Dao-Gang.Qu@stripped wrote:
> #At file:///home/daogangq/mysql/bzrwork/bug45214/5.1-bt/ based on
> revid:davi.arnaut@stripped
>
> 2941 Dao-Gang.Qu@stripped 2009-07-01
> 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 fail, or queries succeed
> but the result retrieved is empty.
>
> The "get_master_version_and_clock(...)" function should try to reconnect
> master
> if queries fail because of transient network problems, and fail otherwise.
> The I/O thread should print a warning information if the queries succeed
> but the result retrieved is empty.
The I/O thread should print a warning if the some system variables do
not exist on master (very old master).
>
> @ mysql-test/extra/rpl_tests/rpl_get_master_version_and_clock.test
> Test script for bug #45214
> @ mysql-test/suite/rpl/r/rpl_get_master_version_and_clock.result
> Test result for bug #45214
> @ mysql-test/suite/rpl/t/rpl_get_master_version_and_clock.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_and_clock.test
> mysql-test/suite/rpl/r/rpl_get_master_version_and_clock.result
> mysql-test/suite/rpl/t/rpl_get_master_version_and_clock.test
> modified:
> sql/slave.cc
> === added file 'mysql-test/extra/rpl_tests/rpl_get_master_version_and_clock.test'
> --- a/mysql-test/extra/rpl_tests/rpl_get_master_version_and_clock.test 1970-01-01
> 00:00:00 +0000
> +++ b/mysql-test/extra/rpl_tests/rpl_get_master_version_and_clock.test 2009-07-01
> 02:53:02 +0000
> @@ -0,0 +1,64 @@
> +#
> +# BUG#45214: http://bugs.mysql.com/bug.php?id=45214
> +# The common part of the "rpl_get_master_version_and_clock" test.
> +# Restart slave under network disconnection between slave and master
> +# following the 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.
> +#
> +# Note: Please make sure initialize the $debug_lock when call the test script.
> +#
Good
> +connection slave;
> +if (`SELECT '$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_and_clock.result'
> --- a/mysql-test/suite/rpl/r/rpl_get_master_version_and_clock.result 1970-01-01
> 00:00:00 +0000
> +++ b/mysql-test/suite/rpl/r/rpl_get_master_version_and_clock.result 2009-07-01
> 02:53:02 +0000
> @@ -0,0 +1,66 @@
> +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= '';
> +reset master;
> +include/stop_slave.inc
> +change master to master_port=SLAVE_PORT;
> +start slave;
> +*** must be having the replicate-same-server-id IO thread error ***
> +Slave_IO_Errno= 1593
> +Slave_IO_Error= Fatal error: 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).
>
> === added file 'mysql-test/suite/rpl/t/rpl_get_master_version_and_clock.test'
> --- a/mysql-test/suite/rpl/t/rpl_get_master_version_and_clock.test 1970-01-01
> 00:00:00 +0000
> +++ b/mysql-test/suite/rpl/t/rpl_get_master_version_and_clock.test 2009-07-01
> 02:53:02 +0000
> @@ -0,0 +1,76 @@
> +#
> +# 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.
> +# Finish the following tests by calling its common test script:
> +# extra/rpl_tests/rpl_get_master_version_and_clock.test.
> +# And meanwhile this test checks that the slave I/O thread refuses to start if
> slave
> +# and master have the same server id (because this is a useless setup,
> +# and otherwise SHOW SLAVE STATUS shows progress but all queries are
> +# ignored, which has caught our customers), unless
> +# --replicate-same-server-id.
> +#
> +
> +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_and_clock.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_and_clock.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_and_clock.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($debug_lock, 1000);
> +
> +set global debug= 'd,debug_lock.before_get_TIME_ZONE_VALUE';
> +source extra/rpl_tests/rpl_get_master_version_and_clock.test;
> +
> +eval set global debug= '$debug_saved';
> +
> +#Test case 5: This test checks that the slave I/O thread refuses to start
> +#if slave and master have the same server id.
> +connection slave;
> +reset master;
> +# replicate ourselves
> +source include/stop_slave.inc;
> +--replace_result $SLAVE_MYPORT SLAVE_PORT
> +eval change master to master_port=$SLAVE_MYPORT;
> +start slave;
> +
> +let $slave_param= Last_IO_Errno;
> +let $slave_param_value= 1593;
> +source include/wait_for_slave_param.inc;
> +--echo *** must be having the replicate-same-server-id IO thread error ***
> +let $last_io_errno= query_get_value("show slave status", Last_IO_Errno, 1);
> +let $last_io_error= query_get_value("show slave status", Last_IO_Error, 1);
> +echo Slave_IO_Errno= $last_io_errno;
> +echo Slave_IO_Error= $last_io_error;
> +
Please also test that different configurations of COLLATION_SERVER and
TIME_ZONE on master and slave will prevent slave to start.
> +# End of tests
>
> === modified file 'sql/slave.cc'
> --- a/sql/slave.cc 2009-06-09 16:44:26 +0000
> +++ b/sql/slave.cc 2009-07-01 02:53:02 +0000
> @@ -38,6 +38,7 @@
> #include <my_dir.h>
> #include <sql_common.h>
> #include <errmsg.h>
> +#include <mysqld_error.h>
> #include <mysys_err.h>
>
> #ifdef HAVE_REPLICATION
> @@ -842,6 +843,35 @@ int init_intvar_from_file(int* var, IO_C
> DBUG_RETURN(1);
> }
>
> +
> +/*
> + Check if the issue is caused by network.
> +
I'd suggest to use work 'error' instead of 'issue', please also consider
changing those below.
> + RETURNS:
> + TRUE network issue
> + FALSE not network issue
> +*/
> +
> +bool is_network_issue(MYSQL* mysql, Master_info* mi)
> +{
> + int errno;
> + errno= mysql_errno(mysql);
> + if (errno == CR_CONNECTION_ERROR ||
> + errno == CR_CONN_HOST_ERROR ||
> + errno == CR_SERVER_GONE_ERROR ||
> + errno == CR_SERVER_LOST ||
> + errno == ER_CON_COUNT_ERROR ||
> + errno == ER_SERVER_SHUTDOWN)
> + {
> + mi->report(WARNING_LEVEL, errno, mysql_error(mysql));
> + sql_print_error("network issue daogang test: %s, %d", mysql_error(mysql),
> errno);
Hmm, I think you forget to remove this line.
> + return TRUE;
> + }
> +
> + return FALSE;
> +}
> +
> +
> /*
> Note that we rely on the master's version (3.23, 4.0.14 etc) instead of
> relying on the binlog's version. This is not perfect: imagine an upgrade
> @@ -854,6 +884,7 @@ 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)
> @@ -864,6 +895,7 @@ 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
> @@ -938,14 +970,26 @@ 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 && is_network_issue(mysql, mi))
> + DBUG_RETURN(2);
> +
> + master_res= mysql_store_result(mysql);
> + if (!master_res && is_network_issue(mysql, mi))
> + DBUG_RETURN(2);
> +
> + if (master_row= mysql_fetch_row(master_res))
> {
> mi->clock_diff_with_master=
> (long) (time((time_t*) 0) - strtoul(master_row[0], 0, 10));
> }
> + else if (!master_row && is_network_issue(mysql, mi))
> + {
> + if (master_res)
> + mysql_free_result(master_res);
> + DBUG_RETURN(2);
> + }
> else if (!check_io_slave_killed(mi->io_thd, mi, NULL))
> {
> mi->clock_diff_with_master= 0; /* The "most sensible" value */
> @@ -967,26 +1011,64 @@ 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)
> + {
> + if (is_network_issue(mysql, mi))
> + DBUG_RETURN(2);
> + /* Fatal error */
> + sql_print_error(mysql_error(mysql));
Please use something like this: sql_print_error("Query \"SHOW VARIABLES
LIKE 'SEVER_ID'\" failed with error: %s (%d)", mysql_error(mysql),
mysql_errno(mysql));
Please also change the following similar cases.
> + errmsg= "The slave I/O thread stops because a fatal error is encountered \
> +when it try to get the value of SERVER_ID variable from master.";
> + err_code= ER_SLAVE_FATAL_ERROR;
> + sprintf(err_buff, ER(err_code), errmsg);
> + goto err;
> + }
> +
> + master_res= mysql_store_result(mysql);
> + if (!master_res)
> + {
> + /* Double check is required because some network issues will affect
> + the execution of the "mysql_store_result()" function */
> + if (is_network_issue(mysql, mi))
> + DBUG_RETURN(2);
> + /* Fatal error */
> + sql_print_error(mysql_error(mysql));
> + errmsg= "The slave I/O thread stops because a fatal error is encountered \
> +when it try to get the value of SERVER_ID variable from master.";
> + err_code= ER_SLAVE_FATAL_ERROR;
> + sprintf(err_buff, ER(err_code), errmsg);
> + goto err;
> + }
> +
> + 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);
> + err_code= ER_SLAVE_FATAL_ERROR;
> + sprintf(err_buff, ER(err_code), errmsg);
> + }
> + else if (!master_row)
> + {
> + if (is_network_issue(mysql, mi))
> + {
> + mysql_free_result(master_res);
> + DBUG_RETURN(2);
> }
> - mysql_free_result(master_res);
> - if (errmsg)
> - goto err;
> + else
> + sql_print_warning("\"SHOW VARIABLES LIKE 'SERVER_ID'\" get empty result from
> 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 +1090,51 @@ 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)
> + {
> + if (is_network_issue(mysql, mi))
> + DBUG_RETURN(2);
> + if (mysql_errno(mysql) == ER_UNKNOWN_SYSTEM_VARIABLE)
> + {
> + sql_print_warning("\"SELECT @@GLOBAL.COLLATION_SERVER\" get empty result \
> +from master, maybe it is a very old master.");
I'd suggest: "Unknown system variable 'COLLATION_SERVER' on master,
maybe ..."
> + goto cspass;
Please reorganize the code and remove this goto.
> + }
> + else
> + {
> + /* Fatal error */
> + sql_print_error(mysql_error(mysql));
> + errmsg= "The slave I/O thread stops because a fatal error is encountered \
> +when it try to get the value of COLLATION_SERVER global variable from master.";
> + err_code= ER_SLAVE_FATAL_ERROR;
> + sprintf(err_buff, ER(err_code), errmsg);
> + goto err;
> + }
> + }
> +
> + master_res= mysql_store_result(mysql);
> + if (!master_res)
> + {
> + /* Double check is required because some network issues will affect
> + the execution of the "mysql_store_result()" function */
> + if (is_network_issue(mysql, mi))
> + DBUG_RETURN(2);
> + /* Fatal error */
> + sql_print_error(mysql_error(mysql));
> + errmsg= "The slave I/O thread stops because a fatal error is encountered \
> +when it try to get the value of COLLATION_SERVER global variable from master.";
> + err_code= ER_SLAVE_FATAL_ERROR;
> + sprintf(err_buff, ER(err_code), errmsg);
> + goto err;
> + }
> +
> + 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 \
> @@ -1022,10 +1142,16 @@ be equal for replication to work";
> err_code= ER_SLAVE_FATAL_ERROR;
> sprintf(err_buff, ER(err_code), errmsg);
> }
> + else if (!master_row && is_network_issue(mysql, mi))
> + {
> + mysql_free_result(master_res);
> + DBUG_RETURN(2);
> + }
> mysql_free_result(master_res);
> if (errmsg)
> goto err;
> }
> +cspass:
>
> /*
> Perform analogous check for time zone. Theoretically we also should
> @@ -1042,13 +1168,42 @@ 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)
> + {
> + if (is_network_issue(mysql, mi))
> + DBUG_RETURN(2);
> + /* Fatal error */
> + sql_print_error(mysql_error(mysql));
> + errmsg= "The slave I/O thread stops because a fatal error is encountered \
> +when it try to get the value of TIME_ZONE global variable from master.";
> + err_code= ER_SLAVE_FATAL_ERROR;
> + sprintf(err_buff, ER(err_code), errmsg);
> + goto err;
> + }
> +
> + master_res= mysql_store_result(mysql);
> + if (!master_res)
> + {
> + /* Double check is required because some network issues will affect
> + the execution of the "mysql_store_result()" function */
> + if (is_network_issue(mysql, mi))
> + DBUG_RETURN(2);
> + /* Fatal error */
> + sql_print_error(mysql_error(mysql));
> + errmsg= "The slave I/O thread stops because a fatal error is encountered \
> +when it try to get the value of TIME_ZONE global variable from master.";
> + err_code= ER_SLAVE_FATAL_ERROR;
> + sprintf(err_buff, ER(err_code), errmsg);
> + goto err;
> + }
> +
> + 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 +1211,11 @@ be equal for replication to work";
> err_code= ER_SLAVE_FATAL_ERROR;
> sprintf(err_buff, ER(err_code), errmsg);
> }
> + else if (!master_row && is_network_issue(mysql, mi))
> + {
> + mysql_free_result(master_res);
> + DBUG_RETURN(2);
> + }
> mysql_free_result(master_res);
>
> if (errmsg)
> @@ -2372,6 +2532,7 @@ 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
> @@ -2451,8 +2612,19 @@ 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)
> {
>
