Apache Hadoop Hive Database (Hcatalog and Metastore via JDBC) - Import - 7.1

Talend Data Catalog Bridges

author
Talend Documentation Team
EnrichVersion
7.1
EnrichProdName
Talend Big Data Platform
Talend Data Fabric
Talend Data Management Platform
Talend Data Services Platform
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Talend Real-Time Big Data Platform
EnrichPlatform
Talend Data Catalog

Bridge Specifications

Vendor Apache
Tool Name Hadoop Hive Database
Tool Version Hive 2.x to 3.x
Tool Web Site http://hive.apache.org/
Supported Methodology [Relational Database] Multi-Model, Data Store (Physical Data Model) via JDBC API
Incremental Harvesting
Remote Repository Browsing for Model Selection
Data Profiling
Multi-Model Harvesting

SPECIFICATIONS
Tool: Apache / Hadoop Hive Database version Hive 2.x to 3.x via JDBC API
See http://hive.apache.org/
Metadata: [Relational Database] Multi-Model, Data Store (Physical Data Model)
Component: ApacheHive version 11.0.0

OVERVIEW
This bridge establishes a JDBC connection to the 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.

This bridge imports the database server metadata as multi models with one model per schema.
Further imports (incremental harvesting) will detect changes in schema to only import changed schemas (reusing already harvested unchanged schemas).
Note that schema change detection is only optimized (and therefore faster) when using the Hive Metastore JDBC connection (instead of direct Hive JDBC connection).

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 its picked up automatically.

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 tool tips.
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 http://metaintegration.com/Products/MIMB/MIMBKnownLimitations.html or bundled in Documentation/ReadMe/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.

Please note that when Kerberos is enabled in Mapr via Mapr Ticket, the ticket should be placed in /tmp and MAPR_HOME should be set to mapr drivers path and the user id (along with the group id) of the user who is running the bridge should match with the user id (along with the group id) of the user for which ticket is generated in the Mapr Cluster

SUPPORT
Provide a trouble shooting 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 option -backup)


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. 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 overwride Kerberos configuration at the client side. Example:
/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. Example:
/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 depends on you 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 depends on you Hadoop/Hive configuration
STRING      
Metastore Database name* Please check 'javax.jdo.option.ConnectionURL' value from your hive-site.xml to determine Hive Metastore Database name
Usually, this file is located in '/etc/alternatives/hive-conf'
or in an another place depending on you Hadoop/Hive configuration
STRING      
Metastore User The Hive Metastore database username on whose behalf the connection is being made. 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 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 '%' wilcard 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'

The list of schemas can be long, and possibly maintained by an external process. Therefore, it can be defined within a text file specified as the value of this parameter, e.g.
C:\Data\ListOfSchema.txt
In such case, all schemas must be defined within that file (with full path) as the only value of this parameter.
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 '%' wilcard 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 Specify miscellaneous options identified with a -option followed by a value if required:

GENERAL OPTIONS
-m <Java Memory's maximum size>
1G by default on 64bits JRE or as set in conf/conf.properties, e.g.
-m 8G
-m 8000M

-j <Java Runtime Environment command line options>
This option must be the last one in the Miscellaneous parameter as all the text after -j is passed "as is" to the JRE, e.g.
-j -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.
-j -Dhttp.proxyHost=127.0.0.1 -Dhttp.proxyPort=3128 -Dhttps.proxyHost=127.0.0.1 -Dhttps.proxyPort=3128 -Dhttp.proxyUser=user -Dhttp.proxyPassword=pass -Dhttps.proxyUser=user -Dhttps.proxyPassword=pass

-jre <Java Runtime Environment full path name>
It can be an absolute path to javaw.exe on Windows or a link/script path on Linux, e.g.
-jre "c:\Program Files\Java\jre1.8.0_211\bin\javaw.exe"

-v <Environment variable value>
None by default, e.g.
-v var1=value1 -v var2="value2 with spaces"

-model.name <model name>
Override the model name, e.g.
-model.name "My Model Name"

-prescript <script name>
The script must be located in the bin directory, 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"

-cache.clear
Clears the cache before the import, and therefore will run a full import without incremental harvesting.
Warning: this is a system option managed by the application calling the bridge and should not be set by users.

${BridgeLib.bp_misc_common_variable}

${BridgeLib.bp_misc_common_model_name}

${BridgeLib.bp_misc_common_prescript}

-backup <directory>
Full path of an empty directory to save the metadata input files for further troubleshooting.

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 extends 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 others 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.
STRING      

 

Bridge Mapping

Meta Integration Repository (MIR)
Metamodel
(based on the OMG CWM standard)
"Apache 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