C#开源磁盘/内存缓存引擎

前言

昨天写了个 《基于STSdb和fastJson的磁盘/内存缓存》，大家可以先看看。下午用到业务系统时候，觉得可以改进一下，昨晚想了一个晚上，刚才重新实现一下。

更新

1. 增加了对批量处理的支持，写操作速度提升5倍，读操作提升100倍

2. 增加了一个存储provider，可以选择不用STSdb做存储，而用物理文件/Dictionary。

3. 增加了对并发的支持

需求

业务系统用的是数据库，数据量大，部分只读或相对稳定业务查询复杂，每次页面加载都要花耗不少时间(不讨论异步)，觉得可以做一下高速缓存，譬如用nosql那种key/value快速存取结果

目的

提供一个简单易用的解决缓存方案，可以根据数据的大小缓存到内存或者磁盘。

实现

存取

方法1. 基于STSdb，提供高效的Key/Value存取，支持磁盘/内存，对Key无限制

方法2. 基于直接物理文件/Dictionary。Key必须是基本类型，譬如int/long/uint/ulong/DateTime/string等。

代码

代码比较简单，花了2个小时写的，很多情况没考虑，譬如磁盘空间/内存不足，自动回收过期缓存等，这些留给大家做家庭作业吧。另外，为了发布方便，STSdb和fastJson的代码都合并到一个项目里。

BaseCahce.cs

这是一个抽象基类，提供存取接口。

using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace Com.SuperCache.Engine{    public abstract class BaseCache    {        protected internal const string KeyExpiration = "Expiration";        public abstract void Add<K>(string Category, K Key, object Data);        public abstract void Add<K, V>(string Category, IEnumerable<KeyValuePair<K, V>> Items, DateTime? ExpirationDate);        public abstract void Add<K>(string Category, K Key, object Data, DateTime? ExpirationDate);        public abstract List<KeyValuePair<K, V>> Get<K, V>(string Category, IEnumerable<K> Keys);        public abstract V Get<K, V>(string Category, K Key);    }}

CahceEngine.cs

主要调用缓存引擎

using System;using System.Collections.Generic;using System.Linq;using System.Text;using STSdb4.Database;using fastJSON;using System.IO;namespace Com.SuperCache.Engine{    public enum CacheProviders    {        Default = 1,        Raw = 2    }    public class CacheEngine    {        private BaseCache cacheProvider = null;        public CacheEngine(string DataPath): this(CacheProviders.Default, DataPath)        {        }        public CacheEngine(CacheProviders Provider, string DataPath)        {            switch (Provider)            {                case CacheProviders.Default:                    cacheProvider = new STSdbCache(DataPath);                    break;                case CacheProviders.Raw:                    cacheProvider = new RawCache(DataPath);                    break;                default:                    break;            }        }        public void Add<K>(string Category, K Key, object Data)        {            cacheProvider.Add<K>(Category, Key, Data);        }        public void Add<K, V>(string Category, IEnumerable<KeyValuePair<K, V>> Items, DateTime? ExpirationDate)        {            cacheProvider.Add<K, V>(Category, Items, ExpirationDate);        }        public void Add<K>(string Category, K Key, object Data, DateTime? ExpirationDate)        {            cacheProvider.Add<K>(Category, Key, Data, ExpirationDate);        }        public List<KeyValuePair<K, V>> Get<K, V>(string Category, IEnumerable<K> Keys)        {            return cacheProvider.Get<K, V>(Category, Keys);        }        public V Get<K, V>(string Category, K Key)        {            return cacheProvider.Get<K, V>(Category, Key);        }    }}

STSdbCache.cs

STSdb存储引擎

using System;using System.Collections.Generic;using System.Linq;using System.Text;using STSdb4.Database;using fastJSON;using System.IO;namespace Com.SuperCache.Engine{    public class STSdbCache : BaseCache    {        private string dataPath;        private static IStorageEngine memoryInstance = null;        private static object syncRoot = new object();        private bool isMemory = false;        public STSdbCache(string DataPath)        {            dataPath = DataPath;            if (!dataPath.EndsWith(Path.DirectorySeparatorChar.ToString()))                dataPath += Path.DirectorySeparatorChar;            isMemory = string.IsNullOrEmpty(DataPath);        }        public override void Add<K>(string Category, K Key, object Data)        {            Add(Category, Key, Data, null);        }        private IStorageEngine Engine        {            get            {                if (isMemory)                {                    lock (syncRoot)                    {                        if (memoryInstance == null)                            memoryInstance = STSdb.FromMemory();                    }                    return memoryInstance;                }                else                    return STSdb.FromFile(GetFile(false), GetFile(true));            }        }        private string GetExpirationTable(string Category)        {            return KeyExpiration + "_" + Category;        }        public override void Add<K, V>(string Category, IEnumerable<KeyValuePair<K, V>> Items, DateTime? ExpirationDate)        {            lock (syncRoot)            {                var engine = Engine;                var table = engine.OpenXIndex<K, string>(Category);                Items.ForEach(i =>                    {                        var key = i.Key;                        var data = i.Value;                        //will only serialize object other than string                        var result = typeof(V) == typeof(string) ? data as string : JSON.Instance.ToJSON(data);                        table[key] = result;                        table.Flush();                        //specify expiration                        var expiration = engine.OpenXIndex<K, DateTime>(GetExpirationTable(Category));                        //default 30 mins to expire from now                        var expirationDate = ExpirationDate == null || ExpirationDate <= DateTime.Now ? DateTime.Now.AddMinutes(30) : (DateTime)ExpirationDate;                        expiration[key] = expirationDate;                        expiration.Flush();                    });                engine.Commit();                //only dispose disk-based engine                if (!isMemory)                    engine.Dispose();            }        }        public override void Add<K>(string Category, K Key, object Data, DateTime? ExpirationDate)        {            Add<K, object>(Category, new List<KeyValuePair<K, object>> { new KeyValuePair<K, object>(Key, Data) }, ExpirationDate);        }        private string GetFile(bool IsData)        {            if (!Directory.Exists(dataPath))                Directory.CreateDirectory(dataPath);            return dataPath + "SuperCache." + (IsData ? "dat" : "sys");        }        public override List<KeyValuePair<K, V>> Get<K, V>(string Category, IEnumerable<K> Keys)        {            var result = new List<KeyValuePair<K, V>>();            lock (syncRoot)            {                var engine = Engine;                var table = engine.OpenXIndex<K, string>(Category);                var expiration = engine.OpenXIndex<K, DateTime>(GetExpirationTable(Category));                var isCommitRequired = false;                Keys.ForEach(key =>                    {                        string buffer;                        V value;                        if (table.TryGet(key, out buffer))                        {                            //will only deserialize object other than string                            value = typeof(V) == typeof(string) ? (V)(object)buffer : JSON.Instance.ToObject<V>(buffer);                            DateTime expirationDate;                            //get expiration date                            if (expiration.TryGet(key, out expirationDate))                            {                                //expired                                if (expirationDate < DateTime.Now)                                {                                    value = default(V);                                    table.Delete(key);                                    table.Flush();                                    expiration.Delete(key);                                    expiration.Flush();                                    isCommitRequired = true;                                }                            }                        }                        else                            value = default(V);                        result.Add(new KeyValuePair<K, V>(key, value));                    });                //only need to commit write actions                if (isCommitRequired)                    engine.Commit();                //only dispose disk-based engine                if (!isMemory)                    engine.Dispose();            }            return result;        }        public override V Get<K, V>(string Category, K Key)        {            var buffer = Get<K, V>(Category, new K[] { Key });            var result = buffer.FirstOrDefault();            return result.Value;        }    }}

RawCache.cs

物理文件/Dictionary引擎

using System;using System.Collections.Generic;using System.Linq;using System.Text;using STSdb4.Database;using fastJSON;using System.IO;namespace Com.SuperCache.Engine{    public class RawCache : BaseCache    {        private string dataPath;        private static Dictionary<string, object> memoryData = new Dictionary<string, object>();        private static Dictionary<string, DateTime?> memoryExpiration = new Dictionary<string, DateTime?>();        private static object syncRoot = new object();        private bool isMemory = false;        public RawCache(string DataPath)        {            dataPath = DataPath;            if (!dataPath.EndsWith(Path.DirectorySeparatorChar.ToString()))                dataPath += Path.DirectorySeparatorChar;            isMemory = string.IsNullOrEmpty(DataPath);        }        public override void Add<K>(string Category, K Key, object Data)        {            Add(Category, Key, Data, null);        }        private string GetExpirationTable(string Category)        {            return KeyExpiration + "_" + Category;        }        public override void Add<K, V>(string Category, IEnumerable<KeyValuePair<K, V>> Items, DateTime? ExpirationDate)        {            lock (syncRoot)            {                Items.ForEach(i =>                    {                        var key = i.Key;                        var data = i.Value;                        if (isMemory)                        {                            var memKey = GetKey(Category, key.ToString());                            memoryData[memKey] = data;                            memoryExpiration[memKey] = ExpirationDate;                        }                        else                        {                            //will only serialize object other than string                            var result = typeof(V) == typeof(string) ? data as string : JSON.Instance.ToJSON(data);                            File.WriteAllText(GetFile(Category, key.ToString(), true), result);                            //specify expiration                            //default 30 mins to expire from now                            var expirationDate = ExpirationDate == null || ExpirationDate <= DateTime.Now ? DateTime.Now.AddMinutes(30) : (DateTime)ExpirationDate;                            File.WriteAllText(GetFile(Category, key.ToString(), false), expirationDate.ToString());                        }                    });            }        }        public override void Add<K>(string Category, K Key, object Data, DateTime? ExpirationDate)        {            Add<K, object>(Category, new List<KeyValuePair<K, object>> { new KeyValuePair<K, object>(Key, Data) }, ExpirationDate);        }        private string GetFile(string Category, string FileName, bool IsData)        {            var path = dataPath + Category.NormalizeFileName() + @"\";            if (!Directory.Exists(path))                Directory.CreateDirectory(path);            return path + FileName.NormalizeFileName() + "." + (IsData ? "dat" : "exp");        }        private string GetKey(string Category, string Key)        {            return Category + "_" + Key;        }        public override List<KeyValuePair<K, V>> Get<K, V>(string Category, IEnumerable<K> Keys)        {            var result = new List<KeyValuePair<K, V>>();            lock (syncRoot)            {                Keys.ForEach(key =>                    {                        string buffer;                        V value;                        if (isMemory)                        {                            var memKey = GetKey(Category, key.ToString());                            object memBuffer;                            if (memoryData.TryGetValue(memKey, out memBuffer))                            {                                value = (V)memBuffer;                                DateTime? expirationDate;                                if (memoryExpiration.TryGetValue(memKey, out expirationDate))                                {                                    //expired                                    if (expirationDate != null && (DateTime)expirationDate < DateTime.Now)                                    {                                        value = default(V);                                        memoryData.Remove(memKey);                                        memoryExpiration.Remove(memKey);                                    }                                }                            }                            else                                value = default(V);                        }                        else                        {                            var dataFilePath = GetFile(Category, key.ToString(), true);                            if (File.Exists(dataFilePath))                            {                                buffer = File.ReadAllText(dataFilePath);                                //will only deserialize object other than string                                value = typeof(V) == typeof(string) ? (V)(object)buffer : JSON.Instance.ToObject<V>(buffer);                                DateTime expirationDate;                                var expirationFilePath = GetFile(Category, key.ToString(), false);                                if (File.Exists(expirationFilePath))                                {                                    buffer = File.ReadAllText(expirationFilePath);                                    expirationDate = Convert.ToDateTime(buffer);                                    //expired                                    if (expirationDate < DateTime.Now)                                    {                                        value = default(V);                                        File.Delete(dataFilePath);                                        File.Delete(expirationFilePath);                                    }                                }                            }                            else                                value = default(V);                        }                        result.Add(new KeyValuePair<K, V>(key, value));                    });            }            return result;        }        public override V Get<K, V>(string Category, K Key)        {            var buffer = Get<K, V>(Category, new K[] { Key });            var result = buffer.FirstOrDefault();            return result.Value;        }    }}

Extensions.cs

扩展函数

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.IO;namespace Com.SuperCache.Engine{    public static class Extensions    {        public static void ForEach<T>(this IEnumerable<T> source, Action<T> action)        {            if (source != null)            {                foreach (var item in source)                {                    action(item);                }            }        }        public static string NormalizeFileName(this string FileName)        {            var result = FileName;            Path.GetInvalidFileNameChars().ForEach(c =>                {                    result = result.Replace(c.ToString(), string.Empty);                });            return result;        }    }}

新建

构造CacheEngine需要传递缓存保存到哪个文件夹。

基于内存

如果你不喜欢基于磁盘的缓存，可以使用基于内存，构造函数传递空字符串便可。

增加/更新

同一个方法：Add。用户可以指定类型（Category），譬如User，Employee等。键（Key）支持泛型，值（Data）是object。有一个overload是过期日期（ExpirationDate），默认当前时间30分钟后

获取

Get方法需要指定类型（Category）和键（Key）。

 

例子

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading;using System.Threading.Tasks;using System.Diagnostics;using Com.SuperCache.Engine;namespace Com.SuperCache.Test{    public class Foo    {        public string Name { get; set; }        public int Age { get; set; }        public double? Some { get; set; }        public DateTime? Birthday { get; set; }    }    class Program    {        static void Main(string[] args)        {            //TestAddGet();            //Thread.Sleep(4000);            //TestExpiration();            TestDefaultDiskPerformance();            TestRawMemoryPerformance();            TestRawDiskPerformance();            TestRawMemoryPerformance();            //TestConcurrent();            Console.Read();        }        private static void TestConcurrent()        {            var w = new Stopwatch();            w.Start();            Parallel.For(1, 3, (a) =>                {                    var employees = Enumerable.Range((a - 1) * 1000, a * 1000).Select(i => new KeyValuePair<int, string>(i, "Wilson " + i + " Chen"));                    var engine = new CacheEngine(@"..\..\data");                    engine.Add<int, string>("Employee", employees, DateTime.Now.AddMinutes(1));                });            w.Stop();            Console.WriteLine("add:" + w.Elapsed);            var engine2 = new CacheEngine(@"..\..\data");            var o = engine2.Get<int, string>("Employee", 1005);            Console.WriteLine(o);        }        private static void TestDefaultDiskPerformance()        {            TestPerformance(CacheProviders.Default, @"..\..\data");        }        private static void TestDefaultMemoryPerformance()        {            TestPerformance(CacheProviders.Default, string.Empty);        }        private static void TestRawDiskPerformance()        {            TestPerformance(CacheProviders.Raw, @"..\..\data");        }        private static void TestRawMemoryPerformance()        {            TestPerformance(CacheProviders.Raw, string.Empty);        }        private static void TestPerformance(CacheProviders Provider, string DataPath)        {            Console.WriteLine("Performance Test: " + Provider.ToString() + ", " + (string.IsNullOrEmpty(DataPath) ? "Memory" : DataPath));            var engine = new CacheEngine(Provider, DataPath);            var w = new Stopwatch();            w.Start();            var employees = Enumerable.Range(0, 1000).Select(i => new KeyValuePair<int, string>(i, "Wilson " + i + " Chen"));            engine.Add<int, string>("Employee", employees, DateTime.Now.AddMinutes(1));            w.Stop();            Console.WriteLine("add:" + w.Elapsed);            /*w.Restart();            employees.ForEach(key =>                {                    var o1 = engine.Get<int, string>("Employee", key.Key);                });            w.Stop();            Console.WriteLine("individual get:" + w.Elapsed);*/            w.Restart();            var keys = employees.Select(i => i.Key);            var o = engine.Get<int, string>("Employee", keys);            w.Stop();            Debug.Assert(o.Count == keys.Count());            Console.WriteLine("get:" + w.Elapsed);            Console.WriteLine();        }        private static void TestExpiration()        {            var engine = new CacheEngine(@"..\..\data");            var o = engine.Get<string, Foo>("User", "wchen");            Console.WriteLine(o != null ? o.Name : "wchen does not exist or expired");        }        private static void TestAddGet()        {            var engine = new CacheEngine(@"..\..\data");            var f = new Foo { Name = "Wilson Chen", Age = 30, Birthday = DateTime.Now, Some = 123.456 };            engine.Add("User", "wchen", f, DateTime.Now.AddSeconds(5));            var o = engine.Get<string, Foo>("User", "wchen");            Console.WriteLine(o.Name);            var o4 = engine.Get<string, Foo>("User", "foo");            Console.WriteLine(o4 != null ? o4.Name : "foo does not exist");            var o3 = engine.Get<string, string>("PlainText", "A");            Console.WriteLine(o3 ?? "A does not exist");        }    }}

 

性能

通过上述性能测试例子，你会发现STSdb的磁盘存取速度要比一个记录对应一个物理文件快。想了解更多，请访问官方网站。

测试条件：1000条记录，7200RPM磁盘，i7。

引擎 介质 写入 读取 STSdb 磁盘 1.3s 0.06s   内存 0.01s 0.008s Raw 磁盘 1.0s 0.16s   内存 0.0004s 0.0008s

 

 

说明

项目中引用了System.Management是因为STSdb支持内存数据库，需要判断最大物理内存。如果不喜欢，大家可以移除引用，并且去掉STSdb4.Database.STSdb.FromMemory方法便可。

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