Metadata Access Service Quick Reference

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Metadata Access Service FAQs

Why do I create a Metadata Access Service?: The Metadata Access Service allows the Developer tool to access Hadoop connection information and to import and preview metadata from a Hadoop distribution.

Can I create multiple Metadata Access Services in a domain?: Yes. If you have multiple Hadoop distributions configured in your domain, Informatica recommends creating a separate Metadata Access Service for each Hadoop distribution.

Can I use a single Metadata Access Service for multiple Hadoop distributions?: Yes. You need to recycle the service to use it for a different Hadoop distribution. However, Informatica does not recommend using a single Metadata Access Service for multiple Hadoop distributions. If you use a common Metadata Access Service instance for different Hadoop distributions, you might face exceptions.

How can I associate a Metadata Access Service with a particular Hadoop distribution?: Set the HadoopDistribution custom property to associate a Metadata Access Service with a particular Hadoop distribution.
In Informatica Administrator, click the
Manage
tab >
Services and Nodes
view.
In the Domain Navigator, select the Metadata Access Service.
Click the
Processes
tab.
Click
Custom Properties
. The
Edit Custom Properties
dialog box appears.
Click
New
to add the
HadoopDistribution
custom property.
ExecutionContextOptions.HadoopDistribution=<distribution>_<version>

For example,
ExecutionContextOptions.HadoopDistribution=CDH_5.13

Recycle the Metadata Access Service.

How can I import metadata from multiple Hadoop distributions?: Ensure that your Informatica administrator creates a separate Metadata Access Service instance for each Hadoop distribution. Select a different Metadata Access Service from the Preferences page before starting the import process.

If I upgrade from previous versions of Informatica to Informatica 10.2.1, will the existing HBase, HDFS, Hive, MapR-DB, and MapRStreams mappings continue to work?: The existing mappings without any modification will continue to work. If you re-import the source or target objects, make sure that a Metadata Access Service exists to import and preview metadata successfully.

I am unable to import metadata for a local complex file even if a Metadata Access Service exists in the domain.: When you import a complex file of Avro or Parquet, the imported object includes the metadata associated with the distribution in the Hadoop environment. If the file is local or the file resides on the Developer tool machine, the import process picks up the distribution information from the
developerCore.ini
file. You must edit the
developerCore.ini
file to point to the distribution directory on the Developer tool machine. You can find the
developerCore.ini
file in the following directory:
<Informatica installation directory>\clients\DeveloperClient

Add the following property:

-DINFA_HADOOP_DIST_DIR=hadoop\<distribution>_<version>

For example,
-DINFA_HADOOP_DIST_DIR=hadoop\mapr_5.2.0

The following error appears when I create a Metadata Access Service:: [DOM_10079] Cannot start service <metadata_access_service_name> on any node specified for the service.

The port number you specified for the Metadata Access Service might be used by another service. Verify and update the port number. Restart the Metadata Access Service.