Moved the check for transaction state before certification step
into separate method abort_or_interrupted() which will check the state
and adjust state and client_state error status accordingly.
Moved the check for abort_or_interrupted() to happen before
the state is changed to certifying and write set data is appended.
This makes the check atomic and reduces the probability of race
conditions. After this check we rely on provider side transaction
state management and error reporting until the certification step
is over.
Change to public API: Pass client_state mutex wrappend in unique_lock
object to client_service::interrupted() call. This way the DBMS side
has a control to the lock object in case it needs to unlock it
temporarily. The underlying mutex will always be locked when the lock
object is passed via interrupted() call.
Other: Allow server_state change from donor to connected. This may
happen if the joiner crashes during SST and the provider reports
it before the DBMS side SST mechanism detects the error.
Fragment removal for SR transaction is done in transaction context
to make it atomic. However, this means that if the BF abort arrives
during fragment removal, the transaction may be rolled back inside
client_service::remove_fragments(), and client_state::after_prepare()
is left in aborted state. This case was not handled in the
post condition checks of after_prepare().
Fixed assertion in after_prepare() and implemented unit test.
* Adds method wsrep::transaction::streaming_step() so that there is a
single place where streaming context unit counter is udpated.
The method also checks that some data has been generated before
attempting fragment replication.
* Emit a warning if there is an attempt to replicate a fragment and
there is no data to replicate.
* Check fragment removal error code in prepare phase. It is possible
that the transaction gets BF aborted during fragment removal.
* Mark fragment certified in certify_fragment() even if the provider
returns cert failed error. With current wsrep-API error codes
it may not be possible to distinquish certification failure
and BF abort during fragment replication. This may also be a
provider bug. As a result rollback fragment may sometimes be
replicated when it would not be necessary.
* Pass condition variable for client_state
* Notify all cond waiters when changing the transcation status to
aborted
* Wait for aborting transaction state aborted in before_command
