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Posted to commits@spark.apache.org by we...@apache.org on 2020/02/11 13:42:42 UTC
[spark] branch branch-3.0 updated: [SPARK-27545][SQL][DOC] Update
the Documentation for CACHE TABLE and UNCACHE TABLE
This is an automated email from the ASF dual-hosted git repository.
wenchen pushed a commit to branch branch-3.0
in repository https://gitbox.apache.org/repos/asf/spark.git
The following commit(s) were added to refs/heads/branch-3.0 by this push:
new 37edbab [SPARK-27545][SQL][DOC] Update the Documentation for CACHE TABLE and UNCACHE TABLE
37edbab is described below
commit 37edbab7803c35eecd664f72447418e79638024e
Author: root1 <ra...@gmail.com>
AuthorDate: Tue Feb 11 20:42:02 2020 +0800
[SPARK-27545][SQL][DOC] Update the Documentation for CACHE TABLE and UNCACHE TABLE
### What changes were proposed in this pull request?
Document updated for `CACHE TABLE` & `UNCACHE TABLE`
### Why are the changes needed?
Cache table creates a temp view while caching data using `CACHE TABLE name AS query`. `UNCACHE TABLE` does not remove this temp view.
These things were not mentioned in the existing doc for `CACHE TABLE` & `UNCACHE TABLE`.
### Does this PR introduce any user-facing change?
Document updated for `CACHE TABLE` & `UNCACHE TABLE` command.
### How was this patch tested?
Manually
Closes #27090 from iRakson/SPARK-27545.
Lead-authored-by: root1 <ra...@gmail.com>
Co-authored-by: iRakson <ra...@gmail.com>
Signed-off-by: Wenchen Fan <we...@databricks.com>
(cherry picked from commit b20754d9ee033091e2ef4d5bfa2576f946c9df50)
Signed-off-by: Wenchen Fan <we...@databricks.com>
---
docs/sql-ref-syntax-aux-cache-cache-table.md | 3 ++-
docs/sql-ref-syntax-aux-cache-uncache-table.md | 6 +++++-
2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/docs/sql-ref-syntax-aux-cache-cache-table.md b/docs/sql-ref-syntax-aux-cache-cache-table.md
index ed6ef97..20ade19 100644
--- a/docs/sql-ref-syntax-aux-cache-cache-table.md
+++ b/docs/sql-ref-syntax-aux-cache-cache-table.md
@@ -20,7 +20,8 @@ license: |
---
### Description
-`CACHE TABLE` statement caches contents of a table or output of a query with the given storage level. This reduces scanning of the original files in future queries.
+`CACHE TABLE` statement caches contents of a table or output of a query with the given storage level. If a query is cached, then a temp view will be created for this query.
+This reduces scanning of the original files in future queries.
### Syntax
{% highlight sql %}
diff --git a/docs/sql-ref-syntax-aux-cache-uncache-table.md b/docs/sql-ref-syntax-aux-cache-uncache-table.md
index e0581d0..69e21c2 100644
--- a/docs/sql-ref-syntax-aux-cache-uncache-table.md
+++ b/docs/sql-ref-syntax-aux-cache-uncache-table.md
@@ -21,11 +21,13 @@ license: |
### Description
`UNCACHE TABLE` removes the entries and associated data from the in-memory and/or on-disk cache for a given table or view. The
-underlying entries should already have been brought to cache by previous `CACHE TABLE` operation. `UNCACHE TABLE` on a non-existent table throws Exception if `IF EXISTS` is not specified.
+underlying entries should already have been brought to cache by previous `CACHE TABLE` operation. `UNCACHE TABLE` on a non-existent table throws an exception if `IF EXISTS` is not specified.
+
### Syntax
{% highlight sql %}
UNCACHE TABLE [ IF EXISTS ] table_identifier
{% endhighlight %}
+
### Parameters
<dl>
<dt><code><em>table_identifier</em></code></dt>
@@ -37,10 +39,12 @@ UNCACHE TABLE [ IF EXISTS ] table_identifier
</code>
</dd>
</dl>
+
### Examples
{% highlight sql %}
UNCACHE TABLE t1;
{% endhighlight %}
+
### Related Statements
* [CACHE TABLE](sql-ref-syntax-aux-cache-cache-table.html)
* [CLEAR CACHE](sql-ref-syntax-aux-cache-clear-cache.html)
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