try {
final Connection connection =
DriverManager.getConnection(url,username,password);
final AtomicInteger start = new AtomicInteger(0);
final AtomicInteger preFix = new AtomicInteger(201401);
final int perCount = 1000;
ScheduledExecutorService service = Executors.newScheduledThreadPool(3);
service.scheduleWithFixedDelay(new Runnable() {
@Override
public void run() {
String sql = "select id,class,function,remark,add_time from ";
sql += "table_";
sql += preFix.get();
sql += " order by id limit ";
sql += start.get();
sql += ",";
sql += perCount;
ResultSet resultSet = null;
List<Email> emailList = new ArrayList<Email>();
try{
PreparedStatement preparedStatement = connection.prepareStatement(sql);
resultSet = preparedStatement.executeQuery();
while (resultSet.next()){
Email email = new Email();
long id = resultSet.getLong("id");
email.setId(id + "");
String userEmail = resultSet.getString("class");
email.setUserEmail(userEmail);
String subject = resultSet.getString("function");
email.setSubject(subject);
String content = resultSet.getString("remark");
email.setContent(content);
long addTime = resultSet.getLong("add_time");
email.setAddDate(addTime);
emailList.add(email);
}
}catch (Exception e){
e.printStackTrace();
}
// List<Email> emailList = emailDao.getEmailList(start.get(),perCount);
List<Order> studentList = new ArrayList<Order>();
if(null != emailList && emailList.size() > 0){
System.out.println("emailList size:" + emailList.size());
for(Email email:emailList){
if(email.getSend() == 1){
Order order = new Order();
order.setOrderId(Integer.valueOf(email.getId()));
String content = new String(email.getContent());
order.setOrderSign(content + "verygood");
studentList.add(order);
}
}
start.set(start.get() + perCount);
}else{//another table
int n = preFix.getAndIncrement();
System.out.println("useing table:" + n);
if(n == 201412){
preFix.set(201401);
}
start.set(0);
}
if(null != studentList){
studentList.clear();
studentList = null;
}
}
},0,200, TimeUnit.MILLISECONDS);
} catch (SQLException e) {
e.printStackTrace();
}
above is my program,when use jvm_option "-server -Xmx50m -Xms50m" the program work well,but when reduce the memory like this "-server -Xmx10m -Xms10m" ,after a seconds program stoped work,and jvm is not doing gc. use command:jstat -gcutil 4116 2s
result is: ![enter image description here][1]
S0 S1 E O P YGC YGCT FGC FGCT GCT
0.00 0.00 12.72 34.90 55.08 36 0.117 36 0.666 0.783
0.00 0.00 12.72 34.90 55.08 36 0.117 36 0.666 0.783
0.00 0.00 12.72 34.90 55.08 36 0.117 36 0.666 0.783
i want know why
