Jukka Zitting wrote:
A) a change log must be persisted as a whole or not at all
I) while a change log is persisted a read must not see partially
stored content
These could both be achieved also with connection pooling, just
acquire a connection at the beginning of PersistenceManager.store()
and commit the changes at the end of the method before releasing the
connection.
Similar pattern would also work for all the load() and exists()
methods to avoid the need to synchronize things on the prepared
statements.
Agreed.
C) this is actually handled by the upper level
ACK, the key is the write lock on SharedItemStateManager. In fact, do
we even need the database persistence managers to be transactional
over multiple method calls?
I can't follow you here. what exactly do you mean by weakening transaction
requirements on the persistence manager? e.g. reading of uncommitted items?
And to follow, could we in fact already
now remove the synchronization of read operations given that
consistency is already achieved on a higher level?
yes, we can. the persistence manager just has to ensure that only committed data
is returned.
regards
marcel
