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Most research indicates feature parity between the two options, although Elasticsearch seems to have better REST API and JSON support. However, being that Apache Solr is more favored in Hadoop-land (supported by more distributions, is the only search engine that Cloudera supports, and has support in Slider to run on YARN), it makes more sense as the first candidate for supporting a search backend. The search backend, however, can be made pluggable, so it could be swiped out for ElasticSearch if users wish to in future.
4.0 Requirements in Apache Solr
Sorting
Sorting (including multiple sort orderings) is supported in Apache Solr using the sort parameter.
Pagination
Pagination is supported as a combination of the start and rows parameters.
Filtering
Filtering is supported using the fq parameter.
Running Apache Solr
Distributed Mode
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