Starburst Hive connector#

The Starburst Hive connector is an extended version of the Hive Connector with configuration and usage identical.

Note

The additional features of the connector require a valid Starburst Enterprise license, unless otherwise noted.

The following improvements are included:

Authorization options#

SEP includes provides several authorization options for use with the Hive connector:

HDFS permissions#

Before running any CREATE TABLE or CREATE TABLE ... AS statements for Hive tables in SEP, you need to check that the operating system user running the SEP server has access to the Hive warehouse directory on HDFS.

The Hive warehouse directory is specified by the configuration variable hive.metastore.warehouse.dir in hive-site.xml, and the default value is /user/hive/warehouse. If that is not the case, either add the following to jvm.config on all of the nodes: -DHADOOP_USER_NAME=USER, where USER is an operating system user that has proper permissions for the Hive warehouse directory, or start the SEP server as a user with similar permissions. The hive user generally works as USER, since Hive is often started with the hive user. If you run into HDFS permissions problems on CREATE TABLE ... AS, remove /tmp/presto-* on HDFS, fix the user as described above, then restart all of the SEP servers.

Storage caching#

The connector supports the default storage caching. In addition, if HDFS Kerberos authentication is enabled in your catalog properties file with the following setting, caching takes the relevant permissions into account and operates accordingly:

hive.hdfs.authentication.type=KERBEROS

Additional configuration for Kerberos is required.

If HDFS Kerberos authentication is enabled, you can also enable user impersonation using:

hive.hdfs.impersonation.enabled=true

The service user assigned to SEP needs to be able to access data files in underlaying storage. Access permissions are checked against impersonated user, yet with caching in place, some read operations happen in context of system user.

Any access control defined with the integration of Apache Ranger or the Privacera platform is also enforced by the storage caching.

Amazon Glue support#

Statistics collection is supported for Hive Metastore and Amazon Glue.

Configuring and using SEP with AWS Glue is described in the AWS Glue support documentation section.

Cloudera compatibility matrix#

The Starburst Hive connector can query the Cloudera Data Platform (CDP), available as version 7.x. It also supports the predecessor Cloudera Distributed Hadoop (CDH) platform, available in versions 5.x and 6.x. Support and compatibility vary based on the version you use, and is detailed in the following table:

CDP/CDH and SEP compatibility matrix#

Cloudera version

350-e

345-e

338-e

332-e

CDP 7

Yes

Yes

Yes

Yes

CDH 6.x

Yes

Yes

Yes

Yes

CDH 5.14+

Yes

Yes

Yes

Yes

CDH 5.13

Yes

Yes

Yes

Yes

CDP 5.12 and lower

No

No

No

No

The following details apply for CDH 6.x users:

  • reading tables and data files created by CDH 6.x is supported

  • transactional table usage is not supported

  • CDH 6.x Hive cannot read ORC files created by SEP, due to the behavior of the included Hive version

  • using the included Apache Sentry is not supported

The following details apply for CDH 5.x users:

  • reading tables and data files created by CDH 5.x is supported

  • transactional table usage is not supported

Working with Hive views#

Hive views are defined in Hive QL and stored in the Hive Metastore Service. They analyzed to allow read access to the data.

The Hive connector includes support for reading Hive views with three different modes.

  • disabled

  • legacy

  • experimental

You can configure the behavior in your catalog properties file.

disabled

The default behavior is to ignore Hive views. This means that your business logic and data encoded in the views is not available in PrestoSQL.

legacy

A very simple implementation to execute Hive views, and therefore allow read access to the data in PrestoSQL, can be enabled with hive.translate-hive-views=true and hive.legacy-hive-view-translation=true.

This legacy behavior interprets any Hive QL query that defines a view as if it is written in SQL. It does not do any translation, but instead relies on the fact that Hive QL is very similar to SQL.

This works for very simple Hive views, but can lead to problems for more complex queries. For example, if a Hive QL function has an identical signature but different behaviors to the SQL version, the returned results may differ. In more extreme cases the queries might fail, or not even be able to be parsed and executed.

experimental

The new behavior is better engineered, and has the potential to become a lot more powerful than the legacy implementation. It can analyze, process, and rewrite Hive views and contained expressions and statements.

It is considered an experimental feature and continues to change with each release. However it is already suitable for many use cases, and usage is encouraged.

You can enable the experimental behavior with hive.translate-hive-views=true.

Keep in mind that numerous features are not yet implemented when experimenting with this feature. The following is an incomplete list of missing functionality:

  • Hive QL current_date, current_timestamp, and others

  • Hive function calls including translate(), window functions and others

  • Common table expressions and simple case expressions

  • Honor timestamp precision setting

  • Support all Hive data types and correct mapping to PrestoSQL types

  • Ability to process custom UDFs

Limitations#

The following limitation apply in addition to the limitations of the Hive Connector.

  • Writing to and creation of transactional tables is not supported.

  • Reading ORC ACID tables created with Hive Streaming ingest is not supported.

  • For security reasons, sys system catalog is not accessible in SEP.

  • Hive’s timestamp with local zone data type is not supported in SEP. It is possible to read from a table having a column of this type, but the column itself will not be accessible. Writing to such a table is not supported.

  • Prest does not correctly read timestamp values from Parquet, RCFile with binary serde and Avro file formats created by Hive 3.1 or later due to Hive issues HIVE-21002, HIVE-22167. When reading from these file formats, SEP returns different results.