NHibernate SysCache 不缓存 children objects

Question

希望得到您的帮助。我有简单的 master-child 集（"player" 和 "playerChildObject"）。获取 "players" 也会获取其链接的 children.

SysCache 缓存玩家，但不缓存 children.

这里是 objects（都用 Cache.ReadWrite() 设置）：

实体：

public class Player
{
    public virtual int Id { get; set; }
    public virtual string Name { get; set; }
    public virtual IList<PlayerChildObject> PlayerChildObjects { get; set; }

    public Player()
    {
        PlayerChildObjects = new List<PlayerChildObject>();
    }
}

public class PlayerChildObject
{
    public virtual int Id { get; protected set; }
    public virtual Player Player { get; set; }
}

映射：

public class PlayerMap : ClassMap<Player>
{
    public PlayerMap()
    {
        Id(x => x.Id).Column("id");
        Map(x => x.Name).Column("name");
        HasMany(x => x.PlayerChildObjects).KeyColumn("PlayerId")
            .Inverse()
            .Cascade.All()
            .Not.LazyLoad();
        Table("accounts");
        Cache.ReadWrite();
    }
}

public class PlayerChildObjectMap : ClassMap<PlayerChildObject>
{
    public PlayerChildObjectMap()
    {
        Id(x => x.Id).Column("id");
        References<Player>(x => x.Player, "playerId");
        Table("playerChildObjects");
        Cache.ReadWrite();
    }
}

会话工厂也有 "UseQueryCache" 和 "UseSecondLevelCache":

Fluently.Configure()
.Database(MySQLConfiguration.Standard.ConnectionString(cs => ...))
.Cache(c => c.UseQueryCache().UseSecondLevelCache()
.ProviderClass(typeof (NHibernate.Caches.SysCache.SysCacheProvider).AssemblyQualifiedName))
.Mappings(m => m.FluentMappings.AddFromAssemblyOf<PlayerChildObjectMap>())
.BuildSessionFactory();

查询本身带有 SetCacheable(true).SetCacheMode(CacheMode.Normal):

using (var session = SessionFactory.OpenSession())
{
    using (var transaction = session.BeginTransaction())
    {
        players = session.CreateCriteria(typeof(Player))
            .SetCacheable(true)
            .SetCacheMode(CacheMode.Normal)
            .List<Player>();
        transaction.Commit();
    }
}

但是，探查器显示玩家已缓存（仅在第一次执行玩家获取代码时调用），而每次 PlayerID 都会检索相同的 PlayerChildObjects。

因此，第一个请求给出 N+1 个 DB 调用（玩家列表 + child objects 每个玩家），所有连续的请求执行 N 个调用（child objects 每个玩家）。

我错过了什么？ 如何让SysCache缓存也children？

系统缓存版本：3.1.0.4000

Answer 1

我想说，有两个问题。首先，即使 one-to-many (HasMany) 也有缓存设置：

HasMany(x => x.PlayerChildObjects).KeyColumn("PlayerId")
    ...
    .Cache.IncludeAll() // or .IncludeNonLazy, .CustomInclude("customInclude")
        .ReadOnly() // or .NonStrictReadWrite(), .ReadWrite(), .Transactional(),
                    //  .CustomUsage("customUsage")        
        .Region("regionName");

查看更多关于HasMany mapping here（Adam Bar 的文章关于按代码映射，但最后是流利的）

文档19.2.1. Cache mappings

其次，我们应该使用批量获取：

public PlayerMap()
{
    BatchSize(25);

    HasMany(x => x.PlayerChildObjects).KeyColumn("PlayerId")
        ...
        .BatchSize(25)
...
public PlayerChildObjectMap()
{
    BatchSize(25);
    ...

在文档 19.1.5. Using batch fetching 或此处阅读更多相关信息：

How to Eager Load Associations without duplication in NHibernate?
How to implement batch fetching with Fluent NHibernate when working with Oracle?

NHibernate SysCache 不缓存 children objects

NHibernate SysCache does not cache children objects

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syscache