Hello,

I have a simple problem :

given a set of identifiers [1,3,98,...], I want to write a function that returns the list of objects that exist with those identifiers in the database. I want also use the second level cache, to only query the db for the non-cached identifiers.

For example if i have the set [1,3,8,43,54]. If i know that 1 and 3 are in second level cache, i use the cache and only query the db for the rest :

select * from object where id in (8,43,54)

For that to work i must know if a particular identifier is present in the second level cache.

I cannot make something like :

Session.load(1)
Session.load(3)
Session.load(8)
Session.load(43)
Session.load(54)

because I am not sure that the identifiers exist in the DB.

And I cannot make

Session.get(1)
Session.get(3)
Session.get(8)
Session.get(43)
Session.get(54)

Because then it will make a query for each non-cached object, which is not efficient.

And i can't make

select * from object where id in (1,3,8,43,54)

because I am not using the second level cache then.

So my conclusion is that I must know if a particular identifier is present in the second level cache. Is there a way to know that?

Thx a lot for your help

Antoine

I don't know, if it should be the users task to interfere with the cache, but you could easily query the session cache by using the statistics API, see the last two paragraphs of:

http://www.hibernate.org/hib_docs/v3/reference/en/html_single/#performance-sessioncache