9d0c6b908a
When a query returns a WSREP error, most of the time it is not something the client application is expecting. To prevent this from affecting the client, it can be treated the same way a transaction rollback is treated: ignore the error and try again.
311 lines
8.3 KiB
C++
311 lines
8.3 KiB
C++
/*
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* Copyright (c) 2018 MariaDB Corporation Ab
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*
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* Use of this software is governed by the Business Source License included
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* in the LICENSE.TXT file and at www.mariadb.com/bsl11.
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*
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* Change Date: 2023-01-01
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*
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* On the date above, in accordance with the Business Source License, use
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* of this software will be governed by version 2 or later of the General
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* Public License.
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*/
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#pragma once
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#include <map>
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#include <memory>
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#include <algorithm>
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#include <maxscale/backend.hh>
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#include <maxscale/modutil.hh>
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#include <maxscale/response_stat.hh>
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#include <maxscale/protocol/mysql.hh>
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namespace maxscale
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{
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/** Move this somewhere else */
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template<typename Smart>
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std::vector<typename Smart::pointer> sptr_vec_to_ptr_vec(const std::vector<Smart>& sVec)
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{
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std::vector<typename Smart::pointer> pVec;
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std::for_each(sVec.begin(), sVec.end(), [&pVec](const Smart& smart) {
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pVec.push_back(smart.get());
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});
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return pVec;
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}
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/** Enum for tracking client reply state */
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enum reply_state_t
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{
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REPLY_STATE_START, /**< Query sent to backend */
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REPLY_STATE_DONE, /**< Complete reply received */
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REPLY_STATE_RSET_COLDEF, /**< Resultset response, waiting for column definitions */
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REPLY_STATE_RSET_COLDEF_EOF,/**< Resultset response, waiting for EOF for column definitions */
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REPLY_STATE_RSET_ROWS /**< Resultset response, waiting for rows */
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};
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typedef std::map<uint32_t, uint32_t> BackendHandleMap; /** Internal ID to external ID */
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class RWBackend;
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// All interfacing is now handled via RWBackend*.
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using PRWBackends = std::vector<RWBackend*>;
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// Internal storage for a class containing RWBackend:s.
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using SRWBackends = std::vector<std::unique_ptr<RWBackend>>;
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class RWBackend : public mxs::Backend
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{
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RWBackend(const RWBackend&);
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RWBackend& operator=(const RWBackend&);
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public:
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class Error
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{
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public:
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Error() = default;
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explicit operator bool() const
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{
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return m_code != 0;
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}
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bool is_rollback() const
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{
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bool rv = false;
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if (m_code != 0)
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{
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mxb_assert(m_sql_state.length() == 5);
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// The 'sql_state' of all transaction rollbacks is "40XXX".
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if (m_sql_state[0] == '4' && m_sql_state[1] == '0')
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{
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rv = true;
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}
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}
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return rv;
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}
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bool is_wsrep_error() const
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{
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return m_code == 1047
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&& m_sql_state == "08S01"
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&& m_message == "WSREP has not yet prepared node for application use";
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}
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bool is_unexpected_error() const
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{
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switch (m_code)
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{
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case ER_CONNECTION_KILLED:
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case ER_SERVER_SHUTDOWN:
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case ER_NORMAL_SHUTDOWN:
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case ER_SHUTDOWN_COMPLETE:
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return true;
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default:
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return false;
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}
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}
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uint32_t code() const
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{
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return m_code;
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}
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const std::string& sql_state() const
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{
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return m_sql_state;
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}
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const std::string& message() const
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{
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return m_message;
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}
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template<class InputIterator>
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void set(uint32_t code,
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InputIterator sql_state_begin, InputIterator sql_state_end,
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InputIterator message_begin, InputIterator message_end)
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{
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mxb_assert(std::distance(sql_state_begin, sql_state_end) == 5);
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m_code = code;
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m_sql_state.assign(sql_state_begin, sql_state_end);
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m_message.assign(message_begin, message_end);
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}
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void clear()
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{
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m_code = 0;
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m_sql_state.clear();
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m_message.clear();
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}
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private:
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uint16_t m_code {0};
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std::string m_sql_state;
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std::string m_message;
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};
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static SRWBackends from_servers(SERVER_REF* servers);
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RWBackend(SERVER_REF* ref);
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virtual ~RWBackend();
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inline reply_state_t get_reply_state() const
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{
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return m_reply_state;
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}
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const char* reply_state_str() const
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{
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switch (m_reply_state)
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{
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case REPLY_STATE_START:
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return "START";
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case REPLY_STATE_DONE:
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return "DONE";
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case REPLY_STATE_RSET_COLDEF:
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return "COLDEF";
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case REPLY_STATE_RSET_COLDEF_EOF:
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return "COLDEF_EOF";
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case REPLY_STATE_RSET_ROWS:
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return "ROWS";
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default:
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return "UNKNOWN";
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}
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}
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void add_ps_handle(uint32_t id, uint32_t handle);
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uint32_t get_ps_handle(uint32_t id) const;
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bool execute_session_command();
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bool continue_session_command(GWBUF* buffer);
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/**
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* Write a query to the backend
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*
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* This function handles the replacement of the prepared statement IDs from
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* the internal ID to the server specific one. Trailing parts of large
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* packets should use RWBackend::continue_write.
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*
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* @param buffer Buffer to write
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* @param type Whether a response is expected
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*
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* @return True if writing was successful
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*/
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bool write(GWBUF* buffer, response_type type = EXPECT_RESPONSE);
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void close(close_type type = CLOSE_NORMAL);
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// For COM_STMT_FETCH processing
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bool consume_fetched_rows(GWBUF* buffer);
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inline uint8_t current_command() const
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{
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return m_command;
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}
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bool local_infile_requested() const
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{
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return m_local_infile_requested;
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}
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void process_reply(GWBUF* buffer);
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/**
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* Updated during the call to @c process_reply().
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*
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* @return The current error state.
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*/
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const Error& error() const
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{
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return m_error;
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}
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/**
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* Check whether the response from the server is complete
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*
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* @return True if no more results are expected from this server
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*/
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bool reply_is_complete() const
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{
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return m_reply_state == REPLY_STATE_DONE;
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}
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/**
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* Check if a partial response has been received from the backend
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*
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* @return True if some parts of the reply have been received
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*/
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bool reply_has_started() const
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{
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return m_size > 0 && m_reply_state != REPLY_STATE_DONE;
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}
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void process_packets(GWBUF* buffer);
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// Controlled by the session
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ResponseStat& response_stat();
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/**
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* Change server replication lag state and log warning when state changes.
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*
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* @param new_state New replication lag state
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* @param max_rlag Maximum allowed lag. Used for the log message.
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*/
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void change_rlag_state(SERVER::RLagState new_state, int max_rlag);
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private:
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reply_state_t m_reply_state;
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BackendHandleMap m_ps_handles; /**< Internal ID to backend PS handle mapping */
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modutil_state m_modutil_state; /**< @see modutil_count_signal_packets */
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uint8_t m_command;
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bool m_opening_cursor; /**< Whether we are opening a cursor */
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uint32_t m_expected_rows; /**< Number of rows a COM_STMT_FETCH is retrieving */
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bool m_local_infile_requested; /**< Whether a LOCAL INFILE was requested */
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ResponseStat m_response_stat;
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uint64_t m_num_coldefs = 0;
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bool m_large_query = false;
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bool m_skip_next = false;
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Error m_error;
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uint64_t m_size = 0;/**< Size of the response */
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/**
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* @param it Iterator pointing to the command byte of an error packet.
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* @param end Iterator pointing one past the end of the error packet.
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*/
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void process_reply_start(mxs::Buffer::iterator it, mxs::Buffer::iterator end);
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/**
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* Update @c m_error.
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*
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* @param it Iterator that points to the first byte of the error code in an error packet.
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* @param end Iterator pointing one past the end of the error packet.
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*/
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void update_error(mxs::Buffer::iterator it, mxs::Buffer::iterator end);
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inline bool is_opening_cursor() const
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{
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return m_opening_cursor;
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}
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inline void set_cursor_opened()
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{
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m_opening_cursor = false;
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}
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inline void set_reply_state(reply_state_t state)
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{
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m_reply_state = state;
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}
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};
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}
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