PG19: publish supported packaging images and exclude unsupported platforms

[ihalatci]

Problem

The merged pg19-support packaging workflow fails exactly seven PG19 cells:

• Run: https://github.com/citusdata/citus/actions/runs/31184648547
• Missing RPM images: oraclelinux-8-pg19, almalinux-8-pg19, almalinux-9-pg19
• DEB all-images lack a usable PostgreSQL 19 pg_config: Debian bullseye/bookworm and Ubuntu focal/jammy

All PG16-18 packaging cells pass.

Verified platform support

• PGDG EL9 testing repositories provide PostgreSQL 19 Beta 2 packages, so AlmaLinux 9 is supportable.
• PGDG EL8 PostgreSQL 19 testing metadata has no server/devel packages; Oracle Linux 8 and AlmaLinux 8 are not supportable without a nonstandard source-build workaround.
• PGDG apt provides PostgreSQL 19 packages for maintained Debian/Ubuntu images used by packaging.
• Ubuntu focal does not publish a PostgreSQL 19 component and cannot support this matrix cell.

Required coordinated changes

citusdata/packaging

• Generate/build/publish citus/packaging:almalinux-9-pg19.
• Add PostgreSQL 19 development packages to supported maintained DEB all-images.
• Explicitly reject/skip unsupported EL8 PG19 generation.

citusdata/citus

• Exclude PG19 only for oraclelinux-8, almalinux-8, and ubuntu-focal-all.
• Keep PG19 packaging tests enabled for AlmaLinux 9, Debian bullseye/bookworm, and Ubuntu jammy.

Acceptance criteria

• Supported images publish successfully.
• Citus packaging workflow has no unsupported PG19 cells.
• Supported PG19 cells pass on a fresh pg19-support run.
• PG16-18 matrix behavior remains unchanged.

Scope note

This is package/image availability work, not a PostgreSQL Beta 1→Beta 2 code regression.

Implementation PRs

• citusdata/packaging Fix error message of start_metadata_sync_to_node #1203 — add supported PG19 packaging images and explicit unsupported-platform guards
• citusdata/citus Exclude unsupported PostgreSQL 19 packaging jobs #8728 — exclude unsupported PG19 packaging test cells while retaining supported cells

Packaging PR #1203 is based on audited commit f373097fb013b4b31c847fe83dfb3c847480f9de with 15 files, +230/-32. Its image build, test-image build, health-check, and nightly workflows are running. No images were manually published.

Implementation PRs: citusdata/packaging#1203 and #8728.

PG19 wal2json image follow-up

PGDG does not publish postgresql-19-wal2json, and wal2json 2.6 does not compile against PG19. The PG19 exttester image therefore published without wal2json.so, causing CDC 016 to fail.

Validated local fix 416304722a7068aea381a515c4404bf62cbb19e0 updates only circleci/images/exttester/Dockerfile: PG16-18 retain strict PGDG package installation; PG19 builds pinned upstream revision 79d516e60463be3093ff927ba72cf6354bde09af, which contains PG19 support.

Validation compiled and loaded the plugin on PG19 Beta 2, created a logical slot, and decoded an inserted row. Publishing this update will use image suffix -dev-4163047.

[ihalatci]

Combined validation confirms four supported PG19 packaging cells still depend on packaging PR #1203 publication. PG19 CDC tests 001-015 pass; optional test 016 fails because the test image lacks wal2json. The image pipeline must confirm/install a PG19-compatible wal2json before the final matrix can be green.