How to limit response from Attachment endpoint using SOQL (LIMIT not working)

Question

We're working on a data driven application at the moment and are attempting to return a list of Attachment Id's.

Right now our SOQL query is effectively:

SELECT Id FROM Attachment WHERE LastModifiedDate >= LAST_N_MONTHS:24 LIMIT 100000

But we're getting an

OPERATION_TOO_LARGE

error telling us our query has exceeded 100k results. Any idea how we can successfully limit a query of the Attachment endpoint?

We can obviously limit it to under 100k by limiting the date range but that feels pretty fragile - any recommendations gratefully received.

EDIT: Update to the question I've tried this but Salesforce simply times out on it - even when limited to 1.

SELECT Id FROM Attachment WHERE ParentID IN (SELECT Id FROM <SObject> WHERE LastModifiedDate >= LAST_N_MONTHS:24) LIMIT 100000

Answer 1

Turns out this code does actually work:

SELECT Id FROM Attachment WHERE ParentID IN (SELECT Id FROM <SObject> WHERE LastModifiedDate >= LAST_N_MONTHS:24) LIMIT 100000

For some reason Workbench occasionally breaks when you run it - but actually running it via CURL to the query endpoint or similar returns results as expected.