Sharding is a critical feature in Apache Solr that allows you to horizontally partition your search index across multiple Solr servers. Here’s a brief overview of how to use sharding in Solr:
1. The “sharding” concept: Sharding in Solr involves dividing your search index into multiple smaller indexes, called “shards”, and distributing those shards across multiple Solr servers. Each shard contains a subset of the total index data, and queries are sent to all shards in parallel to retrieve the search results.
2. Configuring sharding: To configure sharding in Solr, you need to create multiple Solr cores, each containing a subset of the search index data. You can use Solr’s “Split Index” tool to split a large index into multiple smaller indexes. Once you have created the shard cores, you can distribute them across multiple Solr servers. You can use Solr’s “Collection API” to create and manage a collection, which is a group of shards that are logically related.
3. Using sharding: Once sharding is configured in Solr, you can use the “shards” parameter in your search queries to send the query to all shards in parallel. For example, to search for documents that contain the word “Solr” across all shards, you would use the following URL:
http://localhost:8983/solr/collection_name/select?q=Solr&shards=server1:8983/solr/core_name,server2:8983/solr/core_name
This URL specifies that the search query should return documents that contain the word “Solr” and send the query to all shards on “server1” and “server2” (“shards=server1:8983/solr/core_name,server2:8983/solr/core_name”).
By using sharding in Solr, you can horizontally partition your search index across multiple Solr servers, providing scalability and high availability. The Solr documentation provides detailed information on how to configure and use the sharding feature to partition your search index across multiple Solr servers.