HintRouter: Support various hint types, round-robin rotate slaves
Supports hint types: -master -slave -named server -all A default action, which is performed when no hint exists or on error, can be set. The different actions are analogous to the hint types. A maximum connection number for slaves can be set. If more slaves are configured for the service, the filter will rotate slaves for new sessions. Within a session with multiple slaves, the "route_to_slave"-hint will also rotate among the slave backends.
This commit is contained in:
Esa Korhonen
@ -13,65 +13,158 @@
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#define MXS_MODULE_NAME "hintrouter"
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#include "hintrouter.hh"
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#include <limits>
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#include <vector>
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#include <maxscale/log_manager.h>
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#include "dcb.hh"
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static const MXS_ENUM_VALUE default_action_values[] =
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{
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{"master", HINT_ROUTE_TO_MASTER},
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{"slave", HINT_ROUTE_TO_SLAVE},
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{"named_server", HINT_ROUTE_TO_NAMED_SERVER},
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{"route_to_all", HINT_ROUTE_TO_ALL},
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{NULL} /* Last must be NULL */
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};
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static const char DEFAULT_ACTION[] = "default_action";
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static const char DEFAULT_SERVER[] = "default_server";
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static const char MAX_SLAVES[] = "max_slaves";
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HintRouter::HintRouter(SERVICE* pService)
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: maxscale::Router<HintRouter, HintRouterSession>(pService)
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HintRouter::HintRouter(SERVICE* pService, HINT_TYPE default_action, string& default_server,
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int max_slaves)
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: maxscale::Router<HintRouter, HintRouterSession>(pService),
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m_default_action(default_action),
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m_default_server(default_server),
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m_max_slaves(max_slaves),
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m_total_slave_conns(0)
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{
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HR_ENTRY();
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if (m_max_slaves < 0)
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{ // set a reasonable default value
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m_max_slaves = pService->n_dbref - 1;
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}
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MXS_NOTICE("Hint router [%s] created.", pService->name);
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}
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//static
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HintRouter* HintRouter::create(SERVICE* pService, char** pzOptions)
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{
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HR_ENTRY();
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return new HintRouter(pService);
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}
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MXS_CONFIG_PARAMETER* params = pService->svc_config_param;
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HINT_TYPE default_action = (HINT_TYPE)config_get_enum(params, DEFAULT_ACTION,
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default_action_values);
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string default_server(config_get_string(params, DEFAULT_SERVER));
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int max_slaves = config_get_integer(params, MAX_SLAVES);
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return new HintRouter(pService, default_action, default_server, max_slaves);
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}
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HintRouterSession* HintRouter::newSession(MXS_SESSION *pSession)
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{
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typedef HintRouterSession::RefArray::size_type array_index;
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HR_ENTRY();
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HintRouterSession* pRouterSession = NULL;
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Dcb master_Dcb(NULL);
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HintRouterSession::BackendMap all_backends;
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all_backends.rehash(1 + m_max_slaves);
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HintRouterSession::BackendArray slave_arr;
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slave_arr.reserve(m_max_slaves);
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HintRouterSession::Backends backends;
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SERVER_REF* master_ref = NULL;
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HintRouterSession::RefArray slave_refs;
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slave_refs.reserve(m_max_slaves);
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for (SERVER_REF* pSref = m_pService->dbref; pSref; pSref = pSref->next)
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/* Go through the server references, find master and slaves */
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for (SERVER_REF* pSref = pSession->service->dbref; pSref; pSref = pSref->next)
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{
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if (SERVER_REF_IS_ACTIVE(pSref))
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{
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SERVER* pServer = pSref->server;
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HR_DEBUG("Connecting to %s.", pServer->name);
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DCB* pDcb = dcb_connect(pServer, pSession, pServer->protocol);
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if (pDcb)
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if (SERVER_IS_MASTER(pSref->server))
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{
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HR_DEBUG("Connected to %p %s.", pDcb, pServer->name);
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// TODO: What's done here, should be done by dcb_connect().
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atomic_add(&pSref->connections, 1);
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pDcb->service = pSession->service;
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backends.push_back(Dcb(pDcb));
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if (!master_ref)
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{
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master_ref = pSref;
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}
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else
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{
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MXS_WARNING("Found multiple master servers when creating session.\n");
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}
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}
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else
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else if (SERVER_IS_SLAVE(pSref->server))
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{
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HR_DEBUG("Failed to connect to %s.", pServer->name);
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slave_refs.push_back(pSref);
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}
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}
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}
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if (backends.size() != 0)
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if (master_ref)
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{
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pRouterSession = new HintRouterSession(pSession, this, backends);
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// Connect to master
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HR_DEBUG("Connecting to %s.", master_ref->server->name);
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DCB* master_conn = dcb_connect(master_ref->server, pSession, master_ref->server->protocol);
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if (master_conn)
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{
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HR_DEBUG("Connected.");
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atomic_add(&master_ref->connections, 1);
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master_conn->service = pSession->service;
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master_Dcb = Dcb(master_conn);
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string name(master_conn->server->unique_name);
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all_backends.insert(HintRouterSession::MapElement(name, master_Dcb));
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}
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else
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{
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HR_DEBUG("Connection failed.");
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}
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}
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return pRouterSession;
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/* Different sessions may use different slaves if the 'max_session_slaves'-
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* setting is low enough. First, set maximal looping limits noting that the
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* array is treated as a ring. Also, array size may have changed since last
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* time it was formed. */
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if (slave_refs.size())
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{
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array_index size = slave_refs.size();
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array_index begin = m_total_slave_conns % size;
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array_index limit = begin + size;
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int slave_conns = 0;
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array_index current = begin;
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for (;
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(slave_conns < m_max_slaves) && current != limit;
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current++)
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{
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SERVER_REF* slave_ref = slave_refs.at(current % size);
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// Connect to a slave
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HR_DEBUG("Connecting to %s.", slave_ref->server->name);
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DCB* slave_conn = dcb_connect(slave_ref->server, pSession, slave_ref->server->protocol);
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if (slave_conn)
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{
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HR_DEBUG("Connected.");
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atomic_add(&slave_ref->connections, 1);
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slave_conn->service = pSession->service;
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Dcb slave_Dcb(slave_conn);
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slave_arr.push_back(slave_Dcb);
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string name(slave_conn->server->unique_name);
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all_backends.insert(HintRouterSession::MapElement(name, slave_Dcb));
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slave_conns++;
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}
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else
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{
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HR_DEBUG("Connection failed.");
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}
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}
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m_total_slave_conns += slave_conns;
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}
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if (all_backends.size() != 0)
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{
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return new HintRouterSession(pSession, this, all_backends);
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}
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return NULL;
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}
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void HintRouter::diagnostics(DCB* pOut)
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@ -82,10 +175,9 @@ void HintRouter::diagnostics(DCB* pOut)
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uint64_t HintRouter::getCapabilities()
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{
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HR_ENTRY();
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return RCAP_TYPE_NONE;
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return RCAP_TYPE_STMT_INPUT | RCAP_TYPE_RESULTSET_OUTPUT;
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}
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extern "C" MXS_MODULE* MXS_CREATE_MODULE()
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{
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static MXS_MODULE module =
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@ -95,16 +187,24 @@ extern "C" MXS_MODULE* MXS_CREATE_MODULE()
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MXS_ROUTER_VERSION, /* Implemented module API version */
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"A hint router", /* Description */
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"V1.0.0", /* Module version */
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RCAP_TYPE_STMT_OUTPUT,
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RCAP_TYPE_STMT_INPUT | RCAP_TYPE_RESULTSET_OUTPUT,
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&HintRouter::s_object,
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NULL, /* Process init, can be null */
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NULL, /* Process finish, can be null */
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NULL, /* Thread init */
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NULL, /* Thread finish */
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{
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{
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DEFAULT_ACTION,
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MXS_MODULE_PARAM_ENUM,
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default_action_values[0].name,
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MXS_MODULE_OPT_NONE,
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default_action_values
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},
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{DEFAULT_SERVER, MXS_MODULE_PARAM_SERVER, ""},
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{MAX_SLAVES, MXS_MODULE_PARAM_INT, "-1"},
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{MXS_END_MODULE_PARAMS}
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}
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};
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return &module;
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}
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