小编Dha*_*shi的帖子

可能重复:
如何增加JVM内存？

我收到以下错误:

Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
        at SQLite.Vm.step(Native Method)
        at SQLite.Database.get_table(Database.java:314)
        at SQLite.JDBC2z.JDBCStatement.executeQuery(JDBCStatement.java:120)
        at SQLite.JDBC2z.JDBCStatement.executeQuery(JDBCStatement.java:168)
        at TestData.readData(TestData.java:21)
        at TestData.main(TestData.java:41)

我正在使用BerkeleyDB数据库,我正在执行select需要409毫秒的查询.如何提高选择查询性能？

我使用以下代码:

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)+" …