THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
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Metastore Schema Verification
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Hive now records the schema version in the metastore database and verifies that the metastore schema version is compatible with Hive binaries that are going to accesss the metastore. Note that the Hive properties to implicitly create or alter the existing schema are disabled by default. Hive will not attempt to change the metastore schema implicitly. When you execute a Hive query against an old schema, it will fail to access the metastore:
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$ build/dist/bin/hive -e "show tables"
FAILED: Execution Error, return code 1 from org.apache.hadoop.hive.ql.exec.DDLTask. java.lang.RuntimeException: Unable to instantiate org.apache.hadoop.hive.metastore.HiveMetaStoreClient
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The log will contain an error about version information not found:
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Caused by: MetaException(message:Version information not found in metastore. )
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The schematool command invokes the Hive schema tool with these options:
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$ schematool -help
usage: schemaTool
-dbType <databaseType> Metastore database type
-dryRun List SQL scripts (no execute)
-help Print this message
-info Show config and schema details
-initSchema Schema initialization
-initSchemaTo <initTo> Schema initialization to a version
-passWord <password> Override config file password
-upgradeSchema Schema upgrade
-upgradeSchemaFrom <upgradeFrom> Schema upgrade from a version
-userName <user> Override config file user name
-verbose Only print SQL statements
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derby|mysql|postgres|oracle |
Usage Examples
Initialize to current schema for a new Hive setup:
No Format $ schematool -dbType derby -initSchema Metastore connection URL: jdbc:derby:;databaseName=metastore_db;create=true Metastore Connection Driver : org.apache.derby.jdbc.EmbeddedDriver Metastore connection User: APP Starting metastore schema initialization to 0.13.0 Initialization script hive-schema-0.13.0.derby.sql Initialization script completed schemaTool completetedcompleted
Get schema information:
No Format $ schematool -dbType derby -info Metastore connection URL: jdbc:derby:;databaseName=metastore_db;create=true Metastore Connection Driver : org.apache.derby.jdbc.EmbeddedDriver Metastore connection User: APP Hive distribution version: 0.13.0 Metastore schema version: 0.13.0 schemaTool completetedcompleted
Attempt to get schema information with older metastore:
No Format $ schematool -dbType derby -info Metastore connection URL: jdbc:derby:;databaseName=metastore_db;create=true Metastore Connection Driver : org.apache.derby.jdbc.EmbeddedDriver Metastore connection User: APP Hive distribution version: 0.13.0 org.apache.hadoop.hive.metastore.HiveMetaException: Failed to get schema version. *** schemaTool failed ***Since the older metastore doesn't store the version information, the tool reports an error retrieving it.
Upgrade schema from an 0.10.0 release by specifying the 'from' version:
No Format $ schematool -dbType derby -upgradeSchemaFrom 0.10.0 Metastore connection URL: jdbc:derby:;databaseName=metastore_db;create=true Metastore Connection Driver : org.apache.derby.jdbc.EmbeddedDriver Metastore connection User: APP Starting upgrade metastore schema from version 0.10.0 to 0.13.0 Upgrade script upgrade-0.10.0-to-0.11.0.derby.sql Completed upgrade-0.10.0-to-0.11.0.derby.sql Upgrade script upgrade-0.11.0-to-0.12.0.derby.sql Completed upgrade-0.11.0-to-0.12.0.derby.sql Upgrade script upgrade-0.12.0-to-0.13.0.derby.sql Completed upgrade-0.12.0-to-0.13.0.derby.sql schemaTool completetedcompleted
Upgrade dry run can be used to list the required scripts for the given upgrade.
No Format $ build/dist/bin/schematool -dbType derby -upgradeSchemaFrom 0.7.0 -dryRun Metastore Connection Driver : org.apache.derby.jdbc.EmbeddedDriver Metastore connection User: APP Starting upgrade metastore schema from version 0.7.0 to 0.13.0 Upgrade script upgrade-0.7.0-to-0.8.0.derby.sql Upgrade script upgrade-0.8.0-to-0.9.0.derby.sql Upgrade script upgrade-0.9.0-to-0.10.0.derby.sql Upgrade script upgrade-0.10.0-to-0.11.0.derby.sql Upgrade script upgrade-0.11.0-to-0.12.0.derby.sql Upgrade script upgrade-0.12.0-to-0.13.0.derby.sql schemaTool completetedcompleted
This is useful if you just want to find out all the required scripts for the schema upgrade.