void replica::init_checkpoint()
{
check_hashed_access();
// only applicable to primary and secondary replicas
if (status() != PS_PRIMARY && status() != PS_SECONDARY)
return;
// no need to checkpoint
if (_app->is_delta_state_learning_supported())
return;
// already running
if (_secondary_states.checkpoint_task != nullptr)
return;
// private log must be enabled to make sure commits
// are not lost during checkpinting
dassert(nullptr != _private_log, "log_enable_private_prepare must be true for checkpointing");
// TODO: when NOT to checkpoint, but use private log replay to build the state
if (last_committed_decree() - last_durable_decree() < 10000)
return;
// primary is downgraded to secondary for checkpointing as no write can be seen
// during checkpointing (i.e., state is freezed)
if (PS_PRIMARY == status())
{
configuration_update_request proposal;
proposal.config = _primary_states.membership;
proposal.type = CT_DOWNGRADE_TO_SECONDARY;
proposal.node = proposal.config.primary;
downgrade_to_secondary_on_primary(proposal);
}
// secondary can start checkpint in the long running thread pool
else
{
dassert(PS_SECONDARY == status(), "");
_secondary_states.checkpoint_task = tasking::enqueue(
LPC_CHECKPOINT_REPLICA,
this,
&replica::checkpoint,
gpid_to_hash(get_gpid())
);
}
}
void replica::on_config_proposal(configuration_update_request& proposal)
{
check_hashed_access();
ddebug(
"%s: on_config_proposal %s for %s",
name(),
enum_to_string(proposal.type),
proposal.node.to_string()
);
if (proposal.config.ballot < get_ballot())
{
dwarn(
"%s: on_config_proposal is out-dated, %lld vs %lld",
name(),
proposal.config.ballot,
get_ballot()
);
return;
}
if (_primary_states.reconfiguration_task != nullptr)
{
dinfo(
"%s: reconfiguration on the way, skip the incoming proposal",
name()
);
return;
}
if (proposal.config.ballot > get_ballot())
{
if (!update_configuration(proposal.config))
{
// is closing or update failed
return;
}
}
switch (proposal.type)
{
case CT_ASSIGN_PRIMARY:
case CT_UPGRADE_TO_PRIMARY:
assign_primary(proposal);
break;
case CT_ADD_SECONDARY:
add_potential_secondary(proposal);
break;
case CT_DOWNGRADE_TO_SECONDARY:
downgrade_to_secondary_on_primary(proposal);
break;
case CT_DOWNGRADE_TO_INACTIVE:
downgrade_to_inactive_on_primary(proposal);
break;
case CT_REMOVE:
remove(proposal);
break;
default:
dassert (false, "");
}
}
