# Does "STOP GROUP\_REPLICATION" break the cluster?

**URL:** <https://forums.percona.com/t/does-stop-group-replication-break-the-cluster/36620>\
**Category:** Percona Server for MySQL 5.7\
**Tags:** pmm, mysql, percona\
**Created:** [February 10, 2025, 8:18am UTC](https://forums.percona.com/t/does-stop-group-replication-break-the-cluster/36620 "2025-02-10T08:18:23Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![aycelen](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/aycelen/32/23244_2.png) [@aycelen](https://forums.percona.com/u/aycelen)\
**Post date:** [February 10, 2025, 8:18am UTC](https://forums.percona.com/t/does-stop-group-replication-break-the-cluster/36620/1 "2025-02-10T08:18:23Z")

</div>

Hi there,

We have an issue about after SSt.

We need to “mysql\_upgrade” cuz we got an error like;

> “[ERROR] Incorrect definition of table performance\_schema.global\_variables: expected column ‘VARIABLE\_VALUE’ at position 1 t o have type varchar(2048), found type varchar(4096).”

So we need to do that but we anxious about crash all nodes.

If we do this steps;

```auto
mysql -u root -p
STOP GROUP_REPLICATION;
mysql_upgrade -u root -p
sudo systemctl restart mysql
START GROUP_REPLICATION;

```

Will we encounter any problems?

---

<div class="post-metadata">

**Author:** ![matthewb](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/matthewb/32/34_2.png) [@matthewb](https://forums.percona.com/u/matthewb)\
**Post date:** [February 11, 2025, 1:13am UTC](https://forums.percona.com/t/does-stop-group-replication-break-the-cluster/36620/2 "2025-02-11T01:13:45Z")

</div>

> [@aycelen](#):
>
> We have an issue about after SSt.

SST referrs to Percona XtraDB Cluster, not Group Replication (GR). GR does not use SSTs.

> [@aycelen](#):
>
> If we do this steps;

These steps are for Group Replication, which is **not** Percona XtraDB Cluster.

PXC and GR are **two completely different** clustering technologies. Please be sure you are using the correct one, and _only one_ Do not mix GR and PXC.

---

<div class="post-metadata">

**Author:** ![aycelen](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/aycelen/32/23244_2.png) [@aycelen](https://forums.percona.com/u/aycelen)\
**Post date:** [February 11, 2025, 1:08pm UTC](https://forums.percona.com/t/does-stop-group-replication-break-the-cluster/36620/3 "2025-02-11T13:08:14Z")

</div>

You’re right I’didnt used that method.

This is how can I solve the problem.

[ERROR] Incorrect definition of table performance\_schema.session\_variables:

```auto
service mysql stop
ps aux | grep mysql
--if it doesnt work db doesn't stop 

/etc/init.d/mysql status

--first kill the mysql services
ps aux | grep mysql

kill -9 PID --mysql PID's carefull this step dont kill any other service

-- MYSQL STOP CLEARLY THAN START THE MYSQL BELOW METHOD

"mysqld --skip-grant-tables --user=mysql --wsrep-provider='none'"

ps aux | grep mysql

-- CHECH IT AN THAN

mysql_upgrade 

--YOU MAY GET A mysql_upgrade: Got error: 2002: Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2) while connecting to the MySQL server error
--wait finish the mysql activating then try again

mysql_upgrade 

--after finish mysql_upgrade

--stop the mysqld wresp=none than restart the mysql normally 

select * from performance_schema.session_variables; 

--check this query

```

---

<div class="post-metadata">

**Author:** ![matthewb](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/matthewb/32/34_2.png) [@matthewb](https://forums.percona.com/u/matthewb)\
**Post date:** [February 11, 2025, 2:01pm UTC](https://forums.percona.com/t/does-stop-group-replication-break-the-cluster/36620/4 "2025-02-11T14:01:43Z")

</div>

Please also upgrade to MySQL 8.0 as soon as you can. 5.7 has been dead for many years and 8.0 will EOL next year.

---

<div class="post-metadata">

**Author:** ![aycelen](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/aycelen/32/23244_2.png) [@aycelen](https://forums.percona.com/u/aycelen)\
**Post date:** [February 17, 2025, 8:47am UTC](https://forums.percona.com/t/does-stop-group-replication-break-the-cluster/36620/5 "2025-02-17T08:47:11Z")

</div>

Dear matthewb,

You can’t imagine how much I want this.  
But this place like I work, It refuses to evolve.  
They are worried that I will create an extra burden for software developers.

Because you don’t even want to see that a software developer designed the database.

I’m trying it out, I hope I’ll be successful.

When I try this step I got 1 error

1. Schema inconsistencies resulting from file removal or corruption  
Error: Following tables show signs that either table datadir directory or frm  
file was removed/corrupted. Please check server logs, examine datadir to  
detect the issue and fix it before upgrade

I can’t fix it.

I will create a topic for this.

Thanks for your time!