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polardbxengine/plugin/semisync/semisync_slave_plugin.cc

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/* Copyright (C) 2007 Google Inc.
Copyright (c) 2008, 2019, Oracle and/or its affiliates. All rights reserved.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License, version 2.0,
as published by the Free Software Foundation.
This program is also distributed with certain software (including
but not limited to OpenSSL) that is licensed under separate terms,
as designated in a particular file or component or in included license
documentation. The authors of MySQL hereby grant you an additional
permission to link the program and your derivative works with the
separately licensed software that they have included with MySQL.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License, version 2.0, for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
#include <mysql.h>
#include <mysqld_error.h>
#include <stdlib.h>
#include <sys/types.h>
#include "my_dbug.h"
#include "my_inttypes.h"
#include "my_macros.h"
#include "plugin/semisync/semisync_slave.h"
ReplSemiSyncSlave *repl_semisync = nullptr;
/*
indicate whether or not the slave should send a reply to the master.
This is set to true in repl_semi_slave_read_event if the current
event read is the last event of a transaction. And the value is
checked in repl_semi_slave_queue_event.
*/
bool semi_sync_need_reply = false;
static SERVICE_TYPE(registry) *reg_srv = nullptr;
SERVICE_TYPE(log_builtins) *log_bi = nullptr;
SERVICE_TYPE(log_builtins_string) *log_bs = nullptr;
static int repl_semi_apply_slave(Binlog_relay_IO_param *, Trans_param *,
int &) {
// TODO: implement
return 0;
}
static int repl_semi_reset_slave(Binlog_relay_IO_param *) {
// TODO: reset semi-sync slave status here
return 0;
}
static int repl_semi_slave_request_dump(Binlog_relay_IO_param *param, uint32) {
MYSQL *mysql = param->mysql;
MYSQL_RES *res = 0;
#ifndef DBUG_OFF
MYSQL_ROW row = NULL;
#endif
const char *query;
uint mysql_error = 0;
if (!repl_semisync->getSlaveEnabled()) return 0;
/* Check if master server has semi-sync plugin installed */
query = "SELECT @@global.rpl_semi_sync_master_enabled";
if (mysql_real_query(mysql, query, static_cast<ulong>(strlen(query))) ||
!(res = mysql_store_result(mysql))) {
mysql_error = mysql_errno(mysql);
if (mysql_error != ER_UNKNOWN_SYSTEM_VARIABLE) {
LogPluginErr(ERROR_LEVEL, ER_SEMISYNC_EXECUTION_FAILED_ON_MASTER, query,
mysql_error);
return 1;
}
} else {
#ifndef DBUG_OFF
row =
#endif
mysql_fetch_row(res);
}
DBUG_ASSERT(mysql_error == ER_UNKNOWN_SYSTEM_VARIABLE ||
strtoul(row[0], 0, 10) == 0 || strtoul(row[0], 0, 10) == 1);
if (mysql_error == ER_UNKNOWN_SYSTEM_VARIABLE) {
/* Master does not support semi-sync */
LogPluginErr(WARNING_LEVEL, ER_SEMISYNC_NOT_SUPPORTED_BY_MASTER);
rpl_semi_sync_slave_status = 0;
mysql_free_result(res);
return 0;
}
mysql_free_result(res);
/*
Tell master dump thread that we want to do semi-sync
replication
*/
query = "SET @rpl_semi_sync_slave= 1";
if (mysql_real_query(mysql, query, static_cast<ulong>(strlen(query)))) {
LogPluginErr(ERROR_LEVEL, ER_SEMISYNC_SLAVE_SET_FAILED);
return 1;
}
mysql_free_result(mysql_store_result(mysql));
rpl_semi_sync_slave_status = 1;
return 0;
}
static int repl_semi_slave_read_event(Binlog_relay_IO_param *,
const char *packet, unsigned long len,
const char **event_buf,
unsigned long *event_len) {
if (rpl_semi_sync_slave_status)
return repl_semisync->slaveReadSyncHeader(
packet, len, &semi_sync_need_reply, event_buf, event_len);
*event_buf = packet;
*event_len = len;
return 0;
}
static int repl_semi_slave_queue_event(Binlog_relay_IO_param *param,
const char *, unsigned long, uint32) {
if (rpl_semi_sync_slave_status && semi_sync_need_reply) {
/*
We deliberately ignore the error in slaveReply, such error
should not cause the slave IO thread to stop, and the error
messages are already reported.
*/
(void)repl_semisync->slaveReply(param->mysql, param->master_log_name,
param->master_log_pos);
}
return 0;
}
static int repl_semi_slave_io_start(Binlog_relay_IO_param *param) {
return repl_semisync->slaveStart(param);
}
static int repl_semi_slave_io_end(Binlog_relay_IO_param *param) {
return repl_semisync->slaveStop(param);
}
int repl_semi_slave_sql_start(Binlog_relay_IO_param *) { return 0; }
static int repl_semi_slave_sql_stop(Binlog_relay_IO_param *, bool) { return 0; }
static void fix_rpl_semi_sync_slave_enabled(MYSQL_THD, SYS_VAR *, void *ptr,
const void *val) {
*static_cast<char *>(ptr) = *static_cast<const char *>(val);
repl_semisync->setSlaveEnabled(rpl_semi_sync_slave_enabled != 0);
}
static void fix_rpl_semi_sync_trace_level(MYSQL_THD, SYS_VAR *, void *ptr,
const void *val) {
*static_cast<unsigned long *>(ptr) = *static_cast<const unsigned long *>(val);
repl_semisync->setTraceLevel(rpl_semi_sync_slave_trace_level);
}
/* plugin system variables */
static MYSQL_SYSVAR_BOOL(
enabled, rpl_semi_sync_slave_enabled, PLUGIN_VAR_OPCMDARG,
"Enable semi-synchronous replication slave (disabled by default). ",
NULL, // check
&fix_rpl_semi_sync_slave_enabled, // update
0);
static MYSQL_SYSVAR_ULONG(trace_level, rpl_semi_sync_slave_trace_level,
PLUGIN_VAR_OPCMDARG,
"The tracing level for semi-sync replication.",
NULL, // check
&fix_rpl_semi_sync_trace_level, // update
32, 0, ~0UL, 1);
static SYS_VAR *semi_sync_slave_system_vars[] = {
MYSQL_SYSVAR(enabled),
MYSQL_SYSVAR(trace_level),
NULL,
};
/* plugin status variables */
static SHOW_VAR semi_sync_slave_status_vars[] = {
{"Rpl_semi_sync_slave_status", (char *)&rpl_semi_sync_slave_status,
SHOW_BOOL, SHOW_SCOPE_GLOBAL},
{NULL, NULL, SHOW_BOOL, SHOW_SCOPE_GLOBAL},
};
Binlog_relay_IO_observer relay_io_observer = {
sizeof(Binlog_relay_IO_observer), // len
repl_semi_slave_io_start, // start
repl_semi_slave_io_end, // stop
repl_semi_slave_sql_start, // start sql thread
repl_semi_slave_sql_stop, // stop sql thread
repl_semi_slave_request_dump, // request_transmit
repl_semi_slave_read_event, // after_read_event
repl_semi_slave_queue_event, // after_queue_event
repl_semi_reset_slave, // reset
repl_semi_apply_slave // apply
};
static int semi_sync_slave_plugin_init(void *p) {
// Initialize error logging service.
if (init_logging_service_for_plugin(&reg_srv, &log_bi, &log_bs)) return 1;
repl_semisync = new ReplSemiSyncSlave();
if (repl_semisync->initObject()) {
deinit_logging_service_for_plugin(&reg_srv, &log_bi, &log_bs);
return 1;
}
if (register_binlog_relay_io_observer(&relay_io_observer, p)) {
deinit_logging_service_for_plugin(&reg_srv, &log_bi, &log_bs);
return 1;
}
return 0;
}
static int semi_sync_slave_plugin_deinit(void *p) {
if (unregister_binlog_relay_io_observer(&relay_io_observer, p)) return 1;
delete repl_semisync;
repl_semisync = nullptr;
deinit_logging_service_for_plugin(&reg_srv, &log_bi, &log_bs);
return 0;
}
struct Mysql_replication semi_sync_slave_plugin = {
MYSQL_REPLICATION_INTERFACE_VERSION};
/*
Plugin library descriptor
*/
mysql_declare_plugin(semi_sync_slave){
MYSQL_REPLICATION_PLUGIN,
&semi_sync_slave_plugin,
"rpl_semi_sync_slave",
"He Zhenxing",
"Semi-synchronous replication slave",
PLUGIN_LICENSE_GPL,
semi_sync_slave_plugin_init, /* Plugin Init */
NULL, /* Plugin Check uninstall */
semi_sync_slave_plugin_deinit, /* Plugin Deinit */
0x0100 /* 1.0 */,
semi_sync_slave_status_vars, /* status variables */
semi_sync_slave_system_vars, /* system variables */
NULL, /* config options */
0, /* flags */
} mysql_declare_plugin_end;
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