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From Yonik Seeley <>
Subject Re: SolrCloud logical shards
Date Thu, 14 Jan 2010 17:46:05 GMT
I'm actually starting to lean toward "slice" instead of "logical shard".
In the future we'll want to enable overlapping shards I think (due to
an Amazon Dynamo type of replication, or due to merging shards, etc),
and a separate word for a logical slice of the index seems desirable.

For instance, one could specify slice=1000-1999 (defined by the ids or
hashcodes of the ids) and that could end up querying multiple servers.
 For this first iteration, slices would just be opaque identifiers
though (and that functionality would always remain, allowing for user
partitioning by time or by geo region).

So "slice" would be logical, "shard" would be physical.
To get a full result, one needs to query all of the slices of an
index, but not necessarily all of the shards.


On Thu, Jan 14, 2010 at 12:08 PM, Yonik Seeley
<> wrote:
> The shards parameter currently references physical shards.
> There's also a concept of a logical shard (i.e. all physical shards
> with identical index content share the same logical shards...
> sometimes what I've also called a shard replica).
> Should we use logical shard for this, or does anyone have any better ideas?
> Related: it seems like we would want to enable querying of specific
> logical shards (say if a user partitioned their shards by time or by
> geographic region), so the terminology above could affect the
> parameter we use for this.  Suggestions?  logicalshards=shard1,shard2?
> lshards=shard1,shard2?  slice=shard1,shard2? It doesn't seem like it
> would be easy to reuse the "shards" parameter for this since it refers
> to physical shard addresses.
> -Yonik

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