Terracotta Discussion Forums

Hi,
There are lot of topics on L1,L2 for none of them are clear for newbies.

1) How L1 and L2 works?

Lets we have three L1s and one L2 on server

When first L1 loads the data will it look in local cache first and look at L2 and if its not in both , it loads from db and put in L1 ,L2?

When first L1 updates the data it updates its local cache and L2 ? Will the second L1 get updated as well by L2?

Basically I am referring How stale data works in both multiple L1's and L2?

Regards
Chava

Hi, You pretty much nailed it with 1 exception. The L2 doesn't push data to L1's when a person tries to retrieve data from the second L1 it will get faulted from the L2 the first time. That said, if the data is changed the data will be kept fresh in the cluster.

Does that make sense?

Cheers,
Steve

Thank you Steve. The data get refreshed in cluster means, all L1's and L2 will get resfreshed? L2 sends stale message to L1's ? How it works?

Also, do we have to keep local cache ? Is it mandatory? I want to cache zip codes and do not want keep that in every local cache and only in L2. is it possible?

Thank You
Chava

Yeah, entries on nodes that are stale are notified so they can be invalidated.

In answer to your other question. Yes, you can turn off the local cache.

If we use only L2 ,is it slow performance ?

Its looks very promising so far.

L2 should give you milli-second latency vs micro-second latency for things cached in the L1.

When a person tries to retrieve data from the second L1 it will get faulted from the L2 the first time . Its only the data user trying to retrive not all the data on L2 right?

Right, it will get retrieved but only the data that is needed.

You are correct Chava.

Hi,

What are the exact features we are going to missing if we choose open source instead of commercial version?

Thanks
Chava

Any ideas?

I am trying to finish evaluation on this?

Thanks
Chava

Chava - I would suggest you reach out to sales@terracottatech.com and someone will walk you though these differences.

I have already talked to sales people before. I was not that clear.

Try this page for a comparison table:

http://terracotta.org/products/enterprise-suite/compare-editions

You can also read through the documentation -- commercial (enterprise) features are called out.