我看到一些來自nhibernate緩存的奇怪行爲,無法理解推理。做選擇操作像nhibernate緩存linq查詢問題
query.Select(x=>x).ToList()
當我不能夠緩存查詢,但這樣做的時候可以緩存:
var query = session.Linq<Promoter>();
var p = query.ToList();
都產生相同的SQL查詢,並應doign同樣的事情。以下測試解釋了這個問題。
[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();
}
}
我的測試結果顯示第二個查詢的數據庫命中。查詢3和4不應該被擊中分貝:
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_
高速緩存被使用流利配置:
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();