A slot is a logical unit of time in which a query can be scheduled to run. When the query’s capacity demands change, BigQuery re-evaluates the availability of slots and re-allocates and/or pauses them accordingly. This re-evaluation takes into account the effect of other queries on the same server, and also the impact of the query’s current state in the dynamic DAG.
The DAG’s dynamic allocation of slots is based on several factors including the query’s complexity and size, the overall load on the system, the amount of free memory available, the number of concurrent runs and their durations. Unlike renderers, slots cannot be used to run multiple types of content simultaneously. For example, a slot of type Media-image can only contain images, while a slot of type Solutions can only contain content from the repository.
The pay table of a slot machine lists the amount that a player will receive if certain symbols line up on the machine’s “payline”. These tables are often located above and below the machines’ spinning wheels, or displayed on a video screen. In addition to listing the odds of getting each symbol, the pay table must also describe any special features of the machine, such as wild symbols and multipliers. Some slots have an extensive list of possible payout combinations, while others only list the minimum and maximum payout amounts.