Hi Jørgen,
Some unscientific ramblings of a layman follow...
Jørgen Løland wrote:
> I have a few questions regarding replication that would be great
> to hear the community's opinion on before the 10.4 branching. The
> reason for bringing this up before code freeze is that these will
> have impact on existing applications if changed later.
>
> 1. The master of a replicated database ships log records and
> other information to the slave through a network socket. 8001
> is currently default port for this communication. From
> http://www.iana.org/assignments/port-numbers it seems that
> this port is reserved for
>
> vcom-tunnel 8001/tcp VCOM Tunnel
> vcom-tunnel 8001/udp VCOM Tunnel
>
> Should we change port, and maybe even register a port in IANA,
> or is it fine as it is? I have no idea how long it will take
> to register a port, but chances are it will be longer than the
> time we have for 10.4 with the current plan. Another
> alternative is to use a port from the range called "dynamic
> and/or private ports" (49152 through 65535) BTW: I noticed
> that 1527 is registered by Oracle, which may also be a
> problem?
At first blush, registering a port seems like a good idea. It ought to
reduce the likelihood of ugly surprises. I got the impression that the
top range ( dynamic and/or private ports) was for short-lived, transient
conversations. It's probably not the right range if you want to conduct
a long-running conversation on your port.
A little mousing around turned up these resources: The process for
registering a port is defined in section 19.9 of
http://www.rfc-editor.org/rfc/rfc4340.txt and the corresponding form is
at http://www.iana.org/cgi-bin/usr-port-number.pl It appears that IANA
wants to give you a port number rather than vice-versa. So if you want
to register a port, then our user documentation should say that the port
used in 10.4 is likely to change in a future release.
>
> tlisrv 1527/tcp oracle
> tlisrv 1527/udp oracle
>
> Note that this is only a question of default port. The port
> number may be set explicitly by the client starting
> replication.
Oops. Changing this would be a backward compatibility issue and I doubt
you'll find much passion for this in the community.
>
> 2. About a week ago, Dibyendu Majumdar raised a question about
> why the replication modules are placed under services and not
> store. Should replication be moved from
> org.apache.derby.{iapi|impl}.services.replication to e.g.
> org.apache.derby.{iapi|impl}.store.replication, or is it OK to keep
> the current placement?
>
> 3. Should replication be shipped in a separate JAR file? Pros and
> cons as I see it:
>
> + Remove 65KB (unjared) of class files from derby.jar
> + Possible to have a different security policy file for replication?
> - Yet another JAR file
>
This doesn't seem like excessive bloat to me.
Thanks,
-Rick
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