Query sharding for federated query

[rishabhkumar92]

Hi Team,

We have set up -query-frontend.query-sharding-total-shards as 32 and while max query-sharding-max-sharded-queries can still go up to higher number like 128(default).For federated query, we are not seeing more than 32 sharded query.

I was expecting it to more given that we are passing 100 of tenant in header, Can someone confirm if this is a bug or desired behavior?

How to reproduce?

• We are on Mimir version 2.12
• Issue a federated query with 100+ tenants and observed sharded query as 32 on QFEs.

[rishabhkumar92]

cc: @krajorama

[56quarters]

Federation, running the query for multiple tenants, happens in the queriers after the query-frontend has already sharded and split the query. They're not connected to each other.

[rishabhkumar92]

is there a recommended way to optimize performance of federated query further? I saw #5874 which might help in this case

[56quarters]

That doesn't really make sense. The query-frontend shards queries and splits them by time. Each of those sub-queries are handed to a querier. The querier then performs the query for each tenant.

[rishabhkumar92]

yeah I updated the comment above, you mind checking it again.