Ah there is another matter:Entity Cache != Query cache
We this
Session.CreateQuery("from Group g where groupnID
<= 5").SetCacheable(true).List<Group>();
you are using the QueryCache
With this:
Session.CreateQuery("from Group g where groupnID <= 5").List<Group>();
you are using EntityCache (I mean each entity will be loaded in the cache
and used where needed)
2009/6/2 Fabio Maulo <[email protected]>
> Session.CreateQuery("from Group g where groupnID
> <= 5").SetCacheable(true).List<Group>();
> Session.CreateQuery("from Group g where groupnID
> <= 5").SetCacheable(true).List<Group>();
> I'm pretty sure that you can't reproduce what you are saying here.
> If you run the two queries above with the cache active you sure will have
> only one hit to DB.
>
> Not only we have a lot of test about it but even I personally using query
> cache in a lot of projects.
>
> Are you changing something in one of the spaces (Tables) involved in that
> query ?
> Perhaps this post may help you to understand what happening behind:
>
> http://fabiomaulo.blogspot.com/2009/04/tuning-nhibernate-tolerant-querycache.html
>
>
> 2009/6/2 Max Badrak <[email protected]>
>
>
>> Sorry, but I am not quite sure what you mean by "NHibernate.Caches" --
>> right now my lg4net configuration is just set to DEBUG at the root
>> level. I tried various things during the day today, and among them I
>> tried to switch from using Criteria to creating queries explicitly. So
>> here is a piece of code I am actually executing (this is the only code
>> that runs, there's nothing else):
>>
>> Session.CreateQuery("from Group g where groupnID <=
>> 5").SetCacheable(true).List<Group>();
>>
>> Session.CreateQuery("from Group g where groupnID <=
>> 5").SetCacheable(true).List<Group>();
>>
>> This produces the log below. It seems like switching to explicit
>> queries does, at least, make NH look in the cache. However, it still
>> runs two DB queries (I can see the queries in the SQL Profiler), and
>> neither the query itself, nor the query's results (entity IDs) are
>> cached in the second level cache -- only the actual entities are
>> (which I verified by dumping the entire cache). If the query cache is
>> tied to the NH session, it's kind of useless for us -- our app needs
>> the query results cached across multiple HTTP requests...
>>
>> opened session
>> unable to locate HQL query plan in cache; generating (from Group g
>> where groupnID <= 5)
>> compiling query
>> HQL param location recognition took 0 mills (from Group g where
>> groupnID <= 5)
>> located HQL query plan in cache (from Group g where groupnID <= 5)
>> find: from Group g where groupnID <= 5
>> named parameters: {}
>> HQL: from Domain.Group g where groupnID <= 5
>> SQL: select group0_.GroupNID as GroupNID2_, group0_.GroupStatusID as
>> GroupSta2_2_, group0_.Name as Name2_, group0_.Address1 as Address4_2_,
>> group0_.Address2 as Address5_2_, group0_.City as City2_, group0_.Zip
>> as Zip2_, group0_.Phone as Phone2_, group0_.Fax as Fax2_,
>> group0_.ContactPerson as Contact10_2_, group0_.Comments as Comments2_,
>> group0_.LastModifiedDTM as LastMod12_2_, group0_.GoLiveDate as
>> GoLiveDate2_, group0_.be_OID as be14_2_, group0_.StateID as StateID2_
>> from tblGroup group0_ where (groupnID<=5 )
>> Opened new IDbCommand, open IDbCommands: 1
>> Building an IDbCommand object for the SqlString: select
>> group0_.GroupNID as GroupNID2_, group0_.GroupStatusID as GroupSta2_2_,
>> group0_.Name as Name2_, group0_.Address1 as Address4_2_,
>> group0_.Address2 as Address5_2_, group0_.City as City2_, group0_.Zip
>> as Zip2_, group0_.Phone as Phone2_, group0_.Fax as Fax2_,
>> group0_.ContactPerson as Contact10_2_, group0_.Comments as Comments2_,
>> group0_.LastModifiedDTM as LastMod12_2_, group0_.GoLiveDate as
>> GoLiveDate2_, group0_.be_OID as be14_2_, group0_.StateID as StateID2_
>> from tblGroup group0_ where (groupnID<=5 )
>> select group0_.GroupNID as GroupNID2_, group0_.GroupStatusID as
>> GroupSta2_2_, group0_.Name as Name2_, group0_.Address1 as Address4_2_,
>> group0_.Address2 as Address5_2_, group0_.City as City2_, group0_.Zip
>> as Zip2_, group0_.Phone as Phone2_, group0_.Fax as Fax2_,
>> group0_.ContactPerson as Contact10_2_, group0_.Comments as Comments2_,
>> group0_.LastModifiedDTM as LastMod12_2_, group0_.GoLiveDate as
>> GoLiveDate2_, group0_.be_OID as be14_2_, group0_.StateID as StateID2_
>> from tblGroup group0_ where (groupnID<=5 )
>> select group0_.GroupNID as GroupNID2_, group0_.GroupStatusID as
>> GroupSta2_2_, group0_.Name as Name2_, group0_.Address1 as Address4_2_,
>> group0_.Address2 as Address5_2_, group0_.City as City2_, group0_.Zip
>> as Zip2_, group0_.Phone as Phone2_, group0_.Fax as Fax2_,
>> group0_.ContactPerson as Contact10_2_, group0_.Comments as Comments2_,
>> group0_.LastModifiedDTM as LastMod12_2_, group0_.GoLiveDate as
>> GoLiveDate2_, group0_.be_OID as be14_2_, group0_.StateID as StateID2_
>> from tblGroup group0_ where (groupnID<=5 )
>> Obtaining IDbConnection from Driver
>> Opened IDataReader, open IDataReaders: 1
>> processing result set
>> result set row: 0
>> returning '1' as column: GroupNID2_
>> result row: EntityKey[Domain.Group#1]
>> Initializing object from DataReader: [Domain.Group#1]
>> Hydrating entity: [Domain.Group#1]
>> returning <bunch of junk removed>
>> result set row: 1
>> <rows 1 through 4 removed>
>> done processing result set (5 rows)
>> running NHybridDataReader.Dispose()
>> Closed IDataReader, open IDataReaders :0
>> Closed IDbCommand, open IDbCommands: 0
>> aggressively releasing database connection
>> Closing connection
>> total objects hydrated: 5
>> resolving associations for [Domain.Group#1]
>> loading entity: [Domain.State#MA]
>> creating new proxy for entity
>> creating collection wrapper:[Domain.Group.Offices#1]
>> adding entity to second-level cache: [Domain.Group#1]
>> Caching: Domain.Group#1
>> Fetching object 'NHibernate-Cache:Domain.Group:Domain.Group#1' from
>> the cache.
>> Item was already cached: Domain.Group#1
>> done materializing entity [Domain.Group#1]
>> resolving associations for [Domain.Group#2]
>> loading entity: [Domain.State#MA]
>> entity proxy found in session cache
>> creating collection wrapper:[Domain.Group.Offices#2]
>> adding entity to second-level cache: [Domain.Group#2]
>> Caching: Domain.Group#2
>> Fetching object 'NHibernate-Cache:Domain.Group:Domain.Group#2' from
>> the cache.
>> Item was already cached: Domain.Group#2
>> done materializing entity [Domain.Group#2]
>> resolving associations for [Domain.Group#3]
>> loading entity: [Domain.State#MA]
>> entity proxy found in session cache
>> creating collection wrapper:[Domain.Group.Offices#3]
>> adding entity to second-level cache: [Domain.Group#3]
>> Caching: Domain.Group#3
>> Fetching object 'NHibernate-Cache:Domain.Group:Domain.Group#3' from
>> the cache.
>> Item was already cached: Domain.Group#3
>> done materializing entity [Domain.Group#3]
>> resolving associations for [Domain.Group#4]
>> loading entity: [Domain.State#MA]
>> entity proxy found in session cache
>> creating collection wrapper:[Domain.Group.Offices#4]
>> adding entity to second-level cache: [Domain.Group#4]
>> Caching: Domain.Group#4
>> Fetching object 'NHibernate-Cache:Domain.Group:Domain.Group#4' from
>> the cache.
>> Item was already cached: Domain.Group#4
>> done materializing entity [Domain.Group#4]
>> resolving associations for [Domain.Group#5]
>> loading entity: [Domain.State#MA]
>> entity proxy found in session cache
>> creating collection wrapper:[Domain.Group.Offices#5]
>> adding entity to second-level cache: [Domain.Group#5]
>> Caching: Domain.Group#5
>> Fetching object 'NHibernate-Cache:Domain.Group:Domain.Group#5' from
>> the cache.
>> Item was already cached: Domain.Group#5
>> done materializing entity [Domain.Group#5]
>> initializing non-lazy collections
>> after autocommit
>> transaction completion
>> aggressively releasing database connection
>> located HQL query plan in cache (from Group g where groupnID <= 5)
>> located HQL query plan in cache (from Group g where groupnID <= 5)
>> find: from Group g where groupnID <= 5
>> named parameters: {}
>> HQL: from Domain.Group g where groupnID <= 5
>> SQL: select group0_.GroupNID as GroupNID2_, group0_.GroupStatusID as
>> GroupSta2_2_, group0_.Name as Name2_, group0_.Address1 as Address4_2_,
>> group0_.Address2 as Address5_2_, group0_.City as City2_, group0_.Zip
>> as Zip2_, group0_.Phone as Phone2_, group0_.Fax as Fax2_,
>> group0_.ContactPerson as Contact10_2_, group0_.Comments as Comments2_,
>> group0_.LastModifiedDTM as LastMod12_2_, group0_.GoLiveDate as
>> GoLiveDate2_, group0_.be_OID as be14_2_, group0_.StateID as StateID2_
>> from tblGroup group0_ where (groupnID<=5 )
>> Opened new IDbCommand, open IDbCommands: 1
>> Building an IDbCommand object for the SqlString: select
>> group0_.GroupNID as GroupNID2_, group0_.GroupStatusID as GroupSta2_2_,
>> group0_.Name as Name2_, group0_.Address1 as Address4_2_,
>> group0_.Address2 as Address5_2_, group0_.City as City2_, group0_.Zip
>> as Zip2_, group0_.Phone as Phone2_, group0_.Fax as Fax2_,
>> group0_.ContactPerson as Contact10_2_, group0_.Comments as Comments2_,
>> group0_.LastModifiedDTM as LastMod12_2_, group0_.GoLiveDate as
>> GoLiveDate2_, group0_.be_OID as be14_2_, group0_.StateID as StateID2_
>> from tblGroup group0_ where (groupnID<=5 )
>> select group0_.GroupNID as GroupNID2_, group0_.GroupStatusID as
>> GroupSta2_2_, group0_.Name as Name2_, group0_.Address1 as Address4_2_,
>> group0_.Address2 as Address5_2_, group0_.City as City2_, group0_.Zip
>> as Zip2_, group0_.Phone as Phone2_, group0_.Fax as Fax2_,
>> group0_.ContactPerson as Contact10_2_, group0_.Comments as Comments2_,
>> group0_.LastModifiedDTM as LastMod12_2_, group0_.GoLiveDate as
>> GoLiveDate2_, group0_.be_OID as be14_2_, group0_.StateID as StateID2_
>> from tblGroup group0_ where (groupnID<=5 )
>> select group0_.GroupNID as GroupNID2_, group0_.GroupStatusID as
>> GroupSta2_2_, group0_.Name as Name2_, group0_.Address1 as Address4_2_,
>> group0_.Address2 as Address5_2_, group0_.City as City2_, group0_.Zip
>> as Zip2_, group0_.Phone as Phone2_, group0_.Fax as Fax2_,
>> group0_.ContactPerson as Contact10_2_, group0_.Comments as Comments2_,
>> group0_.LastModifiedDTM as LastMod12_2_, group0_.GoLiveDate as
>> GoLiveDate2_, group0_.be_OID as be14_2_, group0_.StateID as StateID2_
>> from tblGroup group0_ where (groupnID<=5 )
>> Obtaining IDbConnection from Driver
>> Opened IDataReader, open IDataReaders: 1
>> processing result set
>> result set row: 0
>> returning '1' as column: GroupNID2_
>> result row: EntityKey[Domain.Group#1]
>> result set row: 1
>> returning '2' as column: GroupNID2_
>> result row: EntityKey[Domain.Group#2]
>> result set row: 2
>> returning '3' as column: GroupNID2_
>> result row: EntityKey[Domain.Group#3]
>> result set row: 3
>> returning '4' as column: GroupNID2_
>> result row: EntityKey[Domain.Group#4]
>> result set row: 4
>> returning '5' as column: GroupNID2_
>> result row: EntityKey[Domain.Group#5]
>> done processing result set (5 rows)
>> running NHybridDataReader.Dispose()
>> Closed IDataReader, open IDataReaders :0
>> Closed IDbCommand, open IDbCommands: 0
>> aggressively releasing database connection
>> Closing connection
>> total objects hydrated: 0
>> initializing non-lazy collections
>> after autocommit
>> transaction completion
>> aggressively releasing database connection
>>
>>
>> On Jun 2, 10:57 am, Jozef Sevcik <[email protected]> wrote:
>> > can you post output from log4net from NHibernate.Caches (and NCache
>> > provider if possible)
>> > what's in log when you are trying to fetch cached objects again ?
>> >
>> > 2009/6/2 Max Badrak <[email protected]>:
>> >
>> >
>> >
>> >
>> >
>> > > Can you please be a bit more specific? I did read this post, as well
>> > > as others written by Ayende on this subject, as well as relevant
>> > > chapters of "Nhibernate in Action", but still apparently don't
>> > > understand something...
>> >
>> > > On Jun 2, 9:00 am, Fabio Maulo <[email protected]> wrote:
>> > >>
>> http://ayende.com/Blog/archive/2009/04/24/nhibernate-2nd-level-cache....
>> > >> 2009/6/2 Max Badrak <[email protected]>
>> >
>> > >> > I have a piece of code that, in essense, does:
>> >
>> > >> > Session.CreateCriteria(typeof (TDomainObject)).SetCacheable
>> > >> > (true).List<TDomainObject>();
>> >
>> > >> > Where Session is NH session, of course. The second level cache is
>> > >> > configured and turned on. hibernate.cache.use_query_cache is set to
>> > >> > true. The TDomainObject has caching enabled in the mapping file.
>> When
>> > >> > I run the program with log level cranked up to DEBUG, I can see NH
>> > >> > putting data into the cache, and I can see the objects in my second
>> > >> > level cache (to be specific, I am using NCache -- an out of proc,
>> > >> > cluster-level cache). The problem is that when the program is run
>> > >> > repeatedly, it always hits the database, regardless of whether the
>> > >> > results are already in the cache or not. If I run
>> Session.Load(typeof
>> > >> > (TDomainObject), 1) when there's something in the cache -- it works
>> as
>> > >> > expected -- i.e. NH checks the cache, and returns the object out of
>> > >> > memory.
>> >
>> > >> > Am I missing something trivial, or is the scenario above just not
>> > >> > supported? What would I need to do to make NH hit the cache? Create
>> an
>> > >> > explicit query in xml, enable caching for it, and use it instead
>> > >> > of .List()?
>> >
>> > >> --
>> > >> Fabio Maulo
>> >
>> > --
>> > Jozef
>> >>
>>
>
>
> --
> Fabio Maulo
>
--
Fabio Maulo
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