AEM 6.5 popular queries

[tushaar_srivastava]

Hi Team, 

We got the list of popular queries made under our system. out of which the below query I am not able to find the source, but it seems to be an OOB query, but anyone, please let me know the cause of the below AEM query:

SELECT * FROM [nt:base] WHERE [jcr:uuid] = $id OPTION(INDEX NAME [uuid], INDEX TAG [uuid])

Thanks 

@kautuk_sahni  @lukasz-m  @arunpatidar  @SantoshSai 

[AmitVishwakarma · Accepted solution]

Hi @tushaar_srivastava ,

The query you're seeing:

SELECT * FROM [nt:base] WHERE [jcr:uuid] = $id OPTION(INDEX NAME [uuid], INDEX TAG [uuid])

is an out-of-the-box (OOB) query used internally by AEM and JCR (Jackrabbit Oak) for resolving nodes by UUID. Here’s a breakdown:

What this query does

  - It fetches a node from the JCR repository using its UUID (jcr:uuid).

  - nt:base is the base node type—so this query matches any node type.

  - The OPTION(INDEX NAME [uuid], INDEX TAG [uuid]) hint tells Oak to use the uuid index, which improves performance when looking up nodes by UUID.

Why and where it is used

This is typically used in:

  - References Resolution (e.g., from Reference or WeakReference properties).

  - Replication or Version Restore operations.

  - Permission Evaluation or Audit Tools.

  - Admin search UIs or Sling ResourceResolver when a resource is accessed directly by UUID.

Action to take

No issue unless it shows abnormal usage or performance impact.

Check if:

  - Custom components are trying to resolve by UUID excessively.

  - Any workflow/process is looping over UUIDs.

  - Use AEM's Query Performance Tool (http://localhost:4502/libs/granite/operations/content/diagnosistools/queryPerformance.html) to trace what is issuing the query, or enable debug logs for:

org.apache.jackrabbit.oak.query.QueryEngineImpl
org.apache.jackrabbit.oak.plugins.index

Regards,
Amit

[SantoshSai]

Hi @tushaar_srivastava,

Let's understand your query by breaking it down:

• SELECT * FROM [nt:base]: This fetches all node types extending from nt:base, which includes all nodes in the JCR repository.

• WHERE [jcr:uuid] = $id: This filters nodes by their universally unique identifier (jcr:uuid). $id is a placeholder for the actual UUID value.

• OPTION(INDEX NAME [uuid], INDEX TAG [uuid]): This hints to the query engine to use a specific index (by name or tag) to speed up the query.

This is a system-level or internal query typically generated by:

• AEM internals: For example, when resolving references to specific nodes by UUID (e.g., ReferenceSearch, PageManager.getPage(String path) behind the scenes, etc.).

• Sling or JCR API usage: If any code (OOB or custom) uses Session.getNodeByIdentifier() or similar, this query is executed under the hood.

• Touch UI / Classic UI authoring interfaces: UUID-based lookups can happen during drag-and-drop references, metadata resolution, etc.

• Replication, workflows, or DAM references: When checking or resolving binary or node references by UUID.

Hope that helps!