Hi Andrei,
I have updated code according to your most comments. Please review the
new patch again. Thanks a lot!
> Dao-Gang, hello.
>
> To follow our telephone conversation,
>
>
>> #At file:///home/daogangq/mysql/bzrwork/bug45214/5.1-bt/ based on
> revid:davi.arnaut@stripped
>>
>> 2941 Dao-Gang.Qu@stripped 2009-06-27
>> Bug #45214 get_master_version_and_clock does not report error when queries
> fail
>>
>> The "get_master_version_and_clock(...)" function in sql/slave.cc ignores
> error
>> and passes directly when queries get a failed response from master because
> of
>> transient network problems between master and slave or get a successful
> response
>> but the value of relational variable is not existent in the result
> retrieved.
>>
>> The "get_master_version_and_clock(...)" function should try to reconnect
> master
>> if the queries get a failed response from master because of transient
> network
>> problems between master and slave.
>>
>
>
>> And it should report a nonexistent value error
>>
>
> It's not clear what's `nonexistent'. You mean the master reported an
> inappropiate value, like a different time_zone, don't you?
>
>
>
NO. I have update the description. Please review again. it didn't
confuse you again.
>> or print a warning information if the queries get a successful response but
> the
>> value of relational variable is not existent in the result retrieved.
>>
>
> We need to state the following.
>
> A failure of mysql_real_query() is tollerable; we need only to print out a warning
> which your patch does not do (TODO).
>
> A failure of mysql_store_result() or mysql_fetch_row() to retrieve
> result set because of different from a network issue, such as
> `CR_SERVER_LOST', is a critical one; what kind of issue is checked with
> mysql_error().
>
> A failure of mysql_fetch_row() to produce not empty set results despite of
> zero return of mysql_error() is a critical failure because of nature of
> being retrieved data. In neither of 4 interaction with the master they
> can't be selected as the null set.
>
> Finally, failures due to the existing logics like
> `The slave I/O thread stops because master and slave have equal MySQL server ids'
> should remain on the error level.
>
>
>
I update the code according to your most comments. But the `CR_SERVER_LOST'
is not a critical error, it's a network error, which is verified in test,
a transient master server shutdown will cause the error.
>> @
> mysql-test/extra/rpl_tests/rpl_get_master_version_clock_on_disconnection.test
>> Test script for bug #45214
>> @
> mysql-test/suite/rpl/r/rpl_get_master_version_clock_on_disconnection.result
>> Test result for bug #45214
>> @ mysql-test/suite/rpl/t/rpl_get_master_version_clock_on_disconnection.test
>> Test script for bug #45214
>> @ sql/slave.cc
>> Update the slave.cc for fixing bug #45214
>>
>> added:
>>
> mysql-test/extra/rpl_tests/rpl_get_master_version_clock_on_disconnection.test
>>
> mysql-test/suite/rpl/r/rpl_get_master_version_clock_on_disconnection.result
>> mysql-test/suite/rpl/t/rpl_get_master_version_clock_on_disconnection.test
>> modified:
>> sql/slave.cc
>> === added file
> 'mysql-test/extra/rpl_tests/rpl_get_master_version_clock_on_disconnection.test'
>> ---
> a/mysql-test/extra/rpl_tests/rpl_get_master_version_clock_on_disconnection.test 1970-01-01
> 00:00:00 +0000
>> +++
> b/mysql-test/extra/rpl_tests/rpl_get_master_version_clock_on_disconnection.test 2009-06-27
> 02:32:25 +0000
>> @@ -0,0 +1,53 @@
>> +# Restart slave under network disconnection between slave and master
>> +
>> +connection slave;
>> +if (`SELECT '$debug_lock' = ''`)
>> +{
>> + --die Cannot continue. Please set value for $debug_lock.
>> +}
>> +
>> +# Restart slave
>> +--disable_warnings
>> +stop slave;
>> +source include/wait_for_slave_to_stop.inc;
>> +start slave;
>> +source include/wait_for_slave_to_start.inc;
>> +
>> +connection master;
>> +# Write file to make mysql-test-run.pl expect the "crash", but don't start
>> +# it until it's told to
>> +--write_file $MYSQLTEST_VARDIR/tmp/mysqld.1.expect
>> +wait
>> +EOF
>> +
>> +# Send shutdown to the connected server and give
>> +# it 10 seconds to die before zapping it
>> +shutdown_server 10;
>> +
>> +connection slave;
>> +eval SELECT RELEASE_LOCK($debug_lock);
>> +
>> +# Write file to make mysql-test-run.pl start up the server again
>> +--append_file $MYSQLTEST_VARDIR/tmp/mysqld.1.expect
>> +restart
>> +EOF
>> +
>> +connection master;
>> +# Turn on reconnect
>> +--enable_reconnect
>> +
>> +# Call script that will poll the server waiting for it to be back online again
>> +--source include/wait_until_connected_again.inc
>> +
>> +# Turn off reconnect again
>> +--disable_reconnect
>> +
>> +connection slave;
>> +source include/wait_for_slave_to_start.inc;
>> +
>> +# Show slave last IO errno
>> +let $last_io_errno= query_get_value("show slave status", Last_IO_Errno, 1);
>> +echo Slave_IO_Errno= $last_io_errno;
>> +
>> +
>> +# End of tests
>>
>> === added file
> 'mysql-test/suite/rpl/r/rpl_get_master_version_clock_on_disconnection.result'
>> ---
> a/mysql-test/suite/rpl/r/rpl_get_master_version_clock_on_disconnection.result 1970-01-01
> 00:00:00 +0000
>> +++
> b/mysql-test/suite/rpl/r/rpl_get_master_version_clock_on_disconnection.result 2009-06-27
> 02:32:25 +0000
>> @@ -0,0 +1,59 @@
>> +stop slave;
>> +drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
>> +reset master;
>> +reset slave;
>> +drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
>> +start slave;
>> +SELECT IS_FREE_LOCK("debug_lock.before_get_UNIX_TIMESTAMP");
>> +IS_FREE_LOCK("debug_lock.before_get_UNIX_TIMESTAMP")
>> +1
>> +SELECT GET_LOCK("debug_lock.before_get_UNIX_TIMESTAMP", 1000);
>> +GET_LOCK("debug_lock.before_get_UNIX_TIMESTAMP", 1000)
>> +1
>> +set global debug= 'd,debug_lock.before_get_UNIX_TIMESTAMP';
>> +stop slave;
>> +start slave;
>> +SELECT RELEASE_LOCK("debug_lock.before_get_UNIX_TIMESTAMP");
>> +RELEASE_LOCK("debug_lock.before_get_UNIX_TIMESTAMP")
>> +1
>> +Slave_IO_Errno= 2013
>> +SELECT IS_FREE_LOCK("debug_lock.before_get_SERVER_ID");
>> +IS_FREE_LOCK("debug_lock.before_get_SERVER_ID")
>> +1
>> +SELECT GET_LOCK("debug_lock.before_get_SERVER_ID", 1000);
>> +GET_LOCK("debug_lock.before_get_SERVER_ID", 1000)
>> +1
>> +set global debug= 'd,debug_lock.before_get_SERVER_ID';
>> +stop slave;
>> +start slave;
>> +SELECT RELEASE_LOCK("debug_lock.before_get_SERVER_ID");
>> +RELEASE_LOCK("debug_lock.before_get_SERVER_ID")
>> +1
>> +Slave_IO_Errno= 2013
>> +SELECT IS_FREE_LOCK("debug_lock.before_get_COLLATION_SERVER_VALUE");
>> +IS_FREE_LOCK("debug_lock.before_get_COLLATION_SERVER_VALUE")
>> +1
>> +SELECT GET_LOCK("debug_lock.before_get_COLLATION_SERVER_VALUE", 1000);
>> +GET_LOCK("debug_lock.before_get_COLLATION_SERVER_VALUE", 1000)
>> +1
>> +set global debug= 'd,debug_lock.before_get_COLLATION_SERVER_VALUE';
>> +stop slave;
>> +start slave;
>> +SELECT RELEASE_LOCK("debug_lock.before_get_COLLATION_SERVER_VALUE");
>> +RELEASE_LOCK("debug_lock.before_get_COLLATION_SERVER_VALUE")
>> +1
>> +Slave_IO_Errno= 2013
>> +SELECT IS_FREE_LOCK("debug_lock.before_get_TIME_ZONE_VALUE");
>> +IS_FREE_LOCK("debug_lock.before_get_TIME_ZONE_VALUE")
>> +1
>> +SELECT GET_LOCK("debug_lock.before_get_TIME_ZONE_VALUE", 1000);
>> +GET_LOCK("debug_lock.before_get_TIME_ZONE_VALUE", 1000)
>> +1
>> +set global debug= 'd,debug_lock.before_get_TIME_ZONE_VALUE';
>> +stop slave;
>> +start slave;
>> +SELECT RELEASE_LOCK("debug_lock.before_get_TIME_ZONE_VALUE");
>> +RELEASE_LOCK("debug_lock.before_get_TIME_ZONE_VALUE")
>> +1
>> +Slave_IO_Errno= 2013
>> +set global debug= '';
>>
>> === added file
> 'mysql-test/suite/rpl/t/rpl_get_master_version_clock_on_disconnection.test'
>> ---
> a/mysql-test/suite/rpl/t/rpl_get_master_version_clock_on_disconnection.test 1970-01-01
> 00:00:00 +0000
>> +++
> b/mysql-test/suite/rpl/t/rpl_get_master_version_clock_on_disconnection.test 2009-06-27
> 02:32:25 +0000
>> @@ -0,0 +1,56 @@
>> +#
>> +# BUG#45214: http://bugs.mysql.com/bug.php?id=45214
>> +# This test verifies if the slave I/O tread tries to reconnect to
>> +# master when it tries to get the values of the UNIX_TIMESTAMP, SERVER_ID,
>> +# COLLATION_SERVER and TIME_ZONE from master under network disconnection.
>> +#
>> +# Steps:
>> +# 1 - Got DBUG_SYNC_POINT lock
>> +# 2 - Set DBUG_SYNC_POINT before call mysql_real_query(...) function in
> get_master_version_and_clock(...) function and hang here
>> +# 3 - shutdown master server for simulating network disconnection
>> +# 4 - Release DBUG_SYNC_POINT lock
>> +# 5 - Check if the slave I/O thread tries to reconnect to master.
>> +
>> +source include/master-slave.inc;
>> +
>> +#Test case 1: Try to get the value of the UNIX_TIMESTAMP from master under
> network disconnection
>> +connection slave;
>> +let $debug_saved= `select @@global.debug`;
>> +
>> +let $debug_lock= "debug_lock.before_get_UNIX_TIMESTAMP";
>> +eval SELECT IS_FREE_LOCK($debug_lock);
>> +eval SELECT GET_LOCK($debug_lock, 1000);
>> +
>> +set global debug= 'd,debug_lock.before_get_UNIX_TIMESTAMP';
>> +source extra/rpl_tests/rpl_get_master_version_clock_on_disconnection.test;
>> +
>> +#Test case 2: Try to get the value of the SERVER_ID from master under network
> disconnection
>> +connection slave;
>> +let $debug_lock= "debug_lock.before_get_SERVER_ID";
>> +eval SELECT IS_FREE_LOCK($debug_lock);
>> +eval SELECT GET_LOCK($debug_lock, 1000);
>> +
>> +set global debug= 'd,debug_lock.before_get_SERVER_ID';
>> +source extra/rpl_tests/rpl_get_master_version_clock_on_disconnection.test;
>> +
>> +#Test case 3: Try to get the value of the COLLATION_SERVER from master under
> network disconnection
>> +connection slave;
>> +let $debug_lock= "debug_lock.before_get_COLLATION_SERVER_VALUE";
>> +eval SELECT IS_FREE_LOCK($debug_lock);
>> +eval SELECT GET_LOCK($debug_lock, 1000);
>> +
>> +set global debug= 'd,debug_lock.before_get_COLLATION_SERVER_VALUE';
>> +source extra/rpl_tests/rpl_get_master_version_clock_on_disconnection.test;
>> +
>> +#Test case 4: Try to get the value of the TIME_ZONE from master under network
> disconnection
>> +connection slave;
>> +let $debug_lock= "debug_lock.before_get_TIME_ZONE_VALUE";
>> +eval SELECT IS_FREE_LOCK($debug_lock);
>> +eval SELECT GET_LOCK($debug_lock, 1000);
>> +
>> +set global debug= 'd,debug_lock.before_get_TIME_ZONE_VALUE';
>> +source extra/rpl_tests/rpl_get_master_version_clock_on_disconnection.test;
>> +
>> +eval set global debug= '$debug_saved';
>> +
>> +# End of tests
>>
>> === modified file 'sql/slave.cc'
>> --- a/sql/slave.cc 2009-06-09 16:44:26 +0000
>> +++ b/sql/slave.cc 2009-06-27 02:32:25 +0000
>> @@ -854,6 +854,7 @@ int init_intvar_from_file(int* var, IO_C
>> RETURNS
>> 0 ok
>> 1 error
>> + 2 transient network problem, the caller should try to reconnect
>> */
>>
>> static int get_master_version_and_clock(MYSQL* mysql, Master_info* mi)
>> @@ -864,7 +865,7 @@ static int get_master_version_and_clock(
>> MYSQL_RES *master_res= 0;
>> MYSQL_ROW master_row;
>> DBUG_ENTER("get_master_version_and_clock");
>> -
>> + int query_re= 0;
>> /*
>> Free old description_event_for_queue (that is needed if we are in
>> a reconnection).
>> @@ -938,10 +939,16 @@ static int get_master_version_and_clock(
>> Compare the master and slave's clock. Do not die if master's clock is
>> unavailable (very old master not supporting UNIX_TIMESTAMP()?).
>> */
>> -
>> - if (!mysql_real_query(mysql, STRING_WITH_LEN("SELECT UNIX_TIMESTAMP()"))
> &&
>> - (master_res= mysql_store_result(mysql)) &&
>> - (master_row= mysql_fetch_row(master_res)))
>> + DBUG_SYNC_POINT("debug_lock.before_get_UNIX_TIMESTAMP", 10);
>> + query_re= mysql_real_query(mysql, STRING_WITH_LEN("SELECT
> UNIX_TIMESTAMP()"));
>> + if (query_re)
>> + DBUG_RETURN(2);
>>
>
> I think you need call to rli->report(WARNING_LEVEL, a message).
> Warnings can be error-logged to provide the user info that can possibly
> indicate on existence of network issues and so on.
>
>
Yes. I take it.
>> +
>> + master_res= mysql_store_result(mysql);
>> + if (!master_res)
>> + DBUG_RETURN(2);
>>
>
> As said above, that could be a Warning only if mysql_error() confirms a network
> problem.
> You may choose engage the working goto-technique:
>
> if (!master_res && mysql_error() is a network issue)
>
> err_buff=...
> error_level= WARNING_LEVEL;
> goto err;
>
>
> provided that you added a variable
>
> enum loglevel err_level= ERR_LEVEL; // default
>
>
> and changed s/ERR_LEVEL/err_level/ the trainling part of the function
>
> if (errmsg)
> {
> DBUG_ASSERT(err_code != 0);
> mi->report(err_level, err_code, err_buff);
> DBUG_RETURN(1);
> }
>
>
>
>> +
>> + if (master_row= mysql_fetch_row(master_res))
>> {
>> mi->clock_diff_with_master=
>> (long) (time((time_t*) 0) - strtoul(master_row[0], 0, 10));
>>
>
> Conversly to above, you need to change the remained
>
> sql_print_warning("\"SELECT UNIX_TIMESTAMP()\"
>
> to generate an Error if mysql_error() does not confirm a network problem.
>
>
> The remained 3 interractions with the master follow the same as above pattern.
>
>
The four interactions follow the main pattern, but they are not same
completely.
So I handle everyone according to its detail. Thanks!
>> @@ -967,26 +974,34 @@ static int get_master_version_and_clock(
>> Note: we could have put a @@SERVER_ID in the previous SELECT
>> UNIX_TIMESTAMP() instead, but this would not have worked on 3.23 masters.
>> */
>> - if (!mysql_real_query(mysql,
>> - STRING_WITH_LEN("SHOW VARIABLES LIKE 'SERVER_ID'"))
> &&
>> - (master_res= mysql_store_result(mysql)))
>> - {
>> - if ((master_row= mysql_fetch_row(master_res)) &&
>> - (::server_id == strtoul(master_row[1], 0, 10)) &&
>> - !mi->rli.replicate_same_server_id)
>> - {
>> - errmsg= "The slave I/O thread stops because master and slave have equal \
>> + DBUG_SYNC_POINT("debug_lock.before_get_SERVER_ID", 10);
>> + query_re= mysql_real_query(mysql, STRING_WITH_LEN("SHOW VARIABLES LIKE
> 'SERVER_ID'"));
>> + if (query_re)
>> + DBUG_RETURN(2);
>> +
>> + master_res= mysql_store_result(mysql);
>> + if (!master_res)
>> + DBUG_RETURN(2);
>> +
>> + master_row= mysql_fetch_row(master_res);
>> + if (master_row && (::server_id == strtoul(master_row[1], 0, 10))
> &&
>> + !mi->rli.replicate_same_server_id)
>> + {
>> + errmsg= "The slave I/O thread stops because master and slave have equal \
>> MySQL server ids; these ids must be different for replication to work (or \
>> the --replicate-same-server-id option must be used on slave but this does \
>> not always make sense; please check the manual before using it).";
>> - err_code= ER_SLAVE_FATAL_ERROR;
>> - sprintf(err_buff, ER(err_code), errmsg);
>> - }
>> - mysql_free_result(master_res);
>> - if (errmsg)
>> - goto err;
>> + err_code= ER_SLAVE_FATAL_ERROR;
>> + sprintf(err_buff, ER(err_code), errmsg);
>> }
>> + else if (!master_row)
>> + sql_print_warning("\"SHOW VARIABLES LIKE 'SERVER_ID'\" failed on master, \
>> +maybe it is a very old master.");
>> + mysql_free_result(master_res);
>>
>> + if (errmsg)
>> + goto err;
>> +
>> /*
>> Check that the master's global character_set_server and ours are the same.
>> Not fatal if query fails (old master?).
>> @@ -1008,13 +1023,20 @@ not always make sense; please check the
>> if (*mysql->server_version == '3')
>> goto err;
>>
>> - if ((*mysql->server_version == '4') &&
>> - !mysql_real_query(mysql,
>> - STRING_WITH_LEN("SELECT @@GLOBAL.COLLATION_SERVER"))
> &&
>> - (master_res= mysql_store_result(mysql)))
>> + if (*mysql->server_version == '4')
>> {
>> - if ((master_row= mysql_fetch_row(master_res)) &&
>> - strcmp(master_row[0],
> global_system_variables.collation_server->name))
>> + DBUG_SYNC_POINT("debug_lock.before_get_COLLATION_SERVER_VALUE", 10);
>> + query_re= mysql_real_query(mysql, STRING_WITH_LEN("SELECT
> @@GLOBAL.COLLATION_SERVER"));
>> + if (query_re)
>> + DBUG_RETURN(2);
>> +
>> + master_res= mysql_store_result(mysql);
>> + if (!master_res)
>> + DBUG_RETURN(2);
>> +
>> + master_row= mysql_fetch_row(master_res);
>> + if (master_row && strcmp(master_row[0],
>> +
> global_system_variables.collation_server->name))
>> {
>> errmsg= "The slave I/O thread stops because master and slave have \
>> different values for the COLLATION_SERVER global variable. The values must \
>> @@ -1022,7 +1044,11 @@ be equal for replication to work";
>> err_code= ER_SLAVE_FATAL_ERROR;
>> sprintf(err_buff, ER(err_code), errmsg);
>> }
>> + else if (!master_row)
>> + sql_print_warning("\"SELECT @@GLOBAL.COLLATION_SERVER\" failed on master,
> \
>> +maybe it is a very old master.");
>> mysql_free_result(master_res);
>> +
>> if (errmsg)
>> goto err;
>> }
>> @@ -1042,13 +1068,20 @@ be equal for replication to work";
>> This check is only necessary for 4.x masters (and < 5.0.4 masters but
>> those were alpha).
>> */
>> - if ((*mysql->server_version == '4') &&
>> - !mysql_real_query(mysql, STRING_WITH_LEN("SELECT @@GLOBAL.TIME_ZONE"))
> &&
>> - (master_res= mysql_store_result(mysql)))
>> - {
>> - if ((master_row= mysql_fetch_row(master_res)) &&
>> - strcmp(master_row[0],
>> - global_system_variables.time_zone->get_name()->ptr()))
>> + if (*mysql->server_version == '4')
>> + {
>> + DBUG_SYNC_POINT("debug_lock.before_get_TIME_ZONE_VALUE", 10);
>> + query_re= mysql_real_query(mysql, STRING_WITH_LEN("SELECT
> @@GLOBAL.TIME_ZONE"));
>> + if (query_re)
>> + DBUG_RETURN(2);
>> +
>> + master_res= mysql_store_result(mysql);
>> + if (!master_res)
>> + DBUG_RETURN(2);
>> +
>> + master_row= mysql_fetch_row(master_res);
>> + if (master_row && strcmp(master_row[0],
>> +
> global_system_variables.time_zone->get_name()->ptr()))
>> {
>> errmsg= "The slave I/O thread stops because master and slave have \
>> different values for the TIME_ZONE global variable. The values must \
>> @@ -1056,6 +1089,13 @@ be equal for replication to work";
>> err_code= ER_SLAVE_FATAL_ERROR;
>> sprintf(err_buff, ER(err_code), errmsg);
>> }
>> + else if (!master_row)
>> + {
>> + errmsg= "The slave I/O thread stops because the value of \
>> +the TIME_ZONE global variable is not existent on master.";
>> + err_code= ER_SLAVE_FATAL_ERROR;
>> + sprintf(err_buff, ER(err_code), errmsg);
>> + }
>> mysql_free_result(master_res);
>>
>> if (errmsg)
>> @@ -2372,6 +2412,7 @@ pthread_handler_t handle_slave_io(void *
>> char llbuff[22];
>> uint retry_count;
>> bool suppress_warnings;
>> + int ret;
>> #ifndef DBUG_OFF
>> uint retry_count_reg= 0, retry_count_dump= 0, retry_count_event= 0;
>> #endif
>> @@ -2382,7 +2423,7 @@ pthread_handler_t handle_slave_io(void *
>> DBUG_ASSERT(mi->inited);
>> mysql= NULL ;
>> retry_count= 0;
>> -
>> +
>> pthread_mutex_lock(&mi->run_lock);
>> /* Inform waiting threads that slave has started */
>> mi->slave_run_id++;
>> @@ -2451,8 +2492,19 @@ connected:
>> mi->slave_running= MYSQL_SLAVE_RUN_CONNECT;
>> thd->slave_net = &mysql->net;
>> thd_proc_info(thd, "Checking master version");
>> - if (get_master_version_and_clock(mysql, mi))
>> + ret= get_master_version_and_clock(mysql, mi);
>> + if (ret == 1)
>> + /* Fatal error */
>> goto err;
>> +
>> + if (ret == 2)
>> + {
>> + /* Try to reconnect because the error was caused by a transient network
> problem */
>> + if (try_to_reconnect(thd, mysql, mi, &retry_count, suppress_warnings,
>> + reconnect_messages[SLAVE_RECON_ACT_REG]))
>> + goto err;
>> + goto connected;
>> + }
>>
>> if (mi->rli.relay_log.description_event_for_queue->binlog_version >
> 1)
>> {
>>
>>
>> # Bazaar merge directive format 2 (Bazaar 0.90)
>> # revision_id: dao-gang.qu@stripped
>> # target_branch: file:///home/daogangq/mysql/bzrwork/bug45214/5.1-bt/
>> # testament_sha1: 314bc0d7091b26dc84ed77172332b7ba88c24146
>> # timestamp: 2009-06-27 10:32:41 +0800
>> # base_revision_id: davi.arnaut@stripped\
>> # jrxxjz0fx90hj9lv
>> #
>>
>
> Finally, please check more carefully next time if you add an unnecessary
> black line changes like
>
Yes. Thanks!
> @@ -2382,7 +2423,7 @@ pthread_handler_t handle_slave_io(void *
> DBUG_ASSERT(mi->inited);
> mysql= NULL ;
> retry_count= 0;
> -
> +
>
> @@ -1022,7 +1044,11 @@ be equal for replication to work";
> err_code= ER_SLAVE_FATAL_ERROR;
> sprintf(err_buff, ER(err_code), errmsg);
> }
> + else if (!master_row)
> + sql_print_warning("\"SELECT @@GLOBAL.COLLATION_SERVER\" failed on master, \
> +maybe it is a very old master.");
> mysql_free_result(master_res);
> +
> if (errmsg)
> goto err;
> }
>
>
> cheers,
>
> Andrei
>
Best Regards,
Daogang
