk to TiKV for reading/writing data and the resulted data is encoded/decoded just like what we do in TiDB.
• Talk to Coprocessor for calculation pushdown

How to build

The alternative way to build a usable jar for testing will be

mvn clean install -Dmaven.test.skip=true

The following command can install dependencies for you.

mvn package

Alternatively, you can use bazel for much faster build. When you try this approach, you should run git submodule update --init --recursive before you build project.

Making a uber jar:

make uber_jar

run Main class:

make run

run test cases:

make test

this project is designed to hook with pd and tikv which you can find in PingCap github page.

When you work with this project, you have to communicate with pd and tikv. There is a script taking care of this. By executing the following commands, pd and tikv can be executed on background.

cd scripts
make pd
make tikv

How to use for now

Since it's not quite complete, a usage sample for now can be given is:

// Init tidb cluster configuration
TiConfiguration conf = TiConfiguration.createDefault("127.0.0.1:2379");
TiSession session = TiSession.create(conf);
Catalog cat = session.getCatalog();
TiDBInfo db = cat.getDatabase("tpch_test");
TiTableInfo table = cat.getTable(db, "customer");
Snapshot snapshot = session.createSnapshot();
 
// Generate select ranges
ByteString startKey = TableCodec.encodeRowKeyWithHandle(table.getId(), Long.MIN_VALUE);
ByteString endKey = TableCodec.encodeRowKeyWithHandle(table.getId(), Long.MAX_VALUE);
Coprocessor.KeyRange keyRange = Coprocessor.KeyRange.newBuilder().setStart(startKey).setEnd(endKey).build();
List<Coprocessor.KeyRange> ranges = new ArrayList<>();
ranges.add(keyRange);

 
// Create select request
TiSelectRequest selectRequest = new TiSelectRequest();
selectRequest.addRanges(ranges);
selectRequest.addField(TiColumnRef.create("c_mktsegment", table));
selectRequest.setTableInfo(table);
selectRequest.setStartTs(session.getTimestamp().getVersion());
selectRequest.addWhere(new GreaterEqual(TiConstant.create(5), TiConstant.create(5)));
selectRequest.addGroupByItem(TiByItem.create(TiColumnRef.create("c_mktsegment"), false));
selectRequest.setLimit(10);
selectRequest.bind();
 
// Fetch data
Iterator<Row> iterator = snapshot.select(selectRequest);
System.out.println("Show result:");
while (iterator.hasNext()) {
  Row rowData = iterator.next();
  for (int i = 0; i < rowData.fieldCount(); i++) {
    System.out.print(rowData.get(i, null) + "\t");
  }
  System.out.println();
}

Result:

Show result:
BUILDING	
AUTOMOBILE	
MACHINERY	
HOUSEHOLD	
FURNITURE	

Raw TiKV-Client in Java

Java Implementation of Raw TiKV-Client

Demo is avaliable in KVRawClientTest

Build

mvn clean install -Dmaven.test.skip=true

Use as maven dependency

After building, add following lines into your pom.xml

<dependency>
    <groupId>com.pingcap.tikv</groupId>
    <artifactId>tikv-client-java</artifactId>
    <version>2.0-SNAPSHOT</version>
</dependency>

Entrance

com.pingcap.tikv.RawKVClient

API

  /**
   * create a RawKVClient using specific pd addresses
   *
   * @param address pd addresses(comma seperated)
   */
  static RawKVClient create(String address)

  /**
   * Put a raw key-value pair to TiKV
   *
   * @param key raw key
   * @param value raw value
   */
   void put(ByteString key, ByteString value)

  /**
   * Get a raw key-value pair from TiKV if key exists
   *
   * @param key raw key
   * @return a ByteString value if key exists, ByteString.EMPTY if key does not exist
   */
  ByteString get(ByteString key)

  /**
   * Scan raw key-value pairs from TiKV in range [startKey, endKey)
   *
   * @param startKey raw start key, inclusive
   * @param endKey raw end key, exclusive
   * @return list of key-value pairs in range
   */
  List<Kvrpcpb.KvPair> scan(ByteString startKey, ByteString endKey)

  /**
   * Scan raw key-value pairs from TiKV in range [startKey, endKey)
   *
   * @param startKey raw start key, inclusive
   * @param limit limit of key-value pairs
   * @return list of key-value pairs in range
   */
  List<Kvrpcpb.KvPair> scan(ByteString startKey, int limit)

  /**
   * Delete a raw key-value pair from TiKV if key exists
   *
   * @param key raw key to be deleted
   */ 
  void delete(ByteString key) 

TODO

Contributions are welcomed. Here is a TODO and you might contact maxiaoyu@pingcap.com if needed.

License

Apache 2.0 license. See the LICENSE file for details.