Performance

cqlsh-rs is significantly faster than Python cqlsh in startup time and query throughput.

Startup time

cqlsh-rs starts in milliseconds compared to seconds for Python cqlsh:

Measured with hyperfine on Linux x86_64.

Benchmarks

Performance is tracked continuously via CI. See the live results:

• Historical Dashboard — Interactive commit-over-commit charts
• Benchmark Workflow Runs — Grouped tables and Criterion artifacts

Running benchmarks locally

# All Criterion micro-benchmarks
cargo bench

# Individual benchmarks
cargo bench --bench startup
cargo bench --bench parser
cargo bench --bench format
cargo bench --bench formatter
cargo bench --bench completion

# Rust vs Python startup comparison (requires hyperfine + pip install cqlsh)
cargo build --release
scripts/bench_comparison.sh

Binary size

Memory usage

cqlsh-rs uses significantly less memory than Python cqlsh due to Rust’s lack of a garbage collector and runtime overhead.