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MXS-1937 Disable server events on master during switchover

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The feature is behind a config setting.
This commit is contained in:
Esa Korhonen
2018-08-31 18:14:50 +03:00
parent a0ea37b2c5
commit 7e6ce2d13f
5 changed files with 217 additions and 53 deletions
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68
server/modules/monitor/mariadbmon/cluster_manipulation.cc
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@ -664,13 +664,21 @@ bool MariaDBMonitor::failover_perform(MariaDBServer* promotion_target, MariaDBSe
bool MariaDBMonitor::switchover_demote_master(MariaDBServer* current_master, json_t** err_out)
{
MXS_NOTICE("Demoting server '%s'.", current_master->name());
bool success = false;
bool query_error = false;
bool gtid_update_error = false;
bool event_disable_error = false;
MYSQL* conn = current_master->m_server_base->con;
const char* query = ""; // The next query to execute. Used also for error printing.
// The presence of an external master changes several things.
const bool external_master = server_is_slave_of_ext_master(current_master->m_server_base->server);
// Helper function for checking if any error is on.
auto any_error = [&query_error, &gtid_update_error, &event_disable_error]() -> bool
{
return query_error || gtid_update_error || event_disable_error;
};
if (external_master)
{
// First need to stop slave. read_only is probably on already, although not certain.
@ -697,28 +705,33 @@ bool MariaDBMonitor::switchover_demote_master(MariaDBServer* current_master, jso
{
query = "FLUSH TABLES;";
query_error = (mxs_mysql_query(conn, query) != 0);
}
if (!query_error)
{
query = "FLUSH LOGS;";
query_error = (mxs_mysql_query(conn, query) != 0);
if (!query_error)
// Disable all events here
if (!query_error && m_handle_event_scheduler && !current_master->disable_events())
{
query = "";
if (current_master->update_gtids())
{
success = true;
}
event_disable_error = true;
}
}
if (!success)
if (!any_error())
{
query = "FLUSH LOGS;";
query_error = (mxs_mysql_query(conn, query) != 0);
if (!query_error && !current_master->update_gtids(&error_desc))
{
gtid_update_error = true;
}
}
if (any_error())
{
// Somehow, a step after "SET read_only" failed. Try to set read_only back to 0. It may not
// work since the connection is likely broken.
error_desc = mysql_error(conn); // Read connection error before next step.
error_fetched = true;
if (query_error)
{
error_desc = mysql_error(conn); // Read connection error before next step.
error_fetched = true;
}
mxs_mysql_query(conn, "SET GLOBAL read_only=0;");
}
}
@ -729,7 +742,7 @@ bool MariaDBMonitor::switchover_demote_master(MariaDBServer* current_master, jso
error_desc = mysql_error(conn);
}
if (!success)
if (any_error())
{
if (query_error)
{
@ -745,21 +758,20 @@ bool MariaDBMonitor::switchover_demote_master(MariaDBServer* current_master, jso
PRINT_MXS_JSON_ERROR(err_out, KNOWN_ERROR, error_desc.c_str(), query);
}
}
else
else if (gtid_update_error)
{
const char * const GTID_ERROR = "Demotion failed due to an error in updating gtid:s. "
"Check log for more details.";
PRINT_MXS_JSON_ERROR(err_out, GTID_ERROR);
const char * const GTID_ERROR = "Demotion failed due to a query error: %s";
PRINT_MXS_JSON_ERROR(err_out, GTID_ERROR, error_desc.c_str());
}
}
else if (!m_demote_sql_file.empty() && !current_master->run_sql_from_file(m_demote_sql_file, err_out))
{
PRINT_MXS_JSON_ERROR(err_out, "%s execution failed when demoting server '%s'.",
CN_DEMOTION_SQL_FILE, current_master->name());
success = false;
query_error = true;
}
return success;
return !any_error();
}
/**
@ -910,7 +922,17 @@ bool MariaDBMonitor::promote_new_master(MariaDBServer* new_master, json_t** err_
query = "SET GLOBAL read_only=0;";
if (mxs_mysql_query(new_master_conn, query) == 0)
{
success = true;
if (m_handle_event_scheduler)
{
if (new_master->enable_events())
{
success = true;
}
}
else
{
success = true;
}
}
}
}