5a512e86e9
### What changes were proposed in this pull request? Document REPAIR TABLE statement in SQL Reference. ### Why are the changes needed? To complete SQL reference. ### Does this PR introduce any user-facing change? Yes. After the change, we will have the following   ### How was this patch tested? Tested using jykyll build --serve Closes #25884 from huaxingao/spark-28800. Authored-by: Huaxin Gao <huaxing@us.ibm.com> Signed-off-by: Sean Owen <sean.owen@databricks.com>
64 lines
2.4 KiB
Markdown
64 lines
2.4 KiB
Markdown
---
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layout: global
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title: REPAIR TABLE
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displayTitle: REPAIR TABLE
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license: |
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Licensed to the Apache Software Foundation (ASF) under one or more
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contributor license agreements. See the NOTICE file distributed with
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this work for additional information regarding copyright ownership.
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The ASF licenses this file to You under the Apache License, Version 2.0
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(the "License"); you may not use this file except in compliance with
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the License. You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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---
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### Description
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`MSCK REPAIR TABLE` recovers all the partitions in the directory of a table and updates the Hive metastore. When creating a table using `PARTITIONED BY` clause, partitions are generated and registered in the Hive metastore. However, if the partitioned table is created from existing data, partitions are not registered automatically in the Hive metastore. User needs to run `MSCK REPAIR TABLE` to register the partitions. `MSCK REPAIR TABLE` on a non-existent table or a table without partitions throws an exception. Another way to recover partitions is to use `ALTER TABLE RECOVER PARTITIONS`.
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### Syntax
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{% highlight sql %}
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MSCK REPAIR TABLE table_name
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{% endhighlight %}
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### Parameters
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<dl>
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<dt><code><em>table_name</em></code></dt>
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<dd>Specifies the name of the table to be repaired.</dd>
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</dl>
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### Examples
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{% highlight sql %}
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-- create a partitioned table from existing data /tmp/namesAndAges.parquet
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CREATE TABLE t1 (name STRING, age INT) USING parquet PARTITIONED BY (age)
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location "/tmp/namesAndAges.parquet";
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-- SELECT * FROM t1 does not return results
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SELECT * FROM t1;
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-- run MSCK REPAIR TABLE to recovers all the partitions
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MSCK REPAIR TABLE t1;
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-- SELECT * FROM t1 returns results
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SELECT * FROM t1;
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+ -------------- + ------+
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| name | age |
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+ -------------- + ------+
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| Michael | 20 |
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+ -------------- + ------+
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| Justin | 19 |
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+ -------------- + ----- +
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| Andy | 30 |
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+ -------------- + ----- +
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{% endhighlight %}
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### Related Statements
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* [ALTER TABLE](sql-ref-syntax-ddl-alter-table.html)
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