Question

使用SQLite，System.Data.SQLite和Dapper（在控制台应用程序中;以后的Windows服务;高吞吐量）;为什么＆＃34;数据库被锁定＆＃34;无论如何还在吗？

我甚至用这种方法抽象了对SQLite数据库的所有调用：

public static void LocalDbScope(Action<IDbConnection> action)
{
    try
    {
        lock (DbLock)
        {
            using (var connection = Open(LocalStorageConnectionString))
            {
                action(connection);
            }
        }
    }
    catch (Exception xux)
    {
        ErrLog.Error(xux);
        throw;
    }
}

启用内存映射选项也无济于事：

connection.Execute("PRAGMA wal_autocheckpoint=32; PRAGMA journal_size_limit = 2048;");
connection.Execute("PRAGMA mmap_size=" + GB);

这是连接字符串：

var builder = new SQLiteConnectionStringBuilder
{
    DataSource = storageDbFilePath,
    FailIfMissing = false,
    PageSize = 32 * KB,
    CacheSize = 10 * MB,
    ForeignKeys = false,
    UseUTF16Encoding = false,
    Pooling = true,
    JournalMode = SQLiteJournalModeEnum.Wal,
    SyncMode = SynchronizationModes.Normal,
    DateTimeKind = DateTimeKind.Utc,
    DateTimeFormat = SQLiteDateFormats.ISO8601,
    DefaultIsolationLevel = IsolationLevel.ReadCommitted,
    DefaultTimeout = (int)TimeSpan.FromMinutes(1).TotalMilliseconds
};
LocalStorageConnectionString = builder.ToString();

我在这里缺少什么？

注意：当你google for＆＃34;数据库被锁定＆＃34;时，所有顶级结果（以及整个第一页）都是关于不同编程语言和平台中的这个问题。似乎SQLite还有其他东西我无法过滤掉这张图片。

Answer 1

正如我的评论所述，我不知道在没有看到更多代码的情况下会发生什么。

但是，如果您不愿意将Dapper更改为Sqlite-net，则下面是一个小的非阻塞示例，使用您的抽象，这不会引发任何异常。希望它可以帮助你搞清楚。

using System;
using System.Data;
using System.Data.SQLite;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Dapper;

namespace MyConsoleApplication
{
    public class Program
    {
        static void Main(string[] args)
        {
            var test = new TestSQLite();
            test.GoForIt();
        }
    }

    public class Entity
    {
        public int Id { get; set; }
        public string Content { get; set; }
    }

    public class TestSQLite
    {
        private const string ConnectionString = "Data Source=sqlitetest.sqlite";
        private static readonly object DbLock = new object();

        public void GoForIt()
        {
            CreateTable();

            var random = new Random();

            for (int i = 0; i < 100; i++)
            {
                if ( i % 2 != 0)
                {
                    Task.Factory.StartNew(() => Thread.Sleep(random.Next(0, 200))).ContinueWith(other => 
                        LocalDbScope(action =>
                            {
                                var entity = new Entity {Content = "hoax"};
                                entity.Id = action.Query<int>(
                                    @"insert into entity (content) values (@Content); select last_insert_rowid()",
                                    entity).First();
                                var ids = action.Query<int>(@"select id from entity").ToList();
                                Console.WriteLine("Inserted id:{0}, all ids:[{1}]", entity.Id, string.Join(",", ids));
                            }));
                }
                else
                {
                    Task.Factory.StartNew(() => Thread.Sleep(random.Next(200, 500))).ContinueWith(other => 
                        LocalDbScope(action =>
                            {
                                action.Execute(@"delete from entity");
                                Console.WriteLine("Deleted all entities");
                            }));
                }
            }

            Console.ReadLine();
        }

        public static void LocalDbScope(Action<IDbConnection> action)
        {
            lock (DbLock)
            {
                using (var connection = new SQLiteConnection(ConnectionString))
                    action(connection);
            }
        }

        private static void CreateTable()
        {
            using (IDbConnection c = new SQLiteConnection(ConnectionString))
            {
                c.Execute(@"drop table if exists entity");
                c.Execute(@"create table entity (id integer primary key autoincrement, content varchar(100))");
            }
        }
    }
}

enter image description here

SQLite和“数据库被锁定”

1 个答案: