diff options
Diffstat (limited to 'wsrep-lib/include/wsrep/client_service.hpp')
| -rw-r--r-- | wsrep-lib/include/wsrep/client_service.hpp | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/wsrep-lib/include/wsrep/client_service.hpp b/wsrep-lib/include/wsrep/client_service.hpp new file mode 100644 index 00000000..d47396df --- /dev/null +++ b/wsrep-lib/include/wsrep/client_service.hpp @@ -0,0 +1,223 @@ +/* + * Copyright (C) 2018 Codership Oy <info@codership.com> + * + * This file is part of wsrep-lib. + * + * Wsrep-lib is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 2 of the License, or + * (at your option) any later version. + * + * Wsrep-lib is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with wsrep-lib. If not, see <https://www.gnu.org/licenses/>. + */ + +/** @file client_service.hpp + * + * This file will define a `callback` abstract interface for a + * DBMS client session service. The interface will define methods + * which will be called by the wsrep-lib. + */ + +#ifndef WSREP_CLIENT_SERVICE_HPP +#define WSREP_CLIENT_SERVICE_HPP + +#include "buffer.hpp" +#include "provider.hpp" +#include "mutex.hpp" +#include "lock.hpp" + +namespace wsrep +{ + class client_service + { + public: + client_service() { } + virtual ~client_service() { } + + /** + * Return true if the current transaction has been interrupted + * by the DBMS. The lock which is passed to interrupted call + * will always have underlying mutex locked. + * + * @param lock Lock object grabbed by the client_state + */ + virtual bool interrupted(wsrep::unique_lock<wsrep::mutex>& lock) const = 0; + + /** + * Reset possible global or thread local parameters associated + * to the thread. + */ + virtual void reset_globals() = 0; + + /** + * Store possible global or thread local parameters associated + * to the thread. + */ + virtual void store_globals() = 0; + + /** + * Set up a data for replication. + */ + virtual int prepare_data_for_replication() = 0; + + /** + * Clean up after transcation has been terminated. + */ + virtual void cleanup_transaction() = 0; + + // + // Streaming + // + /** + * Return true if current statement is allowed for streaming, + * otherwise false. + */ + virtual bool statement_allowed_for_streaming() const = 0; + + /** + * Return the total number of bytes generated by the transaction + * context. + */ + virtual size_t bytes_generated() const = 0; + + /** + * Prepare a buffer containing data for the next fragment to replicate. + * The caller may set log_position to record the database specific + * position corresponding to changes contained in the buffer. + * When the call returns, the log_position will be available to read + * from streaming_context::log_position(). + * + * @return Zero in case of success, non-zero on failure. + * If there is no data to replicate, the method shall return + * zero and leave the buffer empty. + */ + virtual int prepare_fragment_for_replication(wsrep::mutable_buffer& buffer, + size_t& log_position) = 0; + + /** + * Remove fragments from the storage within current transaction. + * Fragment removal will be committed once the current transaction + * commits. + * + * @return Zero in case of success, non-zero on failure. + */ + virtual int remove_fragments() = 0; + + // + // Rollback + // + /** + * Perform brute force rollback. + * + * This method may be called from two contexts, either from + * client state methods when the BF abort condition is detected, + * or from the background rollbacker thread. The task for this + * method is to release all reasources held by the client + * after BF abort so that the high priority thread can continue + * applying. + */ + virtual int bf_rollback() = 0; + + // + // Interface to global server state + // + /** + * Forcefully shut down the DBMS process or replication system. + * This may be called in situations where + * the process may encounter a situation where data integrity + * may not be guaranteed or other unrecoverable condition is + * encontered. + */ + virtual void emergency_shutdown() = 0; + + // Replaying + /** + * Notify that the client will replay. + * + * @todo This should not be visible to DBMS level, should be + * handled internally by wsrep-lib. + */ + virtual void will_replay() = 0; + + /** + * Signal that replay is done. + */ + virtual void signal_replayed() = 0; + + /** + * Replay the current transaction. The implementation must put + * the caller Client Context into applying mode and call + * client_state::replay(). + * + * @todo This should not be visible to DBMS level, should be + * handled internally by wsrep-lib. + */ + virtual enum wsrep::provider::status replay() = 0; + + /** + * Replay the current transaction. This is used for replaying + * prepared XA transactions, which are BF aborted but not + * while orderding commit / rollback. + */ + virtual enum wsrep::provider::status replay_unordered() = 0; + + /** + * Wait until all replaying transactions have been finished + * replaying. + * + * @todo This should not be visible to DBMS level, should be + * handled internally by wsrep-lib. + */ + virtual void wait_for_replayers(wsrep::unique_lock<wsrep::mutex>&) = 0; + + // + // XA + // + /** + * Send a commit by xid + */ + virtual enum wsrep::provider::status commit_by_xid() = 0; + + /** + * Returns true if the client has an ongoing XA transaction. + * This method is used to determine when to cleanup the + * corresponding wsrep-lib transaction object. + * This method should return false when the XA transaction + * is over, and the wsrep-lib transaction object can be + * cleaned up. + */ + virtual bool is_explicit_xa() = 0; + + /** + * Returns true if the currently executing command is + * a rollback for XA. This is used to avoid setting a + * a deadlock error rollback as it may be unexpected + * by the DBMS. + */ + virtual bool is_xa_rollback() = 0; + + // + // Debug interface + // + /** + * Enter debug sync point. + * + * @params sync_point Name of the debug sync point. + */ + virtual void debug_sync(const char* sync_point) = 0; + + /** + * Forcefully kill the process if the crash_point has + * been enabled. + */ + virtual void debug_crash(const char* crash_point) = 0; + }; +} + +#endif // WSREP_CLIENT_SERVICE_HPP |