Sanity checks to detect concurrency bugs were assuming a threading
model where each client state would always be processed within
single thread of execution. This however may be too strong assumption
if the application uses some kind of thread pooling.
This patch relaxes those assumptions by removing current_thread_id_
from client_state and relaxing assertions against owning_thread_id_.
This patch also adds a new method
wait_rollback_complete_and_acquire_ownership() into
client_state. This method is idempotent and can be used to gain
control to client_state before before_command() is called.
The method will wait until possible background rollback process is
over and marks the state to s_exec to protect the state against
new background rollbacks.
Other fixes/improvements:
- High priority globals state is restored after discarding streaming.
- Allowed server_state transition donor -> synced.
- Client state method store_globals() was renamed to acquire_ownership()
to better describe the intent. Method store_globals() was left for
backwards compatibility and marked deprecated.
- populate and pass real error description buffer to provider in case
of applying error
- return 0 from server_state::on_apply() if error voting confirmed
consistency
- remove fragments and rollback after fragment applying failure
- always release streaming applier on commit or rollback
The streaming_rollback() was not called from transaction::bf_abort()
if a streaming transaction was BF aborted in executing state. This
was because the condition to enter streaming_rollback() checked
if the transaction state is executing. However, the transaction
state had already been changed to must_abort before.
As a fix, save the state to local variable when entering
bf_abort() and check against saved state in condition to enter
streaming_rollback().
Added unit test for the correct behavior in the case when streaming
transaction is BF aborted in executing state.
Silenced warning about failing to replicate rollback fragment.
This is pretty normal condition and may happen during shutdown/
configuration changes when SR transactions are rolled back.
* 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.
Storing information that background rollbacker in ongoing in client state has_rollback_
This can be used for detecting if there is ongoing background rollback,
and client should keep waiting in before_command() entry to avoid conflicts
in accessing client state during background rollbacking.
transaction::bf_abort() is modified to set has_rollback_ flag when
backgroung rollbacking has been assigned for the client
sync_rollback_complete() method has been modified to reset the backround
rollbacker flag
Unit tests which cause streaming rollback leaked memory because
the streaming applier handle which was created for rollback
fragment handling was not released. Roll back a streaming transaction
and release applier handle appropriately in corresponding tests.
* Release server lock temporarily when BF aborting local SR
transaction during view event processing
* Check transaction state for BF aborts in before_prepare() after
the lock has acquired after fragment removal
* Send rollback fragment only from streaming_rollback()
* Added server_id into transaction in order to be able to stop
streaming applier during high priority BF abort
* Added missing commit fragment applying
* Don't clear fragments for replaying SR transaction
quite useful as there might not be enough information for it
after the statement has been processed. Better to handle retrying
on DBMS side. Also removed after_statement_result enumeration and
return plain int from after_statement().
