NHibernate二级缓存不返回对象 [英] NHibernate second level caching not returning object
问题描述
我正在使用存储过程进行一个简单的2级缓存实验，并且收到一个表或视图不存在Oracle错误.
I was doing a simple 2 level caching experiment with Stored Procedures and am receiving a table or view does not exist Oracle error.
缓存正在检索我的DTO对象，并试图对数据库进行SQL语句.我猜这是一些配置错误.
The cache is retrieving my DTO object and trying to make a SQL statement to the database. I'm guessing it is some configuration error.
这是app.config
Here's the app.config
<hibernate-configuration xmlns="urn:nhibernate-configuration-2.2">
<session-factory name="NHibernate.Test">
<property name="connection.driver_class">NHibernate.Driver.OracleDataClientDriver</property>
<property name="show_sql">true</property>
<property name="dialect">NHibernate.Dialect.Oracle10gDialect</property>
<property name="query.substitutions">true 1, false 0, yes 'Y', no 'N'</property>
<property name="cache.use_query_cache">true</property>
<property name="cache.use_second_level_cache">true</property>
<property name="cache.provider_class">NHibernate.Caches.SysCache.SysCacheProvider, NHibernate.Caches.SysCache</property>
</session-factory>
</hibernate-configuration>
这是要测试的代码: [测试方法] 公共无效GetNomHeaderInfo_TestingCache_BPNomHeaderShouldBeCached() { //安排 DateTime StartTime； DateTime EndTime; TimeSpan FirstTry； TimeSpan SecondTry;
And here's the code to test: [TestMethod] public void GetNomHeaderInfo_TestingCache_BPNomHeaderShouldBeCached() { //Arrange DateTime StartTime; DateTime EndTime; TimeSpan FirstTry; TimeSpan SecondTry;
//Act
using (var session = factory.OpenSession())
{
var query = session.GetNamedQuery("GetMyDTO");
query.SetInt32("id", 1);
query.SetCacheRegion("Id");
query.SetCacheMode(CacheMode.Normal);
query.SetCacheable(true);
StartTime = DateTime.Now;
myDTO DTO = query.UniqueResult<myDTO>();
EndTime = DateTime.Now;
FirstTry = EndTime - StartTime;
}
using (var session = factory.OpenSession())
{
var query = session.GetNamedQuery("GetMyDTO");
query.SetInt32("id", 1);
query.SetCacheRegion("Id");
query.SetCacheMode(CacheMode.Normal);
query.SetCacheable(true);
StartTime = DateTime.Now;
myDTO DTO = query.UniqueResult<myDTO>();
EndTime = DateTime.Now;
SecondTry = EndTime - StartTime;
}
//Test
Assert.IsTrue(SecondTry < FirstTry);
}
然后我执行第二个查询时出错.错误消息是:
I then error out when I do the second query.UniqueResult(); The error message is:
SELECT blah blah_.blahblah, etc FROM MyDTO SomeAlias_ WHERE SomeAlias_.id=:p0
但是没有myDTO表或视图.我不知道为什么NHibernate会想从缓存myDTO中拉出然后尝试创建SQL语句.
But there's no myDTO table or view. I don't know why NHibernate thinks to pull from the cache myDTO and then tries to create a SQL statement.
这是痕迹:
NHibernate.Cache.StandardQueryCache: DEBUG checking cached query results in region: 'Id'; sql: { call SomePackage.MyProc(?) }; parameters: []; named parameters: {'id'='1'}
NHibernate.Cache.StandardQueryCache: DEBUG checking cached query results in region: 'Id'; sql: { call SomePackage.MyProc(?) }; parameters: []; named parameters: {'id'='1'}
NHibernate.Caches.SysCache.SysCache: DEBUG Fetching object 'NHibernate-Cache:nomId:sql: { call SomePackage.MyProc(?) }; parameters: []; named parameters: {'id'='1'}@601355831' from the cache.
NHibernate.Caches.SysCache.SysCache: DEBUG Fetching object 'NHibernate-Cache:nomId:sql: { call SomePackage.MyProc(?) }; parameters: []; named parameters: {'id'='1'}@601355831' from the cache.
NHibernate.Cache.StandardQueryCache: DEBUG Checking query spaces for up-to-dateness [MyDTO]
NHibernate.Cache.StandardQueryCache: DEBUG Checking query spaces for up-to-dateness [MyDTO]
NHibernate.Caches.SysCache.SysCache: DEBUG Fetching object 'NHibernate-Cache:UpdateTimestampsCache:MyDTO@1270222867' from the cache.
NHibernate.Caches.SysCache.SysCache: DEBUG Fetching object 'NHibernate-Cache:UpdateTimestampsCache:MyDTO@1270222867' from the cache.
NHibernate.Cache.StandardQueryCache: DEBUG returning cached query results for: sql: { call SomePackage.MyProc(?) }; parameters: []; named parameters: {'id'='1'}
NHibernate.Cache.StandardQueryCache: DEBUG returning cached query results for: sql: { call SomePackage.MyProc(?) }; parameters: []; named parameters: {'id'='1'}
NHibernate.Event.Default.DefaultLoadEventListener: DEBUG loading entity: [MyAssembly.MyDTO#1]
NHibernate.Event.Default.DefaultLoadEventListener: DEBUG loading entity: [MyAssembly.MyDTO#1]
NHibernate.Event.Default.DefaultLoadEventListener: DEBUG attempting to resolve: [MyAssembly.MyDTO#1]
NHibernate.Event.Default.DefaultLoadEventListener: DEBUG attempting to resolve: [MyAssembly.MyDTO#1]
NHibernate.Event.Default.DefaultLoadEventListener: DEBUG object not resolved in any cache: [MyAssembly.MyDTO#1]
NHibernate.Event.Default.DefaultLoadEventListener: DEBUG object not resolved in any cache: [MyAssembly.MyDTO#1]
NHibernate.Persister.Entity.AbstractEntityPersister: DEBUG Fetching entity: [MyAssembly.MyDTO#1]
NHibernate.Persister.Entity.AbstractEntityPersister: DEBUG Fetching entity: [MyAssembly.MyDTO#1]
NHibernate.Loader.Loader: DEBUG loading entity: [MyAssembly.MyDTO#1]
NHibernate.Loader.Loader: DEBUG loading entity: [MyAssembly.MyDTO#1]
NHibernate.AdoNet.AbstractBatcher: DEBUG Opened new IDbCommand, open IDbCommands: 1
NHibernate.AdoNet.AbstractBatcher: DEBUG Opened new IDbCommand, open IDbCommands: 1
NHibernate.AdoNet.AbstractBatcher: DEBUG Building an IDbCommand object for the SqlString: SELECT blah blah_.blahblah, etc FROM MyDTO SomeAlias_ WHERE SomeAlias_.id=:p0
有人知道我在做什么错吗?
Anyone know what I'm doing wrong here?
谢谢，比尔N
推荐答案
我看不到您的映射，但这是一个解释.
I can't see your mapping, but here's an explanation.
- 您正在缓存查询结果，但不是您的实体(那些是单独的缓存)
- 缓存查询结果只存储ID.如果您也没有缓存实体，则会发出查询以加载每个返回的实体(通常很糟糕)
- MyDTO类的默认表名是MyDTO，因此就是它的外观
- 这看起来像一个按ID查询，您不应该使用一个松散的命名查询，而是一个适当的
loader(请参阅
- You are caching your query results, but not your entity (those are separate caches)
- Caching a query's results just stores the IDs; if you are not caching your entities too, a query is issued to load each returned entity (this is usually bad)
- The default table name for the MyDTO class is MyDTO, so that's where it's looking
- This looks like a Query by ID, for which you shouldn't be using a loose named query, but a proper
loader(see 17.4. Custom SQL for loading).
一旦设置了加载程序和 entity 缓存，您就可以只使用session.Get<MyDTO>(id)检索对象，只要您执行所有操作，它将使用二级缓存.交易中的工作量，这是推荐做法.
Once you set up the loader and entity caching, you'll just be able to retrieve your objects using just session.Get<MyDTO>(id), which will use the second level cache, as long as you do all of your work inside transactions, which is a recommended practice.
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