Lei, HUANG 98612800ad perf(mito2): make compaction picker asynchronous to avoid blocking the region worker (#8624)
* refactor(mito2): run compaction picking in background with plan tracking

Move the compaction picker out of the region worker's critical path by
dispatching planning to a background task and reporting the result back
via CompactionPickFinished. CompactionStatus now tracks an explicit
picking phase keyed by a monotonic plan id, so stale planning results
are rejected and duplicate regular triggers coalesce while picking.

Before submitting a prepared compaction, the picker output is refreshed
against the current SST version (file handles are re-resolved and
conflicts roll back reservations), ensuring the plan still matches live
state. CompactionExecution identifies the running task by
(plan id, kind, version control) so finish/cancel/fail notifications
from outdated executions are ignored.

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* fix(mito2): notify pick finished even when compaction planning panics

The worker only leaves the picking phase after receiving the
CompactionPickFinished notification. Previously the planning task was
spawned fire-and-forget: if it panicked before sending the notification,
the region would be stuck in the picking phase forever, blocking all
future compactions and pending DDLs (e.g. entering staging) of the
region.

Wrap the planning future with catch_unwind so a panic is converted into
a CompactionPlanningResult::Error and the notification is always sent,
letting the worker run the normal error cleanup path.

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* fix(mito2): dec inflight compaction gauge after re-entrancy guard

DefaultNotifier::notify decremented INFLIGHT_COMPACTION_COUNT before the
re-entrancy guard, so a duplicate notify (which should never happen, but
the guard exists to defend against it) would decrement the gauge an
extra time and let it drift negative. Move the decrement after the
guard, matching the local compaction path's guard-then-account order.

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* fix(mito2): remove idle compaction status to prevent zombie state

When a compaction finished within min_compaction_interval with no
pending requests, on_compaction_finished left an idle status
(phase = None) behind. The worker then skipped chaining the next
compaction due to the interval gate, and the leftover status made
schedule_compaction swallow all future triggers of the region: regular
waiters were queued but never woken, and manual requests stayed pending
forever. The region stopped compacting until close/drop/truncate.

Add CompactionScheduler::remove_idle_status and call it from
handle_compaction_finished when the interval has not elapsed and no
chained planning is scheduled. The chain-until-no-plan semantics for
compactions that outlast the interval is preserved.

Also drops an unused import left by the previous commit.

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* refactor(mito2): make compaction scheduling methods synchronous

schedule_compaction, handle_pending_compaction_request and
schedule_next_compaction no longer await anything after compaction
planning became fire-and-forget. Drop the async signature to make the
no-suspension-point invariant explicit: these methods always run to
completion on the worker loop without reentrancy.

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* fix(mito2): report stale compaction execution instead of region closed

When a compaction finishes but its execution no longer matches the
current one, the region may have been reopened or truncated, or the
compaction was superseded. Reporting RegionClosed to waiters is
misleading; introduce a neutral StaleCompactionExecution error (same
Cancelled status code) for this case.

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* fix(mito2): serialize truncate with compaction

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* fix(mito2): avoid panic-based compaction status lookups

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* fix(mito2): keep in-flight compaction plan when scheduling next

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* fix(mito2): notify cancelled compaction pending ddl

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* typo: rename prefence to pre_fence to bypass typo check

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* test(mito2): trim redundant compaction tests

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* test(mito2): move compaction tests to dedicated file

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* fix: typo and format

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* Revert "test(mito2): move compaction tests to dedicated file"

This reverts commit e202f1f5

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* chore: revert test movement

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* fix(mito2): remove redundant compaction status lookups

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* fix: typo

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* test(mito2): remove duplicate compaction test file

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* test(mito2): prune redundant compaction tests

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* refactor(mito2): simplify compaction plan identity

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* docs(mito2): design pending regular state simplification

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* docs(mito2): plan pending regular state simplification

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* refactor(mito2): simplify pending regular compaction state

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* remove: plan files

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* refactor(mito2): clarify compaction completion handling

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* refactor(mito2): inline compaction phase execution lookup

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* fix(mito2): warn instead of panic on pending DDL for non-compacting region

add_ddl_request_to_pending unwrapped the region status and panicked when
the region was not compacting. Log a warning and skip the request instead,
and inline the now-trivial CompactionStatus::queue_ddl helper.

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* fix(mito2): dispatch pending DDLs before chaining regular compaction

A DDL queued behind a TooLateToCancel compaction (commit started or
remote execution) was deferred behind a whole extra plan/execution
cycle when a regular trigger had been retained during picking. Dispatch
the pending DDLs as soon as the current task finishes instead: satisfy
the retained regular waiters with the just-finished compaction, remove
the region status, and return the DDLs immediately.

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* fix(mito2): demote stale compaction failure logs to debug

Check region presence and execution staleness before logging, so a
superseded execution's terminal failure no longer emits a misleading
error log.

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* refactor(mito2): atomically queue compaction DDLs

Combine compaction cancellation and dependent DDL enqueueing under one
status borrow. Return the typed request unchanged when no compaction is
running, avoiding both an unreachable warning branch and silent DDL
loss if the invariant changes.

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* docs(mito2): explain why picker output handles are re-resolved

Addresses review question on refresh_picker_output: picking runs in
background on a possibly-stale version snapshot, so handles must be
re-resolved against the current version at accept time to detect
removed files and to read/reserve the up-to-date handle.

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* refactor(mito2): keep compaction gate in test module

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* style(mito2): format compaction DDL helper calls

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* refactor(mito2): group active compaction state

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* fix(mito2): fence compaction triggers behind pending DDL

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* refactor(mito2): simplify pending DDL collection in compaction scheduler

Replace the take-and-restore dance of the active compaction state with
an up-front busy check before handling pending compaction requests,
then take the active state once to drain DDL waiters.

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* docs: clarify that pending_request only carries manual StrictWindow compaction in production

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

* fix(mito2): arm DDL gate before cancellation

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>

---------

Signed-off-by: Lei, HUANG <ratuthomm@gmail.com>
2026-07-28 15:02:06 +00:00
2023-08-10 08:08:37 +00:00
2023-06-25 11:05:46 +08:00
2023-11-09 10:38:12 +00:00
2023-03-28 19:14:29 +08:00

GreptimeDB Logo

One database for metrics, logs, and traces
replacing Prometheus, Loki, and Elasticsearch

The unified OpenTelemetry backend — with SQL + PromQL on object storage.

Introduction

GreptimeDB is an open-source observability database built for Observability 2.0 — treating metrics, logs, and traces as one unified data model (wide events) instead of three separate pillars.

Use it as the single OpenTelemetry backend — replacing Prometheus, Loki, and Elasticsearch with one database built on object storage. Query with SQL and PromQL, scale without pain, cut costs up to 50×.

Overview

A quick overview of what GreptimeDB ingests, how it connects to other systems, and what its distributed engine lets you do.

GreptimeDB Overview

Features

Feature Description
Observability 2.0 native Logs, metrics, and traces in one engine with SQL + PromQL. Native OpenTelemetry, Prometheus remote write, and Jaeger. Migrate one signal at a time, or use as a single backend.
Elastic compute-storage separation Scale reads independently with horizontal replicas. Serve high-concurrency workloads from dashboards, alerting, and AI agents — without resharding or data migration.
Sub-second on PBEB-scale data Columnar engine with fulltext, inverted, and skipping indexes. Written in Rust. Designed for high-concurrency point queries, not just analytical scans.
50× lower cost Object storage (S3, GCS, Azure Blob) as primary storage, with a tiered cache (memory + local disk) to keep writes and queries fast.

Perfect for:

  • Replacing Prometheus + Loki + Elasticsearch with a single observability backend
  • Scaling past Prometheus — high cardinality, long-term storage, no Thanos/Mimir overhead
  • AI/agent workloads — store GenAI telemetry (OTel GenAI conventions), and serve high-concurrency reads from SRE/developer agents via horizontal read replicas
  • Cutting observability costs with object storage (up to 50× savings on traces, 30% on logs)
  • Edge-to-cloud observability with unified APIs on resource-constrained devices

Why Observability 2.0? Three separate databases for metrics, logs, and traces means three storage layers, three query languages, and three sets of dashboards. GreptimeDB stores all three as timestamped wide events in one columnar engine — JOIN across signals in SQL, run one stack instead of three, and ingest AI agent telemetry the same way. Read more: Observability 2.0 and the Database for It.

Learn more in Why GreptimeDB.

How GreptimeDB Compares

Capability GreptimeDB Prometheus / Thanos / Mimir Grafana Loki Elasticsearch
Data types Metrics, logs, traces Metrics only Logs only Logs, traces
Query language SQL + PromQL PromQL LogQL Query DSL
Storage Native object storage (S3, etc.) Local disk + object storage (Thanos/Mimir) Object storage (chunks) Local disk
Scaling Compute-storage separation, stateless nodes Federation / Thanos / Mimir — multi-component, ops heavy Stateless + object storage Shard-based, ops heavy
Cost efficiency Up to 50× lower storage cost High at scale Moderate High (inverted index overhead)
OpenTelemetry Native (metrics + logs + traces) Partial (metrics only) Partial (logs only) Via instrumentation

Benchmarks:

Architecture

GreptimeDB can run in two modes:

  • Standalone — single binary for development and small deployments.
  • Distributed — four components, each independently scalable:
    • Frontend — protocol entry (OTel, Prometheus, MySQL/PostgreSQL, gRPC, ingestion APIs for Elasticsearch/InfluxDB/Loki) and the distributed query engine. Stateless, scales horizontally.
    • Datanode — region engine with WAL, memtable, SST, cache, compaction, and indexes. Persists data to object storage. Elastic.
    • Metasrv — metadata, routing, repartitioning, autopilot, and security. Backed by a pluggable KV layer (etcd or RDS).
    • Flownode (optional) — continuous flow computation (streaming and materialized views).

For deeper coverage, see the architecture doc or DeepWiki.

GreptimeDB System Overview

Try GreptimeDB

For AI agents — paste this prompt into your agent:

Read https://docs.greptime.com/SKILL.md and follow the instructions
to deploy, configure, ingest, and query GreptimeDB.
docker run -p 127.0.0.1:4000-4003:4000-4003 \
  -v "$(pwd)/greptimedb_data:/greptimedb_data" \
  --name greptime --rm \
  greptime/greptimedb:latest standalone start \
  --http-addr 0.0.0.0:4000 \
  --rpc-bind-addr 0.0.0.0:4001 \
  --mysql-addr 0.0.0.0:4002 \
  --postgres-addr 0.0.0.0:4003

Dashboard: http://localhost:4000/dashboard

Read more in the full Install Guide.

Troubleshooting:

  • Cannot connect to the database? Ensure that ports 4000, 4001, 4002, and 4003 are not blocked by a firewall or used by other services.
  • Failed to start? Check the container logs with docker logs greptime for further details.

Getting Started

Build From Source

Prerequisites:

  • Rust toolchain — nightly, pinned by rust-toolchain.toml
  • Protobuf compiler (>= 3.15)
  • C/C++ building essentials: gcc / g++ / autoconf and the glibc dev package (libc6-dev on Ubuntu, glibc-devel on Fedora)
  • Python toolchain (optional, only for some test scripts)

Build and run:

make                          # build greptime binary
cargo run -- standalone start # start in standalone mode

Common dev commands:

make fmt            # format Rust code
make clippy         # lint (fails on warnings)
make test           # unit + integration tests (uses cargo-nextest)
make sqlness-test   # SQL regression tests

See the Contribution Guidelines for the full developer workflow.

Tools & Extensions

Project Status

GreptimeDB is at v1.0 GA with stable APIs and regular releases. It runs in production at scale — OceanBase Cloud operates 80+ GreptimeDB clusters managing 300 TB of logs, cutting log storage cost by 60% after migrating from Grafana Loki. See more in case studies.

Read the v1.0 highlights and 2026 roadmap, or browse the version reference.

If GreptimeDB is useful to you, please star the repo.

Star History Chart Known Users

Community

We invite you to engage and contribute!

License

GreptimeDB is an open-core project. Its core is licensed under the Apache License 2.0.

A small set of peripheral, enterprise-only features are gated behind the enterprise Cargo feature (not built by default) and are governed by the separate GreptimeDB Enterprise License. Source files under that license carry an explicit Enterprise License header.

Commercial Support

Running GreptimeDB in your organization? We offer enterprise add-ons, services, training, and consulting. Contact us for details.

Contributing

Acknowledgement

Special thanks to all contributors! See AUTHOR.md.


All trademarks, logos, and brand names referenced in this README and in the Overview diagram are the property of their respective owners. Their use is for identification purposes only and does not imply endorsement or affiliation.

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