356 lines
12 KiB
C
356 lines
12 KiB
C
#pragma once
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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 session.h
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*
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* @verbatim
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* Revision History
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*
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* Date Who Description
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* 01-06-2013 Mark Riddoch Initial implementation
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* 14-06-2013 Massimiliano Pinto Added void *data to session
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* for session specific data
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* 01-07-2013 Massimiliano Pinto Removed backends pointer
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* from struct session
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* 02-09-2013 Massimiliano Pinto Added session ref counter
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* 29-05-2014 Mark Riddoch Support for filter mechanism
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* added
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* 20-02-2015 Markus Mäkelä Added session timeouts
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* 27/06/2016 Martin Brampton Modify session struct for list manager
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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 <time.h>
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#include <maxscale/atomic.h>
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#include <maxscale/buffer.h>
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#include <maxscale/listmanager.h>
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#include <maxscale/spinlock.h>
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#include <maxscale/resultset.h>
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#include <maxscale/log_manager.h>
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MXS_BEGIN_DECLS
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struct dcb;
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struct service;
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struct filter_def;
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/**
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* The session statistics structure
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*/
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typedef struct
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{
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time_t connect; /**< Time when the session was started */
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} SESSION_STATS;
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#define SESSION_STATS_INIT {0}
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typedef enum
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{
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SESSION_STATE_ALLOC, /*< for all sessions */
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SESSION_STATE_READY, /*< for router session */
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SESSION_STATE_ROUTER_READY, /*< for router session */
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SESSION_STATE_STOPPING, /*< session and router are being closed */
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SESSION_STATE_LISTENER, /*< for listener session */
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SESSION_STATE_LISTENER_STOPPED, /*< for listener session */
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SESSION_STATE_TO_BE_FREED, /*< ready to be freed as soon as there are no references */
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SESSION_STATE_FREE, /*< for all sessions */
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SESSION_STATE_DUMMY /*< dummy session for consistency */
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} session_state_t;
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typedef enum
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{
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SESSION_TRX_INACTIVE_BIT = 1, /* 0b0001 */
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SESSION_TRX_ACTIVE_BIT = 2, /* 0b0010 */
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SESSION_TRX_READ_ONLY_BIT = 4, /* 0b0100 */
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SESSION_TRX_READ_WRITE_BIT = 8, /* 0b1000 */
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} session_trx_state_bit_t;
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typedef enum
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{
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/*< There is no on-going transaction. */
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SESSION_TRX_INACTIVE = SESSION_TRX_INACTIVE_BIT,
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/*< A transaction is active. */
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SESSION_TRX_ACTIVE = SESSION_TRX_ACTIVE_BIT,
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/*< An explicit READ ONLY transaction is active. */
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SESSION_TRX_READ_ONLY = (SESSION_TRX_ACTIVE_BIT | SESSION_TRX_READ_ONLY_BIT),
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/*< An explicit READ WRITE transaction is active. */
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SESSION_TRX_READ_WRITE = (SESSION_TRX_ACTIVE_BIT | SESSION_TRX_READ_WRITE_BIT)
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} session_trx_state_t;
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/**
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* Convert transaction state to string representation.
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*
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* @param state A transaction state.
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* @return String representation of the state.
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*/
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const char* session_trx_state_to_string(session_trx_state_t state);
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/**
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* The downstream element in the filter chain. This may refer to
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* another filter or to a router.
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*/
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typedef struct
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{
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void *instance;
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void *session;
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int (*routeQuery)(void *instance, void *session, GWBUF *request);
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} DOWNSTREAM;
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#define DOWNSTREAM_INIT {0}
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/**
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* The upstream element in the filter chain. This may refer to
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* another filter or to the protocol implementation.
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*/
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typedef struct
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{
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void *instance;
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void *session;
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int (*clientReply)(void *instance, void *session, GWBUF *response);
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int (*error)(void *instance, void *session, void *);
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} UPSTREAM;
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#define UPSTREAM_INIT {0}
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/**
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* Structure used to track the filter instances and sessions of the filters
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* that are in use within a session.
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*/
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typedef struct
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{
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struct filter_def *filter;
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void *instance;
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void *session;
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} SESSION_FILTER;
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#define SESSION_FILTER_INIT {0}
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/**
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* Filter type for the sessionGetList call
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*/
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typedef enum
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{
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SESSION_LIST_ALL,
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SESSION_LIST_CONNECTION
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} SESSIONLISTFILTER;
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/**
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* The session status block
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*
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* A session status block is created for each user (client) connection
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* to the database, it links the descriptors, routing implementation
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* and originating service together for the client session.
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*
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* Note that the first few fields (up to and including "entry_is_ready") must
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* precisely match the LIST_ENTRY structure defined in the list manager.
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*/
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typedef struct session
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{
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LIST_ENTRY_FIELDS
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skygw_chk_t ses_chk_top;
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SPINLOCK ses_lock;
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session_state_t state; /*< Current descriptor state */
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size_t ses_id; /*< Unique session identifier */
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int enabled_log_priorities; /*< Bitfield of enabled syslog priorities */
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struct dcb *client_dcb; /*< The client connection */
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void *router_session; /*< The router instance data */
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SESSION_STATS stats; /*< Session statistics */
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struct service *service; /*< The service this session is using */
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int n_filters; /*< Number of filter sessions */
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SESSION_FILTER *filters; /*< The filters in use within this session */
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DOWNSTREAM head; /*< Head of the filter chain */
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UPSTREAM tail; /*< The tail of the filter chain */
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int refcount; /*< Reference count on the session */
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bool ses_is_child; /*< this is a child session */
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session_trx_state_t trx_state; /*< The current transaction state. */
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bool autocommit; /*< Whether autocommit is on. */
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skygw_chk_t ses_chk_tail;
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} SESSION;
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#define SESSION_INIT {.ses_chk_top = CHK_NUM_SESSION, .ses_lock = SPINLOCK_INIT, \
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.stats = SESSION_STATS_INIT, .head = DOWNSTREAM_INIT, .tail = UPSTREAM_INIT, \
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.state = SESSION_STATE_ALLOC, .ses_chk_tail = CHK_NUM_SESSION}
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/** Whether to do session timeout checks */
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extern bool check_timeouts;
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/** When the next timeout check is done. This is compared to hkheartbeat in
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* hk_heartbeat.h */
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extern long next_timeout_check;
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#define SESSION_PROTOCOL(x, type) DCB_PROTOCOL((x)->client_dcb, type)
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/**
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* A convenience macro that can be used by the protocol modules to route
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* the incoming data to the first element in the pipeline of filters and
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* routers.
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*/
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#define SESSION_ROUTE_QUERY(sess, buf) \
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((sess)->head.routeQuery)((sess)->head.instance, \
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(sess)->head.session, (buf))
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/**
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* A convenience macro that can be used by the router modules to route
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* the replies to the first element in the pipeline of filters and
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* the protocol.
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*/
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#define SESSION_ROUTE_REPLY(sess, buf) \
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((sess)->tail.clientReply)((sess)->tail.instance, \
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(sess)->tail.session, (buf))
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SESSION *session_alloc(struct service *, struct dcb *);
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bool session_pre_alloc(int number);
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SESSION *session_set_dummy(struct dcb *);
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bool session_free(SESSION *);
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int session_isvalid(SESSION *);
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int session_reply(void *inst, void *session, GWBUF *data);
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char *session_get_remote(SESSION *);
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char *session_getUser(SESSION *);
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void printAllSessions();
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void printSession(SESSION *);
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void dprintSessionList(DCB *pdcb);
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void dprintAllSessions(struct dcb *);
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void dprintSession(struct dcb *, SESSION *);
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void dListSessions(struct dcb *);
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char *session_state(session_state_t);
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bool session_link_dcb(SESSION *, struct dcb *);
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SESSION* get_session_by_router_ses(void* rses);
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void session_enable_log_priority(SESSION* ses, int priority);
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void session_disable_log_priority(SESSION* ses, int priority);
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RESULTSET *sessionGetList(SESSIONLISTFILTER);
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void process_idle_sessions();
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void enable_session_timeouts();
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/**
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* Get the transaction state of the session.
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*
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* Note that this tells only the state of @e explicitly started transactions.
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* That is, if @e autocommit is OFF, which means that there is always an
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* active transaction that is ended with an explicit COMMIT or ROLLBACK,
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* at which point a new transaction is started, this function will still
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* return SESSION_TRX_INACTIVE, unless a transaction has explicitly been
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* started with START TRANSACTION.
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*
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* Likewise, if @e autocommit is ON, which means that every statement is
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* executed in a transaction of its own, this will return false, unless a
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* transaction has explicitly been started with START TRANSACTION.
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*
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* @note The return value is valid only if either a router or a filter
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* has declared that it needs RCAP_TYPE_TRANSACTION_TRACKING.
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*
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* @param ses The SESSION object.
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* @return The transaction state.
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*/
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session_trx_state_t session_get_trx_state(const SESSION* ses);
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/**
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* Set the transaction state of the session.
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*
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* NOTE: Only the protocol object may call this.
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*
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* @param ses The SESSION object.
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* @param new_state The new transaction state.
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*
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* @return The previous transaction state.
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*/
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session_trx_state_t session_set_trx_state(SESSION* ses, session_trx_state_t new_state);
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/**
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* Tells whether an explicit transaction is active.
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*
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* @see session_get_trx_state
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*
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* @note The return value is valid only if either a router or a filter
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* has declared that it needs RCAP_TYPE_TRANSACTION_TRACKING.
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*
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* @return True if a transaction is active, false otherwise.
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*/
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static inline bool session_trx_is_active(const SESSION* ses)
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{
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return ses->trx_state & SESSION_TRX_ACTIVE_BIT;
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}
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/**
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* Tells whether an explicit READ ONLY transaction is active.
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*
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* @see session_get_trx_state
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*
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* @note The return value is valid only if either a router or a filter
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* has declared that it needs RCAP_TYPE_TRANSACTION_TRACKING.
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*
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* @return True if an explicit READ ONLY transaction is active,
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* false otherwise.
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*/
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static inline bool session_trx_is_read_only(const SESSION* ses)
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{
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return ses->trx_state == SESSION_TRX_READ_ONLY;
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}
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/**
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* Tells whether an explicit READ WRITE transaction is active.
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*
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* @see session_get_trx_state
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*
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* @note The return value is valid only if either a router or a filter
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* has declared that it needs RCAP_TYPE_TRANSACTION_TRACKING.
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*
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* @return True if an explicit READ WRITE transaction is active,
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* false otherwise.
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*/
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static inline bool session_trx_is_read_write(const SESSION* ses)
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{
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return ses->trx_state == SESSION_TRX_READ_WRITE;
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}
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/**
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* Tells whether autocommit is ON or not.
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*
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* Note that the returned value effectively only tells the last value
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* of the statement "set autocommit=...".
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*
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* That is, if the statement "set autocommit=1" has been executed, then
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* even if a transaction has been started, which implicitly will cause
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* autocommit to be set to 0 for the duration of the transaction, this
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* function will still return true.
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*
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* Note also that by default autocommit is ON.
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*
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* @see session_get_trx_state
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*
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* @return True if autocommit has been set ON, false otherwise.
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*/
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static inline bool session_is_autocommit(const SESSION* ses)
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{
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return ses->autocommit;
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}
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/**
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* Sets the autocommit state of the session.
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*
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* NOTE: Only the protocol object may call this.
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*
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* @param enable True if autocommit is enabled, false otherwise.
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* @return The previous state.
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*/
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static inline bool session_set_autocommit(SESSION* ses, bool autocommit)
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{
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bool prev_autocommit = ses->autocommit;
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ses->autocommit = autocommit;
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return prev_autocommit;
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}
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MXS_END_DECLS
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