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docs/content/Druid-vs-Elasticsearch.md

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+
+Druid vs Elasticsearch
+======================
+
+We are not experts on Elasticsearch, if anything is incorrect about our portrayal, please let us know on the mailing list or via some other means.
+
+Elasticsearch is a search server based on Apache Lucene. It provides full text search for schema-free documents and provides access to raw event level data. Elasticsearch also provides support for analytics and aggregations. Based on [user testimony](https://groups.google.com/forum/#!msg/druid-development/nlpwTHNclj8/sOuWlKOzPpYJ), the resource requirements for data ingestion and aggregation in Elasticsearch are higher than those of Druid.
+
+Druid focuses on OLAP work flows. Druid is optimized for high performance (fast aggregation and ingestion) at low cost, and supports a wide range of analytic operations. Druid has some basic search support for structured event data.

docs/content/Druid-vs-Spark.md

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+Druid vs Spark
+==============
+
+We are not experts on Spark, if anything is incorrect about our portrayal, please let us know on the mailing list or via some other means.
+
+Spark is a cluster computing framework built around the concept of Resilient Distributed Datasets (RDDs) and
+can be viewed as a back-office analytics platform.  RDDs enable data reuse by persisting intermediate results
+in memory and enable Spark to provide fast computations for iterative algorithms.
+This is especially beneficial for certain work flows such as machine
+learning, where the same operation may be applied over and over
+again until some result is converged upon.  Spark provides analysts with
+the ability to run queries and analyze large amounts of data with a
+wide array of different algorithms.
+
+Druid is designed to power analytic applications and focuses on the latencies to ingest data and serve queries
+over that data. If you were to build a web UI where users could
+arbitrarily explore data, the latencies seen by using Spark may be too slow for interactive use cases.

docs/content/index.md

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 * [Druid-vs-Vertica](Druid-vs-Vertica.html)
 * [Druid-vs-Cassandra](Druid-vs-Cassandra.html)
 * [Druid-vs-Hadoop](Druid-vs-Hadoop.html)
+* [Druid-vs-Spark](Druid-vs-Spark.html)
+* [Druid-vs-Elasticsearch](Druid-vs-Elasticsearch.html)
 
 
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