From ee630312707f5bf809fe85d971a4c45a57d6a283 Mon Sep 17 00:00:00 2001 From: Kevin Yu Date: Thu, 12 Sep 2019 23:00:42 -0700 Subject: [PATCH] [SPARK-28828][DOC] Document REFRESH TABLE command ### What changes were proposed in this pull request? Document REFRESH TABLE statement in the SQL Reference Guide. ### Why are the changes needed? Currently there is no documentation in the SPARK SQL to describe how to use this command, it is to address this issue. ### Does this PR introduce any user-facing change? Yes. #### Before: There is no documentation for this. #### After: Screen Shot 2019-09-12 at 11 39 21 AM ### How was this patch tested? Using jykll build --serve Closes #25549 from kevinyu98/spark-28828-refreshTable. Authored-by: Kevin Yu Signed-off-by: Xiao Li --- docs/_data/menu-sql.yaml | 2 + docs/sql-ref-syntax-aux-refresh-table.md | 58 ++++++++++++++++++++++++ 2 files changed, 60 insertions(+) create mode 100644 docs/sql-ref-syntax-aux-refresh-table.md diff --git a/docs/_data/menu-sql.yaml b/docs/_data/menu-sql.yaml index 258762f0d9..d03616163c 100644 --- a/docs/_data/menu-sql.yaml +++ b/docs/_data/menu-sql.yaml @@ -172,6 +172,8 @@ url: sql-ref-syntax-aux-cache-uncache-table.html - text: CLEAR CACHE url: sql-ref-syntax-aux-cache-clear-cache.html + - text: REFRESH TABLE + url: sql-ref-syntax-aux-refresh-table.html - text: Describe Commands url: sql-ref-syntax-aux-describe.html subitems: diff --git a/docs/sql-ref-syntax-aux-refresh-table.md b/docs/sql-ref-syntax-aux-refresh-table.md new file mode 100644 index 0000000000..262382a467 --- /dev/null +++ b/docs/sql-ref-syntax-aux-refresh-table.md @@ -0,0 +1,58 @@ +--- +layout: global +title: REFRESH TABLE +displayTitle: REFRESH TABLE +license: | + Licensed to the Apache Software Foundation (ASF) under one or more + contributor license agreements. See the NOTICE file distributed with + this work for additional information regarding copyright ownership. + The ASF licenses this file to You under the Apache License, Version 2.0 + (the "License"); you may not use this file except in compliance with + the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. +--- + +### Description +`REFRESH TABLE` statement invalidates the cached entries, which include data +and metadata of the given table or view. The invalidated cache is populated in +lazy manner when the cached table or the query associated with it is executed again. + +### Syntax +{% highlight sql %} +REFRESH [TABLE] tableIdentifier +{% endhighlight %} + +### Parameters +
+
tableIdentifier
+
+ Specifies a table name, which is either a qualified or unqualified name that designates a table/view. If no database identifier is provided, it refers to a temporary view or a table/view in the current database.

+ Syntax: + + [database_name.]table_name + +
+
+ +### Examples +{% highlight sql %} +-- The cached entries of the table will be refreshed +-- The table is resolved from the current database as the table name is unqualified. +REFRESH TABLE tbl1; + +-- The cached entries of the view will be refreshed or invalidated +-- The view is resolved from tempDB database, as the view name is qualified. +REFRESH TABLE tempDB.view1; +{% endhighlight %} + +### Related Statements +- [CACHE TABLE](sql-ref-syntax-aux-cache-cache-table.html) +- [CLEAR CACHE](sql-ref-syntax-aux-cache-clear-cache.html) +- [UNCACHE TABLE](sql-ref-syntax-aux-cache-uncache-table.html) \ No newline at end of file