java - 使用 CSV 使用 Calcite 创建流式传输示例

Question

我正在尝试使用 Calcite 创建一个基本的流程序，使用 CSV 作为数据源。我可以使用 sqlline 运行查询，但无法以编程方式执行此操作。我的代码是:

示例.json

{
  version: '1.0',
  defaultSchema: 'STREAM',
  schemas: [
    {
      name: 'SS',
      tables: [
        {
          name: 'ORDERS',
          type: 'custom',
          factory: 'org.apache.calcite.adapter.csv.CsvStreamTableFactory',
          stream: {
            stream: true
          },
          operand: {
            file: 'sales/SORDERS.csv',
            flavor: "scannable"
          }
        }
      ]
    }
  ]
}

SORDERS.csv

PRODUCTID:int,ORDERID:int,UNITS:int
3,4,5
2,5,12
2,1,6

SimpleQuery.java

package stream_test;

import org.apache.calcite.adapter.java.ReflectiveSchema;
import org.apache.calcite.jdbc.CalciteConnection;
import org.apache.calcite.schema.SchemaPlus;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

/**
 * Example of using Calcite via JDBC.
 *
 * <p>Schema is specified programmatically.</p>
 */
public class SimpleQuery {
  public static void main(String[] args) throws Exception {
    new SimpleQuery().run();
  }

  public void run() throws ClassNotFoundException, SQLException {
    Class.forName("org.apache.calcite.jdbc.Driver");
    Properties info = new Properties();
    info.setProperty("lex", "JAVA");
    Connection connection =
        DriverManager.getConnection("jdbc:calcite:model="
                + "/home/hduser/Downloads/calcite-master/example/csv/target/test-classes/example.json",info);
    CalciteConnection calciteConnection =
        connection.unwrap(CalciteConnection.class);
    //SchemaPlus rootSchema = calciteConnection.getRootSchema();
    //rootSchema.add("os", new ReflectiveSchema(new Os()));
    Statement statement = connection.createStatement();
    ResultSet resultSet =
            statement.executeQuery("select stream * from SS.ORDERS where SS.ORDERS.UNITS > 5");
    final StringBuilder buf = new StringBuilder();
    while (resultSet.next()) {
      int n = resultSet.getMetaData().getColumnCount();
      for (int i = 1; i <= n; i++) {
        buf.append(i > 1 ? "; " : "")
            .append(resultSet.getMetaData().getColumnLabel(i))
            .append("=")
            .append(resultSet.getObject(i));
      }
      System.out.println(buf.toString());
      buf.setLength(0);
    }
    resultSet.close();
    statement.close();
    connection.close();
  }

}

最后我有 calcite-core 1.8.0、net.sf.opencsv 2.3、calcite-avatica 1.6.0、calcite-linq4j 1.8.0、sqlline 1.1.9、hamcrest-core 1.3、com.github.stephenc.jcip 1.0-1、commons-lang3 3.4、guava 19.0 的依赖项并导入了 calcite-example-csv-1.9.0-SNAPSHOT (我从 github 版本用 maven 打包)。

当我尝试运行代码时，我得到:

Exception in thread "main" java.lang.NoSuchFieldError: CANCEL_FLAG
    at org.apache.calcite.adapter.csv.CsvStreamScannableTable.scan(CsvStreamScannableTable.java:66)
    at org.apache.calcite.interpreter.TableScanNode.createScannable(TableScanNode.java:117)
    at org.apache.calcite.interpreter.TableScanNode.create(TableScanNode.java:94)
    at org.apache.calcite.interpreter.Nodes$CoreCompiler.visit(Nodes.java:68)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.apache.calcite.util.ReflectUtil.invokeVisitorInternal(ReflectUtil.java:257)
    at org.apache.calcite.util.ReflectUtil.invokeVisitor(ReflectUtil.java:214)
    at org.apache.calcite.util.ReflectUtil$1.invokeVisitor(ReflectUtil.java:471)
    at org.apache.calcite.interpreter.Interpreter$Compiler.visit(Interpreter.java:476)
    at org.apache.calcite.interpreter.Interpreter$Compiler.visitRoot(Interpreter.java:433)
    at org.apache.calcite.interpreter.Interpreter.<init>(Interpreter.java:75)
    at Baz.bind(Unknown Source)
    at org.apache.calcite.jdbc.CalcitePrepare$CalciteSignature.enumerable(CalcitePrepare.java:327)
    at org.apache.calcite.jdbc.CalciteConnectionImpl.enumerable(CalciteConnectionImpl.java:282)
    at     package stream_test;

关于如何修复它有什么想法吗？

Answer 1

您的库不匹配(calcite-example-csv 版本 1.9.0-SNAPSHOT，与 calcite-core 版本 1.8.0)。请参阅the discussion on calcite dev list了解更多详情。