89 lines
3.1 KiB
C
89 lines
3.1 KiB
C
#ifndef _READCONNECTION_H
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#define _READCONNECTION_H
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/*
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* This file is distributed as part of the SkySQL Gateway. It is free
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* software: you can redistribute it and/or modify it under the terms of the
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* GNU General Public License as published by the Free Software Foundation,
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* version 2.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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* details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc., 51
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* Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Copyright SkySQL Ab 2013
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*/
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/**
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* @file readconnection.h - The read connection balancing query 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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* Date Who Description
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* 14/06/13 Mark Riddoch Initial implementation
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* 27/06/14 Mark Riddoch Addition of server weight percentage
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*
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* @endverbatim
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*/
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#include <dcb.h>
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/**
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* Internal structure used to define the set of backend servers we are routing
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* connections to. This provides the storage for routing module specific data
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* that is required for each of the backend servers.
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*/
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typedef struct backend {
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SERVER *server; /*< The server itself */
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int current_connection_count; /*< Number of connections to the server */
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int weight; /*< Desired routing weight */
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} BACKEND;
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/**
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* The client session structure used within this router.
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*/
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typedef struct router_client_session {
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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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int rses_versno; /*< even = no active update, else odd */
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bool rses_closed; /*< true when closeSession is called */
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BACKEND *backend; /*< Backend used by the client session */
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DCB *backend_dcb; /*< DCB Connection to the backend */
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struct router_client_session *next;
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int rses_capabilities; /*< input type, for example */
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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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} ROUTER_CLIENT_SES;
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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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int n_sessions; /*< Number sessions created */
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int n_queries; /*< Number of queries forwarded */
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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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SERVICE *service; /*< Pointer to the service using this router */
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ROUTER_CLIENT_SES *connections; /*< Link list of all the client connections */
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SPINLOCK lock; /*< Spinlock for the instance data */
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BACKEND **servers; /*< List of backend servers */
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unsigned int bitmask; /*< Bitmask to apply to server->status */
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unsigned int bitvalue; /*< Required value of server->status */
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ROUTER_STATS stats; /*< Statistics for this router */
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struct router_instance
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*next;
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} ROUTER_INSTANCE;
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#endif
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