Jaa

REPAIR TABLE

  • Artikkeli

Applies to: check marked yes Databricks SQL check marked yes Databricks Runtime

This command repairs or modifies partitions for non-Delta Lake tables. Use the SYNC METADATA clause with Delta Lake to update the catalog service based on table metadata, or to generate Iceberg metadata for tables enabled for Iceberg reads.

Supported functionality differs between Unity Catalog and Hive metastore and whether tables are backed by Delta Lake.

Syntax

[ MSCK ] REPAIR TABLE table_name
{
    [ {ADD | DROP | SYNC} PARTITIONS] | SYNC METADATA
}

For check marked yes Databricks SQL check marked yes Databricks Runtime 12.2 LTS and above, MSCK is optional.

Parameters

  • table_name

    The name of the table. If the table cannot be found Azure Databricks raises a TABLE_OR_VIEW_NOT_FOUND error.

  • ADD or DROP or SYNC PARTITIONS

    Applies to: check marked yes Databricks SQL check marked yes Databricks Runtime 10.4 LTS and above

    When creating a non-Delta table using the PARTITIONED BY clause, partitions are generated and registered in the Hive metastore. However, if you create the partitioned table from existing data, partitions are not registered automatically in the Hive metastore. Run MSCK REPAIR TABLE to register the partitions.

    Another way to recover partitions is to use ALTER TABLE RECOVER PARTITIONS.

    If the table is cached, the command clears the table’s cached data and all dependents that refer to it. The cache fills the next time the table or dependents are accessed.

    • ADD command adds new partitions to the session catalog for all sub-folders in the base table folder that don’t belong to any table partitions. ADD is the default argument if no other option is specified.
    • DROP command drops all partitions from the session catalog that have non-existing locations in the file system.
    • SYNC is the combination of DROP and ADD.

  • SYNC METADATA

    Delta Lake only.

    Reads the transaction log of the target table and updates the metadata info in the catalog service. To run this command, you must have MODIFY and SELECT privileges on the target table and USE SCHEMA and USE CATALOG privileges on the parent schema and catalog.

    This argument works with Hive metastore in Databricks Runtime 16.1 and above. For Hive metastore tables, you must have USAGE and MODIFY privileges.

    If Delta UniForm is enabled (requires Unity Catalog), SYNC METADATA triggers manual conversion of current Delta metadata to Iceberg metadata and syncs the latest Iceberg version for the Unity Catalog Iceberg endpoint. See Use UniForm to read Delta tables with Iceberg clients.

Examples (non-Delta Lake tables)

-- 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

Example (Unity Catalog table)

-- run MSCK REPAIR TABLE t1 SYNC METADATA to update the metadata info to Unity Catalog service
> MSCK REPAIR TABLE t1 SYNC METADATA