CODEWITHSUNDEEP
solr
Amar Singh
Amar Singh

Reputation: 21

Why we need sharding in solr and what is the benifit of it

I am beginner in solr and I have no idea about how to do sharding in solr so my question is why we need sharding when we create collection and what is the benifit of it .If I am not creating sharding what happened.

Upvotes: 1

Views: 372

Answers (2)

MatsLindh
MatsLindh

Reputation: 52802

Sharding allows us to have indexes that span more than a single instance of Solr - i.e. multiple servers or multiple running instances of Solr (which could be useful under specific conditions because of some single thread limitations in Lucene, as well as some memory usage patterns).

If we didn't have sharding, you'd be limited to a total size of your index to whatever you could fit on a single server. Sharding means that one part of the index (for example half of all your documents) will be located on one server, while the other half will be located on the other server. When you query Solr for any results, each shard will receive the query, and the result will then be merged before being returned back to you.

There's a few limitations in features that won't work properly when an index is shared (and scores are calculated locally on each server, which is why you usually want your documents spread as evenly as possible), but in those cases where sharding is useful (and it very often is!), there really isn't any better solutions.

Upvotes: 2

Dimanshu Parihar
Dimanshu Parihar

Reputation: 377

Sharding helps us split the data into multiple replicas.

eg. If you have a collection named Employee with 1 shard and 2 replica. Then assuming there are 100 records,

Employee_shard1_replica1 will have 100 records and

Employee_shard1_replica2 will have 100 records

The replica did the copying of entire records into another core so that you have loan balancing as well as fault taulrence.

Now, eg2. If you have the same collection Employee with 2 shard and 2 replica. In this scenario, the data will be split to both the shards.

Employee_shard1_replica1 will have 50 records

Employee_shard1_replica2 will have 50 records

Employee_shard2_replica2 will have 50 records

Employee_shard2_replica2 will have 50 records

Note : Shard 1 replicas have same data here and shard 2 replicas will have same data.

Upvotes: 0

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