How can I handle redis-cluster with Redis Stack (RediSearch)?

I’m currently having problem dealing with redis-cluster.

creating a redis cluster, I’m using the “redis/redis-stack-server:latest” docker image.

I am doing a query test using RediSearch, but in standalone mode, the number of requests per second is not high than other DBs. so I’m trying to optimize the speed using Redis-Cluster.

When I first started redis-cluster, I thought I would be able to import it across nodes. However, the test results didn’t. I can only access the data within the same node and cannot ft.search (RediSearch) across all the nodes.

so I looked through the document again to find a solution. The document related to RediSearch says to use RSCoordinator.

When Running RediSearch in a clustered database, you can span the index across shards using RSCoordinator. In this case the above does not apply.

but looking at github, it seems that RSCoordinator is already built-in. GitHub - RediSearch/RediSearch at 638de1dbc5e641ca4f8943732c3c468c59c5a47a

Is there a way for redis-cluster to fetch data across all nodes?

Additionally, I wonder if the reason why Redis does not have higher requests per second than other DBs (MongoDB, PostgreSQL, etc…) in large dataset(about 2,400,000) is because Redis is Single Thread? Are there other factors?