high performance hibernate insert
- by luke
I am working on a latency sensitive part of an application, basically i will receive a network event transform the data and then insert all the data into the DB. After profiling i see that basically all my time is spent trying to save the data. here is the code
private void insertAllData(Collection<Data> dataItems)
{
long start_time = System.currentTimeMillis();
long save_time = 0;
long commit_time = 0;
Transaction tx = null;
try
{
Session s = HibernateSessionFactory.getSession();
s.setCacheMode(CacheMode.IGNORE);
s.setFlushMode(FlushMode.NEVER);
tx = s.beginTransaction();
for(Data data : dataItems)
{
s.saveOrUpdate(data);
}
save_time = System.currentTimeMillis();
tx.commit();
s.flush();
s.clear();
}
catch(HibernateException ex)
{
if(tx != null)
tx.rollback();
}
commit_time = System.currentTimeMillis();
System.out.println("Save: " + (save_time - start_time));
System.out.println("Commit: " + (commit_time - save_time));
System.out.println();
}
The size of the collection is always less than 20. here is the timing data that i see:
Save: 27
Commit: 9
Save: 27
Commit: 9
Save: 26
Commit: 9
Save: 36
Commit: 9
Save: 44
Commit: 0
This is confusing to me. I figure that the save should be quick and all the time should be spent on commit. but clearly I'm wrong. I have also tried removing the transaction (its not really necessary) but i saw worse times... I have set hibernate.jdbc.batch_size=20...
i need this operation to be as fast as possible, ideally there would only be one roundtrip to the database. How can i do this?
