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wsrep-lib/include/wsrep/client_service.hpp
2018-07-09 23:03:44 +03:00

163 lines
4.5 KiB
C++

//
// Copyright (C) 2018 Codership Oy <info@codership.com>
//
/** @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 transaction;
class client_service
{
public:
client_service() { }
virtual ~client_service() { }
/**
* Return true if two pahase commit is required for transaction
* to commit.
*/
virtual bool do_2pc() const = 0;
/**
* Return true if the current transaction has been interrupted
* by the DBMS.
*/
virtual bool interrupted() 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;
virtual size_t bytes_generated() const = 0;
virtual int prepare_fragment_for_replication(wsrep::mutable_buffer&) = 0;
/**
* Remove fragments from the storage within current transaction.
* Fragment removal will be committed once the current transaction
* commits.
*/
virtual void 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;
/**
* 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;
/**
* 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;
//
// 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;
};
/**
* Debug callback methods. These methods are called only in
* builds that have WITH_DEBUG defined.
*/
class client_debug_callback
{
public:
};
}
#endif // WSREP_CLIENT_SERVICE_HPP