SequenceStyleGenerator generator badly triggering batcher with Stateless Sessions

[gokhanabatay]

We have a database(Oracle) sequence that increments 100 at a time, sequence mapped with below method so 1000 Entity Save method access calls 10 times to database for new Sequence.nextval.

Wit a stateless session (and adonet.batch_size = 1000, order_updates = true in hibernate.cfg.xml), every 100 + 1 calls, Save triggers the batcher. It's uses same Batcher instance with SequenceStyleGenerator. Why "SequenceStyleGenerator" needs batcher at all, just to reads one line of data?

(With a statefull session (and adonet.batch_size = 1000, order_updates = true in hibernate.cfg.xml), every 100 Save calls just triggers Sequence.nextval. Batcher waits until batch size(1000) to get triggered.)

Fluent Mapping:

Id(x => x.Guid).Column("GUID").GeneratedBy.PooledSequence(100); 

 public static TParent PooledSequence<TParent>(this IdentityGenerationStrategyBuilder<TParent> generationStrategyBuilder, int allocationSize = 1, string sequenceName = "")
 {
            return generationStrategyBuilder.Custom<SequenceStyleGenerator>(p =>
            {
                p.AddParam("sequence_name", string.IsNullOrEmpty(sequenceName) ? DefaultPooledSequenceName : sequenceName);
                p.AddParam("value_column", "NEXT_VALUE");
                p.AddParam("optimizer", "pooled");
                p.AddParam("increment_size", allocationSize.ToString());
            });
 }

[hazzik]

Somehow related to this: hibernate/hibernate-orm@b006a6c

[hazzik]

I was looking into this. It's quite a mess. The fix should be easy.

@gokhanabatay would you be able to submit failing test(s)?

[gokhanabatay]

Hi @hazzik sorry for late response, I need to know how to check batcher access count and how to create custom sequence via nhibernate mappings.

But I think issue is clear let me tell you.

In StatelessSessionImpl.Insert method
object id = persister.IdentifierGenerator.Generate(this, entity); uses directly Batcher so existing waiting commands will be flushed instant.

In SessionImpl uses ActionQueue so accessing Batcher in AbstractSaveEventListener.SaveWithGeneratedId method object generatedId = persister.IdentifierGenerator.Generate(source, entity) for sequences does not trigger waiting inserts/updates/deletes.

For better batching support I think, identity generators should use different batcher, is it realy necessary use Batcher with identity generators at all?