Thursday, April 24, 2008

Eureka - SUMA switch over for table-reorg

First it struck me that
- starting to double send events can be done wo/ synchronization, cause
1) this is basic techinque for node-failure handling
2) it does not matter if new-fragment does not contain full epoch, as it will contain
last part

Then (today) it struck me that
- turning off double send on old "home" for row does not either require synchronization
(except doing it on epoch-boundary) but different fragments can do it on different times, cause
- there is already double send ongoing, so no events will be lost

This makes the task relatively straightforward, but following is still needed,
- replication triggers must be turned off at epoch boundary
- replication triggers must be turned off 3 epochs after "turn off" has been initiated

- all of above means that it can be handled per node...(or maybe node group...)
- have to think more about potential per node group synchronization though...

Hope I'm right! Will discuss @office, to see if anyone can find any holes
(including me, as I got the idea today)


Still only one comment...I think I need to add a contest of something

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