Our Leaderboard system is one of brainCloud’s most popular features. As such, it gets used a lot - by many games in different ways.
Although the system is very flexible and overall performs very well, there is one part of it that performs "less well," which is counting the number of entries in a leaderboard. Due to how MongoDB works (and how we structure our leaderboards), this operation is slower (and less scalable) than we would like. And under some circumstances (e.g., at the end of a tournament or custom LiveOps event, when everyone wants their results), those slowdowns can add up!
As of brainCloud 5.6, Leaderboard counts are now being pre-calculated and stored for two high-usage scenarios:
Tournament results: When a tournament is completed and rewards are calculated, we now count and store the total number of players once and use it for batched and real-time processing of tournament rewards.
Rotated leaderboards: When a leaderboard rotates, we count the entries and store them in the leaderboard version history - automatically using that value when the app calls
GetGlobalLeaderboardEntryCountByVersion().
The above improvements are built-in and automatically enabled for all apps.
NEVER ROTATION Leaderboard Cache
The previous two scenarios calculate and store the count for leaderboards that have been completed. Since these leaderboards are no longer live, the number of entries is no longer growing.
The same cannot be said for NEVER ROTATION leaderboards. These leaderboards are active forever - and can grow to millions of players. As they do, dynamically counting the entries can take some time.
To improve performance for these leaderboards - we have added a new system (the NEVER ROTATION Leaderboard Cache) that periodically (every 2-5 minutes) counts the number of records and caches the result. This cached count is also dynamically incremented/decremented as new scores are added and deleted. As such - this cached count closely tracks the exact number of entries – though it isn’t guaranteed to be 100% accurate.
When a leaderboard is very large - the difference between 1,500,000 or 1,500,001 isn’t significant… though apps with this caching enabled should take care to ensure that they can handle the situation where the system says the player’s rank is 1,500,001 – but also says there are only 1,500,000 entries in the leaderboard. [Hint - in that case - artificially inflate the number of entries to 1,500,001 for display purposes.]
Important notes:
Most apps do not need the NEVER ROTATION cache. Thus, it is turned OFF by default for all apps.
Developers cannot enable the NEVER ROTATION cache themselves. Our support Team enables it on a case-by-case basis for individual apps.
Contact brainCloud Support if you have questions about whether we should enable it for your app!