pogreb

Shape: hash-log (Bitcask-style), pure Go Repository: github.com/akrylysov/pogreb

pogreb is a hash-log key/value store designed for fast random reads on datasets too big to keep in memory. It is the same family as tamnd/kv, but the plain Bitcask design: an append-only log with an in-memory index, no hot tier in front of it, no transactions. That makes it a good reference point for the hash-log shape stripped to its essentials.

Best at

• Fast point reads. 1,748,000 reads/sec cache-resident, third on the board behind tamnd/kv and buntdb. See read-heavy.
• Reads on a working set larger than memory. Out of cache it holds 2,149,000 uniform random reads/sec, near the top of the field, because a read is one index probe and one seek. See read-heavy.
• Steady writes. 17,000 fresh writes/sec out of cache, mid-pack.

Watch out for

• No ordered scan. Same as every hash-log: keys are in write order, no range queries. See range scans.
• Update churn. The plain design has no hot tier, so repeatedly updating the same key leaves old copies in the log to be compacted later. On the 50/50 mixed workload it holds 38,000 ops/sec, well behind tamnd/kv's hot-tier design.
• Durable write rate. 158 per second with a flush on every commit. See durable writes.
• No transactions. It is a plain key/value store; if you need atomic multi-key commits, look elsewhere.

Reach for it when

You want a simple hash-log for a read-mostly dataset larger than memory, and you do not need transactions, ordered scans, or a heavy update mix. If reads are truly the entire workload and the keyset fits in RAM, tamnd/kv reads faster and its hot tier absorbs updates that would churn pogreb's log.