Performance
82 practice items · needed by 13 roles
Easy 8Medium 29Hard 45
Practice questions
- Debounce vs throttle for searchmedium
- Why React.memo did not helphard
- Slow email during signupeasy
- What EXPLAIN tells youeasy
- The N+1 query problemmedium
- Offset or cursor paginationmedium
- Two awaits that could run togethermedium
- Index ignored for lower(email)medium
- Benefit of INCLUDE in an indexmedium
- Fine average, unhappy usersmedium
- Docker rebuild reinstalls everythingmedium
- Cache stampede on a hot keyhard
- One slow route freezes Node.jshard
- Connection pools and autoscalinghard
- Table bloat that VACUUM will not fixhard
- Work continues after the client gives uphard
- Trusting a Bloom filter answerhard
- Index for the few pending rowshard
- Inserts slow down with UUID keyshard
- Pool exhausted during paymentshard
- Concurrent requests from throughputhard
- The N+1 query problemmedium
- Caching hashed static filesmedium
- Three awaits, three times slowermedium
- ETag and If-None-Matchmedium
- One report slows every requestmedium
- Cache expiry takes down the databasehard
- Network calls on the main threadeasy
- Testing speed on a debug buildeasy
- const constructors in Fluttermedium
- Too many recompositionshard
- Jank when parsing a big JSONhard
- Slow cold starthard
- When a Swift array is copiedhard
- derivedStateOf for a scroll buttonhard
- Animation stutters while JS is busyhard
- Memoized rows still re-renderhard
- Spawning many bulletseasy
- GetComponent every frameeasy
- Too many draw callsmedium
- Thousands of detailed treesmedium
- Drawing rooms behind wallsmedium
- Many identical rocksmedium
- Is the game CPU or GPU boundmedium
- Timer text slows the whole HUDmedium
- Why ECS can be fasterhard
- Job safety system errorhard
- Alpha-tested foliage on mobilehard
- Stutter the first time an effect appearshard
- Two hundred animated charactershard
- Slow maths on a Cortex-M4Fhard
- Jitter in a control loop ISRhard
- Throttled at 30 percent CPUhard
- Slow external DNS in Podshard
- Java Pod OOMKilled with free heaphard
- Why put a CDN in front of a siteeasy
- Reducing serverless cold startsmedium
- Slow Docker builds after every changemedium
- Prometheus memory explosionmedium
- DynamoDB throttling under the limithard
- CDN cache hit ratio of 4 percenthard
- Disk latency spike during nightly batchhard
- Reading a slow tracemedium
- Listen queue overflowshard
- Sizing shared_buffersmedium
- WAL volume spikes after checkpointshard
- Indexes bloat on a counter tablehard
- OOM killer after raising work_memhard
- More threads, no extra throughputhard
- Partitioning a big tableeasy
- What causes a shufflemedium
- When to cache in Sparkmedium
- How Parquet skips datamedium
- One task takes foreverhard
- Millions of tiny fileshard
- Cutting warehouse scan costhard
- A slow Python UDF in PySparkhard
- Distinct users on billions of rowshard
- Clustering for two filter columnshard
- Choosing a Redshift DISTKEYhard
- Sensors blocking every workerhard
- Slow dependency install in CImedium