Broadleaf Commerce Discussion Forums

lets say i have a load balancer and two hosts running the same webapp and one database that is used by both hosts.

is it possible that two customer access the domain: customer A ends up on host 1 and customer B ends up on host 2 that they both receive the same customerId ? Looking at the blIdGenerationService the idTypeIdMap could get out of sync on two different hosts, correct ?

thanks

No, this is not correct. The id generation service works in the same way that Hibernate's sequence generator does. Each host connects to the database and says "give me a batch of IDs that nobody else knows about, then increment the database". In the case you presented, Host 1 would grab a batch of ids 100-149 and then Host 2 would grab a batch of IDs 150-199, etc etc. The logic for doing this is in the dao, IdGenerationDaoImpl.findNextId() which the service uses.

but isn't it possible that hypothetically if both hosts call that findNextId() method at the same time that both get the same range ?

i dont see any locking of the idGeneration (blc_id_generation) table

IdGenerationImpl has a column annotated with @Version: https://github.com/BroadleafCommerce/Br ... l.java#L53. This allows Hibernate to do optimistic locking on each record which means that if some other server tries to write a new batch of IDs, then it can't unless it has the latest version. You can see the retry logic at https://github.com/BroadleafCommerce/Br ... .java#L100.