nhibernate与linq查询缓存问题 [英] nhibernate cache problem with linq queries

问题描述

我看到一些来自nhibernate缓存的奇怪行为，不能理解这个推理。我不能缓存查询时执行选择操作，如$ / b>

  query.Select（x => x）.ToList（） 
  

但是可以在执行时缓存：

  var query = session.Linq< Promoter>（）; 
 var p = query.ToList（）; 
  

两者都产生相同的sql查询，应该是同样的东西。以下测试解释了这个问题。

pre $
public void Can_Use_Cache（
{
ISessionFactory factory = Storage.Application.Get< ISessionFactory>（SessionFactory）;
//初始命中数据库并加载到缓存 - 所有罚款
使用（var session = factory.OpenSession（））
{
Console.WriteLine（）;
Console.WriteLine（First Query）;
var query = session.Linq< Promoter>（）;
query.QueryOptions.SetCachable（true）;
query.QueryOptions.SetCacheMode（CacheMode.Normal）;
var p = query.ToList（）;

//在数据库中没有命中，并按预期方式从缓存中检索 - 使用（var session = factory.OpenSession（））
{
.WriteLine（ ）;
Console.WriteLine（Second Query）;
var query = session.Linq< Promoter>（）;
query.QueryOptions.SetCachable（true）;
query.QueryOptions.SetCacheMode（CacheMode.Normal）;
var p = query.ToList（）;

//点击数据库 - 应该来自缓存 - 不工作
使用（var session = factory.OpenSession（））
{
控制台。的WriteLine（ ）;
Console.WriteLine（Third Query）;
var query = session.Linq< Promoter>（）;
query.QueryOptions.SetCachable（true）;
query.QueryOptions.SetCacheMode（CacheMode.Normal）;
var p = query.Select（x => x）.ToList（）;

//再次访问数据库 - 应该来自缓存 - 再次不工作
使用（var session = factory.OpenSession（））
{
Console.WriteLine（ ）;
Console.WriteLine（Fourth Query）;
var query = session.Linq< Promoter>（）;
query.QueryOptions.SetCachable（true）;
query.QueryOptions.SetCacheMode（CacheMode.Normal）;
var p = query.Select（x => x）.ToList（）;


$ / code $ / pre

我的测试结果显示，第二个查询。查询3和4不应该击中数据库：

  2010-02-28 12：05：23,046信息开始日志记录
 
第一个查询
 2010-02-28 12：05：23,156 DEBUG选择this_.Id为Id11_0_，this_.Version为Version11_0_，this_.Name为Name11_0_ FROM Promoters this_ 
 NHibernate： SELECT this_.Id as Id11_0_，this_.Version as Version11_0_，this_.Name as Name11_0_ FROM Promoters this_ 
 
第二个查询
 
第三个查询
 2010-02-28 12：05：23,315 DEBUG选择this_.Id作为Id11_0_，this_.Version作为Version11_0_，this_.Name作为Name11_0_ FROM Promoters this_ 
 NHibernate：选择this_.Id作为Id11_0_，this_.Version作为Version11_0_，this_.Name作为Name11_0_ FROM Promoters this_ 
 
第四个查询
 2010-02-28 12：05：23,318 DEBUG选择this_.Id为Id11_0_，this_.Version为Version11_0_，this_.Name为Name11_0_ FROM Promoters this_ 
 NHibernate：选择this_.Id为Id11_0_，this_.Version为Version11_0_，this_.Name为Name11_0_ FROM Promoters this_ 
  
 
 
缓存配置使用流利：
  .Database（MsSqlConfiguration.MsSql2008 
 .ConnectionString（ConfigurationService.SqlConnectionString）
 .ShowSql（）
 .Cache（c => c 
 
 .UseQueryCache（）
 .ProviderClass（typeof（NHibernate.Cache.HashtableCacheProvider）.AssemblyQualifiedName））
）
 .Mappings（m => m。 FluentMappings.AddFromAssemblyOf< EventMap>（）
 .Conventions.Setup（MappingConventions.GetConventions（）））
 .ExposeConfiguration（BuildSchema）
 .BuildSessionFactory（）; 
  
 
 
解决方案
 b 
 $ b 
  http://nhprof.com/Learn/Alerts/DoNotUseImplicitTransactions 
 
I am seeing some odd behavior from nhibernate caching and cannot understand the reasoning. I am not able to cache queries when doing select operations like 
query.Select(x=>x).ToList() 
but can cache when doing:
var query = session.Linq<Promoter>();
var p = query.ToList();
Both produce the same sql query and should be doign the same thing. The following test explains the problem.
    [Test]
    public void Can_Use_Cache()
    {
       ISessionFactory factory = Storage.Application.Get<ISessionFactory>("SessionFactory");
       // initial hit on the database and load into cache - all fine
        using (var session = factory.OpenSession())
       {
           Console.WriteLine("");
           Console.WriteLine("First Query");
           var query = session.Linq<Promoter>();
           query.QueryOptions.SetCachable(true);
           query.QueryOptions.SetCacheMode(CacheMode.Normal);
           var p = query.ToList();
       }
        // no hit on the database and retrieved from cache as expected - all fine
       using (var session = factory.OpenSession())
       {
           Console.WriteLine("");
           Console.WriteLine("Second Query");
           var query = session.Linq<Promoter>();
           query.QueryOptions.SetCachable(true);
           query.QueryOptions.SetCacheMode(CacheMode.Normal);
           var p = query.ToList();
       }
        // hits the db - should have come from the cache - not working 
       using (var session = factory.OpenSession())
       {
           Console.WriteLine("");
           Console.WriteLine("Third Query");
           var query = session.Linq<Promoter>();
           query.QueryOptions.SetCachable(true);
           query.QueryOptions.SetCacheMode(CacheMode.Normal);
           var p = query.Select(x=>x).ToList();
       }
       // hits the db again - should have come from the cache - again not working
       using (var session = factory.OpenSession())
       {
           Console.WriteLine("");
           Console.WriteLine("Fourth Query");
           var query = session.Linq<Promoter>();
           query.QueryOptions.SetCachable(true);
           query.QueryOptions.SetCacheMode(CacheMode.Normal);
           var p = query.Select(x => x).ToList();
       }
    }
My test results showing the hit on the db for the second query. queries 3 and 4 should not be hitting the db:
2010-02-28 12:05:23,046 INFO Started Logging

First Query
2010-02-28 12:05:23,156 DEBUG SELECT this_.Id as Id11_0_, this_.Version as Version11_0_, this_.Name as Name11_0_ FROM Promoters this_
NHibernate: SELECT this_.Id as Id11_0_, this_.Version as Version11_0_, this_.Name as Name11_0_ FROM Promoters this_

Second Query

Third Query
2010-02-28 12:05:23,315 DEBUG SELECT this_.Id as Id11_0_, this_.Version as Version11_0_, this_.Name as Name11_0_ FROM Promoters this_
NHibernate: SELECT this_.Id as Id11_0_, this_.Version as Version11_0_, this_.Name as Name11_0_ FROM Promoters this_

Fourth Query
2010-02-28 12:05:23,318 DEBUG SELECT this_.Id as Id11_0_, this_.Version as Version11_0_, this_.Name as Name11_0_ FROM Promoters this_
NHibernate: SELECT this_.Id as Id11_0_, this_.Version as Version11_0_, this_.Name as Name11_0_ FROM Promoters this_
The cache is configured using fluent:
SessionFactory = Fluently.Configure()
            .Database(MsSqlConfiguration.MsSql2008
                          .ConnectionString(ConfigurationService.SqlConnectionString)
                          .ShowSql()
                         .Cache(c => c

                                    .UseQueryCache()
                                    .ProviderClass(typeof(NHibernate.Cache.HashtableCacheProvider).AssemblyQualifiedName))
                          )
            .Mappings(m => m.FluentMappings.AddFromAssemblyOf<EventMap>()
                               .Conventions.Setup(MappingConventions.GetConventions()))
            .ExposeConfiguration(BuildSchema)
            .BuildSessionFactory();

解决方案
Have you tried using transactions?

http://nhprof.com/Learn/Alerts/DoNotUseImplicitTransactions

                        
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