[infinispan-dev] TopologySafe Map / Reduce

[Emmanuel Bernard]

On 10 Oct 2014, at 18:06, Dan Berindei <dan.berindei at gmail.com> wrote:

> 
> The biggest downside I see is that it would be horribly slow if the cache store doesn't support efficient iteration of a single segment. So we might want to implement a full retry strategy as well, if some cache stores can't support that.
> 

My understanding from a discussion with Pedro (in a hard, cold and sinister place but that’s another story) is that *today* M/R is kinda horrible for global cache stores anyways that have to do the key per node filtering dance anyways. So it’s not significantly worse.
Plus I said we should do work per segment but in reality if you send 5 Map segment work to the same node, you can optimize and do a single loop only making it feel like they are separated work.
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