Thanks - the specification looks like its close to what I would
like. The model I work from is one used by Sybase (and possibly
others) where you can specify a database dump and a separate
transaction log dump at defined intervals using a script or some
other programmatic method. From what I can tell its not possible to
do this with Derby, since you can only dump the database and not the
logs. Its also unclear how you would load a log file on its own.
What I would like to see is two additional commands added to dump
transaction logs to specified directory or file name and another
command to load a transaction log file from a specified location/
file. Ideally a transaction log file load should function much the
same way a normal user does to allow concurrent user access while
loading a transaction log file.
I would be interested what people think about this approach and
whether there is any way of adding transaction log dump commands
without major rewrite of the derby architecture !!
Cheers
On 08/02/2008, at 2:04 AM, Jørgen Løland wrote:
Duncan Groenewald wrote:
Hi, does anyone know if it is possible to get some kind of log
shipping working with Derby such that it is possible to create a
second database instance that runs and periodically loads
transaction log dumps from the primary database ?
Is it even possible to load a transaction log while a database is
running ?
Basically I want to have a second copy of the database running in
read only mode but still reasonably up to date, say every 15 minutes.
Thanks
Duncan Groenewald
mobile: +61406291205
email: [EMAIL PROTECTED]
Hi Duncan,
There is currently no such feature in Derby, but the next release
will include asynchronous replication based on log shipping from a
master version to a slave version of the database. However, the
first version of replication will not allow read operations on the
slave database.
Take a look at the functional specification for replication on this
page: https://issues.apache.org/jira/browse/DERBY-2872
If what is described there suits your needs, you'll find this
functionality in the next release of Derby (ETA in a few months).
If a read-only second copy of the database is what you really need,
I think you will have to hack something together using scripts
outside Derby for now. I think I can guide you through that, but it
*will* be pretty messy and I have not tried it myself. Please let
me know :)
Hope this helps
--
Jørgen Løland
Duncan Groenewald
mobile: +61406291205
email: [EMAIL PROTECTED]
