Hello Benjamin,
On 9/24/2012 10:52 AM, Stillman, Benjamin wrote:
replicate-same-server-id = 0 keeps MySQL from replicating binary log entries
from itself. For instance, here's a rough overview:
You write to Server A.
Server A writes that to its binary log.
Server B reads Server A's binary log and completes the same thing.
Because log-slave-updates is enabled, Server B writes it to its own binary log.
Server C reads Server B's binary log and completes the same thing.
Again, with log-slave-updates enabled, Server C writes it to its own binary log.
Server A reads Server C's binary log.
Here's where the issue starts. Without replicate-same-server-id = 0, Server A
will complete the insert/update/delete as it reads it from Server C's binary
log. However, this query originated from Server A, so it's just going to do it
again. Then it's again replicated to Server B, Server C, and so on. This can
create a loop and/or break replication. For instance, if you drop a table on A.
It replicates across, and back to A. Replication will error out because when it
tries to drop the same table again, it already doesn't exist. You need
replicate-same-server-id = 0 set so that it knows not to execute any binary log
entries with its own server ID.
Not true.
Replication, by default, operates with --replicate-same-server-id=0. The
only time you need to change it to a 1 is for certain recovery
scenarios. We added this variable specifically to allow for exceptions
to the rule that every server in a replication chain (or ring) must have
their own, unique, --server-id value.
It's not required for normal operations. In fact we recommend you do not
set it at all. Each server will automatically ignore any event that
originates from a server with the same --server-id setting unless you
specifically set --replicate-same-server-id=1 .
Regards
--
Shawn Green
MySQL Principal Technical Support Engineer
Oracle USA, Inc. - Hardware and Software, Engineered to Work Together.
Office: Blountville, TN
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