设置sqlite配置SQLITE_CONFIG_SERIALIZED在iOS 5上返回SQLITE_MISUSE

Question

随着iOS 5的发布,我们在为sqlite数据库设置序列化选项时会遇到越来越多的错误(因此将其保存用于多线程).我们在sqlite3_config上收到SQLITE_MISUSE错误代码.有人注意到这种奇怪的行为吗？有人知道如何解决这个问题吗？它在之前的iOS版本上运行得非常好.

这是代码:

- (sqlite3 *)getNewDBConnection {
    NSLog(@"sqlite3 lib version: %s", sqlite3_libversion());

    //sqlite3_config() has to be called before any sqlite3_open calls.

    if (sqlite3_threadsafe() > 0) {
        int retCode = sqlite3_config(SQLITE_CONFIG_SERIALIZED);
        if (retCode == SQLITE_OK) {
            NSLog(@"Can now use sqlite on multiple threads, using the same connection");
        } else {
            NSLog(@"setting sqlite thread safe mode to serialized failed!!! return code: %d", retCode);
        }
    } else {
        NSLog(@"Your SQLite database is not compiled to be threadsafe.");
    }

    sqlite3 *newDBconnection;

    // Open the database
    if (sqlite3_open([[self getDatabaseFilePath] UTF8String], &newDBconnection) == SQLITE_OK) {
        NSLog(@"Database Successfully Opened :)");
    } else {
        sqlite3_close(newDBconnection);
        NSLog(@"Error in opening database :(");
    }

    return newDBconnection; 
}

这是输出:

sqlite3 lib version: 3.7.7
setting sqlite thread safe mode to serialized failed!!! return code: 21
Database Successfully Opened :)

Answer 1

我也在努力奋斗,终于得到了解决方案.

正如@enobufs所说,sqlite3_config()以前需要调用sqlite3_initialize().但是,操作系统可能会为我们初始化SQLite,所以我也在sqlite3_shutdown()之前做了一个sqlite3_config().

1. sqlite3_shutdown()
2. sqlite3_config()
3. sqlite3_initialize().

然后,还必须为每个查询使用相同的连接,因为它是对序列化的数据库连接的访问​​.如此处所述http://www.sqlite.org/capi3ref.html#sqliteconfigserialized

所以我在应用程序启动后立即创建一个连接,并将该连接传递给需要它的每个类.