Simulation Lab

Bad key, sharded key, and regional rollup design

The lab writes representative telemetry samples, then extrapolates hot-partition risk, WCU pressure, consistency risk, and readiness for the 1M-user Global Trivia Game target.

Scenario controls

1M users, 50k concurrent, US + EU, leaderboard pressure

Simulated users

Peak concurrent

50K

Sample events

1,200

Extrapolated EPS

8,000

Active run

Global Trivia Game - regional rollup projection design

Regional rollups split live writes by region, game shard, and leaderboard bucket while publishing a windowed global projection.

readiness

Hot partition risk

Consistency score

Cost score

Hot partition heatmap

Logical partition pressure

Jun 29, 11:56 PM

REGION#EU#GAME#trivia-finals#SHARD#21

REGION#EU#GAME#trivia-finals#SHARD#9

REGION#US#GAME#trivia-finals#SHARD#8

REGION#US#GAME#trivia-finals#SHARD#20

REGION#EU#GAME#trivia-finals#SHARD#1

REGION#US#GAME#trivia-finals#SHARD#22

REGION#US#GAME#trivia-finals#SHARD#0

REGION#EU#GAME#trivia-finals#SHARD#7

REGION#EU#GAME#trivia-finals#SHARD#29

REGION#US#GAME#trivia-finals#SHARD#30

REGION#US#GAME#trivia-finals#SHARD#14

REGION#EU#GAME#trivia-finals#SHARD#19

What-if shard count estimator

Peak hot key WCU/s

227

Safety WCU target

700

Minimum shards

Recommended shards

Event stream

SUBMIT_ANSWER

REGION#US#GAME#trivia-finals#SHARD#14

low16ms

UPDATE_SCORE

REGION#EU#GAME#trivia-finals#SHARD#1

low35ms

SUBMIT_ANSWER

REGION#US#GAME#trivia-finals#SHARD#28

low32ms

SUBMIT_ANSWER

REGION#EU#GAME#trivia-finals#SHARD#15

low33ms

READ_LEADERBOARD

LEADERBOARD#REGION#US#BUCKET#2

low34ms

READ_LEADERBOARD

LEADERBOARD#GLOBAL#WINDOW#2043-06-03T00#BUCKET#5

low35ms

UPDATE_SCORE

REGION#US#GAME#trivia-finals#SHARD#16

low46ms

READ_LEADERBOARD

LEADERBOARD#REGION#EU#BUCKET#3

low29ms

JOIN_SESSION

USER#user_65494

low48ms

SUBMIT_ANSWER

REGION#EU#GAME#trivia-finals#SHARD#9

low31ms

READ_LEADERBOARD

LEADERBOARD#REGION#EU#BUCKET#11

low31ms

UPDATE_SCORE

REGION#US#GAME#trivia-finals#SHARD#24

low48ms

SUBMIT_ANSWER

REGION#EU#GAME#trivia-finals#SHARD#5

low29ms

SUBMIT_ANSWER

REGION#US#GAME#trivia-finals#SHARD#18

low28ms

QUERY_HISTORY

USER#user_78399#HISTORY

low45ms

READ_LEADERBOARD

LEADERBOARD#REGION#US#BUCKET#12

low26ms

UPDATE_SCORE

REGION#EU#GAME#trivia-finals#SHARD#25

low43ms

SUBMIT_ANSWER

REGION#US#GAME#trivia-finals#SHARD#6

low24ms

SUBMIT_ANSWER

REGION#EU#GAME#trivia-finals#SHARD#19

low23ms

SUBMIT_ANSWER

REGION#US#GAME#trivia-finals#SHARD#0

low22ms

READ_LEADERBOARD

LEADERBOARD#GLOBAL#WINDOW#2043-12-09T20#BUCKET#4

low16ms

SUBMIT_ANSWER

REGION#EU#GAME#trivia-finals#SHARD#15

low17ms

SUBMIT_ANSWER

REGION#US#GAME#trivia-finals#SHARD#14

low22ms

SUBMIT_ANSWER

REGION#EU#GAME#trivia-finals#SHARD#1

low23ms

UPDATE_SCORE

REGION#US#GAME#trivia-finals#SHARD#8

low38ms

READ_LEADERBOARD

LEADERBOARD#GLOBAL#WINDOW#2044-04-20T20#BUCKET#3

low21ms

READ_LEADERBOARD

LEADERBOARD#REGION#US#BUCKET#26

low26ms

READ_EVENT

USER#user_56397

low59ms

SUBMIT_ANSWER

REGION#US#GAME#trivia-finals#SHARD#20

low24ms

UPDATE_SCORE

REGION#EU#GAME#trivia-finals#SHARD#7

low43ms

SUBMIT_ANSWER

REGION#EU#GAME#trivia-finals#SHARD#25

low31ms

QUERY_HISTORY

USER#user_27398#HISTORY

low48ms

SUBMIT_ANSWER

REGION#EU#GAME#trivia-finals#SHARD#23

low19ms

READ_LEADERBOARD

LEADERBOARD#GLOBAL#WINDOW#2044-04-20T15#BUCKET#4

low18ms

SUBMIT_ANSWER

REGION#EU#GAME#trivia-finals#SHARD#29

low21ms

SUBMIT_ANSWER

REGION#US#GAME#trivia-finals#SHARD#10

low20ms

SUBMIT_ANSWER

REGION#EU#GAME#trivia-finals#SHARD#11

low15ms

SUBMIT_ANSWER

REGION#US#GAME#trivia-finals#SHARD#24

low14ms

READ_LEADERBOARD

LEADERBOARD#REGION#EU#BUCKET#17

low17ms

SUBMIT_ANSWER

REGION#US#GAME#trivia-finals#SHARD#30

low16ms

READ_LEADERBOARD

LEADERBOARD#REGION#US#BUCKET#26

low14ms

JOIN_SESSION

USER#user_56493

low33ms

SUBMIT_ANSWER

REGION#US#GAME#trivia-finals#SHARD#16

low22ms

SUBMIT_ANSWER

REGION#EU#GAME#trivia-finals#SHARD#3

low23ms

SUBMIT_ANSWER

REGION#US#GAME#trivia-finals#SHARD#22

low24ms

UPDATE_SCORE

REGION#EU#GAME#trivia-finals#SHARD#9

low43ms

READ_LEADERBOARD

LEADERBOARD#GLOBAL#WINDOW#2043-07-02T18#BUCKET#4

low26ms

SUBMIT_ANSWER

REGION#EU#GAME#trivia-finals#SHARD#15

low27ms

SUBMIT_ANSWER

REGION#US#GAME#trivia-finals#SHARD#2

low28ms

SUBMIT_ANSWER

REGION#EU#GAME#trivia-finals#SHARD#21

low29ms

READ_LEADERBOARD

LEADERBOARD#REGION#EU#BUCKET#23

low33ms

UPDATE_SCORE

REGION#US#GAME#trivia-finals#SHARD#4

low50ms

READ_LEADERBOARD

LEADERBOARD#GLOBAL#WINDOW#2033-11-19T21#BUCKET#1

low23ms

UPDATE_SCORE

REGION#US#GAME#trivia-finals#SHARD#6

low40ms

SUBMIT_ANSWER

REGION#EU#GAME#trivia-finals#SHARD#19

low21ms

SUBMIT_ANSWER

REGION#US#GAME#trivia-finals#SHARD#0

low20ms

UPDATE_SCORE

REGION#EU#GAME#trivia-finals#SHARD#5

low45ms

SUBMIT_ANSWER

REGION#US#GAME#trivia-finals#SHARD#18

low26ms

SUBMIT_ANSWER

REGION#EU#GAME#trivia-finals#SHARD#31

low25ms

SUBMIT_ANSWER

REGION#US#GAME#trivia-finals#SHARD#12

low24ms

SUBMIT_ANSWER

REGION#US#GAME#trivia-finals#SHARD#8

low22ms

SUBMIT_ANSWER

REGION#EU#GAME#trivia-finals#SHARD#27

low23ms

READ_LEADERBOARD

LEADERBOARD#GLOBAL#WINDOW#2033-11-19T15#BUCKET#2

low20ms

SUBMIT_ANSWER

REGION#EU#GAME#trivia-finals#SHARD#21

low21ms

SUBMIT_ANSWER

REGION#US#GAME#trivia-finals#SHARD#28

low18ms

READ_LEADERBOARD

LEADERBOARD#REGION#EU#BUCKET#15

low19ms

SUBMIT_ANSWER

REGION#US#GAME#trivia-finals#SHARD#22

low16ms

SUBMIT_ANSWER

REGION#EU#GAME#trivia-finals#SHARD#9

low17ms

READ_LEADERBOARD

LEADERBOARD#REGION#US#BUCKET#16

low14ms

JOIN_SESSION

USER#user_34691

low33ms

UPDATE_SCORE

REGION#EU#GAME#trivia-finals#SHARD#21

low49ms

SUBMIT_ANSWER

REGION#US#GAME#trivia-finals#SHARD#2

low30ms

READ_EVENT

USER#user_57595

low65ms

READ_LEADERBOARD

LEADERBOARD#REGION#US#BUCKET#8

low32ms

SUBMIT_ANSWER

REGION#EU#GAME#trivia-finals#SHARD#1

low35ms

SUBMIT_ANSWER

REGION#US#GAME#trivia-finals#SHARD#14

low34ms

READ_LEADERBOARD

LEADERBOARD#REGION#EU#BUCKET#7

low15ms

UPDATE_SCORE

REGION#US#GAME#trivia-finals#SHARD#20

low32ms

SUBMIT_ANSWER

REGION#EU#GAME#trivia-finals#SHARD#13

low17ms

JOIN_SESSION

USER#user_25690

low34ms

READ_LEADERBOARD

LEADERBOARD#REGION#US#BUCKET#6

low28ms

JOIN_SESSION

USER#user_23993

low47ms

UPDATE_SCORE

REGION#US#GAME#trivia-finals#SHARD#4

low34ms

READ_LEADERBOARD

LEADERBOARD#GLOBAL#WINDOW#2044-06-11T12#BUCKET#7

low17ms

SUBMIT_ANSWER

REGION#US#GAME#trivia-finals#SHARD#10

low18ms

SUBMIT_ANSWER

REGION#EU#GAME#trivia-finals#SHARD#29

low19ms

READ_LEADERBOARD

LEADERBOARD#GLOBAL#WINDOW#2044-01-30T11#BUCKET#0

low34ms

SUBMIT_ANSWER

REGION#EU#GAME#trivia-finals#SHARD#11

low35ms

SUBMIT_ANSWER

REGION#US#GAME#trivia-finals#SHARD#30

low14ms

SUBMIT_ANSWER

REGION#EU#GAME#trivia-finals#SHARD#17

low15ms

SUBMIT_ANSWER

REGION#EU#GAME#trivia-finals#SHARD#3

low21ms

READ_LEADERBOARD

LEADERBOARD#GLOBAL#WINDOW#2043-04-12T14#BUCKET#0

low20ms

READ_LEADERBOARD

LEADERBOARD#REGION#EU#BUCKET#13

low35ms

SUBMIT_ANSWER

REGION#US#GAME#trivia-finals#SHARD#26

low34ms

SUBMIT_ANSWER

REGION#EU#GAME#trivia-finals#SHARD#7

low33ms

SUBMIT_ANSWER

REGION#US#GAME#trivia-finals#SHARD#20

low32ms

JOIN_SESSION

USER#user_04993

low49ms

READ_LEADERBOARD

LEADERBOARD#REGION#US#BUCKET#14

low30ms

UPDATE_SCORE

REGION#EU#GAME#trivia-finals#SHARD#27

low47ms

SUBMIT_ANSWER

REGION#US#GAME#trivia-finals#SHARD#8

low28ms

Hot key findings

REGION#EU#GAME#trivia-finals#SHARD#21

low

227 estimated WCU/s. Keep shard count tied to estimated peak WCU and monitor per-shard skew.

REGION#EU#GAME#trivia-finals#SHARD#9

low

220 estimated WCU/s. Keep shard count tied to estimated peak WCU and monitor per-shard skew.

REGION#US#GAME#trivia-finals#SHARD#8

low

213 estimated WCU/s. Keep shard count tied to estimated peak WCU and monitor per-shard skew.

REGION#US#GAME#trivia-finals#SHARD#20

low

213 estimated WCU/s. Keep shard count tied to estimated peak WCU and monitor per-shard skew.

REGION#EU#GAME#trivia-finals#SHARD#1

low

207 estimated WCU/s. Keep shard count tied to estimated peak WCU and monitor per-shard skew.

REGION#US#GAME#trivia-finals#SHARD#22

low

193 estimated WCU/s. Keep shard count tied to estimated peak WCU and monitor per-shard skew.

REGION#US#GAME#trivia-finals#SHARD#0

low

193 estimated WCU/s. Keep shard count tied to estimated peak WCU and monitor per-shard skew.

REGION#EU#GAME#trivia-finals#SHARD#7

low

193 estimated WCU/s. Keep shard count tied to estimated peak WCU and monitor per-shard skew.