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MySQL 8 复制可观测性

2023年 9月 25日 83.5k 0

我们中的许多人，旧的MySQL DBA使用Seconds_Behind_Source显示副本状态来找出（异步）复制的状态和正确执行。

请注意新术语。我相信我们都使用过旧术语。

但是，MySQL 复制已经发展了很多，复制团队已经努力包含有关 MySQL 可用的所有复制风格的许多有用信息。

例如，我们添加了并行复制、组复制等。旧版“显示副本状态”结果中缺少所有这些信息。

有更好的方法来监视和观察使用Performance_Schema复制过程。

目前在Performance_Schema中，有 15 个与复制检测相关的表：

select TABLE_SCHEMA,TABLE_NAME,TABLE_ROWS
from information_schema.TABLES
where TABLE_SCHEMA='performance_schema' and table_name like 'replication_%';

+------------------------------------------------------+
| Tables_in_performance_schema (replication%) |
+------------------------------------------------------+
| replication_applier_configuration |
| replication_applier_filters |
| replication_applier_global_filters |
| replication_applier_status |
| replication_applier_status_by_coordinator |
| replication_applier_status_by_worker |
| replication_asynchronous_connection_failover |
| replication_asynchronous_connection_failover_managed |
| replication_connection_configuration |
| replication_connection_status |
| replication_group_communication_information |
| replication_group_configuration_version |
| replication_group_member_actions |
| replication_group_member_stats |
| replication_group_members |
+------------------------------------------------------+
15 rows in set (0.0038 sec)

但确实，理解这些指标的含义以及在哪里寻找对我们 MySQL DBA 重要的有用信息并不总是那么容易：我的复制是否落后于源？

我创建了一些可以安装在 sys 中的视图，以使用这些指标中的大多数来获取与我们 DBA 相关的东西：mysql_8_replication_observability.sql
https://gist.github.com/lefred/1bad64403923664a14e0f20f572d7526

让我们仔细看看这些视图。

复制滞后

select * from sys.replication_lag;
+---------------------------+-----------------------+------------------------+
| channel_name | max_lag_from_original | max_lag_from_immediate |
+---------------------------+-----------------------+------------------------+
| clusterset_replication | 00:00:04.963223 | 00:00:04.940782 |
| group_replication_applier | 0 | 0 |
+---------------------------+-----------------------+------------------------+

从上面的输出中，我们可以看到 MySQL 实例是一个异步副本，但它也是组复制集群的一部分。

事实上，这是 InnoDB ClusterSet 中 DR 集群的主要成员。

我们还可以看到，这个副本晚了将近 5 秒（滞后）。

然后，我们有了复制通道的名称以及原始提交者和直接源（在级联复制的情况下）的最大延迟/滞后（因为在并行复制的情况下可能有几个工作线程）。

在组复制集群（InnoDB 集群）的辅助成员上，我们可以看到以下输出：

select * from sys.replication_lag;
+----------------------------+-----------------------+------------------------+
| channel_name | max_lag_from_original | max_lag_from_immediate |
+----------------------------+-----------------------+------------------------+
| group_replication_recovery | null | null |
| group_replication_applier | 00:00:02.733008 | 00:00:02.733008 |
+----------------------------+-----------------------+------------------------+

我们可以看到用于恢复的通道（读取丢失的二进制日志事件、事务、节点加入组时）未被使用，并且组复制的应用程序有点滞后。

复制状态

此视图更完整，每个工作人员都有一行。

让我们以 InnoDB ClusterSet 的 DR 站点的主要成员为例：

select * from replication_status;
+-------------------------------+----------+----------+---------+-------------------+--------------------+
| channel | io_state | co_state | w_state | lag_from_original | lag_from_immediate |
+-------------------------------+----------+----------+---------+-------------------+--------------------+
| group_replication_applier (1) | ON | ON | ON | none | none |
| group_replication_applier (2) | ON | ON | ON | none | none |
| group_replication_applier (3) | ON | ON | ON | none | none |
| group_replication_applier (4) | ON | ON | ON | none | none |
| clusterset_replication (1) | ON | ON | ON | 00:00:15.395870 | 00:00:15.380884 |
| clusterset_replication (2) | ON | ON | ON | 00:00:15.395686 | 00:00:15.380874 |
| clusterset_replication (3) | ON | ON | ON | 00:00:15.411204 | 00:00:15.388451 |
| clusterset_replication (4) | ON | ON | ON | 00:00:15.406154 | 00:00:15.388434 |
+-------------------------------+----------+----------+---------+-------------------+--------------------+
We can see that parallel (asynchronous) replication from the Primary cluster uses 4 parallel workers.

We can also see that they are falling behind…

You may have noticed that there are 3 states (all at ON). Using SHOW REPLICA STATUS we can only see:

Replica_IO_Running: Yes
Replica_SQL_Running: Yes

对于并行复制，我们在应用二进制日志事件期间有另一个线程参与复制：协调器线程。

复制状态为 FULL

Replication Status Full

当然，我们也可以提供有关复制的更多详细信息。

让我们看一个示例结果：

select * from sys.replication_status_fullG
*************************** 1. row ***************************
channel: group_replication_applier (1)
host:
port: 0
user:
source_uuid: 7b6bf13d-40ed-11ee-bfdd-c8cb9e32df8e
group_name: 7b6bf13d-40ed-11ee-bfdd-c8cb9e32df8e
last_heartbeat_timestamp: 0000-00-00 00:00:00.000000
heartbeat_interval: 30
io_state: ON
io_thread_state: NULL
io_errno: 0
io_errmsg:
io_errtime: 0000-00-00 00:00:00.000000
co_state: ON
co_thread_state: Replica has read all relay log; waiting for more updates
co_errno: 0
co_errmsg:
co_errtime: 0000-00-00 00:00:00.000000
w_state: ON
w_thread_state: Waiting for an event from Coordinator
w_errno: 0
w_errmsg:
w_errtime: 0000-00-00 00:00:00.000000
time_since_last_message: 03:36:40.474223
applier_busy_state: IDLE
lag_from_original: none
lag_from_immediate: none
transport_time: 1.80 us
time_to_relay_log: 12.00 us
apply_time: 784.00 us
last_applied_transaction: 7b6bf4f0-40ed-11ee-bfdd-c8cb9e32df8e:3
last_queued_transaction: 7b6bf4f0-40ed-11ee-bfdd-c8cb9e32df8e:3
queued_gtid_set_to_apply:
*************************** 2. row ***************************
channel: group_replication_applier (2)
host:
port: 0
user:
source_uuid: 7b6bf13d-40ed-11ee-bfdd-c8cb9e32df8e
group_name: 7b6bf13d-40ed-11ee-bfdd-c8cb9e32df8e
last_heartbeat_timestamp: 0000-00-00 00:00:00.000000
heartbeat_interval: 30
io_state: ON
io_thread_state: NULL
io_errno: 0
io_errmsg:
io_errtime: 0000-00-00 00:00:00.000000
co_state: ON
co_thread_state: Replica has read all relay log; waiting for more updates
co_errno: 0
co_errmsg:
co_errtime: 0000-00-00 00:00:00.000000
w_state: ON
w_thread_state: Waiting for an event from Coordinator
w_errno: 0
w_errmsg:
w_errtime: 0000-00-00 00:00:00.000000
time_since_last_message: 03:36:40.474223
applier_busy_state: IDLE
lag_from_original: none
lag_from_immediate: none
transport_time: 1.80 us
time_to_relay_log: 12.00 us
apply_time: 0 ps
last_applied_transaction:
last_queued_transaction: 7b6bf4f0-40ed-11ee-bfdd-c8cb9e32df8e:3
queued_gtid_set_to_apply:
*************************** 3. row ***************************
channel: group_replication_applier (3)
host:
port: 0
user:
source_uuid: 7b6bf13d-40ed-11ee-bfdd-c8cb9e32df8e
group_name: 7b6bf13d-40ed-11ee-bfdd-c8cb9e32df8e
last_heartbeat_timestamp: 0000-00-00 00:00:00.000000
heartbeat_interval: 30
io_state: ON
io_thread_state: NULL
io_errno: 0
io_errmsg:
io_errtime: 0000-00-00 00:00:00.000000
co_state: ON
co_thread_state: Replica has read all relay log; waiting for more updates
co_errno: 0
co_errmsg:
co_errtime: 0000-00-00 00:00:00.000000
w_state: ON
w_thread_state: Waiting for an event from Coordinator
w_errno: 0
w_errmsg:
w_errtime: 0000-00-00 00:00:00.000000
time_since_last_message: 03:36:40.474223
applier_busy_state: IDLE
lag_from_original: none
lag_from_immediate: none
transport_time: 1.80 us
time_to_relay_log: 12.00 us
apply_time: 0 ps
last_applied_transaction:
last_queued_transaction: 7b6bf4f0-40ed-11ee-bfdd-c8cb9e32df8e:3
queued_gtid_set_to_apply:
*************************** 4. row ***************************
channel: group_replication_applier (4)
host:
port: 0
user:
source_uuid: 7b6bf13d-40ed-11ee-bfdd-c8cb9e32df8e
group_name: 7b6bf13d-40ed-11ee-bfdd-c8cb9e32df8e
last_heartbeat_timestamp: 0000-00-00 00:00:00.000000
heartbeat_interval: 30
io_state: ON
io_thread_state: NULL
io_errno: 0
io_errmsg:
io_errtime: 0000-00-00 00:00:00.000000
co_state: ON
co_thread_state: Replica has read all relay log; waiting for more updates
co_errno: 0
co_errmsg:
co_errtime: 0000-00-00 00:00:00.000000
w_state: ON
w_thread_state: Waiting for an event from Coordinator
w_errno: 0
w_errmsg:
w_errtime: 0000-00-00 00:00:00.000000
time_since_last_message: 03:36:40.474223
applier_busy_state: IDLE
lag_from_original: none
lag_from_immediate: none
transport_time: 1.80 us
time_to_relay_log: 12.00 us
apply_time: 0 ps
last_applied_transaction:
last_queued_transaction: 7b6bf4f0-40ed-11ee-bfdd-c8cb9e32df8e:3
queued_gtid_set_to_apply:
*************************** 5. row ***************************
channel: clusterset_replication (1)
host: 127.0.0.1
port: 3310
user: mysql_innodb_cs_b0adbc6c
source_uuid: 2cb77a02-40eb-11ee-83f4-c8cb9e32df8e
group_name:
last_heartbeat_timestamp: 2023-08-22 18:48:41.037817
heartbeat_interval: 30
io_state: ON
io_thread_state: Waiting for source to send event
io_errno: 0
io_errmsg:
io_errtime: 0000-00-00 00:00:00.000000
co_state: ON
co_thread_state: Waiting for replica workers to process their queues
co_errno: 0
co_errmsg:
co_errtime: 0000-00-00 00:00:00.000000
w_state: ON
w_thread_state: waiting for handler commit
w_errno: 0
w_errmsg:
w_errtime: 0000-00-00 00:00:00.000000
time_since_last_message: 00:00:00.001134
applier_busy_state: APPLYING
lag_from_original: 00:00:01.799071
lag_from_immediate: 00:00:01.783404
transport_time: 2.26 ms
time_to_relay_log: 19.00 us
apply_time: 14.63 ms
last_applied_transaction: 54d83026-40eb-11ee-a5d3-c8cb9e32df8e:105180
last_queued_transaction: 54d83026-40eb-11ee-a5d3-c8cb9e32df8e:105547
queued_gtid_set_to_apply: 54d83026-40eb-11ee-a5d3-c8cb9e32df8e:105184-105547
*************************** 6. row ***************************
channel: clusterset_replication (2)
host: 127.0.0.1
port: 3310
user: mysql_innodb_cs_b0adbc6c
source_uuid: 2cb77a02-40eb-11ee-83f4-c8cb9e32df8e
group_name:
last_heartbeat_timestamp: 2023-08-22 18:48:41.037817
heartbeat_interval: 30
io_state: ON
io_thread_state: Waiting for source to send event
io_errno: 0
io_errmsg:
io_errtime: 0000-00-00 00:00:00.000000
co_state: ON
co_thread_state: Waiting for replica workers to process their queues
co_errno: 0
co_errmsg:
co_errtime: 0000-00-00 00:00:00.000000
w_state: ON
w_thread_state: waiting for handler commit
w_errno: 0
w_errmsg:
w_errtime: 0000-00-00 00:00:00.000000
time_since_last_message: 00:00:00.001134
applier_busy_state: APPLYING
lag_from_original: 00:00:01.797743
lag_from_immediate: 00:00:01.783390
transport_time: 2.26 ms
time_to_relay_log: 19.00 us
apply_time: 21.47 ms
last_applied_transaction: 54d83026-40eb-11ee-a5d3-c8cb9e32df8e:105181
last_queued_transaction: 54d83026-40eb-11ee-a5d3-c8cb9e32df8e:105547
queued_gtid_set_to_apply: 54d83026-40eb-11ee-a5d3-c8cb9e32df8e:105184-105547
*************************** 7. row ***************************
channel: clusterset_replication (3)
host: 127.0.0.1
port: 3310
user: mysql_innodb_cs_b0adbc6c
source_uuid: 2cb77a02-40eb-11ee-83f4-c8cb9e32df8e
group_name:
last_heartbeat_timestamp: 2023-08-22 18:48:41.037817
heartbeat_interval: 30
io_state: ON
io_thread_state: Waiting for source to send event
io_errno: 0
io_errmsg:
io_errtime: 0000-00-00 00:00:00.000000
co_state: ON
co_thread_state: Waiting for replica workers to process their queues
co_errno: 0
co_errmsg:
co_errtime: 0000-00-00 00:00:00.000000
w_state: ON
w_thread_state: waiting for handler commit
w_errno: 0
w_errmsg:
w_errtime: 0000-00-00 00:00:00.000000
time_since_last_message: 00:00:00.001134
applier_busy_state: APPLYING
lag_from_original: 00:00:01.786087
lag_from_immediate: 00:00:01.767563
transport_time: 2.26 ms
time_to_relay_log: 19.00 us
apply_time: 21.58 ms
last_applied_transaction: 54d83026-40eb-11ee-a5d3-c8cb9e32df8e:105182
last_queued_transaction: 54d83026-40eb-11ee-a5d3-c8cb9e32df8e:105547
queued_gtid_set_to_apply: 54d83026-40eb-11ee-a5d3-c8cb9e32df8e:105184-105547
*************************** 8. row ***************************
channel: clusterset_replication (4)
host: 127.0.0.1
port: 3310
user: mysql_innodb_cs_b0adbc6c
source_uuid: 2cb77a02-40eb-11ee-83f4-c8cb9e32df8e
group_name:
last_heartbeat_timestamp: 2023-08-22 18:48:41.037817
heartbeat_interval: 30
io_state: ON
io_thread_state: Waiting for source to send event
io_errno: 0
io_errmsg:
io_errtime: 0000-00-00 00:00:00.000000
co_state: ON
co_thread_state: Waiting for replica workers to process their queues
co_errno: 0
co_errmsg:
co_errtime: 0000-00-00 00:00:00.000000
w_state: ON
w_thread_state: waiting for handler commit
w_errno: 0
w_errmsg:
w_errtime: 0000-00-00 00:00:00.000000
time_since_last_message: 00:00:00.001134
applier_busy_state: APPLYING
lag_from_original: 00:00:01.785881
lag_from_immediate: 00:00:01.767550
transport_time: 2.26 ms
time_to_relay_log: 19.00 us
apply_time: 29.59 ms
last_applied_transaction: 54d83026-40eb-11ee-a5d3-c8cb9e32df8e:105183
last_queued_transaction: 54d83026-40eb-11ee-a5d3-c8cb9e32df8e:105547
queued_gtid_set_to_apply: 54d83026-40eb-11ee-a5d3-c8cb9e32df8e:105184-105547

通过此视图，我们有更多详细信息，例如复制检测信号。我们还概述了 GTID（排队、已应用等）。

我们还会看到有关传输时间（网络）、写入中继日志的时间以及最后的应用时间的信息。

当然，您可以使用视图显示所需的任何内容，例如：

MySQL InnoDB Cluster， ClusterSet， Read Replicas

如果您使用由 Admin API 和 MySQL Shell 管理的不错的集成解决方案，则所有这些信息都可以使用 status（） 方法获得。

status（） 方法可以用 3 个值进行扩展：

1：包括有关元数据版本、组协议版本、组名称、集群成员 UUID、集群成员角色和组复制报告的状态以及受防护系统变量列表的信息;
2：包括有关连接和
应用者处理的交易的信息;
3：包括有关每个

集群成员的复制机制的更详细的统计信息;

让我们看一个带有扩展选项 3 个群集示例：

JS> cs.status({extended:3})
{
"clusters": {
"cluster2": {
"clusterRole": "REPLICA",
"clusterSetReplication": {
"applierQueuedTransactionSet": "54d83026-40eb-11ee-a5d3-c8cb9e32df8e:137385-138500",
"applierQueuedTransactionSetSize": 1116,
"applierState": "ON",
"applierStatus": "APPLYING",
"applierThreadState": "waiting for handler commit",
"applierWorkerThreads": 4,
"coordinatorState": "ON",
"coordinatorThreadState": "Waiting for replica workers to process their queues",
"options": {
"connectRetry": 3,
"delay": 0,
"heartbeatPeriod": 30,
"retryCount": 10
},
"receiver": "127.0.0.1:4420",
"receiverStatus": "ON",
"receiverThreadState": "Waiting for source to send event",
"receiverTimeSinceLastMessage": "00:00:00.002737",
"replicationSsl": null,
"source": "127.0.0.1:3310"
},
"clusterSetReplicationStatus": "OK",
"communicationStack": "MYSQL",
"globalStatus": "OK",
"groupName": "7b6bf13d-40ed-11ee-bfdd-c8cb9e32df8e",
"groupViewChangeUuid": "7b6bf4f0-40ed-11ee-bfdd-c8cb9e32df8e",
"paxosSingleLeader": "OFF",
"receivedTransactionSet": "54d83026-40eb-11ee-a5d3-c8cb9e32df8e:129-138500",
"ssl": "REQUIRED",
"status": "OK_NO_TOLERANCE",
"statusText": "Cluster is NOT tolerant to any failures.",
"topology": {
"127.0.0.1:4420": {
"address": "127.0.0.1:4420",
"applierWorkerThreads": 4,
"fenceSysVars": [
"read_only",
"super_read_only"
],
"memberId": "c3d726ac-40ec-11ee-ab38-c8cb9e32df8e",
"memberRole": "PRIMARY",
"memberState": "ONLINE",
"mode": "R/O",
"readReplicas": {},
"replicationLagFromImmediateSource": "00:00:05.420247",
"replicationLagFromOriginalSource": "00:00:05.433548",
"role": "HA",
"status": "ONLINE",
"version": "8.1.0"
},
"127.0.0.1:4430": {
"address": "127.0.0.1:4430",
"applierWorkerThreads": 4,
"fenceSysVars": [
"read_only",
"super_read_only"
],
"memberId": "709b15ea-40ed-11ee-a9b3-c8cb9e32df8e",
"memberRole": "SECONDARY",
"memberState": "ONLINE",
"mode": "R/O",
"readReplicas": {},
"replicationLagFromImmediateSource": "00:00:00.038075",
"replicationLagFromOriginalSource": "00:00:05.432536",
"role": "HA",
"status": "ONLINE",
"version": "8.1.0"
}
},
"transactionSet": "2cb77a02-40eb-11ee-83f4-c8cb9e32df8e:1-4,54d83026-40eb-11ee-a5d3-c8cb9e32df8e:1-137384,54d8329c-40eb-11ee-a5d3-c8cb9e32df8e:1-5,7b6bf4f0-40ed-11ee-bfdd-c8cb9e32df8e:1-3",
"transactionSetConsistencyStatus": "OK",
"transactionSetErrantGtidSet": "",
"transactionSetMissingGtidSet": "54d83026-40eb-11ee-a5d3-c8cb9e32df8e:137385-138552"
},
"myCluster": {
"clusterRole": "PRIMARY",
"communicationStack": "MYSQL",
"globalStatus": "OK",
"groupName": "54d83026-40eb-11ee-a5d3-c8cb9e32df8e",
"groupViewChangeUuid": "54d8329c-40eb-11ee-a5d3-c8cb9e32df8e",
"paxosSingleLeader": "OFF",
"primary": "127.0.0.1:3310",
"ssl": "REQUIRED",
"status": "OK",
"statusText": "Cluster is ONLINE and can tolerate up to ONE failure.",
"topology": {
"127.0.0.1:3310": {
"address": "127.0.0.1:3310",
"applierWorkerThreads": 4,
"fenceSysVars": [],
"memberId": "2cb77a02-40eb-11ee-83f4-c8cb9e32df8e",
"memberRole": "PRIMARY",
"memberState": "ONLINE",
"mode": "R/W",
"readReplicas": {
"127.0.0.1:4410": {
"address": "127.0.0.1:4410",
"applierStatus": "APPLYING",
"applierThreadState": "waiting for handler commit",
"applierWorkerThreads": 4,
"receiverStatus": "ON",
"receiverThreadState": "Waiting for source to send event",
"replicationSources": [
"PRIMARY"
],
"replicationSsl": "TLS_AES_256_GCM_SHA384 TLSv1.3",
"role": "READ_REPLICA",
"status": "ONLINE",
"version": "8.1.0"
}
},
"role": "HA",
"status": "ONLINE",
"version": "8.1.0"
},
"127.0.0.1:3320": {
"address": "127.0.0.1:3320",
"applierWorkerThreads": 4,
"fenceSysVars": [
"read_only",
"super_read_only"
],
"memberId": "327cb102-40eb-11ee-9904-c8cb9e32df8e",
"memberRole": "SECONDARY",
"memberState": "ONLINE",
"mode": "R/O",
"readReplicas": {},
"replicationLagFromImmediateSource": "00:00:04.536190",
"replicationLagFromOriginalSource": "00:00:04.536190",
"role": "HA",
"status": "ONLINE",
"version": "8.1.0"
},
"127.0.0.1:3330": {
"address": "127.0.0.1:3330",
"applierWorkerThreads": 4,
"fenceSysVars": [
"read_only",
"super_read_only"
],
"memberId": "3d141d7e-40eb-11ee-933b-c8cb9e32df8e",
"memberRole": "SECONDARY",
"memberState": "ONLINE",
"mode": "R/O",
"readReplicas": {},
"replicationLagFromImmediateSource": "00:00:04.652745",
"replicationLagFromOriginalSource": "00:00:04.652745",
"role": "HA",
"status": "ONLINE",
"version": "8.1.0"
}
},
"transactionSet": "2cb77a02-40eb-11ee-83f4-c8cb9e32df8e:1-4,54d83026-40eb-11ee-a5d3-c8cb9e32df8e:1-138552,54d8329c-40eb-11ee-a5d3-c8cb9e32df8e:1-5"
}
},
"domainName": "myClusterSet",
"globalPrimaryInstance": "127.0.0.1:3310",
"metadataServer": "127.0.0.1:3310",
"primaryCluster": "myCluster",
"status": "HEALTHY",
"statusText": "All Clusters available."
}

MySQL HeatWave

如果您在 OCI 上的 MySQL HeatWave 中使用任何类型的复制，则可以使用相同的视图，但您需要在不同的数据库上创建它们，因为 sys 是写保护的。

因此，如果您使用的是 HA、只读副本或手动复制通道，您还可以使用相同的视图来准确了解复制。

结论

复制可观测性非常详细，并为 MySQL 8 提供了大量信息。也许现在是更改查看或监视复制方式的好时机。

享受我的 SQL！

原文： https://dev.mysql.com/blog-archive/mysql-8-and-replication-observability/

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