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create_patient_eligibility_trial_index

Add the eligible_trials filter index to caches created before it existed.

metadata.create_all only builds a table's indexes at the moment it creates the table, so a cache predating ix_patient_eligibility_trial_status (declared on the patient_eligibility ORM's __table_args__) never gains the index on open. This migration creates it in place, so an existing pod gets the same index-driven eligible_trials filter that a fresh cache has from its ORM.

Unlike a per-type schema migration this is not tied to a version bump — the record shape is unchanged, only a secondary index is added — so it lives here with the other one-time cache migrations. The DDL is taken from the ORM Index object rather than re-spelled, so the two cannot drift.

Idempotent: a no-op once the index exists (which includes every fresh cache, where create_all already built it). Building the index scans the whole patient_eligibility table, so the first run on a large existing cache costs a few seconds; the migration marker then stops it re-running.

Module​

Functions​

apply​

def apply(cache: CacheProtocol) ‑> int:

Create the trial-filter index if it is missing.

Arguments

  • cache: The cache backend.

Returns 1 if the index was created, 0 if it already existed.

Global variables​

  • NAME - Identifier recorded in the migration marker once this has run.