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

1M

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.

93

readiness

Hot partition risk

23

Consistency score

94

Cost score

88

Hot partition heatmap

Logical partition pressure

Jun 29, 11:45 PM

23

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

21

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

21

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

21

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

19

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

19

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

19

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

19

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

18

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

18

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

18

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

17

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

What-if shard count estimator

Peak hot key WCU/s

227

Safety WCU target

700

Minimum shards

1

Recommended shards

32

Event stream

READ_LEADERBOARD

LEADERBOARD#REGION#US#BUCKET#22

low16ms

READ_LEADERBOARD

LEADERBOARD#GLOBAL#WINDOW#2035-06-07T19#BUCKET#1

low17ms

UPDATE_SCORE

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

low44ms

READ_LEADERBOARD

LEADERBOARD#REGION#EU#BUCKET#7

low27ms

JOIN_SESSION

USER#user_18394

low46ms

SUBMIT_ANSWER

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

low29ms

READ_LEADERBOARD

LEADERBOARD#REGION#US#BUCKET#8

low22ms

QUERY_HISTORY

USER#user_50299#HISTORY

low55ms

SUBMIT_ANSWER

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

low24ms

SUBMIT_ANSWER

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

low25ms

UPDATE_SCORE

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

low35ms

SUBMIT_ANSWER

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

low16ms

SUBMIT_ANSWER

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

low27ms

SUBMIT_ANSWER

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

low26ms

JOIN_SESSION

USER#user_25591

low43ms

READ_LEADERBOARD

LEADERBOARD#REGION#US#BUCKET#4

low24ms

SUBMIT_ANSWER

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

low27ms

SUBMIT_ANSWER

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

low26ms

SUBMIT_ANSWER

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

low25ms

JOIN_SESSION

USER#user_64792

low42ms

SUBMIT_ANSWER

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

low22ms

SUBMIT_ANSWER

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

low23ms

SUBMIT_ANSWER

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

low34ms

SUBMIT_ANSWER

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

low35ms

READ_LEADERBOARD

LEADERBOARD#GLOBAL#WINDOW#2044-02-05T23#BUCKET#0

low32ms

SUBMIT_ANSWER

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

low33ms

SUBMIT_ANSWER

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

low16ms

SUBMIT_ANSWER

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

low17ms

UPDATE_SCORE

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

low32ms

READ_LEADERBOARD

LEADERBOARD#GLOBAL#WINDOW#2044-06-17T23#BUCKET#7

low15ms

SUBMIT_ANSWER

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

low15ms

SUBMIT_ANSWER

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

low14ms

SUBMIT_ANSWER

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

low31ms

SUBMIT_ANSWER

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

low30ms

READ_LEADERBOARD

LEADERBOARD#REGION#EU#BUCKET#5

low33ms

SUBMIT_ANSWER

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

low32ms

UPDATE_SCORE

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

low45ms

SUBMIT_ANSWER

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

low26ms

JOIN_SESSION

USER#user_16793

low47ms

READ_LEADERBOARD

LEADERBOARD#REGION#US#BUCKET#6

low28ms

READ_LEADERBOARD

LEADERBOARD#REGION#US#BUCKET#18

low24ms

READ_LEADERBOARD

LEADERBOARD#GLOBAL#WINDOW#2036-01-05T12#BUCKET#5

low25ms

SUBMIT_ANSWER

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

low26ms

SUBMIT_ANSWER

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

low27ms

SUBMIT_ANSWER

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

low28ms

UPDATE_SCORE

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

low47ms

READ_LEADERBOARD

LEADERBOARD#GLOBAL#WINDOW#2036-05-17T13#BUCKET#4

low30ms

SUBMIT_ANSWER

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

low31ms

SUBMIT_ANSWER

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

low32ms

SUBMIT_ANSWER

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

low33ms

QUERY_HISTORY

USER#user_78799#HISTORY

low49ms

READ_LEADERBOARD

LEADERBOARD#REGION#US#BUCKET#28

low16ms

SUBMIT_ANSWER

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

low23ms

JOIN_SESSION

USER#user_46894

low40ms

READ_LEADERBOARD

LEADERBOARD#REGION#EU#BUCKET#27

low21ms

UPDATE_SCORE

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

low38ms

READ_LEADERBOARD

LEADERBOARD#GLOBAL#WINDOW#2036-05-17T07#BUCKET#5

low27ms

READ_LEADERBOARD

LEADERBOARD#REGION#US#BUCKET#26

low26ms

SUBMIT_ANSWER

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

low25ms

SUBMIT_ANSWER

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

low24ms

UPDATE_SCORE

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

low46ms

READ_LEADERBOARD

LEADERBOARD#REGION#EU#BUCKET#19

low29ms

SUBMIT_ANSWER

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

low20ms

SUBMIT_ANSWER

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

low21ms

READ_LEADERBOARD

LEADERBOARD#REGION#US#BUCKET#4

low18ms

QUERY_HISTORY

USER#user_59799#HISTORY

low51ms

SUBMIT_ANSWER

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

low16ms

UPDATE_SCORE

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

low35ms

SUBMIT_ANSWER

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

low14ms

SUBMIT_ANSWER

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

low15ms

READ_LEADERBOARD

LEADERBOARD#GLOBAL#WINDOW#2035-12-09T05#BUCKET#5

low15ms

READ_LEADERBOARD

LEADERBOARD#REGION#US#BUCKET#26

low14ms

SUBMIT_ANSWER

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

low23ms

SUBMIT_ANSWER

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

low22ms

UPDATE_SCORE

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

low43ms

SUBMIT_ANSWER

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

low24ms

READ_EVENT

USER#user_78895

low59ms

READ_LEADERBOARD

LEADERBOARD#REGION#US#BUCKET#28

low26ms

SUBMIT_ANSWER

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

low29ms

SUBMIT_ANSWER

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

low28ms

SUBMIT_ANSWER

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

low34ms

SUBMIT_ANSWER

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

low35ms

READ_LEADERBOARD

LEADERBOARD#GLOBAL#WINDOW#2044-03-28T15#BUCKET#4

low28ms

SUBMIT_ANSWER

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

low29ms

SUBMIT_ANSWER

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

low30ms

SUBMIT_ANSWER

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

low31ms

SUBMIT_ANSWER

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

low24ms

SUBMIT_ANSWER

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

low25ms

SUBMIT_ANSWER

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

low26ms

READ_LEADERBOARD

LEADERBOARD#REGION#EU#BUCKET#25

low27ms

SUBMIT_ANSWER

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

low27ms

SUBMIT_ANSWER

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

low26ms

JOIN_SESSION

USER#user_26293

low43ms

READ_LEADERBOARD

LEADERBOARD#REGION#US#BUCKET#2

low24ms

UPDATE_SCORE

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

low41ms

SUBMIT_ANSWER

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

low22ms

SUBMIT_ANSWER

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

low21ms

QUERY_HISTORY

USER#user_58198#HISTORY

low52ms

READ_LEADERBOARD

LEADERBOARD#REGION#EU#BUCKET#3

low19ms

UPDATE_SCORE

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

low36ms

Hot key findings

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

low

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

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

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

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

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

low

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

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

low

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

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

low

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

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

low

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

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

low

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