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Re: "Rewind" type of mechanisms?


On Fri, Aug 19, 2022 at 12:37 PM Sam R. <samruohola@xxxxxxxxx> wrote:
> Thank you!
> > "You can automatically resync either with gtid based async replication"
> Few questions:
> resync automatically --> Does it remove a possible (obsolete) rogue row?

In asynchronous replication, yes it does.
In Galera, it doesn't because the node doesn't come online until it is
fully in sync, and replication in Galera is synchronous.

> How long task is such resyncing operation? --> Does it "recreate" the whole DB node?

Provided the replication logs on the other node haven't expired, it
will be an incremental update.
In async replication, that will be done by applying missing
transactions from the donor node.
In Galera it will be done by doing an incremental state transfer,
logically they amount to the same thing.

If the replication logs or the galera cache have expired while the
node was down, Galera will do a full state transfer (all data from
scratch) automatically.
With async replication in that case you will have to reseed the node
yourself using mariabackup or one of several other approaches, but
this is reasonably well automatable.

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