[SPIKE] Compare keyset pagination performance of `security_findings` with and without filtering by `partition_number`

Topic to Evaluate

Timebox: 2 hours

We want to compare the performance of the following queries to choose the best indexing solution for the security_findings table;

1. Querying the security_findings table by only scan_id with keyset pagination
2. Querying the security_fingings table by scan_id, and partition_number with keyset pagination

If the latter performs better, we want to adjust our indices and queries accordingly.

Outcomes of the SPIKE

• Put a comment on this issue with queries used along with their execution plans
• Create an issue to adjust Security::FindingsFinder to keyset pagination based on the SPIKE outcome.