sraghunandan commented on a change in pull request #3294: [CARBONDATA-3462][DOC]Added documentation for index server
URL:
https://github.com/apache/carbondata/pull/3294#discussion_r303287690
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File path: docs/index-server.md
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+
+# Distributed Index Server
+
+## Background
+
+Carbon currently caches all block/blocklet datamap index information into the driver. For bloom
+datamap, it can prune the splits in a distributed way. In the first case, there are limitations
+like driver memory scale up and cache sharing between multiple applications is not possible. In
+the second case, there are limitations like, there is
+no guarantee that the next query goes to the same executor to reuse the cache and hence cache
+would be duplicated in multiple executors.
+Distributed Index Cache Server aims to solve the above mentioned problems.
+
+## Distribution
+When enabled, any query on a carbon table will be routed to the index server application using
+the Hadoop RPC framework in form of a request. The request will consist of the table name, segments,
+filter expression and other information used for pruning.
+
+In IndexServer application a pruning RDD is fired which will take care of the pruning for that
+request. This RDD will be creating tasks based on the number of segments that are applicable for
+pruning. It can happen that the user has specified segments to access for that table, so only the
Review comment:
Mention about the set specified segments requirement and link it here
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