What Is a Slot?
A slot is a narrow opening in a machine or container that can be used to insert objects. It can also refer to a position on a list or schedule. The term is sometimes used in sports to describe an area on the ice rink that is right in front of the goaltender and between the face-off circles. In business, a slot can be a reserved time for a meeting or event.
A casino slot machine is a game where you can win credits by spinning reels. You insert cash or, in “ticket-in, ticket-out” machines, a paper ticket with a barcode into the slot to activate the machine. Then you spin the reels and hope to match a winning combination of symbols, which vary according to the machine’s theme. Symbols often include fruit, bells, and stylized lucky sevens. Most slots have a specific theme and a bonus game.
Advantage play is possible on slot games, but only in very limited circumstances. Serious advantage players carefully balance the effort and cost involved with a potential reward. The goal is to find situations where the odds are in your favor, but not so favorable that they become unduly costly.
The reason that a slot doesn’t appear in the midst of a queued query is because the capacity demand of the query and the current available slots are dynamically re-evaluated as the query progresses through its DAG. BigQuery automatically re-adjusts the number of slots allocated to this and all other queries, pausing and re-allocating as needed. This is done to ensure that, given fair scheduling, every query has access to the same number of slots for its execution time.