Apache Druid

I'm not sure what you mean. Could you elaborate?

yes, if config context as this,
```{"useGroupingSetForExactDistinct": true,  "useApproximateCountDistinct": false}```
and send double query,  this query can’t return result at same time, example: if exec one query need 50s，and double quey need 100s，my version is 0.20.0

<@U04C4593VDY> is this the situation you referred to in that other thread?

I suspect you are running into exhaustion of some concurrently needed resources. The GroupBy query needed for this will use merge Buffers and processing threads and processing buffers. Each processing thread can run one query at a time, if it is a groupBy it will use up to 2 merge buffers to resolve the query. If there are only 2 merge buffers, and they are in use, other queries will wait. Take a look at this subject here: <https://druid.apache.org/docs/latest/operations/basic-cluster-tuning#processing-threads-and-buffers> and here:  <https://druid.apache.org/docs/latest/operations/basic-cluster-tuning#guidelines-for-processing-threads-and-buffers>