## Query redaction for AlloyDB for PostgreSQL

URL: https://docs.atlan.com/apps/connectors/database/alloydb/postgresql/references/query-redaction

> Reference for Redact SQL Text on the AlloyDB for PostgreSQL crawler workflow: what Atlan redacts, what it preserves, and limitations to plan for.

By default, Atlan stores the SQL text it extracts from AlloyDB for PostgreSQL exactly as written at source. That text can contain literal values from your business data, such as email addresses in a `WHERE` clause or account numbers in a view definition.

Query redaction replaces those literal values with placeholders before Atlan stores them. Redaction runs in memory while the workflow extracts data, so the original values aren't written to Atlan's storage or sent outside your environment. Query structure, table references, and column references are preserved, so lineage is unaffected.

Redaction is off by default. You opt in using the _Redact SQL Text_ option on the crawler.

## Enable redaction

| Workflow | Where to find it |
| --- | --- |
| [AlloyDB for PostgreSQL crawler](https://docs.atlan.com/llms/connectors/alloydb-postgresql/crawl-alloydb-postgresql/llms.txt) | _Configure crawler_ screen |

The option appears for both direct and Self-Deployed Runtime extraction. With Self-Deployed Runtime extraction, redaction runs inside your Self-Deployed Runtime.

## What Atlan redacts

Redaction applies to the fields that carry SQL text:

* View and materialized view definitions.
* The bodies of functions and procedures.

Within that text, Atlan replaces:

* **String literals** with `''`.
* **Numeric literals** with `1`. Atlan substitutes a valid number rather than a text placeholder so that the redacted SQL remains parseable.

Atlan also removes comments from redacted SQL and reformats the statement, so stored text won't match the original layout.

### Values Atlan preserves

Some literals are safe to keep and can break the SQL if replaced, so redaction preserves them:

* Date and time literals, such as `'2026-01-01'::date` or `'2026-01-01 14:30:00'`.
* Month and weekday names, and date part keywords such as `MONTH` or `QUARTER`.
* Currency codes, such as `'USD'`.
* Boolean words: `TRUE`, `FALSE`, `YES`, and `NO`.
* Numbers in structural positions, such as the row count in a `LIMIT` clause, where the value controls the shape of the result rather than describing your data.

Everything else is treated as potentially sensitive and redacted.

## Before and after

A view definition extracted by the crawler:

```sql
select order_id, customer_email
from analytics.orders
where region = 'EMEA' and order_total > 500.75
 and created_at >= '2026-01-01' and currency = 'USD'
limit 100;
```

The same definition as Atlan stores it with _Redact SQL Text_ enabled:

```sql
/* redacted: true, hash: <original_hash>, redacted_hash: <redacted_hash> */
SELECT
 order_id,
 customer_email
FROM analytics.orders
WHERE
 region = ''
 AND order_total > 1
 AND created_at >= '2026-01-01'
 AND currency = 'USD'
LIMIT 100
```

Note the following:

* `'EMEA'` was replaced, while the date and the currency code were preserved.
* `500.75` became `1`. Redaction indicates that a number was present, not what it was.
* `LIMIT 100` was preserved, because the number controls the result size rather than describing your data.
* The statement was reformatted.
* Atlan adds a header comment recording that the text was redacted, along with fingerprints of the original and redacted statements. The fingerprint values differ for every statement.
* `analytics.orders`, `order_id`, and `customer_email` are unchanged, which is why lineage still resolves.

## What redaction preserves

Redaction only changes literal values. Because everything Atlan uses to build relationships stays intact, enabling redaction doesn't change:

* Table-level and column-level lineage.
* Asset names, hierarchy, or any other extracted metadata.

## Limitations

**SQL that Atlan can't parse is stored unredacted.** When parsing fails, Atlan stores the original statement under a `redacted: false` header instead of dropping it. Function and procedure bodies written in PL/pgSQL or another procedural language, and dynamic SQL built with `EXECUTE`, are the most common cases.

**Redaction increases workflow runtime.** Expect crawler runs to take longer, and account for this if the crawler already runs close to its schedule interval.

**Enabling redaction rewrites stored SQL.** Because the stored text changes for every asset, the first run after you enable the option updates SQL text across the connection.

## See also

* [Crawl AlloyDB for PostgreSQL](https://docs.atlan.com/llms/connectors/alloydb-postgresql/crawl-alloydb-postgresql/llms.txt): configure and run the AlloyDB for PostgreSQL crawler.
* [What does Atlan crawl from AlloyDB for PostgreSQL](https://docs.atlan.com/llms/connectors/alloydb-postgresql/what-does-atlan-crawl-from-alloydb-postgresql/llms.txt): assets and metadata Atlan extracts.
* [Query redaction for Snowflake](https://docs.atlan.com/llms/connectors/snowflake/query-redaction/llms.txt): the same option on Snowflake workflows.

_Last updated: 15 October 2026._

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