Github user jackylk commented on a diff in the pull request:
https://github.com/apache/carbondata/pull/2215#discussion_r189421956
--- Diff: docs/datamap/lucene-datamap-guide.md ---
@@ -0,0 +1,133 @@
+# CarbonData Lucene DataMap (Alpha feature in 1.4.0)
+
+* [DataMap Management](#datamap-management)
+* [Lucene Datamap](#lucene-datamap-introduction)
+* [Loading Data](#loading-data)
+* [Querying Data](#querying-data)
+* [Data Management](#data-management-with-pre-aggregate-tables)
+
+#### DataMap Management
+Lucene DataMap can be created using following DDL
+ ```
+ CREATE DATAMAP [IF NOT EXISTS] datamap_name
+ ON TABLE main_table
+ USING "lucene"
+ DMPROPERTIES ('index_columns'='city, name', ...)
+ ```
+
+DataMap can be dropped using following DDL:
+ ```
+ DROP DATAMAP [IF EXISTS] datamap_name
+ ON TABLE main_table
+ ```
+To show all DataMaps created, use:
+ ```
+ SHOW DATAMAP
+ ON TABLE main_table
+ ```
+It will show all DataMaps created on main table.
+
+
+## Lucene DataMap Introduction
+ Lucene is a high performance, full featured text search engine. Lucene
is integrated to carbon as
+ an index datamap and managed along with main tables by CarbonData.User
can create lucene datamap
+ to improve query performance on string columns which has content of more
length.
--- End diff --
Please rephrase to describe: this datamap is intended for text content, and
you want to search the tokenized word or pattern of it.
---
