Caching objects when inserted

broden · **Joined:** Thu Jun 16, 2005 12:43 am **Posts:** 4

hello

I'm using the latest Hibernate release with EHCache as a second-level cache. All settings are pretty much default. The app uses very simple bean-like objects with no association, but the rate of writes and reads is very high.

I turned statistics on and noticed that I have 0 second-level cache hits for selects, so apparently all objects are fetched from database.

I wonder if there's a way to make this setup store objects in the second-level cache and fetch then from there instead of selecting from database. Even if there's only one select for each object. Basically using Hibernate + cache as an in-memory object smart cache. Or is it only possible for session first-level cache?
I thought second-level cache did that too but apparently not...

all comments will be greatly appreciated

thanks

Denis.

max · **Posted:** Thu Jun 16, 2005 3:24 am

if you execute queries then we have to go to the database to resolve it - neither first or second level cache is a full fledged SQL database ;)

broden · **Joined:** Thu Jun 16, 2005 12:43 am **Posts:** 4

Oh... I thought if the identity is set up properly, then, under certain scope settings, Hibernate will first look up the cache for the object...
What is the second-level cache for then?

max · **Posted:** Sat Jun 18, 2005 1:54 am

its all in the doc - caches are for looking up entities by *id* to improve performance.

mahikty · **Posted:** Sat Jun 18, 2005 9:35 am

Hi Max,

I have a similar question for Query Caching.
If i execute select queries multiple times the data is read from the cache

but if i make any insert to the table and query mulitple time using
query cache it is not read from cache but an sql is triggered.

It would be greatful if you could give some pointers regarding
this issue.

Regards

max · **Posted:** Sat Jun 18, 2005 12:22 pm

sorry - but all this is explained in great detail in ref. doc, Hibernate in Action and our training........sorry - but to hot weather here now for me to reexplain stuff :)

broden · **Joined:** Thu Jun 16, 2005 12:43 am **Posts:** 4

max wrote:

its all in the doc - caches are for looking up entities by *id* to improve performance.

Yeah that's what I thought - I look up entities by *id*. Insert and then look up by *id*. And still get 0 cache hit, but I also 0 cache miss.... Hibernate in Action does say that caches help when lookup by *id* is conducted, but I'm still having a problem.... :)
thanks though.

max · **Posted:** Mon Jun 20, 2005 1:50 am

and looking up by id (that will look in the cache) is *not* done via a query/criteria, but via .get()/.load() or object navigation.