Release 0.9.0

[fmassot]

Summary

Prepare the 0.9.0 release on top of current main @ eec01c5b.

• Flesh out CHANGELOG.md [0.9.0]: Breaking / Migration notes, ingest V2 as the default, AWS Lambda search offloading, Jaeger v2, Trino-compatible endpoints, composite aggregation, plus the late release-visible work merged after the PR was first opened.
• Refresh the release-note audit for the remaining TODO bucket: DataFusion / Parquet metrics, metrics-rs migration, telemetry exporter changes, mTLS / health API, storage and Lambda fixes, control-plane fixes, dependency/security updates, and the explicit checklist PRs are now represented.
• Update docs/get-started/upgrade.md for the 0.8.x -> 0.9 migration path: ingest V2 default, /api/v1/{index}/ingest-v2 removal, ?use_legacy_ingest=true escape hatch, rest_listen_port -> rest.listen_port, stemming behind multilang, metastore migration / rollback notes, Rust 1.92, and metric-name changes from the metrics-rs migration.
• Bump workspace version in quickwit/Cargo.toml and refresh Cargo.lock, including workspace crates that still needed to move from 0.8.0 to 0.9.0.

Verification

• cargo metadata --locked --format-version 1
• cargo check --workspace --locked
• rest-api-tests/ against a fresh temporary 0.9 server:
  • /tmp/qw-rest-api-tests-venv/bin/python ./run_tests.py --engine quickwit --binary ../target/debug/quickwit
• Empirical 0.8.2 -> 0.9 compat test (file-backed metastore on a 1.5 GB, 10.4 M-doc qwdata): 0.9 rewrites manifest.json from v0.8 to v0.9, spawns pipelines for every pre-existing index, /describe returns unchanged counts, term/range/agg queries match the 0.8.2 counts, WAL replays on startup, round-trip ingest via the default V2 route succeeds.
• CI green on this branch
• Reviewer spot-checks Breaking / Migration section for anything expected but missing

Benchmark numbers captured separately (0.8.2 default ingest v1 vs 0.9 default ingest v2): good improvement in search perf, to be shared soon.

TODO Audit

We wanted to include a few more PRs before release:

• Upgrade some dependencies #6307
• Chitchat fix / bump (Chitchat update fixing bug that was triggering many gossip grpc #6082, bumped chitchat version #6323)
• fix(ui): upgrade yarn dependencies to reduce security vulnerabilities #6341
• fix(deps): update rustls-webpki to 0.103.13 (RUSTSEC-2026-0104) #6342
• truncate split lists in error logs using PrettySample #6315
• fix(lambda): rate-limit retry warn log to avoid log storms #6318
• Make Storage::get_slice zero copy for single-segment bodies #6336
• Others? Audited merged PRs since the original release base and updated release notes / upgrade notes for the release-visible items.

[fulmicoton]

We need the chitchat fix in. Releasing and updating chitchat version this morning.

[fulmicoton]

chitchat was updated. It is forced to 0.10.1 in Cargo.toml now, but you can also just regenerate the Cargo.lock.

[ramnes]

Hey team, we're interested in this release. Anything we can help with?