java - 如何提高Java中的select查询性能？

Question

我正在使用 BerkeleyDB 数据库，并且正在执行需要 409 毫秒的 select 查询。如何提高select查询性能？

我正在使用以下代码:

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

public class ReadData {

Connection con=null;
ResultSet rs=null;
Statement smt = null;

public void readData() 
{
     try
     {
         Class.forName("SQLite.JDBCDriver");
         con = DriverManager.getConnection("jdbc:sqlite:/D:\\DB\\Mediation.db");
         smt = con.createStatement();

         long startTime = System.currentTimeMillis();
         rs = smt.executeQuery("select * from CDRData");             
         while(rs.next())
         {
             System.out.println(rs.getString(1)+" , "+rs.getString(2)+" , "+rs.getString(3)+" , "+rs.getString(4)+" , "+rs.getString(5)+" , "+rs.getString(6)+" , "+rs.getString(7)+" , "+rs.getString(8)+" , "+rs.getString(9)+" , "+rs.getString(10)+" , "+rs.getString(11)+" , "+rs.getString(12)+" , "+rs.getString(13)+" , "+rs.getString(14)+" , "+rs.getString(15)+" , "+rs.getString(16)+" , "+rs.getString(17)+" , "+rs.getString(18)+" , "+rs.getString(19)+" , "+rs.getString(20)+" , "+rs.getString(21)+" , "+rs.getString(22)+" , "+rs.getString(23));
         }
         long finishTime = System.currentTimeMillis();
         System.out.println("The time taken by select query : "+(finishTime-startTime)+ " ms");
     }
     catch(Exception e)
     {
         System.out.println("Error ---- "+e);
     }
}

public static void main(String[] args) {
    ReadData csvread = new ReadData();
    csvread.readData();
}
}

Answer 1

@Dhananjay Joshi 我的第一个建议是需要更改 select * 中的选择，并在执行 select * 时放置您真正需要的字段，您带来了很多字段可能您不需要并且需要更多内存