162 lines
6.5 KiB
C++
162 lines
6.5 KiB
C++
/*
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* Copyright (c) 2016 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: 2020-01-01
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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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#include <maxscale/queryclassifier.hh>
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#include <maxscale/query_classifier.h>
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#include <maxscale/protocol/mysql.h>
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namespace maxscale
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{
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QueryClassifier::QueryClassifier(MXS_SESSION* pSession,
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mxs_target_t use_sql_variables_in)
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: m_pSession(pSession)
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, m_use_sql_variables_in(use_sql_variables_in)
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, m_load_data_state(LOAD_DATA_INACTIVE)
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, m_have_tmp_tables(false)
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, m_large_query(false)
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{
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}
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uint32_t QueryClassifier::get_route_target(uint8_t command, uint32_t qtype)
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{
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bool trx_active = session_trx_is_active(m_pSession);
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uint32_t target = TARGET_UNDEFINED;
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bool load_active = (m_load_data_state != LOAD_DATA_INACTIVE);
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/**
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* Prepared statements preparations should go to all servers
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*/
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if (qc_query_is_type(qtype, QUERY_TYPE_PREPARE_STMT) ||
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qc_query_is_type(qtype, QUERY_TYPE_PREPARE_NAMED_STMT) ||
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command == MXS_COM_STMT_CLOSE ||
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command == MXS_COM_STMT_RESET)
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{
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target = TARGET_ALL;
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}
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/**
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* These queries should be routed to all servers
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*/
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else if (!load_active &&
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(qc_query_is_type(qtype, QUERY_TYPE_SESSION_WRITE) ||
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/** Configured to allow writing user variables to all nodes */
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(m_use_sql_variables_in == TYPE_ALL &&
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qc_query_is_type(qtype, QUERY_TYPE_USERVAR_WRITE)) ||
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qc_query_is_type(qtype, QUERY_TYPE_GSYSVAR_WRITE) ||
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/** enable or disable autocommit are always routed to all */
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qc_query_is_type(qtype, QUERY_TYPE_ENABLE_AUTOCOMMIT) ||
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qc_query_is_type(qtype, QUERY_TYPE_DISABLE_AUTOCOMMIT)))
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{
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/**
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* This is problematic query because it would be routed to all
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* backends but since this is SELECT that is not possible:
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* 1. response set is not handled correctly in clientReply and
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* 2. multiple results can degrade performance.
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*
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* Prepared statements are an exception to this since they do not
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* actually do anything but only prepare the statement to be used.
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* They can be safely routed to all backends since the execution
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* is done later.
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*
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* With prepared statement caching the task of routing
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* the execution of the prepared statements to the right server would be
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* an easy one. Currently this is not supported.
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*/
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if (qc_query_is_type(qtype, QUERY_TYPE_READ))
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{
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MXS_WARNING("The query can't be routed to all "
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"backend servers because it includes SELECT and "
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"SQL variable modifications which is not supported. "
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"Set use_sql_variables_in=master or split the "
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"query to two, where SQL variable modifications "
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"are done in the first and the SELECT in the "
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"second one.");
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target = TARGET_MASTER;
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}
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target |= TARGET_ALL;
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}
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/**
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* Hints may affect on routing of the following queries
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*/
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else if (!trx_active && !load_active &&
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!qc_query_is_type(qtype, QUERY_TYPE_MASTER_READ) &&
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!qc_query_is_type(qtype, QUERY_TYPE_WRITE) &&
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(qc_query_is_type(qtype, QUERY_TYPE_READ) ||
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qc_query_is_type(qtype, QUERY_TYPE_SHOW_TABLES) ||
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qc_query_is_type(qtype, QUERY_TYPE_USERVAR_READ) ||
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qc_query_is_type(qtype, QUERY_TYPE_SYSVAR_READ) ||
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qc_query_is_type(qtype, QUERY_TYPE_GSYSVAR_READ)))
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{
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if (qc_query_is_type(qtype, QUERY_TYPE_USERVAR_READ))
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{
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if (m_use_sql_variables_in == TYPE_ALL)
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{
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target = TARGET_SLAVE;
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}
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}
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else if (qc_query_is_type(qtype, QUERY_TYPE_READ) || // Normal read
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qc_query_is_type(qtype, QUERY_TYPE_SHOW_TABLES) || // SHOW TABLES
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qc_query_is_type(qtype, QUERY_TYPE_SYSVAR_READ) || // System variable
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qc_query_is_type(qtype, QUERY_TYPE_GSYSVAR_READ)) // Global system variable
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{
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target = TARGET_SLAVE;
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}
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/** If nothing matches then choose the master */
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if ((target & (TARGET_ALL | TARGET_SLAVE | TARGET_MASTER)) == 0)
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{
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target = TARGET_MASTER;
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}
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}
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else if (session_trx_is_read_only(m_pSession))
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{
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/* Force TARGET_SLAVE for READ ONLY transaction (active or ending) */
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target = TARGET_SLAVE;
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}
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else
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{
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ss_dassert(trx_active || load_active ||
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(qc_query_is_type(qtype, QUERY_TYPE_WRITE) ||
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qc_query_is_type(qtype, QUERY_TYPE_MASTER_READ) ||
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qc_query_is_type(qtype, QUERY_TYPE_SESSION_WRITE) ||
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(qc_query_is_type(qtype, QUERY_TYPE_USERVAR_READ) &&
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m_use_sql_variables_in == TYPE_MASTER) ||
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(qc_query_is_type(qtype, QUERY_TYPE_SYSVAR_READ) &&
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m_use_sql_variables_in == TYPE_MASTER) ||
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(qc_query_is_type(qtype, QUERY_TYPE_GSYSVAR_READ) &&
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m_use_sql_variables_in == TYPE_MASTER) ||
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(qc_query_is_type(qtype, QUERY_TYPE_GSYSVAR_WRITE) &&
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m_use_sql_variables_in == TYPE_MASTER) ||
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(qc_query_is_type(qtype, QUERY_TYPE_USERVAR_WRITE) &&
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m_use_sql_variables_in == TYPE_MASTER) ||
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qc_query_is_type(qtype, QUERY_TYPE_BEGIN_TRX) ||
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qc_query_is_type(qtype, QUERY_TYPE_ENABLE_AUTOCOMMIT) ||
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qc_query_is_type(qtype, QUERY_TYPE_DISABLE_AUTOCOMMIT) ||
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qc_query_is_type(qtype, QUERY_TYPE_ROLLBACK) ||
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qc_query_is_type(qtype, QUERY_TYPE_COMMIT) ||
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qc_query_is_type(qtype, QUERY_TYPE_EXEC_STMT) ||
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qc_query_is_type(qtype, QUERY_TYPE_CREATE_TMP_TABLE) ||
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qc_query_is_type(qtype, QUERY_TYPE_READ_TMP_TABLE) ||
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qc_query_is_type(qtype, QUERY_TYPE_UNKNOWN)) ||
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qc_query_is_type(qtype, QUERY_TYPE_EXEC_STMT));
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target = TARGET_MASTER;
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}
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return target;
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}
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}
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