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MaxScale/server/modules/routing/readwritesplit/readwritesplit.h
Markus Mäkelä 710012ac5d MXS-827: Add connection keepalive 
The readwritesplit now sends COM_PING queries to backend servers that have
been idle for too long. The option is configured with the
`connection_keepalive` parameter.
2017-03-26 13:57:25 +03:00

365 lines
12 KiB
C
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#pragma once
#ifndef _RWSPLITROUTER_H
#define _RWSPLITROUTER_H
/*
* Copyright (c) 2016 MariaDB Corporation Ab
*
* Use of this software is governed by the Business Source License included
* in the LICENSE.TXT file and at www.mariadb.com/bsl11.
*
* Change Date: 2019-07-01
*
* On the date above, in accordance with the Business Source License, use
* of this software will be governed by version 2 or later of the General
* Public License.
*/
/**
* @file router.h - The read write split router module heder file
*
* @verbatim
* Revision History
*
* See GitHub https://github.com/mariadb-corporation/MaxScale
*
* @endverbatim
*/
#define MXS_MODULE_NAME "readwritesplit"
#include <maxscale/cdefs.h>
#include <math.h>
#include <maxscale/dcb.h>
#include <maxscale/hashtable.h>
#include <maxscale/router.h>
#include <maxscale/service.h>
MXS_BEGIN_DECLS
typedef enum bref_state
{
BREF_IN_USE = 0x01,
BREF_WAITING_RESULT = 0x02, /*< for session commands only */
BREF_QUERY_ACTIVE = 0x04, /*< for other queries */
BREF_CLOSED = 0x08,
BREF_FATAL_FAILURE = 0x10 /*< Backend references that should be dropped */
} bref_state_t;
#define BREF_IS_NOT_USED(s) ((s)->bref_state & ~BREF_IN_USE)
#define BREF_IS_IN_USE(s) ((s)->bref_state & BREF_IN_USE)
#define BREF_IS_WAITING_RESULT(s) ((s)->bref_num_result_wait > 0)
#define BREF_IS_QUERY_ACTIVE(s) ((s)->bref_state & BREF_QUERY_ACTIVE)
#define BREF_IS_CLOSED(s) ((s)->bref_state & BREF_CLOSED)
#define BREF_HAS_FAILED(s) ((s)->bref_state & BREF_FATAL_FAILURE)
typedef enum backend_type_t
{
BE_UNDEFINED = -1,
BE_MASTER,
BE_JOINED = BE_MASTER,
BE_SLAVE,
BE_COUNT
} backend_type_t;
struct router_instance;
typedef enum
{
TARGET_UNDEFINED = 0x00,
TARGET_MASTER = 0x01,
TARGET_SLAVE = 0x02,
TARGET_NAMED_SERVER = 0x04,
TARGET_ALL = 0x08,
TARGET_RLAG_MAX = 0x10
} route_target_t;
#define TARGET_IS_MASTER(t) (t & TARGET_MASTER)
#define TARGET_IS_SLAVE(t) (t & TARGET_SLAVE)
#define TARGET_IS_NAMED_SERVER(t) (t & TARGET_NAMED_SERVER)
#define TARGET_IS_ALL(t) (t & TARGET_ALL)
#define TARGET_IS_RLAG_MAX(t) (t & TARGET_RLAG_MAX)
typedef struct rses_property_st rses_property_t;
typedef struct router_client_session ROUTER_CLIENT_SES;
typedef enum rses_property_type_t
{
RSES_PROP_TYPE_UNDEFINED = -1,
RSES_PROP_TYPE_SESCMD = 0,
RSES_PROP_TYPE_FIRST = RSES_PROP_TYPE_SESCMD,
RSES_PROP_TYPE_TMPTABLES,
RSES_PROP_TYPE_LAST = RSES_PROP_TYPE_TMPTABLES,
RSES_PROP_TYPE_COUNT = RSES_PROP_TYPE_LAST + 1
} rses_property_type_t;
/**
* This criteria is used when backends are chosen for a router session's use.
* Backend servers are sorted to ascending order according to the criteria
* and top N are chosen.
*/
typedef enum select_criteria
{
UNDEFINED_CRITERIA = 0,
LEAST_GLOBAL_CONNECTIONS, /*< all connections established by MaxScale */
LEAST_ROUTER_CONNECTIONS, /*< connections established by this router */
LEAST_BEHIND_MASTER,
LEAST_CURRENT_OPERATIONS,
DEFAULT_CRITERIA = LEAST_CURRENT_OPERATIONS,
LAST_CRITERIA /*< not used except for an index */
} select_criteria_t;
static inline const char* select_criteria_to_str(select_criteria_t type)
{
switch (type)
{
case LEAST_GLOBAL_CONNECTIONS:
return "LEAST_GLOBAL_CONNECTIONS";
case LEAST_ROUTER_CONNECTIONS:
return "LEAST_ROUTER_CONNECTIONS";
case LEAST_BEHIND_MASTER:
return "LEAST_BEHIND_MASTER";
case LEAST_CURRENT_OPERATIONS:
return "LEAST_CURRENT_OPERATIONS";
default:
return "UNDEFINED_CRITERIA";
}
}
/**
* Controls how master failure is handled
*/
enum failure_mode
{
RW_FAIL_INSTANTLY, /**< Close the connection as soon as the master is lost */
RW_FAIL_ON_WRITE, /**< Close the connection when the first write is received */
RW_ERROR_ON_WRITE /**< Don't close the connection but send an error for writes */
};
static inline const char* failure_mode_to_str(enum failure_mode type)
{
switch (type)
{
case RW_FAIL_INSTANTLY:
return "fail_instantly";
case RW_FAIL_ON_WRITE:
return "fail_on_write";
case RW_ERROR_ON_WRITE:
return "error_on_write";
default:
ss_dassert(false);
return "UNDEFINED_MODE";
}
}
/** default values for rwsplit configuration parameters */
#define CONFIG_MAX_SLAVE_CONN 1
#define CONFIG_MAX_SLAVE_RLAG -1 /*< not used */
#define CONFIG_SQL_VARIABLES_IN TYPE_ALL
#define GET_SELECT_CRITERIA(s) \
(strncmp(s,"LEAST_GLOBAL_CONNECTIONS", strlen("LEAST_GLOBAL_CONNECTIONS")) == 0 ? \
LEAST_GLOBAL_CONNECTIONS : ( \
strncmp(s,"LEAST_BEHIND_MASTER", strlen("LEAST_BEHIND_MASTER")) == 0 ? \
LEAST_BEHIND_MASTER : ( \
strncmp(s,"LEAST_ROUTER_CONNECTIONS", strlen("LEAST_ROUTER_CONNECTIONS")) == 0 ? \
LEAST_ROUTER_CONNECTIONS : ( \
strncmp(s,"LEAST_CURRENT_OPERATIONS", strlen("LEAST_CURRENT_OPERATIONS")) == 0 ? \
LEAST_CURRENT_OPERATIONS : UNDEFINED_CRITERIA))))
/**
* Session variable command
*/
typedef struct mysql_sescmd_st
{
#if defined(SS_DEBUG)
skygw_chk_t my_sescmd_chk_top;
#endif
rses_property_t* my_sescmd_prop; /*< parent property */
GWBUF* my_sescmd_buf; /*< query buffer */
unsigned char my_sescmd_packet_type; /*< packet type */
bool my_sescmd_is_replied; /*< is cmd replied to client */
unsigned char reply_cmd; /*< The reply command. One of OK, ERR, RESULTSET or
* LOCAL_INFILE. Slave servers are compared to this
* when they return session command replies.*/
int position; /*< Position of this command */
#if defined(SS_DEBUG)
skygw_chk_t my_sescmd_chk_tail;
#endif
} mysql_sescmd_t;
/**
* Property structure
*/
struct rses_property_st
{
#if defined(SS_DEBUG)
skygw_chk_t rses_prop_chk_top;
#endif
ROUTER_CLIENT_SES* rses_prop_rsession; /*< parent router session */
int rses_prop_refcount;
rses_property_type_t rses_prop_type;
union rses_prop_data
{
mysql_sescmd_t sescmd;
HASHTABLE* temp_tables;
} rses_prop_data;
rses_property_t* rses_prop_next; /*< next property of same type */
#if defined(SS_DEBUG)
skygw_chk_t rses_prop_chk_tail;
#endif
} ;
typedef struct sescmd_cursor_st
{
#if defined(SS_DEBUG)
skygw_chk_t scmd_cur_chk_top;
#endif
ROUTER_CLIENT_SES* scmd_cur_rses; /*< pointer to owning router session */
rses_property_t** scmd_cur_ptr_property; /*< address of pointer to owner property */
mysql_sescmd_t* scmd_cur_cmd; /*< pointer to current session command */
bool scmd_cur_active; /*< true if command is being executed */
int position; /*< Position of this cursor */
#if defined(SS_DEBUG)
skygw_chk_t scmd_cur_chk_tail;
#endif
} sescmd_cursor_t;
/**
* Reference to BACKEND.
*
* Owned by router client session.
*/
typedef struct backend_ref_st
{
#if defined(SS_DEBUG)
skygw_chk_t bref_chk_top;
#endif
SERVER_REF* ref;
DCB* bref_dcb;
bref_state_t bref_state;
int bref_num_result_wait;
sescmd_cursor_t bref_sescmd_cur;
GWBUF* bref_pending_cmd; /**< For stmt which can't be routed due active sescmd execution */
unsigned char reply_cmd; /**< The reply the backend server sent to a session command.
* Used to detect slaves that fail to execute session command. */
#if defined(SS_DEBUG)
skygw_chk_t bref_chk_tail;
#endif
int closed_at; /** DEBUG: Line number where this backend reference was closed */
} backend_ref_t;
typedef struct rwsplit_config_st
{
int rw_max_slave_conn_percent; /**< Maximum percentage of slaves
* to use for each connection*/
int max_slave_connections; /**< Maximum number of slaves for each connection*/
select_criteria_t slave_selection_criteria; /**< The slave selection criteria */
int max_slave_replication_lag; /**< Maximum replication lag */
mxs_target_t use_sql_variables_in; /**< Whether to send user variables
* to master or all nodes */
int max_sescmd_history; /**< Maximum amount of session commands to store */
bool disable_sescmd_history; /**< Disable session command history */
bool master_accept_reads; /**< Use master for reads */
bool strict_multi_stmt; /**< Force non-multistatement queries to be routed
* to the master after a multistatement query. */
enum failure_mode master_failure_mode; /**< Master server failure handling mode.
* @see enum failure_mode */
bool retry_failed_reads; /**< Retry failed reads on other servers */
int connection_keepalive; /**< Send pings to servers that have
* been idle for too long */
} rwsplit_config_t;
#if defined(PREP_STMT_CACHING)
typedef struct prep_stmt_st
{
#if defined(SS_DEBUG)
skygw_chk_t pstmt_chk_top;
#endif
union id
{
int seq;
char* name;
} pstmt_id;
prep_stmt_state_t pstmt_state;
prep_stmt_type_t pstmt_type;
#if defined(SS_DEBUG)
skygw_chk_t pstmt_chk_tail;
#endif
} prep_stmt_t;
#endif /*< PREP_STMT_CACHING */
/**
* The client session structure used within this router.
*/
struct router_client_session
{
#if defined(SS_DEBUG)
skygw_chk_t rses_chk_top;
#endif
bool rses_closed; /*< true when closeSession is called */
rses_property_t* rses_properties[RSES_PROP_TYPE_COUNT]; /*< Properties listed by their type */
backend_ref_t* rses_master_ref;
backend_ref_t* rses_backend_ref; /*< Pointer to backend reference array */
rwsplit_config_t rses_config; /*< copied config info from router instance */
int rses_nbackends;
int rses_nsescmd; /*< Number of executed session commands */
bool rses_load_active; /*< If LOAD DATA LOCAL INFILE is being currently executed */
bool have_tmp_tables;
uint64_t rses_load_data_sent; /*< How much data has been sent */
DCB* client_dcb;
int pos_generator;
backend_ref_t *forced_node; /*< Current server where all queries should be sent */
#if defined(PREP_STMT_CACHING)
HASHTABLE* rses_prep_stmt[2];
#endif
struct router_instance *router; /*< The router instance */
struct router_client_session *next;
#if defined(SS_DEBUG)
skygw_chk_t rses_chk_tail;
#endif
} ;
/**
* The statistics for this router instance
*/
typedef struct
{
int n_sessions; /*< Number sessions created */
int n_queries; /*< Number of queries forwarded */
int n_master; /*< Number of stmts sent to master */
int n_slave; /*< Number of stmts sent to slave */
int n_all; /*< Number of stmts sent to all */
} ROUTER_STATS;
/**
* The per instance data for the router.
*/
typedef struct router_instance
{
SERVICE* service; /*< Pointer to service */
rwsplit_config_t rwsplit_config; /*< expanded config info from SERVICE */
int rwsplit_version; /*< version number for router's config */
ROUTER_STATS stats; /*< Statistics for this router */
bool available_slaves; /*< The router has some slaves avialable */
} ROUTER_INSTANCE;
#define BACKEND_TYPE(b) (SERVER_IS_MASTER((b)->backend_server) ? BE_MASTER : \
(SERVER_IS_SLAVE((b)->backend_server) ? BE_SLAVE : BE_UNDEFINED));
MXS_END_DECLS
#endif /*< _RWSPLITROUTER_H */
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