org.apache.hadoop.hive.metastore.IMetaStoreSchemaInfo Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.hadoop.hive.metastore;
import java.sql.Connection;
import java.util.List;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.hive.metastore.tools.HiveSchemaHelper;
/**
* 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
*/
@InterfaceAudience.Private
public interface IMetaStoreSchemaInfo {
String SQL_FILE_EXTENSION = ".sql";
/***
* Get the list of sql scripts required to upgrade from the give version to current.
*
* @param fromVersion
* @return
* @throws HiveMetaException
*/
List getUpgradeScripts(String fromVersion) throws HiveMetaException;
/***
* Get the name of the script to initialize the schema for given version
*
* @param toVersion Target version. If it's null, then the current server version is used
* @return
* @throws HiveMetaException
*/
String generateInitFileName(String toVersion) throws HiveMetaException;
/**
* Get SQL script that will create the user and database for Metastore to use.
* @return filename
* @throws HiveMetaException if something goes wrong.
*/
String getCreateUserScript() throws HiveMetaException;
/**
* Find the directory of metastore scripts
*
* @return the path of directory where the sql scripts are
*/
String getMetaStoreScriptDir();
/**
* 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.
*
* @param index - index number of the file. The preupgrade script name is derived using the given
* index
* @param scriptName - upgrade script name
* @return name of the pre-upgrade script to be run before running upgrade script
*/
String getPreUpgradeScriptName(int index, String scriptName);
/**
* 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
* @return Hive schema version
*/
String getHiveSchemaVersion();
/**
* 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
*
* @param metastoreDbConnectionInfo Connection information needed to connect to the backend
* database
* @return
* @throws HiveMetaException when unable to fetch the schema version
*/
String getMetaStoreSchemaVersion(
HiveSchemaHelper.MetaStoreConnectionInfo metastoreDbConnectionInfo) throws HiveMetaException;
/**
* 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.
*
* @param productVersion version of hive software
* @param dbVersion version of metastore rdbms schema
* @return true if versions are compatible
*/
boolean isVersionCompatible(String productVersion, String dbVersion);
}