CDF Transformations and cdf_nodes being slow

In order to delete nodes in CDF in a given View because of deletes in the Fabric source table, we need to extract necessary fields for all rows in Fabric to construct the space and ExternalId, and then compare this with a full extraction of the space and externalId in the View.

In one example with ~400k rows/nodes, it takes 1-2 minutes to get the data from Fabric. However, the cdf_nodes is several orders of magnutide slower.

• Only extracting space and externalId for 400k nodes in the View takes ~25 minutes
• Adding a Where clause to check if the externalId has a given prefix as a safeguard makes the query time out.

Using cdf_data_models or other functions does not seem to help either. Is there a reason that listing ids for nodes is so slow? And are there other ways to go about this use case?