Remove methods `is_xa()`, `is_xa_prepare()`, and `xid()` from
client_service interface. Instead, transactions are explicitly
assigned their xid, through at start of XA.
* Add method `restore_prepared_transaction` to `client_state` class
which restores a transaction state from storage given its xid.
* Add method `commit_or_rollback_by_xid` to terminate prepared XA
transactions by xid.
* Make sure that transactions in prepared state are not rolled back
when their master fails/partitions away.
Class streaming_context can now keep track of database specific log
position for streaming. Previously, it was assumed that the log
position was based of off the buffer size which was filled in
client_service::prepare_fragment_for_replication(). However, for XA
the buffer may contain data that is not in the log. Therefore,
subsequent calls to prepare_fragment_for_replication() could not find
the appropriate log_position based on the certified_bytes(), which
would returns the total number of bytes return in the buffers that
were certified.
next_fragment is called outside the scope of a high_priority_switch,
and we may be in a different thread context then the streaming applier
was created in
Force fragment replication when XA transaction is prepared, with
prepare fragment. Commit fragment happens in before_commit().
Adjusted fragment removal, which cannot happen in atomically with the
executing transaction.
Added a wsrep::thread_service interface to allow application to
inject instrumented thread, mutex and condition variable implementation
for provider.
The interface is defined in include/wsrep/thread_service.hpp.
Sample implementation is provided in dbsim/db_threads.[h|c]pp.
This patch will also clean up some remaining dependencies to
wsrep-API compilation units so that the dependency to wsrep-API
is header only. This will extending the provider support to
later wsrep-API versions.
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
Added version header which contains definitions for major, minor
and patch version numbers, as well as for lowest and highest supported
wsrep-API versions. The library versioning follows Semantic Versioning.
Handle CMake policy CMP0048 in top level CMakeLists.txt.
Fixes a bug where the fact that an SR master leaves the primary view
gets missed. When two consecutive primary views have the same
membership we now assume that every SR needs to be rolled back, as the
system may have been through a state of only non-primary components.
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.
Check if the superproject has already enabled C++11 before enabling
it in CMakeLists.txt.
Added utility file atomic.hpp to select the correct atomics header
to work around issues with ancient GCC 4.4.
The empty implementation of log_dummy_write_set() in dbsim
high priority service implementation left unreleased commit
order critical section behind whenever remote write set failed
certification. Added calls to do empty commit to release the
critical section.
Other:
Implemented ostream operator<< for wsrep:🧵:id, and added
printout of owning thread into transaction debug output.
Introduced server_service recover_streaming_appliers() interface
call which will be called in total order whenever streaming appliers
must be recovered. The call comes with two overloads, one which
can be called from client context (e.g. after SST has been received)
and the other from high priority context (e.g. view event handling).
The client context overload should be eventually be deprecated once
there is a mechanism to make provider signal that it has joined to
the cluster and will start applying events.
* Implemented encryption callback and enc_set_key
* Added pure virtual functions for encryption functionality
* Set enc key if provider was not loaded on time
In general the position where the storage recovers after a SST
cannot be known untile the recovery process is over. This in turn
means that the position cannot be known when the server_state
sst_received() method is called. Worked around the problem by
introducing get_position() method into server service which
can be used to get the position from stable storage after SST
has completed and the state has been recovered.
* 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.
Intruduced server_state::interrupt_state_waiters() to interrupt
all waiters inside server_state::wait_until_state(). This mechanism
is needed when an error is encountered during state change processing
and waiting threads may need to be interrupted to check and handle
the error condition.
Made server_state::wait_until_state() to throw exception if the
wait was interrupted and the new server state is either disconnecting
or disconnected, which usually indicates error condition.
Transition from server_state connected state to disconnecting must
be allowed to deal with errors during server startup.
Added SST first test cases for server_state transitions:
* Successful join via SST
* Error in connect state
* Error in joiner state
