OpenMetadata/openmetadata-docs/content/v1.7.x/connectors/ingestion/workflows/reverse-metadata.md

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Reverse Metadata Ingestion Collate | Feature & Configuration	/connectors/ingestion/workflows/reverse-metadata	true

Reverse Metadata

Reverse Metadata is an advanced feature in OpenMetadata that facilitates bi-directional synchronization between OpenMetadata and the source database systems. While standard ingestion pulls metadata into OpenMetadata, reverse ingestion enables pushing metadata changes made within OpenMetadata back to the source systems. This ensures consistency and alignment across the entire data infrastructure.

{% note %} Reverse Metadata uses the existing service connection configuration provided during the initial metadata ingestion. You do not need to reconfigure the service connection. In order to use Reverse Metadata, this connections must use a role with write permissions. {% /note %}

Supported Databases and Features

Database	Update Description	Update Tags	Update Owners	Custom SQL Support	Documentation
Athena	✅ (Table)	❌	❌	✅	Link
BigQuery	✅ (Schema, Table)	✅ (Schema, Table)	❌	✅	Link
Clickhouse	✅ (Table, Column)	❌	❌	✅	Link
Databricks	✅	✅	✅ (Database, Schema, Table)	✅	Link
MSSQL	✅ (Schema, Table, Column)	❌	✅ (Database, Schema)	✅	Link
MySQL	✅ (Table)	❌	❌	✅	Link
Oracle	✅ (Table, Column)	❌	❌	✅	Link
PostgreSQL	✅	❌	✅ (Database, Schema, Table)	✅	Link
Redshift	✅	❌	✅ (Database, Schema, Table)	✅	Link
Snowflake	✅	✅ (Schema, Table, Column)	❌	✅	Link
Unity Catalog	✅	✅	✅ (Database, Schema, Table)	✅	Link

Key Features

Description Management

• Multi-level Support: Update descriptions at database, schema, table, and column levels.
• Consistency: Maintain uniform documentation across all systems.

Ownership Management

• Owner Assignment: Add new owners to data assets.
• Owner Removal: Remove existing owners when needed.

Tag and Label Management

• Bidirectional Sync: Synchronize tags between OpenMetadata and source systems.
• Tag Operations: Add new tags or remove existing ones.
• Conflict Prevention: Built-in protection against ambiguous tag situations.

Custom SQL Template

You can define a custom SQL template to handle the metadata changes. The template is interpreted using python f-strings. These are the available variables:

Variable	Description	Context	Type
database	The identifier of the database or catalog	Always	String
schema	The identifier of the schema	Always	String
table	The identifier of the table	Always	String
column	The identifier of the column	Always	String
description	Refers to the description	Description update	String
owner	The identifier of the owner being added or removed. This value can be a username or an email and depends on the source system.	Owner update	String
tag_key	The key of the tag being added or removed (Classification)	Tag update	String
tag_value	The value of the tag being added or removed	Tag update	String
tags	Refers to a list of tags (e.g., BigQuery). Example: [('my_tag', 'value'), ('env', 'prod')]	Always	List[Tuple[String, String]]

You can see examples of custom SQL templates in the specific connector documentation.

{% note %} When updating tags during reverse ingestion, it is important to understand the difference in tag structures. Most databases support key-value pairs for tags, whereas OpenMetadata organizes tags using classifications and tag names. During reverse ingestion, OpenMetadata maps the classification name as the tag key and the tag name as the tag value. If a new tag from the same classification is applied to a data asset that already has a tag from that classification, the reverse ingestion process may raise an ambiguous tag error. This behavior is intended to prevent accidental overwriting of existing tags at the source system. {% /note %}

Getting Started

Channels

Reverse Metadata is handled in "channels". Each channel can be customized to handle different types of metadata changes. Channels can have different filtering configurations depending on the source system and different operations to be performed. If a metadata update is processed by multiple channels, the metadata will be updated multiple times. This should not be an issue for trivial cases but can be an issue when the logic is different for each channel.

Configuration Setup

1. Navigate to the Applications section.

{% image src="/images/v1.7/features/ingestion/workflows/reverse-metadata/reverse-metadata1.png" alt="Reverse Metadata Navigation" caption="Reverse Metadata Navigation" /%}

2. Locate and install the Reverse Metadata app.

{% image src="/images/v1.7/features/ingestion/workflows/reverse-metadata/reverse-metadata2.png" alt="Reverse Metadata App" caption="Reverse Metadata App" /%}

3. Select your database service, configure the required settings, and click Submit.

{% image src="/images/v1.7/features/ingestion/workflows/reverse-metadata/reverse-metadata3.png" alt="Reverse Metadata Configuration" caption="Reverse Metadata Configuration" /%}

Testing

• Start with a single type of update.
• Verify changes in the source system.
• Gradually expand to other features.
• Monitor for any errors or warnings.

{% image src="/images/v1.7/features/ingestion/workflows/reverse-metadata/reverse-metadata4.png" alt="Monitor Reverse Metadata Ingestion" caption="Monitor Reverse Metadata Ingestion" /%}