Github user pwendell commented on a diff in the pull request:
https://github.com/apache/spark/pull/1681#discussion_r15628521
--- Diff: docs/sql-programming-guide.md ---
@@ -769,3 +769,15 @@ To start the Spark SQL CLI, run the following in the
Spark directory:
Configuration of Hive is done by placing your `hive-site.xml` file in
`conf/`.
You may run `./bin/spark-sql --help` for a complete list of all available
options.
+
+# Cache tables
+
+Spark SQL can cache tables using an in-memory columnar format by calling
`cacheTable("tableName")`.
--- End diff --
Some grammar fixes:
```
Spark SQL can cache tables using an in-memory columnar format by calling
`cacheTable("tableName")`.
Then Spark SQL will scan only required columns and will automatically
select best compression to
minimize memory usage an GC pressure. You can call
`uncacheTable("tableName")` to remove the
table from memory.
Note that if you just call `cache` rather than `cacheTable`, tables will
_not_ be cached in
in-memory columnar format. So we strongly recommend using `cacheTable`
whenever you want to
cache tables.
```
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