ea0dcea5d6
The createInstace, newSession, closeSession and freeSession functions were cleaned up and reorganized to be a bit clearer for the reader. Removed unnecessary comments and replaced them with ones that explain what's happening in the code. Removed unused linked lists from both sessions and instances and replaced them with better alternatives. This should improve performance since new session don't have to acquire the instance level lock to put themselves into the session list.
320 lines
11 KiB
C
320 lines
11 KiB
C
#pragma once
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#ifndef _RWSPLITROUTER_H
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#define _RWSPLITROUTER_H
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/*
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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/bsl.
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*
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* Change Date: 2019-07-01
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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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/**
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* @file router.h - The read write split router module heder file
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*
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* @verbatim
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* Revision History
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*
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* See GitHub https://github.com/mariadb-corporation/MaxScale
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*
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* @endverbatim
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*/
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#include <maxscale/cdefs.h>
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#include <maxscale/dcb.h>
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#include <maxscale/hashtable.h>
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#include <math.h>
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MXS_BEGIN_DECLS
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typedef enum bref_state
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{
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BREF_IN_USE = 0x01,
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BREF_WAITING_RESULT = 0x02, /*< for session commands only */
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BREF_QUERY_ACTIVE = 0x04, /*< for other queries */
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BREF_CLOSED = 0x08,
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BREF_SESCMD_FAILED = 0x10 /*< Backend references that should be dropped */
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} bref_state_t;
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#define BREF_IS_NOT_USED(s) ((s)->bref_state & ~BREF_IN_USE)
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#define BREF_IS_IN_USE(s) ((s)->bref_state & BREF_IN_USE)
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#define BREF_IS_WAITING_RESULT(s) ((s)->bref_num_result_wait > 0)
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#define BREF_IS_QUERY_ACTIVE(s) ((s)->bref_state & BREF_QUERY_ACTIVE)
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#define BREF_IS_CLOSED(s) ((s)->bref_state & BREF_CLOSED)
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#define BREF_HAS_FAILED(s) ((s)->bref_state & BREF_SESCMD_FAILED)
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typedef enum backend_type_t
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{
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BE_UNDEFINED = -1,
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BE_MASTER,
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BE_JOINED = BE_MASTER,
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BE_SLAVE,
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BE_COUNT
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} backend_type_t;
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struct router_instance;
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typedef enum
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{
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TARGET_UNDEFINED = 0x00,
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TARGET_MASTER = 0x01,
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TARGET_SLAVE = 0x02,
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TARGET_NAMED_SERVER = 0x04,
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TARGET_ALL = 0x08,
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TARGET_RLAG_MAX = 0x10
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} route_target_t;
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#define TARGET_IS_MASTER(t) (t & TARGET_MASTER)
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#define TARGET_IS_SLAVE(t) (t & TARGET_SLAVE)
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#define TARGET_IS_NAMED_SERVER(t) (t & TARGET_NAMED_SERVER)
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#define TARGET_IS_ALL(t) (t & TARGET_ALL)
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#define TARGET_IS_RLAG_MAX(t) (t & TARGET_RLAG_MAX)
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typedef struct rses_property_st rses_property_t;
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typedef struct router_client_session ROUTER_CLIENT_SES;
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typedef enum rses_property_type_t
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{
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RSES_PROP_TYPE_UNDEFINED = -1,
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RSES_PROP_TYPE_SESCMD = 0,
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RSES_PROP_TYPE_FIRST = RSES_PROP_TYPE_SESCMD,
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RSES_PROP_TYPE_TMPTABLES,
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RSES_PROP_TYPE_LAST = RSES_PROP_TYPE_TMPTABLES,
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RSES_PROP_TYPE_COUNT = RSES_PROP_TYPE_LAST + 1
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} rses_property_type_t;
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/**
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* This criteria is used when backends are chosen for a router session's use.
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* Backend servers are sorted to ascending order according to the criteria
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* and top N are chosen.
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*/
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typedef enum select_criteria
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{
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UNDEFINED_CRITERIA = 0,
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LEAST_GLOBAL_CONNECTIONS, /*< all connections established by MaxScale */
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LEAST_ROUTER_CONNECTIONS, /*< connections established by this router */
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LEAST_BEHIND_MASTER,
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LEAST_CURRENT_OPERATIONS,
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DEFAULT_CRITERIA = LEAST_CURRENT_OPERATIONS,
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LAST_CRITERIA /*< not used except for an index */
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} select_criteria_t;
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/** default values for rwsplit configuration parameters */
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#define CONFIG_MAX_SLAVE_CONN 1
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#define CONFIG_MAX_SLAVE_RLAG -1 /*< not used */
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#define CONFIG_SQL_VARIABLES_IN TYPE_ALL
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#define GET_SELECT_CRITERIA(s) \
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(strncmp(s,"LEAST_GLOBAL_CONNECTIONS", strlen("LEAST_GLOBAL_CONNECTIONS")) == 0 ? \
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LEAST_GLOBAL_CONNECTIONS : ( \
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strncmp(s,"LEAST_BEHIND_MASTER", strlen("LEAST_BEHIND_MASTER")) == 0 ? \
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LEAST_BEHIND_MASTER : ( \
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strncmp(s,"LEAST_ROUTER_CONNECTIONS", strlen("LEAST_ROUTER_CONNECTIONS")) == 0 ? \
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LEAST_ROUTER_CONNECTIONS : ( \
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strncmp(s,"LEAST_CURRENT_OPERATIONS", strlen("LEAST_CURRENT_OPERATIONS")) == 0 ? \
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LEAST_CURRENT_OPERATIONS : UNDEFINED_CRITERIA))))
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/**
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* Session variable command
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*/
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typedef struct mysql_sescmd_st
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{
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#if defined(SS_DEBUG)
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skygw_chk_t my_sescmd_chk_top;
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#endif
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rses_property_t* my_sescmd_prop; /*< parent property */
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GWBUF* my_sescmd_buf; /*< query buffer */
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unsigned char my_sescmd_packet_type; /*< packet type */
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bool my_sescmd_is_replied; /*< is cmd replied to client */
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unsigned char reply_cmd; /*< The reply command. One of OK, ERR, RESULTSET or
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* LOCAL_INFILE. Slave servers are compared to this
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* when they return session command replies.*/
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int position; /*< Position of this command */
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#if defined(SS_DEBUG)
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skygw_chk_t my_sescmd_chk_tail;
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#endif
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} mysql_sescmd_t;
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/**
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* Property structure
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*/
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struct rses_property_st
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{
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#if defined(SS_DEBUG)
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skygw_chk_t rses_prop_chk_top;
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#endif
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ROUTER_CLIENT_SES* rses_prop_rsession; /*< parent router session */
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int rses_prop_refcount;
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rses_property_type_t rses_prop_type;
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union rses_prop_data
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{
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mysql_sescmd_t sescmd;
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HASHTABLE* temp_tables;
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} rses_prop_data;
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rses_property_t* rses_prop_next; /*< next property of same type */
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#if defined(SS_DEBUG)
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skygw_chk_t rses_prop_chk_tail;
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#endif
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} ;
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typedef struct sescmd_cursor_st
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{
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#if defined(SS_DEBUG)
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skygw_chk_t scmd_cur_chk_top;
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#endif
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ROUTER_CLIENT_SES* scmd_cur_rses; /*< pointer to owning router session */
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rses_property_t** scmd_cur_ptr_property; /*< address of pointer to owner property */
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mysql_sescmd_t* scmd_cur_cmd; /*< pointer to current session command */
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bool scmd_cur_active; /*< true if command is being executed */
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int position; /*< Position of this cursor */
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#if defined(SS_DEBUG)
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skygw_chk_t scmd_cur_chk_tail;
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#endif
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} sescmd_cursor_t;
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/**
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* Reference to BACKEND.
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*
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* Owned by router client session.
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*/
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typedef struct backend_ref_st
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{
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#if defined(SS_DEBUG)
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skygw_chk_t bref_chk_top;
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#endif
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SERVER_REF* ref;
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DCB* bref_dcb;
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bref_state_t bref_state;
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int bref_num_result_wait;
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sescmd_cursor_t bref_sescmd_cur;
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GWBUF* bref_pending_cmd; /**< For stmt which can't be routed due active sescmd execution */
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unsigned char reply_cmd; /**< The reply the backend server sent to a session command.
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* Used to detect slaves that fail to execute session command. */
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#if defined(SS_DEBUG)
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skygw_chk_t bref_chk_tail;
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#endif
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} backend_ref_t;
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/**
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* Controls how master failure is handled
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*/
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enum failure_mode
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{
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RW_FAIL_INSTANTLY, /**< Close the connection as soon as the master is lost */
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RW_FAIL_ON_WRITE, /**< Close the connection when the first write is received */
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RW_ERROR_ON_WRITE /**< Don't close the connection but send an error for writes */
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};
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typedef struct rwsplit_config_st
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{
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int rw_max_slave_conn_percent; /**< Maximum percentage of slaves
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* to use for each connection*/
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int rw_max_slave_conn_count; /**< Maximum number of slaves for each connection*/
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select_criteria_t rw_slave_select_criteria; /**< The slave selection criteria */
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int rw_max_slave_replication_lag; /**< Maximum replication lag */
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target_t rw_use_sql_variables_in; /**< Whether to send user variables
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* to master or all nodes */
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int rw_max_sescmd_history_size; /**< Maximum amount of session commands to store */
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bool rw_disable_sescmd_hist; /**< Disable session command history */
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bool rw_master_reads; /**< Use master for reads */
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bool rw_strict_multi_stmt; /**< Force non-multistatement queries to be routed
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* to the master after a multistatement query. */
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enum failure_mode rw_master_failure_mode; /**< Master server failure handling mode.
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* @see enum failure_mode */
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} rwsplit_config_t;
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#if defined(PREP_STMT_CACHING)
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typedef struct prep_stmt_st
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{
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#if defined(SS_DEBUG)
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skygw_chk_t pstmt_chk_top;
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#endif
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union id
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{
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int seq;
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char* name;
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} pstmt_id;
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prep_stmt_state_t pstmt_state;
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prep_stmt_type_t pstmt_type;
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#if defined(SS_DEBUG)
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skygw_chk_t pstmt_chk_tail;
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#endif
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} prep_stmt_t;
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#endif /*< PREP_STMT_CACHING */
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/**
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* The client session structure used within this router.
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*/
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struct router_client_session
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{
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#if defined(SS_DEBUG)
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skygw_chk_t rses_chk_top;
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#endif
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SPINLOCK rses_lock; /*< protects rses_deleted */
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bool rses_closed; /*< true when closeSession is called */
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rses_property_t* rses_properties[RSES_PROP_TYPE_COUNT]; /*< Properties listed by their type */
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backend_ref_t* rses_master_ref;
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backend_ref_t* rses_backend_ref; /*< Pointer to backend reference array */
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rwsplit_config_t rses_config; /*< copied config info from router instance */
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int rses_nbackends;
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int rses_nsescmd; /*< Number of executed session commands */
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bool rses_autocommit_enabled;
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bool rses_transaction_active;
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bool rses_load_active; /*< If LOAD DATA LOCAL INFILE is being currently executed */
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bool have_tmp_tables;
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uint64_t rses_load_data_sent; /*< How much data has been sent */
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DCB* client_dcb;
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int pos_generator;
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backend_ref_t *forced_node; /*< Current server where all queries should be sent */
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#if defined(PREP_STMT_CACHING)
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HASHTABLE* rses_prep_stmt[2];
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#endif
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struct router_instance *router; /*< The router instance */
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struct router_client_session *next;
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#if defined(SS_DEBUG)
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skygw_chk_t rses_chk_tail;
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#endif
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} ;
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/**
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* The statistics for this router instance
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*/
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typedef struct
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{
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int n_sessions; /*< Number sessions created */
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int n_queries; /*< Number of queries forwarded */
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int n_master; /*< Number of stmts sent to master */
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int n_slave; /*< Number of stmts sent to slave */
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int n_all; /*< Number of stmts sent to all */
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} ROUTER_STATS;
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/**
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* The per instance data for the router.
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*/
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typedef struct router_instance
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{
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SERVICE* service; /*< Pointer to service */
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SPINLOCK lock; /*< Lock for the instance data */
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rwsplit_config_t rwsplit_config; /*< expanded config info from SERVICE */
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int rwsplit_version; /*< version number for router's config */
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ROUTER_STATS stats; /*< Statistics for this router */
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bool available_slaves; /*< The router has some slaves avialable */
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} ROUTER_INSTANCE;
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#define BACKEND_TYPE(b) (SERVER_IS_MASTER((b)->backend_server) ? BE_MASTER : \
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(SERVER_IS_SLAVE((b)->backend_server) ? BE_SLAVE : BE_UNDEFINED));
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MXS_END_DECLS
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#endif /*< _RWSPLITROUTER_H */
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