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### 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 <raksonrakesh@gmail.com> Co-authored-by: iRakson <raksonrakesh@gmail.com> Signed-off-by: Wenchen Fan <wenchen@databricks.com>
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| layout | title | displayTitle | license |
|---|---|---|---|
| global | UNCACHE TABLE | UNCACHE TABLE | 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
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 an exception if IF EXISTS is not specified.
Syntax
{% highlight sql %} UNCACHE TABLE [ IF EXISTS ] table_identifier {% endhighlight %}
Parameters
table_identifier-
Specifies the table or view name to be uncached. The table or view name may be optionally qualified with a database name.
Syntax:[ database_name. ] table_name
Examples
{% highlight sql %} UNCACHE TABLE t1; {% endhighlight %}