740 lines
22 KiB
C++
740 lines
22 KiB
C++
/*
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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/bsl11.
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*
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* Change Date: 2020-01-01
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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 mm_mon.c - A Multi-Master Multi Muster cluster monitor
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*/
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#define MXS_MODULE_NAME "mmmon"
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#include "mmmon.h"
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#include <maxscale/dcb.h>
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#include <maxscale/alloc.h>
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#include <maxscale/mysql_utils.h>
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static void monitorMain(void *);
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/* @see function load_module in load_utils.c for explanation of the following
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* lint directives.
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*/
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/*lint -e14 */
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MXS_MODULE info =
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{
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MXS_MODULE_API_MONITOR,
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MXS_MODULE_BETA_RELEASE,
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MXS_MONITOR_VERSION,
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"A Multi-Master Multi Master monitor",
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"V1.1.1"
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};
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/*lint +e14 */
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static MXS_MONITOR_INSTANCE *createInstance(MXS_MONITOR *);
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static void destroyInstance(MXS_MONITOR_INSTANCE *);
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static bool startMonitor(MXS_MONITOR_INSTANCE *, const MXS_CONFIG_PARAMETER *);
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static void stopMonitor(MXS_MONITOR_INSTANCE *);
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static void diagnostics(const MXS_MONITOR_INSTANCE *, DCB *);
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static json_t* diagnostics_json(const MXS_MONITOR_INSTANCE *);
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static void detectStaleMaster(void *, int);
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static MXS_MONITORED_SERVER *get_current_master(MXS_MONITOR *);
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static bool isMySQLEvent(mxs_monitor_event_t event);
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extern "C"
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{
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/**
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* The module entry point routine. It is this routine that
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* must populate the structure that is referred to as the
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* "module object", this is a structure with the set of
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* external entry points for this module.
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*
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* @return The module object
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*/
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MXS_MODULE* MXS_CREATE_MODULE()
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{
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MXS_NOTICE("Initialise the Multi-Master Monitor module.");
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static MXS_MONITOR_API MyObject =
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{
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createInstance,
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destroyInstance,
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startMonitor,
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stopMonitor,
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diagnostics,
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diagnostics_json
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};
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static MXS_MODULE info =
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{
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MXS_MODULE_API_MONITOR,
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MXS_MODULE_BETA_RELEASE,
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MXS_MONITOR_VERSION,
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"A Multi-Master Multi Master monitor",
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"V1.1.1",
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MXS_NO_MODULE_CAPABILITIES,
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&MyObject,
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NULL, /* Process init. */
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NULL, /* Process finish. */
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NULL, /* Thread init. */
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NULL, /* Thread finish. */
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{
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{"detect_stale_master", MXS_MODULE_PARAM_BOOL, "false"},
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{
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"script",
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MXS_MODULE_PARAM_PATH,
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NULL,
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MXS_MODULE_OPT_PATH_X_OK
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},
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{
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"events",
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MXS_MODULE_PARAM_ENUM,
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MXS_MONITOR_EVENT_DEFAULT_VALUE,
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MXS_MODULE_OPT_NONE,
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mxs_monitor_event_enum_values
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},
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{MXS_END_MODULE_PARAMS}
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}
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};
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return &info;
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}
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}
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/*lint +e14 */
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static MXS_MONITOR_INSTANCE* createInstance(MXS_MONITOR *mon)
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{
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MM_MONITOR* handle = static_cast<MM_MONITOR*>(MXS_CALLOC(1, sizeof(MM_MONITOR)));
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if (handle)
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{
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handle->shutdown = 0;
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handle->id = MXS_MONITOR_DEFAULT_ID;
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handle->master = NULL;
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handle->monitor = mon;
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handle->detectStaleMaster = false;
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handle->script = NULL;
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handle->events = 0;
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handle->checked = false;
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}
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return handle;
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}
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static void destroyInstance(MXS_MONITOR_INSTANCE* mon)
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{
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MM_MONITOR* handle = static_cast<MM_MONITOR*>(mon);
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ss_dassert(!handle->thread);
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ss_dassert(!handle->script);
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MXS_FREE(handle);
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}
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/**
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* Start the instance of the monitor, returning a handle on the monitor.
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*
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* This function creates a thread to execute the actual monitoring.
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*
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* @param arg The current handle - NULL if first start
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* @return A handle to use when interacting with the monitor
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*/
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static bool startMonitor(MXS_MONITOR_INSTANCE *mon, const MXS_CONFIG_PARAMETER *params)
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{
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bool started = false;
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MM_MONITOR *handle = static_cast<MM_MONITOR*>(mon);
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ss_dassert(handle);
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if (!handle->checked)
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{
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if (!check_monitor_permissions(handle->monitor, "SHOW SLAVE STATUS"))
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{
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MXS_ERROR("Failed to start monitor. See earlier errors for more information.");
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}
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else
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{
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handle->checked = true;
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}
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}
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if (handle->checked)
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{
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handle->detectStaleMaster = config_get_bool(params, "detect_stale_master");
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handle->script = config_copy_string(params, "script");
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handle->events = config_get_enum(params, "events", mxs_monitor_event_enum_values);
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if (thread_start(&handle->thread, monitorMain, handle, 0) == NULL)
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{
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MXS_ERROR("Failed to start monitor thread for monitor '%s'.", handle->monitor->name);
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MXS_FREE(handle->script);
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handle->script = NULL;
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}
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else
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{
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started = true;
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}
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}
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return started;
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}
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/**
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* Stop a running monitor
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*
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* @param arg Handle on thr running monior
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*/
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static void
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stopMonitor(MXS_MONITOR_INSTANCE *mon)
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{
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MM_MONITOR *handle = static_cast<MM_MONITOR*>(mon);
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ss_dassert(handle->thread);
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handle->shutdown = 1;
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thread_wait(handle->thread);
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handle->thread = 0;
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handle->shutdown = 0;
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MXS_FREE(handle->script);
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handle->script = NULL;
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}
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/**
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* Diagnostic interface
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*
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* @param dcb DCB to print diagnostics
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* @param arg The monitor handle
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*/
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static void diagnostics(const MXS_MONITOR_INSTANCE *mon, DCB *dcb)
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{
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const MM_MONITOR *handle = static_cast<const MM_MONITOR*>(mon);
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dcb_printf(dcb, "Detect Stale Master:\t%s\n", (handle->detectStaleMaster == 1) ? "enabled" : "disabled");
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}
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/**
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* Diagnostic interface
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*
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* @param arg The monitor handle
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*/
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static json_t* diagnostics_json(const MXS_MONITOR_INSTANCE *mon)
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{
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const MM_MONITOR *handle = static_cast<const MM_MONITOR*>(mon);
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json_t* rval = json_object();
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json_object_set_new(rval, "detect_stale_master", json_boolean(handle->detectStaleMaster));
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return rval;
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}
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/**
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* Monitor an individual server
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*
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* @param handle The MySQL Monitor object
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* @param database The database to probe
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*/
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static void
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monitorDatabase(MXS_MONITOR* mon, MXS_MONITORED_SERVER *database)
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{
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MYSQL_ROW row;
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MYSQL_RES *result;
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int isslave = 0;
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int ismaster = 0;
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unsigned long int server_version = 0;
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char *server_string;
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/* Don't probe servers in maintenance mode */
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if (SERVER_IN_MAINT(database->server))
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{
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return;
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}
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/** Store previous status */
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database->mon_prev_status = database->server->status;
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mxs_connect_result_t rval = mon_ping_or_connect_to_db(mon, database);
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if (!mon_connection_is_ok(rval))
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{
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if (mysql_errno(database->con) == ER_ACCESS_DENIED_ERROR)
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{
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server_set_status_nolock(database->server, SERVER_AUTH_ERROR);
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monitor_set_pending_status(database, SERVER_AUTH_ERROR);
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}
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server_clear_status_nolock(database->server, SERVER_RUNNING);
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monitor_clear_pending_status(database, SERVER_RUNNING);
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/* Also clear M/S state in both server and monitor server pending struct */
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server_clear_status_nolock(database->server, SERVER_SLAVE);
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server_clear_status_nolock(database->server, SERVER_MASTER);
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monitor_clear_pending_status(database, SERVER_SLAVE);
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monitor_clear_pending_status(database, SERVER_MASTER);
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/* Clean addition status too */
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server_clear_status_nolock(database->server, SERVER_STALE_STATUS);
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monitor_clear_pending_status(database, SERVER_STALE_STATUS);
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if (mon_status_changed(database) && mon_print_fail_status(database))
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{
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mon_log_connect_error(database, rval);
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}
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return;
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}
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else
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{
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server_clear_status_nolock(database->server, SERVER_AUTH_ERROR);
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monitor_clear_pending_status(database, SERVER_AUTH_ERROR);
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}
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/* Store current status in both server and monitor server pending struct */
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server_set_status_nolock(database->server, SERVER_RUNNING);
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monitor_set_pending_status(database, SERVER_RUNNING);
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/* get server version from current server */
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server_version = mysql_get_server_version(database->con);
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/* get server version string */
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mxs_mysql_set_server_version(database->con, database->server);
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server_string = database->server->version_string;
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/* get server_id form current node */
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if (mxs_mysql_query(database->con, "SELECT @@server_id") == 0
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&& (result = mysql_store_result(database->con)) != NULL)
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{
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long server_id = -1;
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if (mysql_field_count(database->con) != 1)
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{
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mysql_free_result(result);
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MXS_ERROR("Unexpected result for 'SELECT @@server_id'. Expected 1 column."
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" MySQL Version: %s", server_string);
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return;
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}
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while ((row = mysql_fetch_row(result)))
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{
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server_id = strtol(row[0], NULL, 10);
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if ((errno == ERANGE && (server_id == LONG_MAX
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|| server_id == LONG_MIN)) || (errno != 0 && server_id == 0))
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{
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server_id = -1;
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}
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database->server->node_id = server_id;
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}
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mysql_free_result(result);
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}
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else
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{
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mon_report_query_error(database);
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}
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/* Check if the Slave_SQL_Running and Slave_IO_Running status is
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* set to Yes
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*/
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/* Check first for MariaDB 10.x.x and get status for multimaster replication */
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if (server_version >= 100000)
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{
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if (mxs_mysql_query(database->con, "SHOW ALL SLAVES STATUS") == 0
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&& (result = mysql_store_result(database->con)) != NULL)
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{
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int i = 0;
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long master_id = -1;
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if (mysql_field_count(database->con) < 42)
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{
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mysql_free_result(result);
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MXS_ERROR("\"SHOW ALL SLAVES STATUS\" returned less than the expected"
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" amount of columns. Expected 42 columns MySQL Version: %s",
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server_string);
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return;
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}
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while ((row = mysql_fetch_row(result)))
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{
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/* get Slave_IO_Running and Slave_SQL_Running values*/
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if (strncmp(row[12], "Yes", 3) == 0
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&& strncmp(row[13], "Yes", 3) == 0)
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{
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isslave += 1;
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}
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/* If Slave_IO_Running = Yes, assign the master_id to current server: this allows building
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* the replication tree, slaves ids will be added to master(s) and we will have at least the
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* root master server.
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* Please note, there could be no slaves at all if Slave_SQL_Running == 'No'
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*/
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if (strncmp(row[12], "Yes", 3) == 0)
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{
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/* get Master_Server_Id values */
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master_id = atol(row[41]);
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if (master_id == 0)
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{
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master_id = -1;
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}
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}
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i++;
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}
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/* store master_id of current node */
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memcpy(&database->server->master_id, &master_id, sizeof(long));
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mysql_free_result(result);
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/* If all configured slaves are running set this node as slave */
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if (isslave > 0 && isslave == i)
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{
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isslave = 1;
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}
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else
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{
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isslave = 0;
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}
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}
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else
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{
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mon_report_query_error(database);
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}
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}
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else
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{
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if (mxs_mysql_query(database->con, "SHOW SLAVE STATUS") == 0
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&& (result = mysql_store_result(database->con)) != NULL)
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{
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long master_id = -1;
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if (mysql_field_count(database->con) < 40)
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{
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mysql_free_result(result);
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if (server_version < 5 * 10000 + 5 * 100)
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{
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if (database->log_version_err)
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{
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MXS_ERROR("\"SHOW SLAVE STATUS\" "
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" for versions less than 5.5 does not have master_server_id, "
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"replication tree cannot be resolved for server %s."
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" MySQL Version: %s", database->server->name, server_string);
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database->log_version_err = false;
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}
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}
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else
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{
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MXS_ERROR("\"SHOW SLAVE STATUS\" "
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"returned less than the expected amount of columns. "
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"Expected 40 columns. MySQL Version: %s", server_string);
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}
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return;
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}
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while ((row = mysql_fetch_row(result)))
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{
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/* get Slave_IO_Running and Slave_SQL_Running values*/
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if (strncmp(row[10], "Yes", 3) == 0
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&& strncmp(row[11], "Yes", 3) == 0)
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{
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isslave = 1;
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}
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/* If Slave_IO_Running = Yes, assign the master_id to current server: this allows building
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* the replication tree, slaves ids will be added to master(s) and we will have at least the
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* root master server.
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* Please note, there could be no slaves at all if Slave_SQL_Running == 'No'
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*/
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if (strncmp(row[10], "Yes", 3) == 0)
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{
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/* get Master_Server_Id values */
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master_id = atol(row[39]);
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if (master_id == 0)
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{
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master_id = -1;
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}
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}
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}
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/* store master_id of current node */
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memcpy(&database->server->master_id, &master_id, sizeof(long));
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mysql_free_result(result);
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}
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else
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{
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mon_report_query_error(database);
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}
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}
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/* get variable 'read_only' set by an external component */
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if (mxs_mysql_query(database->con, "SHOW GLOBAL VARIABLES LIKE 'read_only'") == 0
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&& (result = mysql_store_result(database->con)) != NULL)
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{
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if (mysql_field_count(database->con) < 2)
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{
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mysql_free_result(result);
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MXS_ERROR("Unexpected result for \"SHOW GLOBAL VARIABLES LIKE 'read_only'\". "
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"Expected 2 columns. MySQL Version: %s", server_string);
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return;
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}
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while ((row = mysql_fetch_row(result)))
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{
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if (strncasecmp(row[1], "OFF", 3) == 0)
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{
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ismaster = 1;
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}
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else
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{
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isslave = 1;
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}
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}
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mysql_free_result(result);
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}
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else
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{
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mon_report_query_error(database);
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}
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/* Remove addition info */
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monitor_clear_pending_status(database, SERVER_STALE_STATUS);
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/* Set the Slave Role */
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/* Set the Master role */
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if (ismaster)
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{
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monitor_clear_pending_status(database, SERVER_SLAVE);
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monitor_set_pending_status(database, SERVER_MASTER);
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/* Set replication depth to 0 */
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database->server->depth = 0;
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}
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else if (isslave)
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{
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monitor_set_pending_status(database, SERVER_SLAVE);
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/* Avoid any possible stale Master state */
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monitor_clear_pending_status(database, SERVER_MASTER);
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/* Set replication depth to 1 */
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database->server->depth = 1;
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}
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/* Avoid any possible Master/Slave stale state */
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else
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{
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monitor_clear_pending_status(database, SERVER_SLAVE);
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monitor_clear_pending_status(database, SERVER_MASTER);
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}
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}
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/**
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* The entry point for the monitoring module thread
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*
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* @param arg The handle of the monitor
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*/
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static void
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monitorMain(void *arg)
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{
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MM_MONITOR *handle = (MM_MONITOR *)arg;
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MXS_MONITOR* mon = handle->monitor;
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MXS_MONITORED_SERVER *ptr;
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int detect_stale_master = false;
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MXS_MONITORED_SERVER *root_master = NULL;
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size_t nrounds = 0;
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detect_stale_master = handle->detectStaleMaster;
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if (mysql_thread_init())
|
|
{
|
|
MXS_ERROR("Fatal : mysql_thread_init failed in monitor module. Exiting.");
|
|
return;
|
|
}
|
|
|
|
handle->status = MXS_MONITOR_RUNNING;
|
|
load_server_journal(mon, &handle->master);
|
|
|
|
while (1)
|
|
{
|
|
if (handle->shutdown)
|
|
{
|
|
handle->status = MXS_MONITOR_STOPPING;
|
|
mysql_thread_end();
|
|
handle->status = MXS_MONITOR_STOPPED;
|
|
return;
|
|
}
|
|
|
|
/** Wait base interval */
|
|
thread_millisleep(MXS_MON_BASE_INTERVAL_MS);
|
|
/**
|
|
* Calculate how far away the monitor interval is from its full
|
|
* cycle and if monitor interval time further than the base
|
|
* interval, then skip monitoring checks. Excluding the first
|
|
* round.
|
|
*/
|
|
if (nrounds != 0 &&
|
|
(((nrounds * MXS_MON_BASE_INTERVAL_MS) % mon->interval) >=
|
|
MXS_MON_BASE_INTERVAL_MS) && (!mon->server_pending_changes))
|
|
{
|
|
nrounds += 1;
|
|
continue;
|
|
}
|
|
nrounds += 1;
|
|
|
|
lock_monitor_servers(mon);
|
|
servers_status_pending_to_current(mon);
|
|
|
|
/* start from the first server in the list */
|
|
ptr = mon->monitored_servers;
|
|
|
|
while (ptr)
|
|
{
|
|
/* copy server status into monitor pending_status */
|
|
ptr->pending_status = ptr->server->status;
|
|
|
|
/* monitor current node */
|
|
monitorDatabase(mon, ptr);
|
|
|
|
if (mon_status_changed(ptr) ||
|
|
mon_print_fail_status(ptr))
|
|
{
|
|
MXS_DEBUG("Backend server [%s]:%d state : %s",
|
|
ptr->server->address,
|
|
ptr->server->port,
|
|
STRSRVSTATUS(ptr->server));
|
|
}
|
|
if (SERVER_IS_DOWN(ptr->server))
|
|
{
|
|
/** Increase this server'e error count */
|
|
ptr->mon_err_count += 1;
|
|
}
|
|
else
|
|
{
|
|
/** Reset this server's error count */
|
|
ptr->mon_err_count = 0;
|
|
}
|
|
|
|
ptr = ptr->next;
|
|
}
|
|
|
|
/* Get Master server pointer */
|
|
root_master = get_current_master(mon);
|
|
|
|
/* Update server status from monitor pending status on that server*/
|
|
|
|
ptr = mon->monitored_servers;
|
|
while (ptr)
|
|
{
|
|
if (!SERVER_IN_MAINT(ptr->server))
|
|
{
|
|
/* If "detect_stale_master" option is On, let's use the previus master */
|
|
if (detect_stale_master && root_master &&
|
|
(!strcmp(ptr->server->address, root_master->server->address) &&
|
|
ptr->server->port == root_master->server->port) && (ptr->server->status & SERVER_MASTER) &&
|
|
!(ptr->pending_status & SERVER_MASTER))
|
|
{
|
|
/* in this case server->status will not be updated from pending_status */
|
|
MXS_NOTICE("root server [%s:%i] is no longer Master, let's "
|
|
"use it again even if it could be a stale master, you have "
|
|
"been warned!", ptr->server->address, ptr->server->port);
|
|
/* Set the STALE bit for this server in server struct */
|
|
server_set_status_nolock(ptr->server, SERVER_STALE_STATUS);
|
|
}
|
|
else
|
|
{
|
|
ptr->server->status = ptr->pending_status;
|
|
}
|
|
}
|
|
ptr = ptr->next;
|
|
}
|
|
|
|
/**
|
|
* After updating the status of all servers, check if monitor events
|
|
* need to be launched.
|
|
*/
|
|
mon_process_state_changes(mon, handle->script, handle->events);
|
|
|
|
mon_hangup_failed_servers(mon);
|
|
servers_status_current_to_pending(mon);
|
|
store_server_journal(mon, handle->master);
|
|
release_monitor_servers(mon);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Enable/Disable the MySQL Replication Stale Master dectection, allowing a previouvsly detected master to still act as a Master.
|
|
* This option must be enabled in order to keep the Master when the replication is stopped or removed from slaves.
|
|
* If the replication is still stopped when MaxSclale is restarted no Master will be available.
|
|
*
|
|
* @param arg The handle allocated by startMonitor
|
|
* @param enable To enable it 1, disable it with 0
|
|
*/
|
|
/* Not used
|
|
static void
|
|
detectStaleMaster(void *arg, int enable)
|
|
{
|
|
MONITOR* mon = (MONITOR*) arg;
|
|
MM_MONITOR *handle = (MM_MONITOR *) mon->handle;
|
|
memcpy(&handle->detectStaleMaster, &enable, sizeof(int));
|
|
}
|
|
*/
|
|
|
|
/*******
|
|
* This function returns the master server
|
|
* from a set of MySQL Multi Master monitored servers
|
|
* and returns the root server (that has SERVER_MASTER bit)
|
|
* The server is returned even for servers in 'maintenance' mode.
|
|
*
|
|
* @param handle The monitor handle
|
|
* @return The server at root level with SERVER_MASTER bit
|
|
*/
|
|
|
|
static MXS_MONITORED_SERVER *get_current_master(MXS_MONITOR *mon)
|
|
{
|
|
MM_MONITOR* handle = static_cast<MM_MONITOR*>(mon->instance);
|
|
MXS_MONITORED_SERVER *ptr;
|
|
|
|
ptr = mon->monitored_servers;
|
|
|
|
while (ptr)
|
|
{
|
|
/* The server could be in SERVER_IN_MAINT
|
|
* that means SERVER_IS_RUNNING returns 0
|
|
* Let's check only for SERVER_IS_DOWN: server is not running
|
|
*/
|
|
if (SERVER_IS_DOWN(ptr->server))
|
|
{
|
|
ptr = ptr->next;
|
|
continue;
|
|
}
|
|
|
|
if (ptr->server->depth == 0)
|
|
{
|
|
handle->master = ptr;
|
|
}
|
|
|
|
ptr = ptr->next;
|
|
}
|
|
|
|
|
|
/*
|
|
* Return the root master
|
|
*/
|
|
|
|
if (handle->master != NULL)
|
|
{
|
|
/* If the root master is in MAINT, return NULL */
|
|
if (SERVER_IN_MAINT(handle->master->server))
|
|
{
|
|
return NULL;
|
|
}
|
|
else
|
|
{
|
|
return handle->master;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
return NULL;
|
|
}
|
|
}
|