A queue is a store in which the queue server collects documents to be indexed and administration information.
There is a queue for each index. The queue server creates a queue automatically as soon as you create a new index. The queue has the same ID as the index.
A queue has several parameters that control the behavior of the queue. In particular, the parameters specify when the queue server triggers indexing and optimization of documents. It is important for performance reasons that you have optimum settings for the queue parameters.