4

我有一个运行多个线程的绑定服务，这些线程可以读取和写入 SQLite 数据库。我创建了我的数据库助手的一个实例，并在我的服务的 onCreate 中获得了与数据库的连接，该连接应该在主线程上执行。由于它是一项绑定服务，因此内存中应该只有一个服务实例。但是，当服务尝试打开数据库或其中一个线程尝试执行语句时，我仍然偶尔会遇到异常。

服务代码：

@Override
    public void onCreate() {
        super.onCreate();

        MyDatabaseHelper helper = new MyDatabaseHelper(this);
        database = helper.getWritableDatabase();
}

例外：

java.lang.RuntimeException: Unable to create service uk.co.example.service.MyService: 
   android.database.sqlite.SQLiteException: unable to open database file
at android.app.ActivityThread.handleCreateService(ActivityThread.java:1959)
at android.app.ActivityThread.access$2500(ActivityThread.java:117)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:989)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:123)
at android.app.ActivityThread.main(ActivityThread.java:3691)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:507)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:847)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:605)
at dalvik.system.NativeStart.main(Native Method)
Caused by: android.database.sqlite.SQLiteException: unable to open database file
at android.database.sqlite.SQLiteDatabase.dbopen(Native Method)
at android.database.sqlite.SQLiteDatabase.<init>(SQLiteDatabase.java:1960)
at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:887)
at android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:965)
at android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:958)
at android.app.ContextImpl.openOrCreateDatabase(ContextImpl.java:585)
at android.content.ContextWrapper.openOrCreateDatabase(ContextWrapper.java:203)
at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:118)
at uk.co.example.service.MyService.onCreate(MyService.java:69)
at android.app.ActivityThread.handleCreateService(ActivityThread.java:1949)
... 10 more

android.database.sqlite.SQLiteException: error code 5: database is locked
at android.database.sqlite.SQLiteStatement.native_execute(Native Method)
at android.database.sqlite.SQLiteStatement.execute(SQLiteStatement.java:61)
at uk.co.example.a.a.a.a(MyTable.java:147)
at uk.co.example.service.b.a.m.run(MySaveTask.java:84)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1088)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:581)
at java.lang.Thread.run(Thread.java:1019)

有什么想法可能导致这种情况吗？

谢谢

大卫

4

1 回答 1

0

Sqlite 现在支持一种名为 Writing-Ahead Logging 的新日志模式，适用于对 sqlite 的并发访问。你可能想看看http://www.sqlite.org/wal.html。

于 2013-10-29T14:30:47.047 回答