Database / ScyllaDB Interview questions
How can you optimize write performance in ScyllaDB?
- Design partition keys to avoid hotspots - uneven key distribution caps throughput on a few nodes regardless of cluster size.
- Use a shard-aware driver so writes go directly to the owning shard, avoiding an internal network hop.
- Prefer single-partition batches over multi-partition ones, or skip batching for unrelated writes entirely.
- Pick an appropriate consistency level - LOCAL_QUORUM instead of QUORUM avoids unnecessary cross-datacenter latency for most workloads.
- Match compaction strategy to workload - STCS or ICS for write-heavy tables reduces compaction overhead competing with foreground writes.
- Use asynchronous/pipelined writes from the client instead of waiting for each write to complete before issuing the next.
As with reads, most sustained write bottlenecks trace back to schema design (a hot partition key) rather than something tunable purely at the client or cluster-configuration level, so it's worth checking per-partition and per-shard metrics before assuming the fix is purely operational.
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