Databricks Delta Lake Hadoop Hive Database (HCatalog and Metastore via JDBC) - Import
Bridge Requirements
This bridge:requires Internet access to https://repo.maven.apache.org/maven2/ and/or other tool sites to download drivers into <TDC_HOME>/data/download/MIMB/.
Bridge Specifications
| Vendor | Databricks |
| Tool Name | Delta Lake Hadoop Hive Database |
| Tool Version | Hive 2.x to 3.x - Azure Databricks 8.x to 9.x |
| Tool Web Site | https://databricks.com/product/delta-lake-on-databricks |
| Supported Methodology | [Relational Database] Multi-Model, Data Store (Physical Data Model) via JDBC API |
| Data Profiling |  |
| Incremental Harvesting | |
| Multi-Model Harvesting | |
| Remote Repository Browsing for Model Selection | |
SPECIFICATIONS
Tool: Databricks / Delta Lake Hadoop Hive Database version Hive 2.x to 3.x - Azure Databricks 8.x to 9.x via JDBC API
See https://databricks.com/product/delta-lake-on-databricks
Metadata: [Relational Database] Multi-Model, Data Store (Physical Data Model)
Component: ApacheHiveImport.Databricks version 11.2.0
DISCLAIMER
This import bridge requires internet access to download third-party libraries:
- such as https://repo.maven.apache.org/maven2/ to download open source third-party libraries,
- and more sites for other third-party software such as database specific JDBC drivers.
The downloaded third-party libraries are stored into $HOME/data/download/MIMB/
- If HTTPS fails, the import bridge then tries with HTTP.
- If a proxy is used to access internet, you must configure that proxy in the JRE (see the -j option in the Miscellaneous parameter).
- If the import bridge does not have full access to internet, that $HOME/data/download/MIMB/ directory can be copied from another server with internet access where the command $HOME/bin/MIMB.sh (or .bat) -d can be used to download all third-party libraries used by all bridges at once.
By running this import bridge, you hereby acknowledge responsibility for the license terms and any potential security vulnerabilities from these downloaded third-party software libraries.
OVERVIEW
IMPORTING FROM MAPR HIVE USING JDBC.
This bridge establishes a JDBC connection to the Databricks Hive server in order to extract the physical metadata. In case of a very large Hive database, this bridge can also establish a JDBC connection to the Hive Metastore server (see all parameter names starting with Metastore) in order to accelerate the extraction of the physical metadata.
REQUIREMENTS
If you have custom SerDe for one or more of your tables, then they should be part of the Hive class path. You can add them to HIVE_HOME/lib directory so it is picked up automatically.
In order to successfully import the Databricks Metastore, the bridge requires a proper driver to connect with the Metastore database, please employ the SQL Server JDBC driver.
PERMISSIONS
- Databricks Cloud Authentication:
To connect to Databricks on Azure, Amazon Web Services or Google Cloud Platform, get the Server Hostname and HTTP Path cluster connection details and specify them in the URL parameter by following the syntax below:
jdbc:databricks://<Server Hostname>:443;HttpPath=<Http Path>[;property=value[;property=value]]
How to retrieve the connection details in order to connect with Azure Databricks: https://learn.microsoft.com/en-us/azure/databricks/integrations/jdbc-odbc-bi#--retrieve-the-connection-details
- Personal Access Token (PAT) Authentication:
To connect with Databricks on any cloud specify a Databricks PAT (Personal Access Token) in the Password parameter and "AuthMech=3;UID=token" connection details in the URL parameter. E.g.
URL=jdbc:databricks://<Server Hostname>:443;HttpPath=<Http Path>;AuthMech=3;UID=token
Password=<Databricks Personal Access Token>
How to retrieve the connection details in order to connect with Azure Databricks personal access token(s) manually: https://learn.microsoft.com/en-us/azure/databricks/dev-tools/auth#--azure-databricks-personal-access-tokens
- Azure Active Directory Token Authentication:
To instruct the bridge to authenticate with Databricks using Azure Active Directory automatically and manually:
You must specify "AuthMech=11" in the URL parameter and use JDBC drivers 2.6.15 and above. E.g.
URL=jdbc:databricks://<Server Hostname>:443;HttpPath=<Http Path>;AuthMech=11
Automatic Method
The automatic method is available when you run the bridge from a Data Catalog instance and use it to specify the Azure Cloud Identity for authentication. The identity must have the appropriate permissions to connect and read metadata from Azure Databricks. See https://learn.microsoft.com/en-us/azure/databricks/integrations/jdbc-odbc-bi#requirements
Data Catalog uses the Azure Cloud Identity to generate a temporary access token that passes to the bridge using __$Secret_Azure_AccessToken_Databricks hidden bridge parameter.
To use the automatic method, leave the Password parameter empty. E.g.
Password=
Manual Method
To authenticate with Azure Databricks using Azure Active Directory by specifying an Azure Active Directory Token in the Password parameter. E.g.
Password=<Azure Active Directory Token>
The manual method requires generating an Azure Active Directory access token. How to: https://learn.microsoft.com/en-us/azure/databricks/dev-tools/api/latest/aad/app-aad-token#get-token.
The Azure Active Directory access token has a default lifetime of 1 hour. See the JDBC driver installation guide for instructions about how to refresh the token https://learn.microsoft.com/en-us/azure/databricks/integrations/jdbc-odbc-bi#jdbc-driver-guide (See section Configuring Authentication > Using OAuth 2.0).
In case of the MariaDB database as an external metastore:
The user should have SELECT permission granted for metastore database that this bridge queries metadata from:
grant SELECT on <database_name>.* to <user_name>;
flush privileges;
FREQUENTLY ASKED QUESTIONS
Q: How do I test/debug the Windows JDBC client connection to a secured (e.g. Kerberos) Hadoop Hive server?
A: In order to establish connection to a secured (e.g. Kerberos) Hadoop Hive server, you must use the proper Hadoop distribution vendor specific URL (parameter URL), and the security related parameters of this bridge (Kerberos configuration file, Keytab file, user proxy, and Miscellaneous). Follow the instructions within each of these parameter's tooltips.
In order to test/debug the connectivity to a secured (e.g. Kerberos) Hadoop Hive server, you must have access to all the Hadoop server and Kerberos messages which are not always transmitted to the user interface. Therefore, you can use the utility provided at '${MODEL_BRIDGE_HOME}\bin\hive_test.bat'. Edit that batch file to provide similar parameters, and run that script to analyze the Hadoop Hive server and Kerberos messages.
LIMITATIONS
Refer to the current general known limitations at https://metaintegration.com/Products/MIMB/Help/#!Documents/mimbknownlimitations.html
If Hive cannot find the custom serializer for a given table, then it will throw an exception and the bridge will skip reading metadata for that table.
SUPPORT
Provide a troubleshooting package with:
- the debug log (can be set in the UI or in conf/conf.properties with MIR_LOG_LEVEL=6)
- the metadata backup if available (can be set in the Miscellaneous parameter with -backup option, although this common option is not implemented on all bridges for technical reasons).
Bridge Parameters
| Parameter Name | Description | Type | Values | Default | Scope |
| Java library directory | Directory containing JAR files necessary to access HiveServer2: - JDBC driver JAR files specific for the Hadoop distribution - Hadoop client JAR files (when using Kerberos secure mode. Usually available at /usr/lib/hadoop/client) - Java Cryptography Extension JAR files (when using high strength encryption. Usually available at Oracle Java website) - 'bin' directory with winutils.exe to avoid non-critical exceptions when running on Windows without Hadoop installed Generic Apache Hive documentation for HiveServer2 JDBC Clients connectivity: https://cwiki.apache.org/confluence/display/Hive/HiveServer2+Clients#HiveServer2Clients-RunningtheJDBCSampleCode |
DIRECTORY | |||
| URL | Enter the JDBC URL where Hive server is running, e.g. jdbc:hive://COMPUTER_NAME_OR_IP:10000 OR jdbc:hive2://COMPUTER_NAME_OR_IP:10000 |
STRING | jdbc:hive2://hostname:portNumber/ | ||
| User | The Hive username on whose behalf the connection is being made. Refer to the PERMISSIONS section of this import bridge's main documentation. |
STRING | |||
| Password | The Hive user's password on whose behalf the connection is being made. | PASSWORD | |||
| SerDe jars list | This option may be used to specify a semicolon separated list of fully qualified path names to the SerDe jars the bridge will use to execute remotely on the Hive system. | STRING | |||
| Kerberos configuration file | To overwrite Kerberos configuration at the client side. E.g. /etc/krb5/krb5.conf |
STRING | |||
| Keytab file | In the case where Kerberos is used for Hive authentication, this option may be used to specify the fully qualified path name to the Kerberos keytab file. E.g. /etc/security/keytabs/hive.service.keytab |
STRING | |||
| User proxy | In the case where Kerberos is used for Hive authentication, this option may be used to specify a proxy user or group name. | STRING | |||
| Metastore JDBC driver location | Specify valid JARs folder location. All JARs will be added to the CLASSPATH from this folder. | DIRECTORY | |||
| Metastore JDBC driver class* | Please copy/paste here 'javax.jdo.option.ConnectionDriverName' value from your hive-site.xml Usually, this file is located in '/etc/alternatives/hive-conf' or in an another place depending on your Hadoop/Hive configuration, e.g. com.mysql.jdbc.Driver |
STRING | |||
| Metastore JDBC URL* | Please find 'javax.jdo.option.ConnectionURL' value from your hive-site.xml and define connection to DB server (MySQL, PostgreSQL, etc.) URL (Example:jdbc:mysql://127.0.0.1) Usually, this file is located in '/etc/alternatives/hive-conf' or in an another place depending on your Hadoop/Hive configuration It is recommended to specify the database name in the URL. |
STRING | |||
| Metastore database name | This option is used for backwards compatibility only. Please provide the Hive Metastore database name in 'Metastore JDBC URL*' |
STRING | |||
| Metastore user | The Hive Metastore database username on whose behalf the connection is being made. USER PERMISSIONS This bridge needs a user with (read only) access to 'metastore' database. Here is the MySQL example: GRANT SELECT ON metastore.* TO 'user'@'%'; |
STRING | |||
| Metastore password | The Hive Metastore database user's password on whose behalf the connection is being made. | PASSWORD | |||
| Multiple threads | Number of worker threads to harvest metadata asynchronously. - Leave the parameter blank to have the import bridge compute the value, between 1 and 6, based on JVM architecture and number of available CPU cores. - Specify a numeric value greater or equal to 1 to provide the actual number of threads. If the value specified is invalid, a warning will be issued and 1 will be used instead. If you experience out of memory conditions when harvesting metadata asynchronously, experiment with smaller numbers. If your machine has a lot of available memory (e.g. 10 GB or more), you can try larger numbers when harvesting many documents at once. Note that setting the number too high can actually decrease the performance due to resource contention. |
NUMERIC | |||
| Schema | Specify a list of Hive schemas to import. When the list is empty, all available schemas are imported. The list can have one or more schema names separated by semicolons (e.g. schema1; schema2). You can specify schema name patterns using '%' wildcard symbol or 'NOT' keyword. Patterns support inclusions and exclusions. Here is an example of inclusion syntax, "A%; %B; %C%; D" that tries to get schema names that: - start with A or - end with B or - contain C or - equal D To exclude a pattern, prefix it with 'NOT'. Here is an example of exclusion syntax, "A%; NOT %def" that imports schemas with name started with 'A' and not ended with 'def' As the list of schemas can become a long string, it is possible to load it from a file which must be located in ${MODEL_BRIDGE_HOME}\data\MIMB\parameters and have the extension .txt. In such case, all schemas must be defined within that file as the only value of this parameter, e.g. HIVE/ListOfSchema.txt |
REPOSITORY_SUBSET | |||
| Table | Specify a list of Hive tables to import. When the list is empty, all available tables are imported. The list can have one or more table names separated by semicolons (e.g. sample_07; sample_08). You can specify table name patterns using '%' wildcard symbol or 'NOT' keyword. Patterns support inclusions and exclusions. Here is an example of inclusion syntax, "A%; %B; %C%; D" that tries to get table names that: - start with A or - end with B or - contain C or - equal D To exclude a pattern, prefix it with 'NOT'. Here is an example of exclusion syntax, "A%; NOT %def" that imports tables with name started with 'A' and not ended with 'def' |
STRING | |||
| Miscellaneous | INTRODUCTION Specify miscellaneous options starting with a dash and optionally followed by parameters, e.g. -connection.cast MyDatabase1="MICROSOFT SQL SERVER" Some options can be used multiple times if applicable, e.g. -connection.rename NewConnection1=OldConnection1 -connection.rename NewConnection2=OldConnection2; As the list of options can become a long string, it is possible to load it from a file which must be located in ${MODEL_BRIDGE_HOME}\data\MIMB\parameters and have the extension .txt. In such case, all options must be defined within that file as the only value of this parameter, e.g. ETL/Miscellaneous.txt JAVA ENVIRONMENT OPTIONS -java.memory <Java Memory's maximum size> (previously -m) 1G by default on 64bits JRE or as set in conf/conf.properties, e.g. -java.memory 8G -java.memory 8000M -java.parameters <Java Runtime Environment command line options> (previously -j) This option must be the last one in the Miscellaneous parameter as all the text after -java.parameters is passed "as is" to the JRE, e.g. -java.parameters -Dname=value -Xms1G The following option must be set when a proxy is used to access internet (this is critical to access https://repo.maven.apache.org/maven2/ and exceptionally a few other tool sites) in order to download the necessary third-party software libraries. Note: The majority of proxies are concerned with encrypting (HTTPS) the outside (of the company) traffic and trust the inside traffic that can access proxy over HTTP. In this case, an HTTPS request reaches the proxy over HTTP where the proxy HTTPS-encrypts it. -java.parameters -java.parameters -Dhttp.proxyHost=127.0.0.1 -Dhttp.proxyPort=3128 -Dhttp.proxyUser=user -Dhttp.proxyPassword=pass MODEL IMPORT OPTIONS -model.name <model name> Override the model name, e.g. -model.name "My Model Name" -prescript <script name> This option allows running a script before the bridge execution. The script must be located in the bin directory (or as specified with M_SCRIPT_PATH in conf/conf.properties), and have .bat or .sh extension. The script path must not include any parent directory symbol (..). The script should return exit code 0 to indicate success, or another value to indicate failure. For example: -prescript "script.bat arg1 arg2" -postscript <script name> This option allows running a script after successful execution of the bridge. The script must be located in the bin directory (or as specified with M_SCRIPT_PATH in conf/conf.properties), and have .bat or .sh extension. The script path must not include any parent directory symbol (..). The script should return exit code 0 to indicate success, or another value to indicate failure. For example: -postscript "script.bat arg1 arg2" -cache.clear Clears the cache before the import, and therefore will run a full import without incremental harvesting. If the model was not changed and the -cache.clear parameter is not used (incremental harvesting), then a new version will not be created. If the model was not changed and the -cache.clear parameter is set (full source import instead of incremental), then a new version will be created. -backup <directory> Allows to save the input metadata for further troubleshooting. The provided <directory> must be empty. -restore <directory> Specify the backup <directory> to be restored. DATA CONNECTION OPTIONS Data Connections are produced by the import bridges typically from ETL/DI and BI tools to refer to the source and target data stores they use. These data connections are then used by metadata management tools to connect them (metadata stitching) to their actual data stores (e.g. databases, file system, etc.) in order to produce the full end to end data flow lineage and impact analysis. The name of each data connection is unique by import model. The data connection names used within DI/BI design tools are used when possible, otherwise connection names are generated to be short but meaningful such as the database / schema name, the file system path, or Uniform Resource Identifier (URI). The following option allows to manipulate connections. These options replaces the legacy options -c, -cd, and -cs. -connection.cast ConnectionName=ConnectionType Casts a generic database connection (e.g. ODBC/JDBC) to a precise database type (e.g. ORACLE) for SQL Parsing, e.g. -connection.cast "My Database"="MICROSOFT SQL SERVER". The list of supported data store connection types includes: ACCESS APACHE CASSANDRA DB2/UDB DENODO GOOGLE BIGQUERY HIVE MYSQL NETEZZA ORACLE POSTGRESQL PRESTO REDSHIFT SALESFORCE SAP HANA SNOWFLAKE MICROSOFT SQL AZURE MICROSOFT SQL SERVER SYBASE SQL SERVER SYBASE AS ENTERPRISE TERADATA VECTORWISE HP VERTICA -connection.rename OldConnection=NewConnection Renames an existing connection to a new name, e.g. -connection.rename OldConnectionName=NewConnectionName Multiple existing database connections can be renamed and merged into one new database connection, e.g. -connection.rename MySchema1=MyDatabase -connection.rename MySchema2=MyDatabase -connection.split oldConnection.Schema1=newConnection Splits a database connection into one or multiple database connections. A single database connection can be split into one connection per schema, e.g. -connection.split MyDatabase All database connections can be split into one connection per schema, e.g. -connection.split * A database connection can be explicitly split creating a new database connection by appending a schema name to a database, e.g. -connection.split MyDatabase.schema1=MySchema1 -connection.map SourcePath=DestinationPath Maps a source path to destination path. This is useful for file system connections when different paths points to the same object (directory or file). On Hadoop, a process can write into a CSV file specified with the HDFS full path, but another process reads from a Hive table implemented (external) by the same file specified using a relative path with default file name and extension, e.g. -connection.map /user1/folder=hdfs://host:8020/users/user1/folder/file.csv On Linux, a given directory (or file) like /data can be referred to by multiple symbolic links like /users/john and /users/paul, e.g. -connection.map /data=/users/John -connection.map /data=/users/paul On Windows, a given directory like C:\data can be referred to by multiple network drives like M: and N:, e.g. -connection.map C:\data=M:\ -connection.map C:\data=N:\ -connection.casesensitive ConnectionName... Overrides the default case insensitive matching rules for the object identifiers inside the specified connection, provided the detected type of the data store by itself supports this configuration (e.g. Microsoft SQL Server, MySql etc.), e.g. -connection.casesensitive "My Database" -connection.caseinsensitive ConnectionName... Overrides the default case sensitive matching rules for the object identifiers inside the specified connection, provided the detected type of the data store by itself supports this configuration (e.g. Microsoft SQL Server, MySql etc.), e.g. -connection.caseinsensitive "My Database" -connection.level AggregationLevel Specifies the aggregation level for the external connections, e.g.-connection.level catalog The list of the supported values: server catalog schema (default) HIVE OPTIONS -i Import Indexes. -d Enables the Kerberos Debugging mode that allows you to follow the bridge execution of the Kerberos V5 protocol. The bridge sets the system property sun.security.krb5.debug to "true". When you have a Kerberos configuration issue please enable the -d option and send the execution log to support. -location.skip Disables tables connections to external files -location.pattern <Hive location-based partition directories paths> The bridge tries to detect partitions automatically for standard partitions locations when the location contains the Hive table name and partitions names. You can extend the detection process for some or all partitions by specifying them in this parameter. Specify the Hive partition locations pattern. Separate multiple paths with the, (or ;) character. The following example will create an employee dataset even if the employee has any other folders. -location.pattern hdfs://localhost:9000/user/hive/warehouse/employee -partition.import Imports all table partitions locations into a table merged location. -partition.allsamples Imports all table partitions locations samples into [PartitionLocationsWithSamples] property -tblproperties.skip Do not import (skip) table properties (like CreationTime, SerDe Library, or numRows that change when data changes) that are independent of the structural metadata of the table. Skipping such volatile table properties (like operational metadata) will prevent over-detection of changes and provide more efficient incremental harvesting. -model.split (previously -multiModel) Splits a large database model into multi models (e.g. one schema per model). Warning: this is a system option managed by the application calling this import bridge and should not be set by users. |
STRING |
Bridge Mapping
| Meta Integration Repository (MIR) Metamodel (based on the OMG CWM standard) |
"Databricks Delta Lake Hadoop Hive Database (HCatalog and Metastore via JDBC)" Metamodel Apache Hive (Database) |
Mapping Comments |
| Attribute | Column, Partition Column | Columns which are part of the partition on the table. |
| Comment | Comment | |
| Description | Description | |
| ExtraConstraint | Constraint | |
| InitialValue | Initial Value | |
| Name | Name | |
| NativeId | Native Id | |
| Optional | Nullable | |
| Position | Position | |
| Class | Table | |
| Comment | Comment | |
| Description | Description | |
| Name | Name | |
| NativeId | Native Id | |
| ClassDiagram | Diagram | |
| Description | Description | |
| Name | Name | |
| ConnectionPackage | HDFS Folder | |
| Description | Description | |
| Name | Name | |
| DatabaseSchema | Database | |
| Comment | Comment | |
| Description | Description | |
| Name | Name | |
| NativeId | Native Id | |
| DesignPackage | Subject Area | |
| Description | Description | |
| Name | Name | |
| FlatTextFile | External File | |
| Description | Description | |
| Name | Name | |
| Index | Index, CLUSTERED | Clustered by or bucketed columns |
| Comment | Comment | |
| Description | Description | |
| Name | Name | |
| NativeId | Native Id | |
| Join | Logical Relationship | |
| Description | Description | |
| Name | Name | |
| SQLViewAttribute | View Column | |
| Comment | Comment | |
| Description | Description | |
| Name | Name | |
| NativeId | Native Id | |
| Position | Position | |
| SQLViewEntity | View | |
| Comment | Comment | |
| Description | Description | |
| Name | Name | |
| NativeId | Native Id | |
| ViewStatement | View Statement | |
| StoreConnection | External Tables Connections | |
| Description | Description | |
| Name | Name | |
| StoreModel | Hive Model | |
| Author | Author | |
| Comment | Comment | |
| CreationTime | Creation Time | |
| Description | Description | |
| ModificationTime | Modification Time | |
| Modifier | Modifier | |
| Name | Name | |
| NativeId | Native Id | |
| StoreType | Store Type | |
| SystemMajorVersion | System Major Version | |
| SystemMinorVersion | System Minor Version | |
| SystemReleaseVersion | System Release Version | |
| SystemType | System Type | |
| SystemTypeOld | System Type Old |