Set options in sys.options to enable and manage query queuing, which is turned off by default. There are two types of queues: large and small. You configure a maximum number of queries that each queue allows by configuring the following options in the sys.options table:
- exec.queue.large - exec.queue.small Example Configuration For example, you configure the queue reserved for large queries to hold a 5-query maximum. You configure the queue reserved for small queue to hold 20 queries. Users start to run queries, and Drill receives the following query requests in this order: - Query A (blue): 1 billion records, Drill estimates 10 million rows will be processed - Query B (red): 2 billion records, Drill estimates 20 million rows will be processed - Query C: 1 billion records - Query D: 100 records The exec.queue.threshold default is 30 million, which is the estimated rows to be processed by the query. Queries A and B are queued in the large queue. The estimated rows to be processed reaches the 30 million threshold, filling the queue to capacity. The query C request arrives and goes on the wait list, and then query D arrives. Query D is queued immediately in the small queue because of its small size, as shown in the following diagram: [image: Inline image 1] The Drill queuing configuration in this example tends to give many users running small queries a rapid response. Users running a large query might experience some delay until an earlier-received large query returns and the large queue is available to continue processing large queries. Kristine Hahn Sr. Technical Writer 415-497-8107 @krishahn On Thu, Apr 30, 2015 at 12:04 AM, Richard Shaw <rs...@maprtech.com> wrote: > I'd like to better understand queuing, if it's in fact possible to > serialise incoming queries, especially where I have a very small Drill > installation with limited resources. > > Thank you > > Kind Regards, > Richard >
