Benchmarks

Recorded benchmark results from an Apple M4 MacBook Air (arm64, 10 cores, Go 1.26.3).

Source: benchmarks/m4-macbook-air-results.txt, benchmarks/PallasDB-M4-Benchmark.md, benchmarks/performance-optimizations-2026-06-03.md

Summary results

All runs reported missing: 0 and errors: 0.

Benchmark phases

Each benchmark run executes the following sequential phases:

Detailed results

128-byte values, 2 million keys

populate:      19,993 ops/sec  (1m40s total)
compact:       12.7s
reopen:        890 µs
random_read:   26,588 ops/sec  (18.8s for 500k reads)
iterate_keys:  1,014,357 ops/sec
iterate_values: 974,720 ops/sec
data_dir_size: 324,396,366 bytes (~309 MiB)

1 KiB values, 500k keys

populate:      43,362 ops/sec  (11.5s total)
compact:       5.6s
reopen:        425 µs
random_read:   33,529 ops/sec  (8.9s for 300k reads)
iterate_keys:  911,829 ops/sec
iterate_values: 732,912 ops/sec
data_dir_size: 529,099,166 bytes (~505 MiB)

16 KiB values, 50k keys

populate:      12,281 ops/sec  (4.1s total)
compact:       3.7s
reopen:        222 µs
random_read:   5,364 ops/sec   (18.6s for 100k reads)
iterate_keys:  322,315 ops/sec
iterate_values: 141,650 ops/sec
data_dir_size: 820,910,006 bytes (~783 MiB)

Performance optimizations (2026-06-03)

Two optimizations were applied after the initial benchmark run, resulting in significant improvements for large-value workloads:

1. Binary search key-only reads

Previously, compareKeyAt read both key and value bytes during binary search. The fix reads only the key during comparison, fetching the value separately only after the binary search confirms a match.

2. Fast-path append for ordered writes

When a transaction's updates are ordered after all existing memtable keys and no concurrent transactions are open, the commit appends directly to the memtable slices instead of performing a full merge. This eliminates O(n) work for sequential-key batch inserts.

Before vs. after (16 KiB values):

Running benchmarks

Smoke test (fast verification)

go run ./cmd/pallasdb local benchmark \
  --data-dir /tmp/smoke \
  --reset --keys 20000 --value-size 128 \
  --batch-size 500 --read-ops 20000 \
  --scan-limit 20000 --compact \
  --format text

Full scaled benchmark

go run ./cmd/pallasdb local benchmark \
  --data-dir /tmp/bench-v128 \
  --reset --keys 2000000 --value-size 128 \
  --batch-size 1000 --read-ops 500000 \
  --compact --format text \
  --output benchmarks/results.txt

Verifying the benchmark implementation

go test ./cmd/pallasdb -run 'TestLocalBenchmark'
go test ./db ./cmd/pallasdb

Environment

All recorded results were produced on: