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/* Copyright (C) 2007 Google Inc.
Copyright (C) 2008 MySQL AB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
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 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 "semisync_slave.h"
#include <mysql.h>
ReplSemiSyncSlave repl_semisync;
/*
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;
int repl_semi_reset_slave(Binlog_relay_IO_param *param)
{
// TODO: reset semi-sync slave status here
return 0;
}
int repl_semi_slave_request_dump(Binlog_relay_IO_param *param,
uint32 flags)
{
MYSQL *mysql= param->mysql;
MYSQL_RES *res= 0;
MYSQL_ROW row;
const char *query;
if (!repl_semisync.getSlaveEnabled())
return 0;
/* Check if master server has semi-sync plugin installed */
query= "SHOW VARIABLES LIKE 'rpl_semi_sync_master_enabled'";
if (mysql_real_query(mysql, query, strlen(query)) ||
!(res= mysql_store_result(mysql)))
{
mysql_free_result(mysql_store_result(mysql));
sql_print_error("Execution failed on master: %s", query);
return 1;
}
row= mysql_fetch_row(res);
if (!row)
{
/* Master does not support semi-sync */
sql_print_warning("Master server does not support semi-sync, "
"fallback to asynchronous replication");
rpl_semi_sync_slave_status= 0;
return 0;
}
/*
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, strlen(query)))
{
sql_print_error("Set 'rpl_semi_sync_slave=1' on master failed");
mysql_free_result(mysql_store_result(mysql));
return 1;
}
mysql_free_result(mysql_store_result(mysql));
rpl_semi_sync_slave_status= 1;
return 0;
}
int repl_semi_slave_read_event(Binlog_relay_IO_param *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;
}
int repl_semi_slave_queue_event(Binlog_relay_IO_param *param,
const char *event_buf,
unsigned long event_len,
uint32 flags)
{
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;
}
int repl_semi_slave_io_start(Binlog_relay_IO_param *param)
{
return repl_semisync.slaveStart(param);
}
int repl_semi_slave_io_end(Binlog_relay_IO_param *param)
{
return repl_semisync.slaveStop(param);
}
static void fix_rpl_semi_sync_slave_enabled(MYSQL_THD thd,
SYS_VAR *var,
void *ptr,
const void *val)
{
*(char *)ptr= *(char *)val;
repl_semisync.setSlaveEnabled(rpl_semi_sync_slave_enabled != 0);
return;
}
static void fix_rpl_semi_sync_trace_level(MYSQL_THD thd,
SYS_VAR *var,
void *ptr,
const void *val)
{
*(unsigned long *)ptr= *(unsigned long *)val;
repl_semisync.setTraceLevel(rpl_semi_sync_slave_trace_level);
return;
}
/* 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, ~0L, 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},
{NULL, NULL, SHOW_BOOL},
};
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_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
};
static int semi_sync_slave_plugin_init(void *p)
{
if (repl_semisync.initObject())
return 1;
if (register_binlog_relay_io_observer(&relay_io_observer, p))
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;
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 */
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 */
}
mysql_declare_plugin_end;
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