我正在使用BerkeleyDB数据库,并且正在执行需要409毫秒的select
查询。如何提高选择查询的性能?
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();
}
}
最佳答案
@Dhananjay Joshi我的第一个建议是需要更改select *
的选择,并在执行select *
时放置您真正需要的字段,从而带来很多可能不需要的字段,并且需要更多的内存
关于java - 如何提高Java中的选择查询性能?,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/6441499/