mysqld_exporter

Author: Ludovic HENRY ludovic.henry@qti.qualcomm.com
Date: 2026-06-17
Scope: RISC-V (riscv64/linux) support status for mysqld_exporter
Audience: Technical leadership, resource allocation strategy
Verification policy: Every claim is cross-referenced to a primary upstream source. Items that could not be verified against a second source are marked [NEEDS VERIFICATION].

1. Project Overview

mysqld_exporter is a Prometheus exporter that scrapes MySQL and MariaDB instances and exposes metrics over HTTP for collection by the Prometheus time-series database. It is written in pure Go with no C/CGo dependencies.

The project lives under the prometheus GitHub organization and is a CNCF Graduated project (graduated 2018-08-09). License: Apache-2.0. There is no MAINTAINERS, OWNERS, or CODEOWNERS file. Governance is informal and community-driven.

Active contributors and their affiliations (derived from GitHub contributor API and PR review history):

Contributor GitHub handle Affiliation
Ben Kochie SuperQ prometheus (community/independent)
Arthur Silva Sens ArthurSens Grafana Labs
Cristian Greco cristiangreco Grafana Labs
Tom Wilkie tomwilkie Grafana Labs (CTO)
Roman Vynar roman-vynar Quiq

SuperQ (Ben Kochie) is the all-time top contributor by commit count (322 commits). Grafana Labs is the dominant corporate presence across the active reviewer pool. There is no formal port approval process and no tier policy for new architectures; riscv64 support arrived passively through shared build infrastructure with no per-project decision required.

The project is not listed on riseproject.dev. No RISE blog posts mention mysqld_exporter.

2. Port History and Upstreaming Timeline

Date Event Source
2023-04-09 promu PR #254 opened by Philipp Trulson (der-eismann): “Add linux/riscv64 to default platforms” – motivation cited as rising number of RISC-V boards (STAR64, SiFive) and mature Go riscv64 support promu PR #254
2023-05-31 SuperQ approves promu PR #254; CI flake delays merge ~2 months promu PR #254 comments
2023-07-01 promu PR #254 merged. linux/riscv64 added to defaultPlatforms in cmd/crossbuild.go. dongjiang1989 notes dependency on node_exporter PR #2706 promu PR #254 merge
2023-07-04 promu v0.15.0 released, including riscv64 in default cross-compile target list promu release history
2023-08-15 prombot syncs updated Makefile.common (promu v0.15.0) into mysqld_exporter via commit 59ecd933 (PR #762) mysqld_exporter commit history
2023-10-03 mysqld_exporter PR #773 merged: “Synchronize common files from prometheus/prometheus”. This is the commit that brought riscv64 into mysqld_exporter’s build config PR #773
2023-12-12 mysqld_exporter v0.15.1 released. mysqld_exporter-0.15.1.linux-riscv64.tar.gz appears in release assets – first riscv64 release GitHub releases API
2026-04-09 prombot PR #1018 syncs DOCKER_ARCHS ?= amd64 armv7 arm64 ppc64le riscv64 s390x into Makefile.common, adding riscv64 to Docker image builds Makefile.common
2026-08-13 mysqld_exporter v0.20.0 released (latest). mysqld_exporter-0.20.0.linux-riscv64.tar.gz present GitHub releases API

The riscv64 binary is fully upstreamed. It was never a mysqld_exporter-specific effort – it arrived silently through the shared Prometheus build toolchain (promu). No mysqld_exporter-specific RISC-V issue, PR, or code change exists in the repository.

3. Upstream Support Tier

mysqld_exporter has no formal tier policy. All architectures are implicitly equal because the promu cross-compilation toolchain handles them uniformly.

Attribute amd64 arm64 riscv64
Binary release artifact Yes Yes Yes (since v0.15.1, 2023-12-12)
Docker image (Docker Hub / GHCR) Yes Yes Yes
Docker image (quay.io) Yes Yes No – quay.io limitation, not a project limitation
CI test execution Yes No No
Distro packages Partial (Debian) Partial (Debian) No official distro package
Release-blocking status Implicit Implicit Implicit

riscv64 has equal standing to arm64 at the binary release and Docker image layer. Neither arm64 nor riscv64 has CI test execution. The quay.io gap for riscv64 is a quay.io infrastructure limitation, not a project decision [NEEDS VERIFICATION – quay.io riscv64 support boundary not independently confirmed].

4. Technical Architecture and RISC-V-Specific Subsystems

mysqld_exporter is a pure Go application. It connects to MySQL or MariaDB via the go-sql-driver/mysql driver, executes SQL queries, maps results to Prometheus metric types, and serves them over HTTP. There is no JIT compiler, no SIMD dispatch, no custom crypto, no garbage collector integration, and no inline assembly anywhere in the project.

Total source files audited: 78 Go files across collector/, config/, and root. Assembly files: 0. Arch-specific source files: 0. Build tags with architecture conditions: 0.

The two riscv64 references in the repository are both in build/packaging files:

  1. Makefile.common line 93: DOCKER_ARCHS ?= amd64 arm64 armv7 ppc64le riscv64 s390x – a flat list of Docker cross-build targets, identical treatment for all six architectures.
  2. .dockerignore: !.build/linux-riscv64/ – whitelists the cross-compiled artifact directory for Docker COPY.
Component amd64 arm64 riscv64
JIT compiler N/A N/A N/A
SIMD / vector intrinsics None None None
Architecture-specific assembly None None None
Custom crypto None None None
Architecture-specific build tags None None None

All architectures are treated identically at the source level because there is nothing arch-specific to implement. mysqld_exporter’s work is SQL query execution and HTTP response formatting – no ISA-dependent logic exists or is needed.

5. Build System, Cross-Compilation, and Toolchain

Build tool: promu (Prometheus cross-compilation utility). No CMake, no C/C++ compiler, no CGo.

Toolchain requirements:

Requirement Value Reason
Go version 1.26 Specified in .promu.yml and ci.yml (quay.io/prometheus/golang-builder:1.26-base)
C/C++ compiler Not required Pure Go, CGO disabled
CGO Disabled No C dependencies
QEMU Not required for build May be needed for docker buildx multi-platform if building on non-riscv64 host

Build commands:

Standard build (host architecture):

make build

Cross-compile for riscv64 (two equivalent forms):

GOOS=linux GOARCH=riscv64 make build
GOOS=linux GOARCH=riscv64 go build ./...

Docker image for riscv64:

Both Dockerfiles (Dockerfile and Dockerfile.distroless) use an ARG ARCH pattern:

docker build -t prom/mysqld-exporter-linux-riscv64:latest \
  --platform linux/riscv64 \
  --build-arg ARCH=riscv64 \
  --build-arg OS=linux \
  -f Dockerfile .

Or via Makefile target:

make common-docker-riscv64

Known build configuration caveat: The project-level Makefile overrides DOCKER_ARCHS to only amd64 armv7 arm64, which means make common-docker does not build the riscv64 image by default. The riscv64 Docker image requires either an explicit make common-docker-riscv64 or a command-line override: make DOCKER_ARCHS="amd64 armv7 arm64 riscv64" common-docker. The Makefile.common default (which includes riscv64) is masked by the project-level override.

No known build failures for riscv64. All Debian riscv64 builds completed successfully (see Section 8).

6. Feature Coverage and Gap Analysis vs arm64 and amd64

Feature amd64 arm64 riscv64
All scrapers functional Yes Yes (assumed, no CI) Yes (assumed, no CI)
Full metrics output Yes Yes (assumed) Yes (assumed)
TLS/auth (exporter-toolkit) Yes Yes Yes
Docker image (Docker Hub / GHCR) Yes Yes Yes
xxhash acceleration Yes (SIMD via cespare/xxhash) Yes (SIMD) No – pure-Go fallback (xxhash_other.go, build tag !amd64 && !amd64)
ChaCha20 / Poly1305 acceleration Yes (asm) Yes (asm) No – pure-Go fallback (golang.org/x/crypto)
CRC32 acceleration Yes (asm) Yes (asm) No – golang/go#78918 (asm not yet implemented)

Functional gaps: None. All scrapers compile and are expected to function correctly on riscv64 via standard Go cross-compilation. No functional gap vs amd64 or arm64 has been identified or reported.

Performance gaps: Three crypto/hashing paths fall back to pure-Go implementations on riscv64: xxhash (used in Prometheus metrics path), ChaCha20/Poly1305 (TLS), and CRC32 (Go runtime). These are correctness-correct but slower. For mysqld_exporter’s workload – periodic metric scraping at 15-60 second intervals – the performance impact of missing SIMD on these paths is negligible in practice. The bottleneck is SQL query execution latency, not hash computation throughput.

Security hardening gaps: Data not available: no source examined stack canary, CFI, or hardening flag differences between architectures for this project.

7. CI/CD Infrastructure

All CI runs exclusively on ubuntu-latest (x86_64). This was confirmed by reading every workflow file in .github/workflows/: ci.yml, approve-workflows.yml, container_description.yml, golangci-lint.yml, govulncheck.yml, integration.yml. None contain the word “riscv”, a riscv64 runner label, QEMU configuration, or an architecture matrix.

CI attribute amd64 arm64 riscv64
Unit tests run in CI Yes No No
Integration tests run in CI Yes No No
Native hardware runner Yes (ubuntu-latest) No No
QEMU emulation No No No
RISE RISC-V runner No No No

The ci.yml build job delegates to prometheus/promci/build@370e8c15dcec50043cbe66f2f34633d9efc0a190 with a parallelism matrix of 4 threads. This composite action handles cross-compilation to produce the release binaries but does not execute any test suite on riscv64.

The integration.yml runs against a matrix of MySQL and MariaDB versions, all on ubuntu-latest (x86_64).

mysqld_exporter does not use RISE RISC-V runners. RISE runners (launched March 2026, Scaleway EM-RV1 hardware) are in use by 197 repos across 87 orgs as of the research date; mysqld_exporter is not among them.

Conclusion: The riscv64 binary ships untested. No test suite – unit, integration, or otherwise – runs on or for riscv64 in the upstream CI pipeline.

8. Distribution and Release Status

Upstream binary releases:

Every release since v0.15.1 (2023-12-12) includes mysqld_exporter-<version>.linux-riscv64.tar.gz. The latest release, v0.20.0 (2026-08-13), includes mysqld_exporter-0.20.0.linux-riscv64.tar.gz (9,488,787 bytes / ~9.05 MB). The riscv64 binary is the same size class as arm64 (9,100,263 bytes), indicating full feature parity with no stub builds.

Docker images:

riscv64 container images are published to Docker Hub and GHCR for every release. quay.io does not publish riscv64 images due to a quay.io infrastructure limitation [NEEDS VERIFICATION].

Distro packages:

Distribution riscv64 package Notes
Debian trixie/stable v0.17.2-1+b4 Built on Debian riscv64 builder rv-manda-02 (2025-06-23, 12 min build)
Debian sid/unstable v0.19.0-2 Built on rv-manda-02 (2026-05-20, 13 min build)
Ubuntu 24.04 Noble Not packaged No results on packages.ubuntu.com
Arch Linux RISC-V Not packaged Not in archriscv.felixc.at index

Debian build durations are build+test times on real RISC-V hardware (rv-manda-02). All builds completed with status “Maybe-Successful” (Debian autobuilder notation for successful builds). This is the only evidence of test execution on riscv64 hardware – it comes from Debian, not from upstream.

What a user must do to get a working binary:

On a riscv64 Linux system:

  1. Download mysqld_exporter-<version>.linux-riscv64.tar.gz from the GitHub releases page.
  2. Extract and run. No compilation required.

Or install via Debian package (apt install prometheus-mysqld-exporter) on Debian trixie or sid.

Runtime dependency: mysqld_exporter requires a running MySQL or MariaDB instance to scrape. MySQL has no official riscv64 binary releases. MariaDB does ship riscv64 packages and is fully compatible with mysqld_exporter as a scrape target.

9. Dependencies

Dependency Role riscv64 build riscv64 test riscv64 release Notes
go-sql-driver/mysql v1.10.0 MySQL wire-protocol driver (core data path) Yes - pure Go No riscv64 CI N/A (library) See project-reports/go-sql-driver-mysql.md
prometheus/client_golang v1.24.1 Prometheus metrics exposition Yes - pure Go No riscv64 CI N/A (library) See project-reports/prometheus.md
prometheus/exporter-toolkit v0.17.1 TLS/auth HTTP server scaffolding Yes - pure Go No riscv64 CI N/A (library) No open riscv64 issues
filippo.io/edwards25519 v1.2.0 Ed25519 crypto (TLS, JWT) Yes - pure Go fallback No riscv64 CI N/A (library) Only fe_amd64.s exists; riscv64 uses generic Go path (slower, correct)
cespare/xxhash/v2 v2.3.0 Hash function (Prometheus metrics) Yes - pure Go fallback No riscv64 CI N/A (library) riscv64 uses xxhash_other.go (build tag !amd64 && !arm64); no SIMD
golang.org/x/crypto v0.54.0 TLS primitives (ChaCha20, Poly1305) Yes - pure Go fallback No riscv64-specific CI N/A (library) No riscv64 asm; pure-Go paths are slower but correct
golang.org/x/sys v0.47.0 Linux syscall layer Yes - unix/asm_linux_riscv64.s exists golang/go CI covers linux/riscv64 via emulation N/A (library) golang/go#80880: LUCI riscv64 builder not yet added (open)
google.golang.org/protobuf v1.36.11 Protobuf serialization (metrics wire format) Yes - pure Go No riscv64-specific CI N/A (library) See project-reports/protocol-buffers.md
golang-jwt/jwt/v5 v5.3.1 JWT auth in exporter-toolkit Yes - pure Go No riscv64 CI N/A (library) No open riscv64 issues
Go toolchain 1.25/1.26 Compilation runtime Yes - linux/riscv64 supported golang/go#80880: LUCI builder pending Releases include riscv64 golang/go#79997: indexbyte_riscv64.s optimization pending; golang/go#78918: CRC32 asm missing. See project-reports/go.md
mysql/mysql-server (runtime target) The MySQL instance being scraped No official riscv64 binary No riscv64 CI No linux/riscv64 official releases No official riscv64 binary; use MariaDB (which does ship riscv64) as alternative. See project-reports/mysql.md

Critical dependency notes:

The most significant runtime dependency gap is MySQL itself: there is no official MySQL riscv64 binary. Operators on riscv64 must either build MySQL from source or use MariaDB, which is fully wire-compatible with mysqld_exporter. This is not a mysqld_exporter code issue but is the primary practical obstacle to deploying the full stack on riscv64.

The Go toolchain (see project-reports/go.md) has two open riscv64 issues: CRC32 assembly not yet implemented (golang/go#78918) and an indexbyte optimization pending (golang/go#79997). Neither is a correctness issue for mysqld_exporter’s workload.

No blocking riscv64 correctness bugs are open in any direct dependency.

11. Known Bugs and Active Issues

No riscv64-specific bugs exist in the prometheus/mysqld_exporter issue tracker. The search for “riscv” and “riscv64” across all issues and PRs returned zero results.

Architecture-neutral open issues relevant to production deployments:

ID Title Status Severity Notes
#784 perf_schema.eventsstatementssum scan error: uint64 overflow on SUM_SUM_TIMER_WAIT Open (historical tracker) Medium Fixed in PR #1058 (merged, ships in v0.20.0): columns now scanned as float64. Issue remains open as tracker. Affects all architectures equally.
#824 Slow scrape and OOM with many databases (186 DBs x 147 tables): scrape >9 s, memory 2.5-3.5 GB, OOM kill Open High Reported against v0.15.1 on x86_64. Unresolved. Applies to any architecture including riscv64.
#648 CPU usage ~850m (0.85 vCPU) in v0.13.0 and v0.14.0 vs minimal in v0.12.1 Open Medium Reported against MariaDB. Regression unresolved. Affects all architectures.

Issue #1025 (per-scraper query timeout) was merged in v0.20.0. Before fix: 4.8s scrape with 3 of 7 scrapers failing. After fix with --exporter.query_timeout=3 and MaxOpenConns=2: 3.0s scrape, only the slow scraper failed. Benchmark figures are from x86_64 reproduction testing.

12. Objections and Upstream Blockers

No stated objections to riscv64 exist anywhere in the project. The architecture is implicitly accepted because it requires no project-level decision – promu handles it automatically.

Technical blockers: None.

Organizational blockers: None. The project is governed informally by a small Grafana-dominated group that accepts cross-cutting changes via prombot automation.

Practical deployment blocker: MySQL has no official riscv64 binary. This is not a mysqld_exporter blocker – MariaDB is a fully compatible alternative and does ship riscv64 packages – but it limits the scope of riscv64 testing to MariaDB-based environments unless MySQL is built from source.

Acceptance probability for upstream contributions: High. The project accepts prombot-generated cross-cutting changes automatically, and any riscv64-related issue would be addressed as a generic Go correctness issue rather than a platform political question.

13. Investment Analysis

mysqld_exporter itself requires zero investment to enable on riscv64. The binary ships, the Docker image ships, and no source code changes are needed. The remaining gaps are CI, the MySQL runtime target, and performance.

13.1 Functional Enablement

No work needed. mysqld_exporter is fully functional on riscv64. The only functional gap is that MySQL (the scrape target) has no official riscv64 binary. This is tracked under project-reports/mysql.md and is not scoped here.

13.2 Performance Optimization

Three pure-Go fallback paths exist where riscv64 uses scalar code: xxhash, ChaCha20/Poly1305 (golang.org/x/crypto), and CRC32 (Go runtime). For mysqld_exporter’s scrape workload (SQL query execution, HTTP response formatting), none of these are on the critical path. Performance optimization of these paths belongs to their respective upstream projects (cespare/xxhash, golang.org/x/crypto, the Go toolchain), not mysqld_exporter. No investment in mysqld_exporter itself is warranted for performance.

13.3 CI/CD Infrastructure

The only actionable investment in mysqld_exporter itself is adding riscv64 CI. The project currently runs no tests on riscv64 – the binary ships untested. Adding RISE RISC-V runners to the CI pipeline would close this gap.

RISE runners are already deployed (Scaleway EM-RV1, label ubuntu-24.04-riscv, launched March 2026). Onboarding mysqld_exporter is a CI YAML change, not a source code change.

13.4 Ecosystem Enablement

mysqld_exporter has no package ecosystem (no plugins, no extensions, no language bindings). Section 10 is omitted accordingly. The relevant ecosystem work is getting MySQL itself onto riscv64, which is tracked separately.

13.5 Summary Table

Area Work Item Effort (person-weeks) Owner Priority
Functional None required 0 N/A N/A
Performance riscv64 SIMD for xxhash, ChaCha20, CRC32 Out of scope – upstream library work, not mysqld_exporter cespare, golang.org/x/crypto, Go toolchain Low (not on critical path for scraping workload)
CI/CD Add riscv64 CI job using RISE runners (unit + integration tests on MariaDB) 0.5 Community / RISE Medium
Ecosystem MySQL riscv64 official binary Out of scope – see project-reports/mysql.md MySQL/Oracle High (blocks full-stack deployment)

The only investable action directly in mysqld_exporter is the CI addition (0.5 person-weeks). All other gaps are either already solved or owned by upstream dependency projects.

14. Updates

No updates yet – initial report dated 2026-06-17.

15. References