Creating a property oak index at the project level

Could you share the index definition? It should work at your project level /content/project/oak:index

OAK index has specific standards to make it work. I recommend that you watch this GEMS session.

Adobe Experience Manager Help | Oak Lucene Indexes

We have Lucene indexes at the same level and they are working fine. This one is a single property index.

Here is the index xml

<oak:index jcr:primaryType="nt:unstructured">

        <email

            jcr:primaryType="oak:QueryIndexDefinition"

            info="Oak Index used for searching by email"

            propertyNames="{Name}[email]"

            reindex="{Boolean}false"

            reindexCount="{Long}3"

            type="property"

            unique="{Boolean}false"/>

    </oak:index>

Below are the screenshots. What message do you get in your case? Does it generate the stats?

*INFO* [qtp175495745-1958] org.apache.jackrabbit.oak.plugins.index.IndexUpdate Indexing report

    - /content/we-retail/oak:index/myNodeApps*(4)

You need to limit the query explicitly to that folder (as outlined in the example of gauravd83019631​).

Your approach is possible but In most cases even project indexes are dropped into /oak:index.

i am using

select * from [nt:base] as a where isdescendantnode(a, '/content/project') and a.[email]='test@test.com'

but it says

It does generate the stats but says that no indexes are used, this is a traversal query.

Did you get a chance to check screenshots posted above?

1) Check if the index is picked up and no issues with syntax -

http://localhost:4502/libs/granite/operations/content/diagnosistools/indexManager.html

2) Add 'nodeTypeListDefined' and 'declaringNodeTypes', if you want to restrict it to certain nodes for lower cost

3) Check if index stats are getting generated, perform reindex and check the logs -

http://localhost:4502/system/console/jmx/org.apache.jackrabbit.oak%3Aname%3DProperty+Index+statistics%2Ctype%3DPropertyI…

4) Check the permissions on this path /content/project/oak:index - the service users should have read permissions, if not already available.

Refer - Jackrabbit Oak – The Property Index

• declaringNodeTypes (Name, multi-valued): the index only applies to a certain node type.
• includedPaths (String, multi-valued): the paths that are included (‘/’ if not set). Since Oak version 1.4 (OAK-3263). The index is only used if the query has a path restriction that is not excluded, and part of the included paths.