CALL apoc.periodic.iterate(
    "
        MATCH (ya:YoutubeAsset)-[:APPEARS_IN_VIDEO]->(:Video)
        WHERE NOT (ya)<-[:REPRESENTS]-(:GlobalSoundRecording)
        MATCH (gsr:GlobalSoundRecording {isrc: ya.isrc})
        RETURN ya, gsr
    ",
    "
        WITH *, 'python-neo4j-cypher-scheduler/augment-metadata/missing-youtube-asset-gsr-link' AS by

        MERGE (ya)<-[r:REPRESENTS]-(gsr)
        ON CREATE SET
            r.createdAt = datetime(),
            r.createdBy = by
    ",
    {batchSize:100, iterateList:true, parallel:false}
)
YIELD total, failedOperations, errorMessages
CALL apoc.util.validate(failedOperations > 0, "At least one sub-operation failed: %s", [reduce(all_errors = "", error IN keys(errorMessages) | all_errors + ", " + error)])
RETURN total;