[ZODB-Dev] replicated ZEO idea

[Toby Dickenson]

I have been thinking about the storages 'copyTransactionsFrom' method, wh=
ich=20
uses another storages 'iterator' method to copy all of the transactions f=
rom=20
one storage to another. This is usually used for transferring data betwee=
n=20
different storage implementations, but I think this technique could also =
be=20
used as the basis for a lightweight replication option.... Given two ZEO=20
servers, an external process could perform the following operations using=
 the=20
ZEO protocol:

1. connect to ZEO server B and determine his most recent transaction id.
2. connect to ZEO server A, and use the 'iterator' method to learn about =
all
   transactions more recent than B
3. copy those recent transactions from A to B.

That would be trivially easy, except that the 'iterator' method isnt expo=
sed=20
by the ZEO server.

Is there any good reason why it isnt? Any objections to adding it for som=
e=20
later release? Has anyone looked at this before?