# SQ-025: Compression & Performance Tuning

**Status:** `[x] DONE`
**Blocked by:** SQ-024
**Priority:** Low

## Description

Add zstd compression to S3 segment shipping and create a benchmark suite.

## Files to Create/Modify

- `crates/sq-storage/src/object_store/shipper.rs` - add zstd compression
- `crates/sq-storage/src/object_store/reader.rs` - add zstd decompression
- `crates/sq-storage/benches/` - throughput benchmarks

## Benchmarks

- Write throughput: messages/sec at various payload sizes
- Read throughput: messages/sec sequential scan
- Compression ratio: raw vs compressed segment size
- S3 round-trip: write, ship, trim, read from S3

## Acceptance Criteria

- [ ] Compressed segments round-trip correctly (write -> compress -> upload -> download -> decompress -> read)
- [ ] Compression ratio metrics are logged
- [ ] Benchmarks produce readable output
- [ ] No correctness regressions (all existing tests still pass)