THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
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select max_value(s0) from root.sg1.d1 where s0<0 group by ([1, 10000000), 1000ms)
实验结果
如上表所示，可以发现，在进行原始数据查询和聚合查询时，当选择率较低的场景下，查询执行时间有明显的提升，选择率大于50%的场景下与原有时间持平。groupby查询时与原有时间持平。如上表所示，可以发现，在进行原始数据查询和聚合查询时，当选择率较低的场景下，查询执行时间有明显的提升，选择率大于50%以及groupby查询的场景下与原有时间持平。
实验代码
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import org.apache.iotdb.jdbc.IoTDBSQLException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class JDBCQuery {
public static void main(String[] args) throws ClassNotFoundException, SQLException {
Class.forName("org.apache.iotdb.jdbc.IoTDBDriver");
try (Connection connection =
DriverManager.getConnection("jdbc:iotdb://127.0.0.1:6667/", "root", "root");
Statement statement = connection.createStatement()) {
String sql = "select s0 from root.sg1.d1 where s0<0";
System.out.println(sql);
long startTime=System.currentTimeMillis();
ResultSet resultSet = statement.executeQuery(sql);
outputResult(resultSet);
long endTime=System.currentTimeMillis();
System.out.println("time： "+(endTime-startTime)+"ms");
} catch (IoTDBSQLException e) {
System.out.println(e.getMessage());
}
}
private static void outputResult(ResultSet resultSet) throws SQLException {
if (resultSet != null) {
System.out.println("--------------------------");
System.out.println();
while (resultSet.next()) {
}
}
System.out.println("--------------------------\n");
}
}
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