Quick answer: Use a sorted structure that supports rank queries directly, and precompute percentile buckets so a player's standing is a fast lookup, not a count.
Counting everyone above a player to find their rank is slow. The right structure makes it instant. Here is how.
How to fix it
1. Use rank-capable structures
Store scores in a structure that returns a member's rank directly rather than by counting.
2. Precompute percentiles
Maintain percentile buckets so 'top 5%' is a lookup, not a full scan.
3. Cache the player view
Cache each player's rank neighborhood since they check it repeatedly.
Catching the ones you can't reproduce
The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.
Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.
This is where a tool like Bugnet earns its place. Its SDK captures every backend error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.
Ship the fix, watch the signature disappear from the next build. That's how you know it's really gone.