[jboss-user] [JBoss Cache: Core Edition] - Re: Jdbc Cahce Loader Issue

[manik.surtani@jboss.com]

Hi

"shanthi_jbosscache" wrote : 
  |   1. I want to know the difference between fetchpersistentstate and fetchinmemorystate.
  | 
  | My understanding is below
  | 
  |    (i).  if fetchinmemorystate is TRUE  - It acquires the initial state from the existing members in the cluster during startup
  | 

Correct, but only from the in-memory state of neighbouring caches.

"shanthi_jbosscache" wrote : 
  |    (ii).  if fetchpersistent state is TRUE - Reads the data from database and loads the data into its cache
  | 

Wrong.  If fetchPersistentState is true, then state is retrieved from the persistent state of neighbouring caches.

"shanthi_jbosscache" wrote : 
  |    (iii). if fetchinmemorystate is  TRUE and if fetchpersistent state is TRUE 
  |             a.it acquires the persistent state from the existing member in the cluster
  |             b.Deletes the record(s) from the DB.
  |             c.Persist the data fetched from the existing member in the cluster to DB
  |             d.Retrieves the data from DB and reloads the data into its cache
  | 

Correct.


"shanthi_jbosscache" wrote : 
  | 2. Can we set both fetchpersistentstate and fetchinmemorystate to TRUE. If we can, please explain how it will work and the need(advantage) behind this setting.
  | 

You can do this if you don't have a shared cache loader, but instead configure each cache instance with it's own standalone cache loader, e.g., on a file system.  This can help by loading up-to-date state from neighbouring caches' cache loaders in case your "persistent" state becomes out of date.  

"shanthi_jbosscache" wrote : 
  | 3. What is the impact on cache clustering if fetchpersistentstate is set to FALSE?
  | 

No negative impact at all since your cache loader is *shared* between all cache instances!

HTH,
Manik

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