Spark SQL Guide

REPAIR TABLE

Description

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.

Syntax

MSCK REPAIR TABLE table_identifier

Parameters

table_identifier
Specifies the name of the table to be repaired. The table name may be optionally qualified with a database name.

Syntax: [ database_name. ] table_name

Examples

 -- create a partitioned table from existing data /tmp/namesAndAges.parquet
 CREATE TABLE t1 (name STRING, age INT) USING parquet PARTITIONED BY (age)
     location "/tmp/namesAndAges.parquet";

 -- SELECT * FROM t1 does not return results
 SELECT * FROM t1;

 -- run MSCK REPAIR TABLE to recovers all the partitions
 MSCK REPAIR TABLE t1;

 -- SELECT * FROM t1 returns results
 SELECT * FROM t1;

     + -------------- + ------+
     | name           | age   |
     + -------------- + ------+
     | Michael        | 20    |
     + -------------- + ------+
     | Justin         | 19    |
     + -------------- + ----- +
     | Andy           | 30    |
     + -------------- + ----- +