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repmgrd: initial code for cascaded standby failover

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This commit is contained in:
Ian Barwick
2017-07-04 23:14:05 +09:00
parent e1f4384f7e
commit 24c6b2c9f1
3 changed files with 203 additions and 17 deletions
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181
repmgrd.c
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@@ -651,8 +651,15 @@ monitor_streaming_standby(void)
// handle failure - do we want to loop here?
upstream_conn = establish_db_connection(upstream_node_info.conninfo, false);
// fix for cascaded standbys
primary_conn = upstream_conn;
if (upstream_node_info.type == STANDBY)
{
// XXX check result
primary_conn = establish_primary_db_connection(local_conn, false);
}
else
{
primary_conn = upstream_conn;
}
/* Log startup event */
if (startup_event_logged == false)
@@ -980,12 +987,145 @@ do_primary_failover(void)
return false;
}
/*
* do_upstream_standby_failover()
*
* Attach cascaded standby to primary
*
* Currently we will try to attach to the cluster primary, as "repmgr
* standby follow" doesn't support attaching to another node.
*
* If this becomes supported, it might be worth providing a selection
* of reconnection strategies as different behaviour might be desirable
* in different situations;
* or maybe the option not to reconnect might be required?
*
* XXX check this handles replication slots gracefully
*/
static bool
do_upstream_standby_failover(void)
{
// not implemented yet
return false;
PQExpBufferData event_details;
t_node_info primary_node_info = T_NODE_INFO_INITIALIZER;
RecordStatus record_status;
int r;
// check status
record_status = get_primary_node_record(local_conn, &primary_node_info);
/*
* Verify that we can still talk to the cluster primary, even though
* the node's upstream is not available
*/
// consolidate below code
if (is_server_available(primary_node_info.conninfo) == false)
{
log_warning(_("connection to primary %i lost"), primary_node_info.node_id);
if (primary_conn != NULL)
{
PQfinish(primary_conn);
primary_conn = NULL;
}
}
if (PQstatus(primary_conn) != CONNECTION_OK)
{
log_info(_("attempting to reconnect"));
primary_conn = establish_db_connection(primary_node_info.conninfo, false);
if (PQstatus(primary_conn) != CONNECTION_OK)
{
log_warning(_("reconnection failed"));
}
else
{
log_info(_("reconnected"));
}
}
/* grandparent upstream is inactive */
if (primary_node_info.active == false)
{
// XXX
}
/* Close the connection to this server */
PQfinish(local_conn);
local_conn = NULL;
initPQExpBuffer(&event_details);
log_debug(_("standby follow command is:\n \"%s\""),
config_file_options.follow_command);
r = system(config_file_options.follow_command);
if (r != 0)
{
appendPQExpBuffer(&event_details,
_("unable to execute follow command:\n %s"),
config_file_options.follow_command);
log_error("%s", event_details.data);
/* It may not possible to write to the event notification
* table but we should be able to generate an external notification
* if required.
*/
create_event_record(primary_conn,
&config_file_options,
local_node_info.node_id,
"repmgrd_failover_follow",
false,
event_details.data);
termPQExpBuffer(&event_details);
}
if (update_node_record_set_upstream(primary_conn,
local_node_info.node_id,
primary_node_info.node_id) == false)
{
appendPQExpBuffer(&event_details,
_("unable to set node %i's new upstream ID to %i"),
local_node_info.node_id,
primary_node_info.node_id);
log_error("%s", event_details.data);
create_event_record(NULL,
&config_file_options,
local_node_info.node_id,
"repmgrd_failover_follow",
false,
event_details.data);
termPQExpBuffer(&event_details);
terminate(ERR_BAD_CONFIG);
}
appendPQExpBuffer(&event_details,
_("node %i is now following primary node %i"),
local_node_info.node_id,
primary_node_info.node_id);
log_notice("%s", event_details.data);
create_event_record(primary_conn,
&config_file_options,
local_node_info.node_id,
"repmgrd_failover_follow",
true,
event_details.data);
termPQExpBuffer(&event_details);
local_conn = establish_db_connection(config_file_options.conninfo, true);
return true;
}
@@ -1049,10 +1189,10 @@ promote_self(void)
{
int primary_node_id;
primary_conn = get_primary_connection(local_conn,
upstream_conn = get_primary_connection(local_conn,
&primary_node_id, NULL);
if (PQstatus(primary_conn) == CONNECTION_OK && primary_node_id == failed_primary.node_id)
if (PQstatus(upstream_conn) == CONNECTION_OK && primary_node_id == failed_primary.node_id)
{
log_notice(_("original primary (id: %i) reappeared before this standby was promoted - no action taken"),
failed_primary.node_id);
@@ -1063,7 +1203,7 @@ promote_self(void)
failed_primary.node_name,
failed_primary.node_id);
create_event_record(primary_conn,
create_event_record(upstream_conn,
&config_file_options,
local_node_info.node_id,
"repmgrd_failover_abort",
@@ -1072,7 +1212,6 @@ promote_self(void)
termPQExpBuffer(&event_details);
//PQfinish(primary_conn);
//primary_conn = NULL;
// XXX handle this!
@@ -1254,11 +1393,11 @@ follow_new_primary(int new_primary_id)
PQfinish(local_conn);
local_conn = NULL;
primary_conn = establish_db_connection(new_primary.conninfo, false);
upstream_conn = establish_db_connection(new_primary.conninfo, false);
if (PQstatus(primary_conn) == CONNECTION_OK)
if (PQstatus(upstream_conn) == CONNECTION_OK)
{
RecoveryType primary_recovery_type = get_recovery_type(primary_conn);
RecoveryType primary_recovery_type = get_recovery_type(upstream_conn);
if (primary_recovery_type == RECTYPE_PRIMARY)
{
new_primary_ok = true;
@@ -1266,7 +1405,7 @@ follow_new_primary(int new_primary_id)
else
{
log_warning(_("new primary is not in recovery"));
PQfinish(primary_conn);
PQfinish(upstream_conn);
}
}
@@ -1319,8 +1458,8 @@ follow_new_primary(int new_primary_id)
// XXX check success
record_status = get_node_record(primary_conn, new_primary_id, &upstream_node_info);
record_status = get_node_record(primary_conn, local_node_info.node_id, &local_node_info);
record_status = get_node_record(upstream_conn, new_primary_id, &upstream_node_info);
record_status = get_node_record(upstream_conn, local_node_info.node_id, &local_node_info);
local_conn = establish_db_connection(local_node_info.conninfo, false);
initPQExpBuffer(&event_details);
@@ -1331,7 +1470,7 @@ follow_new_primary(int new_primary_id)
log_notice("%s\n", event_details.data);
create_event_record(primary_conn,
create_event_record(upstream_conn,
&config_file_options,
local_node_info.node_id,
"repmgrd_failover_follow",
@@ -1808,10 +1947,20 @@ close_connections()
if (PQisBusy(primary_conn) == 1)
cancel_query(primary_conn, config_file_options.primary_response_timeout);
PQfinish(primary_conn);
primary_conn = NULL;
}
if (upstream_conn != NULL && PQstatus(upstream_conn) == CONNECTION_OK)
{
PQfinish(upstream_conn);
upstream_conn = NULL;
}
if (PQstatus(local_conn) == CONNECTION_OK)
{
PQfinish(local_conn);
local_conn = NULL;
}
}