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Cleanup slave status handling

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Further reduce direct indexing slave status array to improve compatibility with
multimaster replication.
This commit is contained in:
Esa Korhonen
2018-09-11 16:09:41 +03:00
parent 2e069fa892
commit 02ac394e38
5 changed files with 24 additions and 33 deletions
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21
server/modules/monitor/mariadbmon/cluster_manipulation.cc
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@ -1251,9 +1251,10 @@ MariaDBServer* MariaDBMonitor::select_promotion_target(MariaDBServer* demotion_t
// Check which candidate is best
string current_best_reason;
int64_t gtid_domain = m_master_gtid_domain;
for (MariaDBServer* cand : candidates)
{
if (is_candidate_better(cand, current_best, m_master_gtid_domain, &current_best_reason))
if (is_candidate_better(cand, current_best, demotion_target, gtid_domain, &current_best_reason))
{
// Select the server for promotion, for now.
current_best = cand;
@ -1263,9 +1264,9 @@ MariaDBServer* MariaDBMonitor::select_promotion_target(MariaDBServer* demotion_t
// Check if any of the excluded servers would be better than the best candidate. Only print one item.
if (log_mode == Log::ON)
{
for (MariaDBServer* excluded_info : valid_but_excluded)
for (MariaDBServer* excluded : valid_but_excluded)
{
const char* excluded_name = excluded_info->name();
const char* excluded_name = excluded->name();
if (current_best == NULL)
{
const char EXCLUDED_ONLY_CAND[] = "Server '%s' is a viable choice for new master, "
@ -1273,7 +1274,7 @@ MariaDBServer* MariaDBMonitor::select_promotion_target(MariaDBServer* demotion_t
MXS_WARNING(EXCLUDED_ONLY_CAND, excluded_name);
break;
}
else if (is_candidate_better(excluded_info, current_best, m_master_gtid_domain))
else if (is_candidate_better(excluded, current_best, demotion_target, gtid_domain))
{
// Print a warning if this server is actually a better candidate than the previous best.
const char EXCLUDED_CAND[] = "Server '%s' is superior to current best candidate '%s', "
@ -1319,19 +1320,25 @@ bool MariaDBMonitor::server_is_excluded(const MariaDBServer* server)
*
* @param candidate_info Server info of new candidate
* @param current_best_info Server info of current best choice
* @param demotion_target Server which will be demoted
* @param gtid_domain Which domain to compare
* @param reason_out Why is the candidate better than current_best
* @return True if candidate is better
*/
bool MariaDBMonitor::is_candidate_better(const MariaDBServer* candidate,
const MariaDBServer* current_best,
const MariaDBServer* demotion_target,
uint32_t gtid_domain,
std::string* reason_out)
{
const SlaveStatus* cand_slave_conn = candidate->slave_connection_status(demotion_target);
const SlaveStatus* curr_best_slave_conn = current_best->slave_connection_status(demotion_target);
mxb_assert(cand_slave_conn && curr_best_slave_conn);
uint64_t cand_io = cand_slave_conn->gtid_io_pos.get_gtid(gtid_domain).m_sequence;
uint64_t curr_io = curr_best_slave_conn->gtid_io_pos.get_gtid(gtid_domain).m_sequence;
string reason;
bool is_better = false;
uint64_t cand_io = candidate->m_slave_status[0].gtid_io_pos.get_gtid(gtid_domain).m_sequence;
uint64_t curr_io = current_best->m_slave_status[0].gtid_io_pos.get_gtid(gtid_domain).m_sequence;
// A slave with a later event in relay log is always preferred.
if (cand_io > curr_io)
{
@ -1597,7 +1604,7 @@ void MariaDBMonitor::check_cluster_operations_support()
server->name());
printer.cat(all_reasons, reason);
}
if (!server->uses_gtid())
else if (server->m_slave_status[0].gtid_io_pos.empty())
{
supported = false;
auto reason = string_printf("Server '%s' is not using gtid-replication.", server->name());

12
server/modules/monitor/mariadbmon/mariadbmon.cc
View File

@ -603,12 +603,14 @@ void MariaDBMonitor::update_external_master()
{
if (m_master->is_slave_of_ext_master())
{
mxb_assert(!m_master->m_slave_status.empty());
if (m_master->m_slave_status[0].master_host != m_external_master_host
|| m_master->m_slave_status[0].master_port != m_external_master_port)
mxb_assert(!m_master->m_slave_status.empty() && !m_master->m_node.external_masters.empty());
// TODO: Add support for multiple external masters.
auto& master_sstatus = m_master->m_slave_status[0];
if (master_sstatus.master_host != m_external_master_host ||
master_sstatus.master_port != m_external_master_port)
{
const string new_ext_host = m_master->m_slave_status[0].master_host;
const int new_ext_port = m_master->m_slave_status[0].master_port;
const string new_ext_host = master_sstatus.master_host;
const int new_ext_port = master_sstatus.master_port;
if (m_external_master_port == PORT_UNKNOWN)
{
MXS_NOTICE("Cluster master server is replicating from an external master: %s:%d",

1
server/modules/monitor/mariadbmon/mariadbmon.hh
View File

@ -281,6 +281,7 @@ private:
bool server_is_excluded(const MariaDBServer* server);
bool is_candidate_better(const MariaDBServer* candidate,
const MariaDBServer* current_best,
const MariaDBServer* demotion_target,
uint32_t gtid_domain,
std::string* reason_out = NULL);
bool promote_new_master(MariaDBServer* new_master, json_t** err_out);

12
server/modules/monitor/mariadbmon/mariadbserver.cc
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@ -601,16 +601,6 @@ json_t* MariaDBServer::to_json() const
return result;
}
bool MariaDBServer::uses_gtid(std::string* error_out)
{
bool using_gtid = !m_slave_status.empty() && !m_slave_status[0].gtid_io_pos.empty();
if (!using_gtid && error_out)
{
*error_out = string_printf("Server '%s' is not using gtid replication.", name());
}
return using_gtid;
}
bool MariaDBServer::can_replicate_from(MariaDBServer* master, string* error_out)
{
bool rval = false;
@ -1085,7 +1075,7 @@ bool MariaDBServer::can_be_promoted(ClusterOperation op,
return promotable;
}
const SlaveStatus* MariaDBServer::slave_connection_status(const MariaDBServer* target)
const SlaveStatus* MariaDBServer::slave_connection_status(const MariaDBServer* target) const
{
// The slave node may have several slave connections, need to find the one that is
// connected to the parent. This section is quite similar to the one in

11
server/modules/monitor/mariadbmon/mariadbserver.hh
View File

@ -274,7 +274,7 @@ public:
* @param target Immediate master or relay server
* @return The slave status info of the slave thread, or NULL if not found or not accepted
*/
const SlaveStatus* slave_connection_status(const MariaDBServer* target);
const SlaveStatus* slave_connection_status(const MariaDBServer* target) const;
/**
* Is binary log on? 'update_replication_settings' should be ran before this function to query the data.
@ -384,15 +384,6 @@ public:
*/
std::string diagnostics() const;
/**
* Check if server is using gtid replication.
*
* @param error_out Error output
* @return True if using gtid-replication. False if not, or if server is not a slave or otherwise does
* not have a gtid_IO_Pos.
*/
bool uses_gtid(std::string* error_out = NULL);
/**
* Checks if this server can replicate from master. Only considers gtid:s and only detects obvious errors.
* The non-detected errors will mostly be detected once the slave tries to start replicating.