为什么会出现SQLException:数据库已锁定在JDBC SQLite数据库上?

问题描述

我有一个单线程应用程序，该应用程序在本地文件系统上的3个不同文件中使用3个SQLite数据库.

I have a single-threaded application that uses 3 SQLite databases in 3 different files on the local file system.

我创建了一个DbAdapter帮手类，该类打开了与SQLite数据库文件的连接.在此类中，我有一个创建连接的open方法和一个释放所有内容的close方法.

I have created a DbAdapter helper class that opens the connection to the SQLite database file. In this class I have an open method that creates the connection, and a close method that releases everything.

从派生DbAdapter的类访问这3个数据库.

The 3 databases are accessed from a class that derives DbAdapter.

在我的程序中，每个数据库访问都是这样的:

In my program every database access look like this:

MyDbAdapter DB = new MyDBAdapter();
int stuff = DB.getStuff(); // queries the database
DB.close();
// now do something with `stuff`

我已将所有对DbAdapter.open和DbAdapter.close的呼叫记录到stdout.每次出现open()时，附近都会出现close().
我还要小心关闭所有Statement(这也会导致关联的ResultSet也被关闭).

I have logged to stdout all calls to DbAdapter.open and DbAdapter.close. Everytime there's an open(), a close() follows close by.
I also take the care to close all my Statements (which will cause the associated ResultSets to be closed aswell).

所以我想我的数据库访问是干净的，因为我试图使它们尽可能短，并且在不再需要它们时会立即释放所有资源.

So I guess that my database accesses are clean because I'm trying to get them as short as possible, and I release all the resources as soon as I no longer need them.

但是，我仍然得到一个java.sql.SQLException: database is locked.

Yet, I'm still getting a java.sql.SQLException: database is locked.

有什么我做不正确的事情吗?我知道我没有显示任何代码，但是我必须发布很多代码，并且这将无关紧要.我只是问我是否在这里使用了最佳做法，因为我认为我已经这样做了，而且仍然有例外.

Is there anything that I'm not doing properly? I know I haven't shown any code, but I'd have to post a LOT of code and it won't be relevant. I'm just asking if I'm using the best practises here, because I think I do and I'm still getting exceptions.

这是Xerial.org的sqlite-jdbc-3.7.2驱动程序Java 1.6，在Mac OS 10.6 x64上实现的

This is with Java 1.6, Xerial.org's sqlite-jdbc-3.7.2 driver, on Mac OS 10.6 x64

推荐答案

我注意到我有无法杀死的奇怪Java进程.我跑了:

I noticed that I had strange Java processes that I couldn't kill. I ran:

ps aux | grep java | grep -v grep | awk '{print$2}' | xargs sudo kill -9

但是那些进程仍然在这里(具有相同的PID).

But those processes were still here (with same PID).

我重新启动，问题不再出现.这没有任何意义，因为我能够进行很多数据库调用而不会发生任何崩溃，只有一个调用导致了异常.我完全不了解发生了什么，但是我不再遇到这个问题.

I rebooted, and the problem doesn't appear anymore. This doesn't make sense because I was able to make a lot of DB calls without any crash, there was just one single call that caused the exception. I don't understand at ALL what happened, but I'm no longer having this issue.

任何 真实 回答欢迎.

Any real answer welcome.

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