Too many simultaneous queries in clickhouse

Question

Our clickhouse server had several exceptions when running small queries under a peak load:

 DB::Exception: Too much simultaneous queries. Maximum: 100

Is there a setting to increase this number and what can the increase of this setting cause?

Answer 1

<max_concurrent_queries>100</max_concurrent_queries>

Just read config.xml https://github.com/ClickHouse/ClickHouse/blob/master/programs/server/config.xml#L237

Probably you want some proxy like haproxy in front of ClickHouse.