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Re: replica write-through

On Sunday 17 September 2006 10:18, Howard Chu wrote:
> The chaining overlay will allow any slave (slurpd or syncrepl) to
> forward writes to the master. Matthew is asking for something slightly
> different, he wants the receiving slave to update its own database
> immediately, while forwarding the write to the master.
> We've talked about this on the lists several times in the past. I wrote
> the code for it a couple years ago, it was a simple patch. But it turns
> out to be a bad idea, because (especially with slurpd) you don't really
> know that the receiving slave is in sync with the master at the time.
> The write could easily fail on the master, after the slave had already
> committed it,
Hm, but this would not be a problem if the slave would only commit the 
operation locally after it was successfully chained and commited on the 
master. Or am I overlooking something?

> then you'd just need to do even more work to undo it.