Kolmos is a cloud database engine built for PostgreSQL, MySQL, and MongoDB workloads. It combines self-compressing storage, columnar architecture, and multi-wire compatibility to reduce database storage and cloud infrastructure costs.

Which database wire protocols does Kolmos support?

Kolmos natively supports PostgreSQL (port 5432), MySQL (port 3306), and MongoDB (port 27017) wire protocols. Standard drivers, ORMs (Prisma, Drizzle, SQLAlchemy, Hibernate), and database clients connect seamlessly with zero application code changes.

How does Kolmos reduce cloud database storage costs?

Kolmos uses an autonomous Explanation Ladder that mines Minimum Description Length (MDL) formulas and prototype clusters to compress data 1.66×–2.12× smaller than Parquet-zstd. It stores files directly on Cloudflare R2 object storage ($0.015/GB/mo) with zero data egress fees, cutting overall cloud database storage bills by 10× to 40×.

Is Kolmos data recovery 100% lossless?

Yes. Kolmos guarantees 100% mathematical fidelity via Invariant #1: decode(encode(x)) == x across all SQL and BSON data types. Every row decodes bit-perfectly with zero precision drift.

How does Kolmos execute fast analytical queries on cloud object storage?

Kolmos embeds min/max statistics and Bloom filters into segment headers. Using Apache DataFusion vectorized execution and predicate pushdown, the engine prunes irrelevant segments and streams zero-copy Apache Arrow memory buffers without downloading unneeded data.

What prevents vendor lock-in with Kolmos storage formats?

Every Kolmos segment footer pins an open, self-contained WASM decoder covenant executed in an isolated Wasmtime sandbox. This guarantees your database files remain readable perpetually decades later without requiring proprietary server runtimes.

Docs/Reference

CLI Reference

Every kolmos subcommand and the most important flags for each.

Last Updated: August 2026

1. Global Flags

These apply before the subcommand, on the root `kolmos` command: - `--root <dir>` (default `.`) — store root directory - `--store {local,s3}` (default `local`) - `--s3-bucket`, `--s3-region` (default `us-east-1`), `--s3-endpoint`, `--s3-access-key-id`, `--s3-secret-key` (env fallback `KOLMOS_S3_SECRET_KEY`), `--s3-prefix` (default `""`), `--s3-force-path-style`

bashKOLMOS Reference

kolmos --root /data --store s3 --s3-bucket kolmos-prod --s3-region auto <subcommand> ...

2. Subcommands

`ingest`, `query`, `serve`, `export`, `stats`, `explain-report`, `analyze`, `compact`, `vacuum`, `workload compile`, `verify`, `backup`, `restore`, `backup-log`, `derive`, `pg-ingest`, `mysql-ingest`, `mongo-ingest`, `demote`, `promote`, `demotion-policy {set,get,clear}`. See the Backup & Disaster Recovery guide for `backup`/`restore`/`backup-log`, and the storage guide for `compact`/`vacuum`/`demote`/`promote`.

3. serve — Full Flag Reference

The most commonly used flags for the long-running server process: - `--host` (default `127.0.0.1`), `--port` (default `5432`, Postgres wire) - `--username` (default `kolmos`), `--password` (env `KOLMOS_SERVE_PASSWORD`), `--auth-file <path>` - `--mysql-port`, `--mongo-port` — opt-in additional wire listeners - `--multi-store`, `--api-port`, `--api-token` (env `KOLMOS_API_TOKEN`), `--max-open-stores` (default `32`), `--idle-timeout-secs` (default `1800`) - `--tls-cert`, `--tls-key` - `--metrics-port`, `--log-format {text,json}` (default `text`) - `--vacuum-interval-secs` (default `300`, `0` disables), `--refresh-interval-secs` (default `5`, `0` disables — HA read-refresh worker)

bashKOLMOS Reference

kolmos --root /data serve --host 0.0.0.0 --port 5432 \
  --mysql-port 3306 --mongo-port 27017 \
  --tls-cert /certs/server.crt --tls-key /certs/server.key \
  --username kolmos --auth-file /auth.txt \
  --metrics-port 9090 --log-format json

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