Write-through Cache behavior during Transactional Operation

Question

If a put is called on a write-through cache during a transaction(with Optimistic Read-Committed settings) that involves multiple caches some set to write-through and others to write-behind, when will the store operation on the corresponding CacheStore be attempted?
     a) Immediately after the put() is called on the cache but before the transaction commit
     or
     b) Immediately after the transaction is committed irrespective of when the put is called

Answer 1

Hi Abhay,
     The backing map (in this case, <tt>com.tangosol.net.cache.ReadWriteBackingMap</tt>) is responsible for calling the CacheStore implementation. When "commit" is called, Coherence will synchronously send the data to the backing map; the backing map then determines what to do with the data. In the case of ReadWriteBackingMap, it will either (depending on its configuration) synchronously call CacheStore (meaning that a store exception will interrupt your transaction) or queue the update for later (meaning that any store exception will occur after the cache transaction has completed).
     In 3.0, the <rollback-cachestore-failures> element under <read-write-backing-map-scheme> controls whether CacheStore exceptions are propagated back to the client. If you are using a release prior to 3.0, please see this FAQ Item on CacheStore Exceptions.
     Jon Purdy
     Tangosol, Inc.