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[Election] optimize election bahavior

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This commit is contained in:
obdev
2022-11-07 03:05:47 +00:00
committed by wangzelin.wzl
parent e1f4909c8c
commit 5ac1a95bc9
9 changed files with 163 additions and 120 deletions
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64
src/logservice/palf/election/algorithm/election_proposer.cpp
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@ -12,6 +12,7 @@
#include "logservice/palf/election/message/election_message.h"
#include "ob_role.h"
#include "share/ob_occam_time_guard.h"
#include "election_proposer.h"
#include "common/ob_clock_generator.h"
@ -275,9 +276,17 @@ int ElectionProposer::reschedule_or_register_prepare_task_after_(const int64_t d
} else if (CLICK_FAIL(p_election_->timer_->schedule_task_repeat_spcifiy_first_delay(devote_task_handle_,
delay_us,
CALCULATE_MAX_ELECT_COST_TIME(),
[this]() {
[this, delay_us]() {
int ret = OB_SUCCESS;
LockGuard lock_guard(p_election_->lock_);
this->prepare(ObRole::FOLLOWER);
if (check_leader()) {// Leader不应该靠定时任务主动做Prepare，只能被动触发Prepare
LOG_RENEW_LEASE(INFO, "leader not allow do prepare in timer task before lease expired, this log may printed when message delay too large");
} else {
if (role_ == ObRole::LEADER) {
role_ = ObRole::FOLLOWER;
}
this->prepare(role_);// 只有Follower可以走到这里
}
return false;
}))) {
LOG_INIT(ERROR, "first time register devote task failed");
@ -369,34 +378,35 @@ void ElectionProposer::on_prepare_request(const ElectionPrepareRequestMsg &prepa
ELECT_TIME_GUARD(500_ms);
#define PRINT_WRAPPER KR(ret), K(prepare_req), K(*this)
int ret = OB_SUCCESS;
// 1. 忽略leader prepare消息，不触发一呼百应
if (static_cast<ObRole>(prepare_req.get_role()) == ObRole::LEADER) {// leader prepare不触发一呼百应
} else if (static_cast<ObRole>(prepare_req.get_role()) != ObRole::FOLLOWER) {
// 非candidate prepare是非预期的
LOG_ELECT_LEADER(ERROR, "unexpected code path");
// 2. 尝试一呼百应
} else if (memberlist_with_states_.get_member_list().get_addr_list().empty()) {
LOG_ELECT_LEADER(INFO, "memberlist is empty, give up do prepare this time");
} else {
// 2.1 拒绝旧消息
if (prepare_req.get_ballot_number() <= ballot_number_) {
// 注意这里是<=，若本轮已经发过一呼百应，则不会再重试，否则将无限循环
if (prepare_req.get_ballot_number() < ballot_number_) {
ElectionPrepareResponseMsg prepare_res_reject(p_election_->get_self_addr(),
prepare_req);
prepare_res_reject.set_rejected(ballot_number_);
if (CLICK_FAIL(p_election_->send_(prepare_res_reject))) {
LOG_ELECT_LEADER(ERROR, "create prepare request failed");
}
// 0. 拒绝旧消息、过滤本轮次消息、根据新消息推大轮次
if (prepare_req.get_ballot_number() <= ballot_number_) {
if (prepare_req.get_ballot_number() < ballot_number_) {// 对于旧消息发送拒绝响应
ElectionPrepareResponseMsg prepare_res_reject(p_election_->get_self_addr(),
prepare_req);
prepare_res_reject.set_rejected(ballot_number_);
if (CLICK_FAIL(p_election_->send_(prepare_res_reject))) {
LOG_ELECT_LEADER(ERROR, "create prepare request failed");
} else {
LOG_ELECT_LEADER(INFO, "has been send prepare request in this ballot, give up this time");
LOG_ELECT_LEADER(INFO, "send reject response cause prepare message ballot too small");
}
// 2.2 一呼百应
} else {// 对于本轮次消息，需要过滤，否则无限循环
LOG_ELECT_LEADER(INFO, "has been send prepare request in this ballot, give up this time");
}
} else {// 对于新的消息，推大本机选举轮次
LOG_ELECT_LEADER(INFO, "receive bigger ballot prepare request");
(void) advance_ballot_number_and_reset_related_states_(prepare_req.get_ballot_number(),
"receive bigger ballot prepare request");
// 1. 忽略leader prepare消息，不触发一呼百应
if (static_cast<ObRole>(prepare_req.get_role()) == ObRole::LEADER) {
LOG_ELECT_LEADER(INFO, "proposer ignore leader prepare");
} else if (static_cast<ObRole>(prepare_req.get_role()) != ObRole::FOLLOWER) {
// 非candidate prepare是非预期的
LOG_ELECT_LEADER(ERROR, "unexpected code path");
// 2. 尝试一呼百应
} else if (memberlist_with_states_.get_member_list().get_addr_list().empty()) {
LOG_ELECT_LEADER(INFO, "memberlist is empty, give up do prepare this time");
} else {
LOG_ELECT_LEADER(INFO, "receive bigger ballot prepare request");
(void) p_election_->refresh_priority_();
(void) advance_ballot_number_and_reset_related_states_(prepare_req.get_ballot_number(),
"receive bigger ballot prepare request");
ElectionPrepareRequestMsg prepare_followed_req(p_election_->id_,
p_election_->get_self_addr(),
restart_counter_,
@ -409,7 +419,7 @@ void ElectionProposer::on_prepare_request(const ElectionPrepareRequestMsg &prepa
LOG_ELECT_LEADER(INFO, "self is not in memberlist, give up do prepare");
} else if (CLICK_FAIL(p_election_->broadcast_(prepare_followed_req,
memberlist_with_states_.get_member_list()
.get_addr_list()))) {
.get_addr_list()))) {
LOG_ELECT_LEADER(ERROR, "broadcast prepare request failed");
} else {
last_do_prepare_ts_ = ObClockGenerator::getCurrentTime();