MySQL Replication can be fragile: whenever it encounters a
connectivity error, it will retry and if it is a serious error,
it will simply stop. Obviously in the latter case, you will need
to repair the broken replication yourself.
The most common problems with replication are when it stops due
to either master failure or network problems. In case the master
fails, the whole topology becomes read-only and this means the
write queries cannot be applied anymore. This is where normally
you would promote one of the replicas to become the new master.
To illustrate the difference in promotion between GTID and
non-GTID cases, we will go through the manual promotion process
below.
Most advanced slave without GTID
The first step in this promotion is to find the most advanced
slave. As the master is no longer available, not all replicas may
have copied and applied the same amount of transactions. So it is
key to find the most …
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