Innodb cluster- For better understanding virtual synchronous

[Chaitanya Tondlekar]

Hello,

I have implemented Innodb Cluster with default mode i.e single primary mode.

I want to know which type of replication is being performed between this.

Group replication has been implemented with virtual synchronous.

Can anyone just explain exactly what does virtual synchronous replication means?

Through some of links, i have read that single primary mode behaves closer to asynchronous replication.

PFB links : https://www.slideshare.net/freshdaz/mysql-innodb-cluster-a-complete-high-availability-solution-for-mysql

New Primary election is based on group_replication_member_weight and server_uuid.


If that is the case :

consider Innodb cluster has M1 as Master, R1 as secondary 1 and R2 has secondary 2.

R1 & R2 has same group_replication_member_weight and UUID of R2 is greater (lexicographical) order.

And large transaction is being executed on master and if in some case R1 Relay log has been updated and R2 relay log has not been updated.

And now M1 fail's, how's new primary gets elected?


Any help would be appreciated.