Comments on PrimeBase XT: Replication is dead, long live Replication!

Yes, I looked at that, and I think I don't have to...

2008-04-09T08:48:00.000+02:00

Yes, I looked at that, and I think I don't have to wait for the Acknowledge of the second message.

So the primary writes a phase 1 message to the log. This is propagated to the secondaries, and the primary waits for OK or abort from the secondaries.

On OK of all it writes a phase 2 commit record to the log. At this point it can acknowledge the commit to the user.

The secondaries will commit when they receive commit, but do not need to Ack this.

Being XA, two round trips?

2008-04-08T23:59:00.000+02:00

Being XA, two round trips?

Hi Brian,Good question! As you noted XA is require...

2008-04-08T17:40:00.000+02:00

Hi Brian,

Good question! As you noted XA is required for bi-directional replication (and I would want it to be transactional).

Of course it is difficult to say at this stage exactly what the performance will be like. The overhead of XA is something to keep in mind.

In general this is only going to work if I can minimize flushing and the amount of data that is being sent over the network. I think I have found a way to do this.

If I am correct then the main hit for XA will be the network latency. Basically the cost of one round trip.

I'm looking forward to hearing more about the memcached "write through" functionality.

Best regards,

Paul

Hi!Syncronous replication for scaling writes? What...

2008-04-08T17:11:00.000+02:00

Hi!

Syncronous replication for scaling writes? What is the XA hit for that? If you are transactional that is...

Write through caching is next, memcached is just read through.

Cheers,
-Brian