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 push down

How to build

The following command can install dependencies for you.

mvn package

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

It is not recommended to use tikv java client directly; it is better to use together with TiSpark

// Init tidb cluster configuration
TiConfiguration conf = TiConfiguration.createDefault("127.0.0.1:2379");
TiSession session = TiSession.getInstance(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
TiDAGRequest dagRequest = new TiDAGRequest();
dagRequest.addRanges(ranges);
dagRequest.addField(TiColumnRef.create("c_mktsegment", table));
dagRequest.setTableInfo(table);
dagRequest.setStartTs(session.getTimestamp().getVersion());
dagRequest.addWhere(new GreaterEqual(TiConstant.create(5), TiConstant.create(5)));
dagRequest.addGroupByItem(TiByItem.create(TiColumnRef.create("c_mktsegment"), false));
dagRequest.setLimit(10);
dagRequest.resolve();
 
// Fetch data
Iterator<Row> iterator = snapshot.tableRead(dagRequest, table.getId());
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	

TODO

Contributions are welcomed. Here is a TODO and you might contact [email protected] if needed.

License

Apache 2.0 license. See the LICENSE file for details.