Double booking

Quorum 18
SQLUsers100 req/sPostgres1 vCPU · 1 GB
SQLUsers100 req/sPostgres1 vCPU · 1 GB

Fix the board. Turn every goal green.

Traffic
100 req/s · reads only
Limit
Postgres answers about 15,000 reads/s
Bill
  • Postgres4 USD/mo
4 of 20 USD/mo

Goals

Not tested yet

Copies of data that do not match.What the servers and services cost each month.

Two transactions scan the same empty booking range, then each inserts a different row for slot 9. Prevent a phantom read and keep at most one committed booking in that range.

0:00. Two bookings hold slot 9. Graph: bookings in the range step from 0 to 2.

An order and its event commit togetherTap to turn the outbox on or off

Outbox · 10 orders · 10 events · 0 lost