Re: [bailey-developers] lattice master

[Ning L. <nin...@gm...>]

Subject: Terms

"Node" and "host" are clear now. "Range" and "index" are still a bit confusing.

On Thu, Feb 28, 2008 at 4:31 PM, Doug Cutting <cu...@ap...> wrote:
>  > 1) Shard: The distinct starting positions of all the virtual nodes
>  > divide the ring into shards. For example, starting positions
>  > (A B C D E) divide the ring into 5 shards: AB, BC, CD, DE, DA.
>
>  I prefer to call these "ranges".  "Shard" to me sounds like something
>  physical, and ranges are not physical.
>
>  > 2) Index on a virtual node (suggest a name?): A virtual node
>  > serves a number of continuous shards. For example, with
>  > 3-way replication, the indexes on the virtual nodes are:
>  > AB-BC-CD, BC-CD-DE, CD-DE-EA, DE-EA-AB, EA-AB-BC.

If AB is called a "range", then "AB-BC-CD" is a "node-range"?
Feel free to give better names. :)

>  > Now, should an index on a virtual node be implemented as
>  > one Lucene index or N Lucene indexes (one per shard)?
>
>  My hunch is one index per range.  That way we can search a set of
>  indexes that completes the ring, and search maximally large segments.

You mean one "index" per "node-range" and we need filtering,
right? Since later you said "I'm assuming a 1:1 mapping between
index and node."

Ning