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Backport BUG#45848 Semisynchronous replication internals are visible in SHOW PROCESSLIST and logs

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Semi-sync uses an extra connection from slave to master to send
replies, this is a normal client connection, and used a normal
SET query to set the reply information on master, which is visible
to user and may cause some confusion and complaining.

This problem is fixed by using the method of sending reply by
using the same connection that is used by master dump thread to
send binlog to slave. Since now the semi-sync plugins are integrated
with the server code, it is not a problem to use the internal net
interfaces to do this.

The master dump thread will mark the event requires a reply and
wait for the reply when the event just sent is the last event
of a transaction and semi-sync status is ON; And the slave will
send a reply to master when it received such an event that requires
a reply.
This commit is contained in:
He Zhenxing 2009-10-12 20:55:01 +08:00
commit f8155de078
10 changed files with 343 additions and 143 deletions
Download patch file Download diff file Expand all files Collapse all files

50
plugin/semisync/semisync_master_plugin.cc
View file

@ -69,8 +69,16 @@ int repl_semi_binlog_dump_start(Binlog_transmit_param *param,
bool semi_sync_slave= repl_semisync.is_semi_sync_slave();
if (semi_sync_slave)
{
/* One more semi-sync slave */
repl_semisync.add_slave();
/*
Let's assume this semi-sync slave has already received all
binlog events before the filename and position it requests.
*/
repl_semisync.reportReplyBinlog(param->server_id, log_file, log_pos);
}
sql_print_information("Start %s binlog_dump to slave (server_id: %d), pos(%s, %lu)",
semi_sync_slave ? "semi-sync" : "asynchronous",
param->server_id, log_file, (unsigned long)log_pos);
@ -114,6 +122,18 @@ int repl_semi_before_send_event(Binlog_transmit_param *param,
int repl_semi_after_send_event(Binlog_transmit_param *param,
const char *event_buf, unsigned long len)
{
if (repl_semisync.is_semi_sync_slave())
{
THD *thd= current_thd;
/*
Possible errors in reading slave reply are ignored deliberately
because we do not want dump thread to quit on this. Error
messages are already reported.
*/
(void) repl_semisync.readSlaveReply(&thd->net,
param->server_id, event_buf);
thd->clear_error();
}
return 0;
}
@ -142,11 +162,6 @@ static void fix_rpl_semi_sync_master_enabled(MYSQL_THD thd,
void *ptr,
const void *val);
static void fix_rpl_semi_sync_master_reply_log_file_pos(MYSQL_THD thd,
SYS_VAR *var,
void *ptr,
const void *val);
static MYSQL_SYSVAR_BOOL(enabled, rpl_semi_sync_master_enabled,
PLUGIN_VAR_OPCMDARG,
"Enable semi-synchronous replication master (disabled by default). ",
@ -168,22 +183,10 @@ static MYSQL_SYSVAR_ULONG(trace_level, rpl_semi_sync_master_trace_level,
&fix_rpl_semi_sync_master_trace_level, // update
32, 0, ~0L, 1);
/*
Use a SESSION instead of GLOBAL variable for slave to send reply to
avoid requiring SUPER privilege.
*/
static MYSQL_THDVAR_STR(reply_log_file_pos,
PLUGIN_VAR_NOCMDOPT,
"The log filename and position slave has queued to relay log.",
NULL, // check
&fix_rpl_semi_sync_master_reply_log_file_pos,
"");
static SYS_VAR* semi_sync_master_system_vars[]= {
MYSQL_SYSVAR(enabled),
MYSQL_SYSVAR(timeout),
MYSQL_SYSVAR(trace_level),
MYSQL_SYSVAR(reply_log_file_pos),
NULL,
};
@ -228,19 +231,6 @@ static void fix_rpl_semi_sync_master_enabled(MYSQL_THD thd,
return;
}
static void fix_rpl_semi_sync_master_reply_log_file_pos(MYSQL_THD thd,
SYS_VAR *var,
void *ptr,
const void *val)
{
const char *log_file_pos= *(char **)val;
if (repl_semisync.reportReplyBinlog(log_file_pos))
sql_print_error("report slave binlog reply failed.");
return;
}
Trans_observer trans_observer = {
sizeof(Trans_observer), // len