THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
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Configuration values specific to running the Metastore with various RDBMSs, embedded or as a service, and without Hive are discussed in the relevant sections. The following configuration values apply to the Metastore regardless of how it is being run. This table covers only commonly customized configuration values. For less commonly changed configuration values see Less Commonly Changed Configuration Parameters.
| Parameter | Hive 2 .0 Parameter | Default Value | Description |
|---|---|---|---|
| metastore.warehouse.dir | hive.metastore.warehouse.dir | URI of the default location for tables in the default catalog and database. | |
| datanucleus.schema.autoCreateAll | datanucleus.schema.autoCreateAll | false | Auto creates the necessary schema in the RDBMS at startup if one does not exist. Set this to false after creating it once. To enable auto create also set hive.metastore.schema.verification=false. Auto creation is not recommended in production; run |
| metastore.schema.verification | hive.metastore.schema.verification | true | Enforce metastore schema version consistency. When set to true: verify that version information stored in is compatible with the version of the Metastore jar. Also disable automatic schema migration. Users are required to manually migrate the schema after upgrade, which ensures proper schema migration. |
| metastore.hmshandler.retry.attempts | hive.hmshandler.retry.attempts | 10 | The number of times to retry a call to the meastore when there is a connection error. |
| metastore.hmshandler.retry.interval | hive.hmshandler.retry.interval | 2 sec | Time between retry attempts. |
| metastore.log4j.file | hive.log4j.file | none | Log4j configuration file. If unset will look for metastore-log4j2.properties in $METASTORE_HOME/conf |
| metastore.stats.autogather | hive.stats.autogather | true | Whether to automatically gather basic statistics during insert commands. |
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Except in the case of HiveServer2, using this mode does raise raises a few concerns. First, having many clients will put a burden on the backing RDBMS since each client will have its own set of connections.
Security Considerations
Metastore Server
javax.jdo.option.ConnectionURL | JDBC connection string for the data store which contains metadata |
javax.jdo.option.ConnectionDriverName | JDBC Driver class name for the data store which contains metadata |
hive.metastore.uris |
THRIFT_URI_SELECTIONStarting and Stopping the Service
Remember to discuss command line options like defining a configuration value
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. Second, every client must have read/write access to the RDBMS. This makes it hard to properly secure the RDBMS. Therefore embedded mode is not recommended in production use cases with the exception of HiveServer2.
Metastore Server
To run the Metastore as a service, you must first configure it with a URL.
| Configured On | Parameter | Hive 2 Parameter | Format | Default Value | Comment |
|---|---|---|---|---|---|
| Client | metastore.thrift.uris | hive.metastore.uris | thrift://<HOST>:<PORT>[, thrift://<HOST>:<PORT>...] | none | HOST = hostname, PORT = port, default is 9083. |
| Server | metastore.thrift.port | hive.metastore.port | integer | 9083 | Port Thrift will listen on. |
Once you have configured your clients, you can start the Metastore on a server using the start-metastore utility. See the -help option of that utility for available options. There is no stop-metastore script. Instead you must locate the process id for the metastore and kill that process.
High Availability
The Metastore service is stateless. This allows you to start multiple instances the service to provide for high availability. It also allows you to configure some clients to embed the metastore (e.g. HiveServer2) while still running a Metastore service for other clients. If you are running multiple Metastore services you can put all their URIs into your client's metastore.thrift.uris value and then set metastore.thrift.uri.selection ( in Hive 2 hive.metastore.uri.selection) to RANDOM or SEQUENTIAL. RANDOM will cause your client to randomly select one of the servers in the list, while SEQUENTIAL will cause it to start at the beginning of the list and attempt to connect to each server in order.
Securing the Service
CLIENT_KERBEROS_PRINCIPAL, KERBEROS_*, SSL*, USE_SSL, USE_THRIFT_SASL
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