org.apache.hadoop.hive.metastore

Interface IMetaStoreSchemaInfo

All Known Implementing Classes:

MetaStoreSchemaInfo

@InterfaceAudience.Private
public interface IMetaStoreSchemaInfo

Defines the method which must be implemented to be used using schema tool to support metastore schema upgrades. The configuration hive.metastore.schema.info.class is used to create instances of this type by SchemaTool. Instances of this interface should be created using MetaStoreSchemaInfoFactory class which uses two Strings argument constructor to instantiate the implementations of this interface

Field Summary

Fields

Modifier and Type	Field and Description
static String	SQL_FILE_EXTENSION

Method Summary

Modifier and Type	Method and Description
String	generateInitFileName(String toVersion) Get the name of the script to initialize the schema for given version
String	getCreateUserScript() Get SQL script that will create the user and database for Metastore to use.
String	getHiveSchemaVersion() Get hive distribution schema version.
String	getMetaStoreSchemaVersion(HiveSchemaHelper.MetaStoreConnectionInfo metastoreDbConnectionInfo) Get the schema version from the backend database.
String	getMetaStoreScriptDir() Find the directory of metastore scripts
String	getPreUpgradeScriptName(int index, String scriptName) Get the pre-upgrade script for a given script name.
List<String>	getUpgradeScripts(String fromVersion) Get the list of sql scripts required to upgrade from the give version to current.
boolean	isVersionCompatible(String productVersion, String dbVersion) A dbVersion is compatible with hive version if it is greater or equal to the hive version.

Field Detail

SQL_FILE_EXTENSION

static final String SQL_FILE_EXTENSION

See Also:

Constant Field Values

Method Detail

getUpgradeScripts

List<String> getUpgradeScripts(String fromVersion)
                        throws HiveMetaException

Get the list of sql scripts required to upgrade from the give version to current.

Parameters:

fromVersion -

Returns:

Throws:

HiveMetaException

generateInitFileName

String generateInitFileName(String toVersion)
                     throws HiveMetaException

Get the name of the script to initialize the schema for given version

Parameters:

toVersion - Target version. If it's null, then the current server version is used

Returns:

Throws:

HiveMetaException

getCreateUserScript

String getCreateUserScript()
                    throws HiveMetaException

Get SQL script that will create the user and database for Metastore to use.

Returns:

filename

Throws:

HiveMetaException - if something goes wrong.

getMetaStoreScriptDir

String getMetaStoreScriptDir()

Find the directory of metastore scripts

Returns:

the path of directory where the sql scripts are

getPreUpgradeScriptName

String getPreUpgradeScriptName(int index,
                               String scriptName)

Get the pre-upgrade script for a given script name. Schema tool runs the pre-upgrade scripts returned by this method before running any upgrade scripts. These scripts could contain setup statements may fail on some database versions and failure is ignorable.

Parameters:

index - - index number of the file. The preupgrade script name is derived using the given index

scriptName - - upgrade script name

Returns:

name of the pre-upgrade script to be run before running upgrade script

getHiveSchemaVersion

String getHiveSchemaVersion()

Get hive distribution schema version. Schematool uses this version to identify the Hive version. It compares this version with the version found in metastore database to determine the upgrade or initialization scripts

Returns:

Hive schema version

getMetaStoreSchemaVersion

String getMetaStoreSchemaVersion(HiveSchemaHelper.MetaStoreConnectionInfo metastoreDbConnectionInfo)
                          throws HiveMetaException

Get the schema version from the backend database. This version is used by SchemaTool to to compare the version returned by getHiveSchemaVersion and determine the upgrade order and scripts needed to upgrade the metastore schema

Parameters:

metastoreDbConnectionInfo - Connection information needed to connect to the backend database

Returns:

Throws:

HiveMetaException - when unable to fetch the schema version

isVersionCompatible

boolean isVersionCompatible(String productVersion,
                            String dbVersion)

A dbVersion is compatible with hive version if it is greater or equal to the hive version. This is result of the db schema upgrade design principles followed in hive project. The state where db schema version is ahead of hive software version is often seen when a 'rolling upgrade' or 'rolling downgrade' is happening. This is a state where hive is functional and returning non zero status for it is misleading.

Parameters:

productVersion - version of hive software

dbVersion - version of metastore rdbms schema

Returns:

true if versions are compatible