Write skew

  • Fix
  • Quorum 17

Difficulty 3 of 5

Ada and Bo are both on call. Each transaction reads both rows, then sets its own row to off call. Keep at least one doctor on call when both transactions run at the same time.

0:00. Both doctors are off call. Graph: the on-call count drops from 2 to 0 in one step.

Play level

SQLUsers100 req/sPostgres1 vCPU · 1 GB
SQLUsers100 req/sPostgres1 vCPU · 1 GB
The board at the start of the level
An order and its event commit togetherTap to turn the outbox on or off

Outbox · 10 orders · 10 events · 0 lost

Goals and limits

Data mismatches
none
Write skew
none
Monthly cost
under 20 USD/mo
Edit limit
2
Traffic
100 req/s

Concepts

How players did

Player results load from the server.

All levels