问题描述
我正在开发一大堆应用程序（在网络上运行）并连接到常见的MySQL数据库。
这些应用程序中，大多数都涉及等待表格
1.换个新行
2.更改字段
3.按字段条件检索行
我的第一直觉是使用System.Threading.Thread（AddressOf X）创建一个线程
然后在里面有一个While True循环继续查询表然后睡了很短的时间（大约250 - 1000ms）
问题是应用程序导致系统CPU使用率上升到100％（请注意，我使用的是四核，4GB内存），内存使用率也达到100％！ br />
通常从系统运行的应用程序数量并不重要。
所以我开始认为线程可能不是答案。是不是因为不断的查询？
任何有DB观看经验的人都可以帮帮我吗？
我已经有了基于线程的应用程序。大多数都是这样的：
1. MainUI.frm将有一个Class
I am developing a whole bunch of applications (that run on a network) and connect to common MySQL DB.
Of these applications, most of them involve waiting for a table to
1. Have a new row
2. Change a field
3. Retrieve rows by a field condition
My first instinct was to create a thread using System.Threading.Thread(AddressOf X)
and then have a While True loop inside that keeps on querying the table and then sleeps for a small amount of time (around 250 - 1000ms)
The problem is that the applications cause my System CPU usage to jump to 100% (mind you, I am using a Quad Core, 4GB RAM) and memory usage to hit 100% too!
It doesn't usually matter how many of the applications are running from a system.
So I got to thinking that maybe threading is not the answer. Is it because of the constant Querying?
Could anyone experienced in DB watching please help me out?
I already have the threading based applications. Most of them are like this:
1. MainUI.frm will have a Class
TableWatcherX
2.
2.
TableWatcherX将有一个Start（）方法和一个
will have a Start() method and a
private workingThread as Thread
3.在Start（）方法中，我把
3. In the Start() method, I put
workingThread = new Thread(AddressOf KeepWorking)
workingThread.Start()
4.方法KeepWorking（）
4. In the method KeepWorking()
While True
Using ATable as <datasettable> = <datasetadapter>.getData
For each of the rows, process and do stuff...
End Using
End While</datasetadapter></datasettable>
显然出现了问题，因为我的内存和CPU完全锁定了！
有什么想法吗？
Apparently something is wrong, as I've got my memory and CPU completely locked!
Any thoughts?
推荐答案
Dim hasData as Boolean
Dim cmd as SqlCommand = new SqlCommand()
' setup your SqlCommand object to connect to your db and call the stored proc
while True
hasData = CTyle(cmd.ExecutreScalar(), Boolean)
if (hasData) Then
'query the database (using a stored procedure again)
'process ythe returned data
End If
Thread.Sleep(5000) 'sleep for 5 seconds
End While
此外，在该代码周围放置一个try / catch块并处理 ThreadAbortException 。可以使用异常，因为线程在调用 Thread.Abort 方法时中止。
Also, put a try/catch block around that code and handle the ThreadAbortException. It'ds okay to eat the exception because the thread aborts when you call the Thread.Abort method.
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