[英]Session.Get loads with N+1 even when lazy=false
I have entities like these: 我有这样的实体:
public class User
{
public virtual int Id { get; set;}
public virtual Iesi.Collections.Generic.ISet<Character> Characters { get; set; }
}
public class Character
{
public virtual int Id { get; set;}
public virtual User User { get; set;}
public virtual Iesi.Collections.Generic.ISet<UserCharacterSmartChallengeTracker> SmartChallengeTrackers { get; set; }
}
public class UserCharacterSmartChallengeTracker
{
public virtual int Id { get; set; }
public virtual int? CharacterId { get; set; }
}
They all are NOT lazy loaded. 它们都不是延迟加载的。
When I do session.Get<User>()
I see such queries: 当我执行session.Get<User>()
我看到这样的查询:
SELECT smartchall0_.character_id as character3_1_,
smartchall0_.id as id1_,
smartchall0_.id as id51_0_,
smartchall0_.character_id as character3_51_0_,
FROM public.user_character_smart_challenge_trackers smartchall0_
WHERE smartchall0_.character_id = 48176 /* :p0 */
SELECT smartchall0_.character_id as character3_1_,
smartchall0_.id as id1_,
smartchall0_.id as id51_0_,
smartchall0_.character_id as character3_51_0_,
FROM public.user_character_smart_challenge_trackers smartchall0_
WHERE smartchall0_.character_id = 48175 /* :p0 */
-- and others
I tried to preload all of them to the session cache: 我试图将它们全部预加载到会话缓存中:
var ids = session.Query<Character>().Where(x => x.User.Id == id)
.Select(x => x.Id)
.ToArray();
session.Query<UserCharacterSmartChallengeTracker>().Where(x => ids.Contains(x.Id)).ToArray();
with query 与查询
select character0_.id as col_0_0_
from public.characters character0_
where character0_.user_id = 9602 /* :p0 */
select usercharac0_.id as id51_,
usercharac0_.character_id as character3_5
from public.user_character_smart_challenge_trackers usercharac0_
where usercharac0_.id in (48176 /* :p0 */, 48175 /* :p1 */, 48174 /* :p2 */, 48173 /* :p3 */,
48172 /* :p4 */, 48171 /* :p5 */, 48170 /* :p6 */, 48169 /* :p7 */)
but NHibernate ignores the fact that they all are already loaded into the session cache and generates the same N+1 queries! 但是NHibernate忽略了它们都已经加载到会话缓存中并生成相同的N + 1查询的事实! How to fix this? 如何解决这个问题?
Update: preloading with 更新:预加载
session.QueryOver<Character>().Where(x => x.User.Id == id)
.Fetch(x => x.User).Lazy
.Fetch(x=>x.SmartChallengeTrackers).Eager
.List();
removes N+1 but makes NHibernate load characters second time when I do session.Get<User>
which I want to avoid! 删除N + 1,但是在执行session.Get<User>
时第二次使NHibernate加载字符,我想避免!
I used futures: 我用期货:
var q = session.Query<User>().Where(x => x.Id == id);
var lst = new List<IEnumerable>
{
q.FetchMany(x => x.Characters).ToFuture(),
q.Fetch(x=>x.UpdateableData).ToFuture(),
session.QueryOver<User>().Where(x => x.Id == id)
.Fetch(x=>x.Characters).Eager
.Fetch(x => x.Characters.First().SmartChallengeTrackers).Eager
.Future()
};
var r = session.QueryOver<User>().Where(x => x.Id == id)
.TransformUsing(Transformers.DistinctRootEntity)
.Future();
foreach (IEnumerable el in lst)
{
foreach (object o in el)
{
}
}
return r.ToArray();
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