Apache Drill目前不支持在Kudu表上执行范围和哈希多级分区查询。但是,您可以通过编写自定义函数来实现此功能。下面是一个示例代码,展示了如何在Apache Drill中执行范围查询和哈希多级分区:
import org.apache.drill.exec.expr.holders.VarCharHolder;
import org.apache.drill.exec.expr.holders.NullableVarCharHolder;
import io.netty.buffer.DrillBuf;
import org.apache.drill.exec.expr.annotations.Param;
import org.apache.drill.exec.expr.annotations.FunctionTemplate;
import org.apache.drill.exec.expr.annotations.Output;
import org.apache.drill.exec.expr.annotations.Workspace;
import org.apache.drill.exec.expr.annotations.FunctionTemplate.FunctionScope;
import org.apache.drill.exec.expr.annotations.FunctionTemplate.NullHandling;
import javax.inject.Inject;
@FunctionTemplate(name = "kudu_range_query", scope = FunctionScope.SIMPLE, nulls = NullHandling.NULL_IF_NULL)
public class KuduRangeQueryFunction {
@Inject
DrillBuf buffer;
@Param
VarCharHolder startKey;
@Param
VarCharHolder endKey;
@Output
NullableVarCharHolder out;
public void setup() {}
public void eval() {
byte[] start = new byte[startKey.end - startKey.start];
buffer.getBytes(startKey.start, start, 0, startKey.end - startKey.start);
byte[] end = new byte[endKey.end - endKey.start];
buffer.getBytes(endKey.start, end, 0, endKey.end - endKey.start);
// TODO: Implement the logic to perform range query on Kudu table
// ...
// Set the output value
out.isSet = 1;
byte[] result = "Range query result".getBytes();
out.buffer = buffer;
out.start = 0;
out.end = result.length;
buffer.setBytes(0, result);
}
}
$ javac -cp KuduFunctions.java
{
"name": "kudu_functions",
"functions": [
{
"name": "kudu_range_query",
"params": [
{
"name": "startKey",
"type": "VARCHAR"
},
{
"name": "endKey",
"type": "VARCHAR"
}
],
"return": {
"type": "VARCHAR"
},
"deterministic": true,
"class": "com.example.KuduRangeQueryFunction"
}
]
}
0: jdbc:drill:zk=local> ALTER SESSION SET `planner.enable_decimal_data_type` = true;
0: jdbc:drill:zk=local> CREATE FUNCTION kudu_range_query(VARCHAR, VARCHAR) RETURNS VARCHAR
-> CLASSPATH 'path_to_compiled_class/KuduFunctions.jar' USING JAR;
0: jdbc:drill:zk=local> ALTER SESSION SET `store.hive.plugin.kudu.partitioning.deprecated` = true;
0: jdbc:drill:zk=local> SELECT kudu_range_query('start_key', 'end_key') FROM my_kudu_table;
请注意,这只是一个示例代码,您需要根据您的实际业务逻辑来实现自定义函数。同时,您还可以根据需要添加其他函数和逻辑。