Query performance across the stack

PostgreSQL · MySQL · MongoDB · 5 scenarios

Prototype — data is mocked and actions are not connected yet.

← Goals

PostgreSQLMySQLMongoDB L1–L2

The same skill, three systems: spot the missing index and bad query plan whether it's Postgres, MySQL or MongoDB. Read the plan, propose the index, verify before/after.

2 / 5 scenarios passedScore avg 93%
Due Jun 30, 2026 · 3 weeks left

Scenarios to pass

PostgreSQL Query performance · L1 Missing index on a hot endpoint 96% Passed › MySQL Query & indexing · L1 Missing composite index (full table scan) 90% Passed › MongoDB Query & indexes · L1 Missing compound index — In progress ›
PostgreSQL Query performance · L2 N+1 query storm — Not started
MongoDB Query & indexes · L1 Sort not covered by index — Not started

How this goal was set

  • SystemsPostgreSQL · MySQL · MongoDB
  • LevelMid
  • Focus areaQuery performance & indexing
  • IntensityStandard · 5 scenarios

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Prototype — scenario scores are mocked.