Data Discovery
Sensitive data discovery (SDD) is an Immuta feature that uses data patterns to determine what type of data your column represents. Using identification frameworks and identifiers, Immuta evaluates your data and can assign the appropriate tags to your data dictionary based on what it finds. This saves the time of identifying your data manually and provides the benefit of a standard taxonomy across all your data sources in Immuta.
Supported technologies
Sensitive data discovery is supported for data sources from the following technologies:
Starburst (Trino): Sensitive data discovery for Starburst (Trino) is currently in public preview and available to all accounts. Reach out to your Immuta representative to enable it on your tenant.
Redshift: Sensitive data discovery for Redshift is currently in private preview and available to all accounts. Reach out to your Immuta representative to enable it on your tenant.
Architecture
To evaluate your data, SDD generates a SQL query using the identification framework's identifiers; the Immuta system account then executes that query in the native technology. Immuta receives the query result, containing the column name and the matching identifiers but no raw data values. These results are then used to apply the resulting tags to the appropriate columns.
This evaluating and tagging process occurs when identification runs and happens automatically from the following events, if a global framework is set:
A new data source is created.
Schema monitoring is enabled, and a new data source is detected.
The following actions will also trigger identification:
Column detection is enabled, and new columns are detected. Here, SDD will only run on new columns, and no existing tags will be removed or changed. Note, this will use the identification framework that already ran on the data source.
A user manually triggers it from the data source health check menu. Note, this will use the identification framework that already applies to the data source or the global framework, if set.
A user manually triggers it from the identification frameworks page.
A user manually triggers it through the API.
Users can manually run identification from a data source's overview page or the identification frameworks page.
Components
Sensitive data discovery (SDD) runs frameworks to discover data. These frameworks are a collection of identifiers. These identifiers contain a single criteria and the tags that will be applied when the criteria's conditions have been met. See the sections below for more information on each component.
Identification framework
An identification framework is a group of identifiers that will look for particular criteria and tag any columns where those conditions are met.
While organizations can have multiple frameworks, only one may be applied to each data source. Immuta has the built-in "Default Framework," which contains all the built-in identifiers and assigns the built-in Discovered tags.
For a how-to on the framework actions users can take, see the Manage frameworks page.
Global framework
Each organization can set a global framework to apply to all the data sources in Immuta by default unless they have a different framework assigned. It is labeled on the frameworks page with a globe icon. If a global framework is set, identification will run on all new data sources. If a global framework is not set, identification will only run on data sources manually applied to an identification framework.
Users can set any framework as the global framework or leave the global framework field blank.
Identifier
An identifier is a criteria and the tags to apply to data that matches the criteria. When Immuta recognizes that criteria, it can tag the data to describe the type.
Immuta comes with built-in identifiers to discover common categories of data. These identifiers cannot be modified or deleted. Users can also create their own unique identifiers to find their specific data.
Improved identifiers
A new and improved pack of the built-in identifiers was released October 2024.
If you are interested in these improved identifiers, reach out to your Immuta support professional.
For a how-to on the identifier actions users can take, see the Create an identifier page.
Criteria
Criteria are the conditions that need to be met for resulting tags to be applied to data.
SDD only supports regular expressions (regex) written in RE2 syntax.
Supported criteria types for identifiers
Competitive criteria analysis: This criteria is a process that will review all the regex and dictionary criteria within the identifiers of the framework and search for the identifier with the best fit. In this review, each competitive criteria analysis identifier in the framework competes against each other to find the best and most specific identifier that fits the data. The resulting tags for the best identifier are then applied to the column. Only one competitive criteria analysis identifier will apply per column. To learn more about the competitive nature, see the How competitive criteria analysis works guide.
Regex: This criteria contains a case-insensitive regular expression that searches for matches against column values.
Dictionary: This criteria contains a list of words and phrases to match against column values.
Column name: This criteria includes a case-insensitive regular expression matched against column names, not against the values in the column. The identifier's tags will be applied to the column where the name is found. Multiple column name identifiers can match a column and be applied.
Create a new identifier in the Immuta UI or with the sdd/classifier endpoint.
Configuration
Only application admins can enable sensitive data discovery (SDD) globally on the Immuta app settings page. Then, data source creators can disable SDD on a data-source-by-data-source basis.
Tag mutability
When SDD is manually triggered by a data owner, all column tags previously applied by SDD are removed and the tags prescribed by the latest run are applied. However, if SDD is triggered because a new column is detected by schema monitoring, tags will only be applied to the new column, and no tags will be modified on existing columns. Additionally, governors, data source owners, and data source experts can disable any unwanted Discovered tags in the data dictionary to prevent them from being used and auto-tagged on that data source in the future.
Performance
The amount of time it takes to run identification on a data source depends on several factors:
Columns: The time to run identification grows nearly linearly with the number of text columns in the data source.
Identifiers: The number of identifiers being used weakly impacts the time to run identification.
Row count: Performance of identification may vary depending on the sampling method used by each technology. For Snowflake, the number of rows has little impact on the time because data sampling has near-constant performance.
Views: Performance on views is limited by the performance of the query that defines the view.
The time it takes to run identification for all newly onboarded data sources in Immuta is not limited by SDD performance but by the execution of background jobs in Immuta. Consult your Immuta account manager when onboarding a large number of data sources to ensure the advanced settings are set appropriately for your organization.
Testing
For users interested in testing SDD, note that the built-in identifiers by Immuta require a 90% match to data to be assigned to a column. This means that with synthetic data, there may be situations where the data is not real enough to fit the confidence needed to match identifiers. To test SDD, use a dev environment, create copies of your tables, or use the API to run a dryRun and see the tags that would be applied to your data by SDD.
Considerations
Deleting the built-in Discovered tags is not recommended: If you do delete built-in Discovered tags and use the Default Framework, then when the identifier is matched the column will not be tagged. As an alternative, tags can be disabled on a column-by-column basis from the data dictionary, or SDD can be turned off on a data-source-by-data-source basis when creating a data source.
Supported data types and casing
Data regex*
Text string columns
Case-sensitive
Column name regex
Any column
Not case-sensitive
Dictionary
Text string columns
Can be toggled in the identifier definition
*Two built-in patterns support and match based on additional data types:
DATE: Columns will match this identifier if they are string and the regex matches or if the data type is date, date+time, or timestamp.TIME: Columns will match this identifier if they are string and the regex matches or if the data type is time. Note that if the date is included in the data, it will not match this identifier.
Limitations with dictionary patterns
Immuta compiles dictionary patterns into a regex that is sent in the body of a query.
For Snowflake, the size of the dictionary is limited by the overall query text size limit in Snowflake of 1 MB.
Databricks limitation
For Databricks, Immuta will start up a Databricks cluster to complete the SDD job if one is not already running. This can cause unnecessary costs if the cluster becomes idle. Follow Databricks best practices to automatically terminate inactive clusters after a set period of time.
Starburst (Trino) limitation
SDD will only work on Starburst (Trino) data sources authenticated with username and password. OAuth 2.0 is not supported with SDD.
Redshift limitations
Redshift Spectrum is not supported with SDD.
The Redshift cluster must be up and running for SDD to successfully run.
Redshift supported authentication methods
The username and password auth method is fully supported with SDD.
Okta is not supported with SDD.
AWS access key is supported with limitations with SDD:
The AWS access key used to register the data source can do a minimum of the following redshift-data API actions:
redshift-data:BatchExecuteStatementredshift-data:CancelStatementredshift-data:DescribeStatementredshift-data:ExecuteStatementredshift-data:GetStatementResultredshift-data:ListStatements
The AWS access key used to register the data source must have
redshift:GetClusterCredentialsfor the cluster, user, and database that they onboard their data sources with.If using a custom URL, then the data source registered with the AWS access key must have the
regionandclusteridincluded in the additional connection string options formatted like the following:Redshift Serverless data sources are not supported for native SDD with the AWS access key authentication method.
Migrating from legacy to native SDD
These limitations are only relevant to users who have previously enabled and run Immuta SDD.
Immuta has improved the performance and behavior of sensitive data discovery (SDD), so references to two types of SDD can be found in the product:
Legacy SDD was available before October 2023. It is no longer available, but some users may still see the term "legacy SDD" in the context of their data tags.
Native SDD was released to Snowflake and Databricks in May 2023. It was released to Starburst (Trino) and Redshift in April 2024. Native SDD is the only type of SDD available. It is often just referred to as SDD.
If you had legacy SDD enabled, running native SDD can result in different tags being applied because native SDD is more accurate and has fewer false positives than legacy SDD. Running a new SDD scan against a table will change the context of the resulting tags, but no Discovered tags previously applied by legacy SDD will be removed.
See the Migrate from legacy to native SDD page for more information.
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