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Diffstat (limited to 'wsrep-lib/include/wsrep/client_state.hpp')
| -rw-r--r-- | wsrep-lib/include/wsrep/client_state.hpp | 1075 |
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diff --git a/wsrep-lib/include/wsrep/client_state.hpp b/wsrep-lib/include/wsrep/client_state.hpp new file mode 100644 index 00000000..d8449d7a --- /dev/null +++ b/wsrep-lib/include/wsrep/client_state.hpp @@ -0,0 +1,1075 @@ +/* + * Copyright (C) 2018-2019 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_state.hpp + * + * + * Return value conventions: + * + * The calls which may alter either client_state or associated + * transaction state will generally return zero on success and + * non-zero on failure. More detailed error information is stored + * into client state and persisted there until explicitly cleared. + */ + +#ifndef WSREP_CLIENT_STATE_HPP +#define WSREP_CLIENT_STATE_HPP + +#include "provider.hpp" +#include "transaction.hpp" +#include "client_id.hpp" +#include "mutex.hpp" +#include "lock.hpp" +#include "buffer.hpp" +#include "thread.hpp" +#include "xid.hpp" +#include "chrono.hpp" + +namespace wsrep +{ + class client_service; + class server_state; + class provider; + class condition_variable; + + enum client_error + { + e_success, + e_error_during_commit, + e_deadlock_error, + e_interrupted_error, + e_size_exceeded_error, + e_append_fragment_error, + e_not_supported_error, + e_timeout_error + }; + + static inline const char* to_c_string(enum client_error error) + { + switch (error) + { + case e_success: return "success"; + case e_error_during_commit: return "commit_error"; + case e_deadlock_error: return "deadlock_error"; + case e_interrupted_error: return "interrupted_error"; + case e_size_exceeded_error: return "size_exceeded_error"; + case e_append_fragment_error: return "append_fragment_error"; + case e_not_supported_error: return "not_supported_error"; + case e_timeout_error: return "timeout_error"; + } + return "unknown"; + } + + static inline std::string to_string(enum client_error error) + { + return to_c_string(error); + } + /** + * Client State + */ + class client_state + { + public: + /** + * Client mode enumeration. + */ + enum mode + { + /** undefined mode */ + m_undefined, + /** Locally operating client session. */ + m_local, + /** High priority mode */ + m_high_priority, + /** Client is in total order isolation mode */ + m_toi, + /** Client is executing rolling schema upgrade */ + m_rsu, + /** Client is executing NBO */ + m_nbo + }; + + static const int n_modes_ = m_nbo + 1; + /** + * Client state enumeration. + * + */ + enum state + { + /** + * Client session has not been initialized yet. + */ + s_none, + /** + * Client is idle, the control is in the application which + * uses the DBMS system. + */ + s_idle, + /** + * The control of the client processing is inside the DBMS + * system. + */ + s_exec, + /** + * Client handler is sending result to client. + */ + s_result, + /** + * The client session is terminating. + */ + s_quitting + }; + + static const int state_max_ = s_quitting + 1; + + /** + * Aqcuire ownership on the thread. + * + * This method should be called every time the thread + * operating the client state changes. This method is called + * implicitly from before_command() and + * wait_rollback_complete_and_acquire_ownership(). + */ + void acquire_ownership() + { + wsrep::unique_lock<wsrep::mutex> lock(mutex_); + do_acquire_ownership(lock); + } + + /** + * @deprecated Use acquire_ownership() instead. + */ + void store_globals() + { + acquire_ownership(); + } + + /** + * Destructor. + */ + virtual ~client_state(); + + /** @name Client session handling */ + /** @{ */ + /** + * This method should be called when opening the client session. + * + * Initializes client id and changes the state to s_idle. + */ + void open(wsrep::client_id); + + /** + * This method should be called before closing the client session. + * + * The state is changed to s_quitting and any open transactions + * are rolled back. + */ + void close(); + + /** + * This method should be called after closing the client session + * to clean up. + * + * The state is changed to s_none. + */ + void cleanup(); + + /** + * Overload of cleanup() method which takes lock as argument. + * This method does not release the lock during execution, but + * the lock is needed for debug build sanity checks. + */ + void cleanup(wsrep::unique_lock<wsrep::mutex>& lock); + /** @} */ + + /** @name Client command handling */ + /** @{ */ + /** + * This mehod should be called before the processing of command + * received from DBMS client starts. + * + * This method will wait until the possible synchronous + * rollback for associated transaction has finished unless + * wait_rollback_complete_and_acquire_ownership() has been + * called before. + * + * The method has a side effect of changing the client + * context state to executing. + * + * The value set by keep_command_error has an effect on + * how before_command() behaves when it is entered after + * background rollback has been processed: + * + * - If keep_command_error is set true, the current error + * is set and success will be returned. + * - If keep_command_error is set false, the transaction is + * cleaned up and the return value will be non-zero to + * indicate error. + * + * @param keep_command_error Make client state to preserve error + * state in command hooks. + * This is needed if a current command is not supposed to + * return an error status to the client and the protocol must + * advance until the next client command to return error status. + * + * @return Zero in case of success, non-zero in case of the + * associated transaction was BF aborted. + */ + int before_command(bool keep_command_error); + + int before_command() + { + return before_command(false); + } + + /** + * This method should be called before returning + * a result to DBMS client. + * + * The method will check if the transaction associated to + * the connection has been aborted. Rollback is performed + * if needed. After the call, current_error() will return an error + * code associated to the client state. If the error code is + * not success, the transaction associated to the client state + * has been aborted and rolled back. + */ + void after_command_before_result(); + + /** + * Method which should be called after returning the + * control back to DBMS client.. + * + * The method will do the check if the transaction associated + * to the connection has been aborted. If so, rollback is + * performed and the transaction is left to aborted state. + * The next call to before_command() will return an error and + * the error state can be examined after after_command_before_resul() + * is called. + * + * This method has a side effect of changing state to + * idle. + */ + void after_command_after_result(); + /** @} */ + + /** @name Statement level operations */ + /** @{ */ + /** + * Before statement execution operations. + * + * Check if server is synced and if dirty reads are allowed. + * + * @return Zero in case of success, non-zero if the statement + * is not allowed to be executed due to read or write + * isolation requirements. + */ + int before_statement(); + + /** + * After statement execution operations. + * + * * Check for must_replay state + * * Do rollback if requested + */ + int after_statement(); + /** @} */ + + /** + * Perform cleanup after applying a transaction. + * + * @param err Applying error (empty for no error) + */ + void after_applying(); + + /** @name Replication interface */ + /** @{ */ + /** + * Start a new transaction with a transaction id. + * + * @todo This method should + * - Register the transaction on server level for bookkeeping + * - Isolation levels? Or part of the transaction? + */ + int start_transaction(const wsrep::transaction_id& id); + + /** + * Establish read view ID of the transaction. + * + * This method should be preferably called immediately before any + * first read or write operation in the transaction is performed, + * Then it can be called with default NULL parameter and will use + * the current last committed GTID. + * Alternatively it can be called at any time before commit with an + * explicit GTID that corresponds to transaction read view. + * + * @param gtid optional explicit GTID of the transaction read view. + */ + int assign_read_view(const wsrep::gtid* const gtid = NULL); + + /** + * Append a key into transaction write set. + * + * @param key Key to be appended + * + * @return Zero on success, non-zero on failure. + */ + int append_key(const wsrep::key& key); + + /** + * Append keys in key_array into transaction write set. + * + * @param keys Array of keys to be appended + * + * @return Zero in case of success, non-zero on failure. + */ + int append_keys(const wsrep::key_array& keys); + + /** + * Append data into transaction write set. + */ + int append_data(const wsrep::const_buffer& data); + + /** @} */ + + /** @name Streaming replication interface */ + /** @{ */ + /** + * This method should be called after every row operation. + */ + int after_row(); + + /** + * Set streaming parameters. + * + * @param fragment_unit Desired fragment unit + * @param fragment_size Desired fragment size + */ + void streaming_params(enum wsrep::streaming_context::fragment_unit + fragment_unit, + size_t fragment_size); + + /** + * Enable streaming replication. + * + * Currently it is not possible to change the fragment unit + * for active streaming transaction. + * + * @param fragment_unit Desired fragment unit + * @param fragment_size Desired fragment size + * + * @return Zero on success, non-zero if the streaming cannot be + * enabled. + */ + int enable_streaming( + enum wsrep::streaming_context::fragment_unit + fragment_unit, + size_t fragment_size); + + /** + * Disable streaming for context. + */ + void disable_streaming(); + + void fragment_applied(wsrep::seqno seqno); + /** + * Prepare write set meta data for ordering. + * This method should be called before ordered commit or + * rollback if the commit time meta data was not known + * at the time of the start of the transaction. + * This mostly applies to streaming replication. + * + * @param ws_handle Write set handle + * @param ws_meta Write set meta data + * @param is_commit Boolean to denote whether the operation + * is commit or rollback. + */ + int prepare_for_ordering(const wsrep::ws_handle& ws_handle, + const wsrep::ws_meta& ws_meta, + bool is_commit); + /** @} */ + + /** @name Applying interface */ + /** @{ */ + int start_transaction(const wsrep::ws_handle& wsh, + const wsrep::ws_meta& meta); + + int next_fragment(const wsrep::ws_meta& meta); + + /** @name Commit ordering interface */ + /** @{ */ + int before_prepare(); + + int after_prepare(); + + int before_commit(); + + int ordered_commit(); + + int after_commit(); + /** @} */ + int before_rollback(); + + int after_rollback(); + + /** + * This method should be called by the background rollbacker + * thread after the rollback is complete. This will allow + * the client to proceed through before_command() and + * wait_rollback_complete_and_acquire_ownership(). + */ + void sync_rollback_complete(); + + /** + * Wait for background rollback to complete. This method can + * be called before before_command() to verify that the + * background rollback has been finished. After the call returns, + * it is guaranteed that BF abort does not launch background + * rollback process before after_command_after_result() is called. + * This method is idempotent, it can be called many times + * by the same thread before before_command() is called. + */ + void wait_rollback_complete_and_acquire_ownership(); + /** @} */ + + // + // XA + // + /** + * Assign transaction external id. + * + * Other than storing the xid, the transaction is marked as XA. + * This should be called when XA transaction is started. + * + * @param xid transaction id + */ + void assign_xid(const wsrep::xid& xid) + { + transaction_.assign_xid(xid); + } + + /** + * Restores the client's transaction to prepared state + * + * The purpose of this method is to restore transaction state + * during recovery of a prepared XA transaction. + */ + int restore_xid(const wsrep::xid& xid) + { + return transaction_.restore_to_prepared_state(xid); + } + + /** + * Commit transaction with the given xid + * + * Sends a commit fragment to terminate the transaction with + * the given xid. For the fragment to be sent, a streaming + * applier for the transaction must exist, and the transaction + * must be in prepared state. + * + * @param xid the xid of the the transaction to commit + * + * @return Zero on success, non-zero on error. In case of error + * the client_state's current_error is set + */ + int commit_by_xid(const wsrep::xid& xid) + { + return transaction_.commit_or_rollback_by_xid(xid, true); + } + + /** + * Rollback transaction with the given xid + * + * Sends a rollback fragment to terminate the transaction with + * the given xid. For the fragment to be sent, a streaming + * applier for the transaction must exist, and the transaction + * must be in prepared state. + * + * @param xid the xid of the the transaction to commit + * + * @return Zero on success, non-zero on error. In case of error + * the client_state's current_error is set + */ + int rollback_by_xid(const wsrep::xid& xid) + { + return transaction_.commit_or_rollback_by_xid(xid, false); + } + + /** + * Detach a prepared XA transaction + * + * This method cleans up a local XA transaction in prepared state + * and converts it to high priority mode. + * This can be used to handle the case where the client of a XA + * transaction disconnects, and the transaction must not rollback. + * After this call, a different client may later attempt to terminate + * the transaction by calling method commit_by_xid() or rollback_by_xid(). + */ + void xa_detach(); + + /** + * Replay a XA transaction + * + * Replay a XA transaction that is in s_idle state. + * This may happen if the transaction is BF aborted + * between prepare and commit. + * Since the victim is idle, this method can be called + * by the BF aborter or the backround rollbacker. + */ + void xa_replay(); + + // + // BF aborting + // + /** + * Brute force abort a transaction. This method should be + * called by a transaction which needs to BF abort a conflicting + * locally processing transaction. + * + * @param lock Lock to protect client state. + * @param bf_seqno Seqno of the BF aborter. + */ + int bf_abort(wsrep::unique_lock<wsrep::mutex>& lock, wsrep::seqno bf_seqno); + /** + * Wrapper to bf_abort() call, grabs lock internally. + */ + int bf_abort(wsrep::seqno bf_seqno); + + /** + * Brute force abort a transaction in total order. This method + * should be called by the TOI operation which needs to + * BF abort a transaction. + */ + int total_order_bf_abort(wsrep::unique_lock<wsrep::mutex>& lock, wsrep::seqno bf_seqno); + + /** + * Wrapper to total_order_bf_abort(), grabs lock internally. + */ + int total_order_bf_abort(wsrep::seqno bf_seqno); + + /** + * Adopt a streaming transaction state. This is must be + * called from high_priority_service::adopt_transaction() + * during streaming transaction rollback. The call will + * set up enough context for handling the rollback + * fragment. + */ + void adopt_transaction(const wsrep::transaction& transaction); + + /** + * Adopt (store) transaction applying error for further processing. + */ + void adopt_apply_error(wsrep::mutable_buffer& err); + + /** + * Clone enough state from another transaction so that replaing will + * be possible with a transaction contained in this client state. + * + * @param transaction Transaction which is to be replied in this + * client state + */ + void clone_transaction_for_replay(const wsrep::transaction& transaction) + { + transaction_.clone_for_replay(transaction); + } + + /** @name Non-transactional operations */ + /** @{*/ + + /** + * Enter total order isolation critical section. If the wait_until + * is given non-default value, the operation is retried until + * successful, the given time point is reached or the client is + * interrupted. + * + * @param key_array Array of keys + * @param buffer Buffer containing the action to execute inside + * total order isolation section + * @param flags Provider flags for TOI operation + * @param wait_until Time point to wait until for successful + * certification. + * + * @return Zero on success, non-zero otherwise. + */ + int enter_toi_local( + const wsrep::key_array& key_array, + const wsrep::const_buffer& buffer, + std::chrono::time_point<wsrep::clock> + wait_until = + std::chrono::time_point<wsrep::clock>()); + /** + * Enter applier TOI mode + * + * @param ws_meta Write set meta data + */ + void enter_toi_mode(const wsrep::ws_meta& ws_meta); + + /** + * Return true if the client_state is under TOI operation. + */ + bool in_toi() const + { + return (toi_meta_.seqno().is_undefined() == false); + } + + /** + * Return the mode where client entered into TOI mode. + * The return value can be either m_local or + * m_high_priority. + */ + enum mode toi_mode() const + { + return toi_mode_; + } + + /** + * Leave total order isolation critical section. + * (for local mode clients) + * + * @param err definition of the error that happened during the + * execution of TOI operation (empty for no error) + */ + int leave_toi_local(const wsrep::mutable_buffer& err); + + /** + * Leave applier TOI mode. + */ + void leave_toi_mode(); + + /** + * Begin rolling schema upgrade operation. + * + * @param timeout Timeout in seconds to wait for committing + * connections to finish. + */ + int begin_rsu(int timeout); + + /** + * End rolling schema upgrade operation. + */ + int end_rsu(); + + /** + * Begin non-blocking operation. + * + * The NBO operation is started by grabbing TOI critical + * section. The keys and buffer are certifed as in TOI + * operation. If the call fails due to error returned by + * the provider, the provider error code can be retrieved + * by current_error_status() call. + * + * If the wait_until is given non-default value, the operation is + * retried until successful, the given time point is reached or the + * client is interrupted. + * + * @param keys Array of keys for NBO operation. + * @param buffer NBO write set + * @param wait_until Time point to wait until for successful certification. + * @return Zero in case of success, non-zero in case of failure. + */ + int begin_nbo_phase_one( + const wsrep::key_array& keys, + const wsrep::const_buffer& buffer, + std::chrono::time_point<wsrep::clock> + wait_until = + std::chrono::time_point<wsrep::clock>()); + + /** + * End non-blocking operation phase after aquiring required + * resources for operation. + * + * @param err definition of the error that happened during the + * execution of phase one (empty for no error) + */ + int end_nbo_phase_one(const wsrep::mutable_buffer& err); + + /** + * Enter in NBO mode. This method should be called when the + * applier launches the asynchronous process to perform the + * operation. The purpose of the call is to adjust + * the state and set write set meta data. + * + * @param ws_meta Write set meta data. + * + * @return Zero in case of success, non-zero on failure. + */ + int enter_nbo_mode(const wsrep::ws_meta& ws_meta); + + /** + * Begin non-blocking operation phase two. The keys argument + * passed to this call must contain the same keys which were + * passed to begin_nbo_phase_one(). + * + * If the wait_until is given non-default value, the operation is + * retried until successful, the given time point is reached or the + * client is interrupted. + * + * @param keys Key array. + * @param wait_until Time point to wait until for entering TOI for + * phase two. + */ + int begin_nbo_phase_two(const wsrep::key_array& keys, + std::chrono::time_point<wsrep::clock> + wait_until = + std::chrono::time_point<wsrep::clock>()); + + /** + * End non-blocking operation phase two. This call will + * release TOI critical section and set the mode to m_local. + * + * @param err definition of the error that happened during the + * execution of phase two (empty for no error) + */ + int end_nbo_phase_two(const wsrep::mutable_buffer& err); + + /** + * Get reference to the client mutex. + * + * @return Reference to the client mutex. + */ + wsrep::mutex& mutex() { return mutex_; } + + /** + * Get server context associated the the client session. + * + * @return Reference to server context. + */ + wsrep::server_state& server_state() const + { return server_state_; } + + wsrep::client_service& client_service() const + { return client_service_; } + /** + * Get reference to the Provider which is associated + * with the client context. + * + * @return Reference to the provider. + * @throw wsrep::runtime_error if no providers are associated + * with the client context. + * + * @todo Should be removed. + */ + wsrep::provider& provider() const; + + /** + * Get Client identifier. + * + * @return Client Identifier + */ + client_id id() const { return id_; } + + /** + * Get Client mode. + * + * @todo Enforce mutex protection if called from other threads. + * + * @return Client mode. + */ + enum mode mode() const { return mode_; } + + /** + * Get Client state. + * + * @todo Enforce mutex protection if called from other threads. + * + * @return Client state + */ + enum state state() const { return state_; } + + /** + * Return a const reference to the transaction associated + * with the client state. + */ + const wsrep::transaction& transaction() const + { + return transaction_; + } + + /** + * Mark the transaction associated with the client state + * (if any), as unsafe for parallel applying + * + * @return Zero on success, non-zero on error. + */ + int mark_transaction_pa_unsafe() + { + if (transaction_.active()) + { + transaction_.pa_unsafe(true); + return 0; + } + return 1; + } + + const wsrep::ws_meta& toi_meta() const + { + return toi_meta_; + } + + /** + * Do sync wait operation. If the method fails, current_error() + * can be inspected about the reason of error. + * + * @param Sync wait timeout in seconds. + * + * @return Zero on success, non-zero on error. + */ + int sync_wait(int timeout); + + /** + * Return the current sync wait GTID. + * + * Sync wait GTID is updated on each sync_wait() call and + * reset to wsrep::gtid::undefined() in after_command_after_result() + * method. The variable can thus be used to check if a sync wait + * has been performend for the current client command. + */ + const wsrep::gtid& sync_wait_gtid() const + { + return sync_wait_gtid_; + } + /** + * Return the last written GTID. + */ + const wsrep::gtid& last_written_gtid() const + { + return last_written_gtid_; + } + + /** + * Set debug logging level. + * + * Levels: + * 0 - Debug logging is disabled + * 1..n - Debug logging with increasing verbosity. + */ + void debug_log_level(int level) { debug_log_level_ = level; } + + /** + * Return current debug logging level. The return value + * is a maximum of client state and server state debug log + * levels. + * + * @return Current debug log level. + */ + int debug_log_level() const + { + return std::max(debug_log_level_, + wsrep::log::debug_log_level()); + } + + // + // Error handling + // + + /** + * Reset the current error state. + * + * @todo There should be some protection about when this can + * be done. + */ + void reset_error() + { + current_error_ = wsrep::e_success; + } + + /** + * Return current error code. + * + * @return Current error code. + */ + enum wsrep::client_error current_error() const + { + return current_error_; + } + + enum wsrep::provider::status current_error_status() const + { + return current_error_status_; + } + + /** + * Return true if rollbacker is active. The caller should + * hold the mutex protecting client_state. + */ + bool is_rollbacker_active() + { + return rollbacker_active_; + } + protected: + /** + * Client context constuctor. This is protected so that it + * can be called from derived class constructors only. + */ + client_state(wsrep::mutex& mutex, + wsrep::condition_variable& cond, + wsrep::server_state& server_state, + wsrep::client_service& client_service, + const client_id& id, + enum mode mode) + : owning_thread_id_(wsrep::this_thread::get_id()) + , rollbacker_active_(false) + , mutex_(mutex) + , cond_(cond) + , server_state_(server_state) + , client_service_(client_service) + , id_(id) + , mode_(mode) + , toi_mode_(m_undefined) + , state_(s_none) + , state_hist_() + , transaction_(*this) + , toi_meta_() + , nbo_meta_() + , allow_dirty_reads_() + , sync_wait_gtid_() + , last_written_gtid_() + , debug_log_level_(0) + , current_error_(wsrep::e_success) + , current_error_status_(wsrep::provider::success) + , keep_command_error_() + { } + + private: + client_state(const client_state&); + client_state& operator=(client_state&); + + friend class client_state_switch; + friend class high_priority_context; + friend class transaction; + + void do_acquire_ownership(wsrep::unique_lock<wsrep::mutex>& lock); + // Wait for sync rollbacker to finish, with lock. Changes state + // to exec. + void do_wait_rollback_complete_and_acquire_ownership( + wsrep::unique_lock<wsrep::mutex>& lock); + void update_last_written_gtid(const wsrep::gtid&); + void debug_log_state(const char*) const; + void debug_log_keys(const wsrep::key_array& keys) const; + void state(wsrep::unique_lock<wsrep::mutex>& lock, enum state state); + void mode(wsrep::unique_lock<wsrep::mutex>& lock, enum mode mode); + + // Override current client error status. Optionally provide + // an error status from the provider if the error was caused + // by the provider call. + void override_error(enum wsrep::client_error error, + enum wsrep::provider::status status = + wsrep::provider::success); + + // Poll provider::enter_toi() until return status from provider + // does not indicate certification failure, timeout expires + // or client is interrupted. + enum wsrep::provider::status + poll_enter_toi(wsrep::unique_lock<wsrep::mutex>& lock, + const wsrep::key_array& keys, + const wsrep::const_buffer& buffer, + wsrep::ws_meta& meta, + int flags, + std::chrono::time_point<wsrep::clock> wait_until, + bool& timed_out); + void enter_toi_common(wsrep::unique_lock<wsrep::mutex>&); + void leave_toi_common(); + + wsrep::thread::id owning_thread_id_; + bool rollbacker_active_; + wsrep::mutex& mutex_; + wsrep::condition_variable& cond_; + wsrep::server_state& server_state_; + wsrep::client_service& client_service_; + wsrep::client_id id_; + enum mode mode_; + enum mode toi_mode_; + enum state state_; + std::vector<enum state> state_hist_; + wsrep::transaction transaction_; + wsrep::ws_meta toi_meta_; + wsrep::ws_meta nbo_meta_; + bool allow_dirty_reads_; + wsrep::gtid sync_wait_gtid_; + wsrep::gtid last_written_gtid_; + int debug_log_level_; + enum wsrep::client_error current_error_; + enum wsrep::provider::status current_error_status_; + bool keep_command_error_; + + /** + * Marks external rollbacker thread for the client + * as active. This will block client in before_command(), until + * rolbacker has released the client. + */ + void set_rollbacker_active(bool value) + { + rollbacker_active_ = value; + } + }; + + static inline const char* to_c_string( + enum wsrep::client_state::state state) + { + switch (state) + { + case wsrep::client_state::s_none: return "none"; + case wsrep::client_state::s_idle: return "idle"; + case wsrep::client_state::s_exec: return "exec"; + case wsrep::client_state::s_result: return "result"; + case wsrep::client_state::s_quitting: return "quit"; + } + return "unknown"; + } + + static inline std::string to_string(enum wsrep::client_state::state state) + { + return to_c_string(state); + } + + static inline const char* to_c_string(enum wsrep::client_state::mode mode) + { + switch (mode) + { + case wsrep::client_state::m_undefined: return "undefined"; + case wsrep::client_state::m_local: return "local"; + case wsrep::client_state::m_high_priority: return "high priority"; + case wsrep::client_state::m_toi: return "toi"; + case wsrep::client_state::m_rsu: return "rsu"; + case wsrep::client_state::m_nbo: return "nbo"; + } + return "unknown"; + } + + static inline std::string to_string(enum wsrep::client_state::mode mode) + { + return to_c_string(mode); + } + + /** + * Utility class to switch the client state to high priority + * mode. The client is switched back to the original mode + * when the high priority context goes out of scope. + */ + class high_priority_context + { + public: + high_priority_context(wsrep::client_state& client); + virtual ~high_priority_context(); + private: + wsrep::client_state& client_; + enum wsrep::client_state::mode orig_mode_; + }; +} + +#endif // WSREP_CLIENT_STATE_HPP |