hybrid: added system.hybrid_watermarks to inspect the Hybrid table watermarks

[mkmkme]

Changelog category (leave one):

• Improvement

Changelog entry (a user-readable short description of the changes that goes to CHANGELOG.md):

Added system.hybrid_watermarks to introspect the hybrid tables watermarks

Documentation entry for user-facing changes

...

CI/CD Options

Exclude tests:

• Fast test
• Integration Tests
• Stateless tests
• Stateful tests
• Performance tests
• All with ASAN
• All with TSAN
• All with MSAN
• All with UBSAN
• All with Coverage
• All with Aarch64
• All Regression
• Disable CI Cache

Regression jobs to run:

• Fast suites (mostly <1h)
• Aggregate Functions (2h)
• Alter (1.5h)
• Benchmark (30m)
• ClickHouse Keeper (1h)
• Iceberg (2h)
• LDAP (1h)
• Parquet (1.5h)
• RBAC (1.5h)
• SSL Server (1h)
• S3 (2h)
• S3 Export (2h)
• Swarms (30m)
• Tiered Storage (2h)

[github-actions]

Workflow [PR], commit [fcc2455]

[arthurpassos]

LGTM

[arthurpassos]

Covers Hybrid tables visible to getTablesIterator() plus session-local temporary Hybrid tables

does this really need to be in the user facing documentation?

[arthurpassos]

Do we really need to sort it? wouldn't it make more sense to let the user do the sorting?

[alsugiliazova]

Verification: PR #1789

PR-added test — all GREEN

03682_system_hybrid_watermarks — 6/6 OK across every stateless job that picked it up:

Job	Status
Stateless tests (amd_asan, db disk, distributed plan, sequential)	OK
Stateless tests (amd_debug, distributed plan, s3 storage, sequential)	OK
Stateless tests (amd_debug, sequential)	OK
Stateless tests (arm_asan, azure, sequential, 1/2)	OK
Stateless tests (arm_asan, targeted)	OK
Stateless tests (arm_binary, sequential)	OK
Fast test	SKIPPED (expected)

The new system.hybrid_watermarks table has clean positive coverage on all stateless flavors.

CI overview (head commit)

• PR test workflow: 48 success / 48 skipped / 1 failure
• Regression workflow: 28 success / 67 skipped / 3 failure (chronic baseline; one suite fewer than typical)

PR test-workflow failure

Check	Verdict
Stateless tests (arm_binary, sequential) — 00157_cache_dictionary	Pre-existing flake (78 fails / 25 PRs in 30d). Unrelated to Hybrid system-table diff.

Regression-workflow failures (chronic baseline on antalya-26.3)

Suite	Fails
Swarms (Aarch64 + Release)	456
Parquet (Aarch64 + Release)	36
S3Export part (Aarch64 + Release)	28

Same fingerprint as sibling antalya-26.3 PRs (1788, 1782, 1776, 1783, 1775, …). S3Export partition was actually green on this run. No new failure modes.

Caveat — partial frontport

PR lands on antalya-26.3 while companion features from antalya-26.1 are still being frontported in parallel. Final re-verify recommended once the rest of the bundle lands.

Verdict

Safe to merge.

[alsugiliazova]

Audit: PR #1789 — hybrid: added system.hybrid_watermarks to inspect the Hybrid table watermarks

AI audit note: generated by AI (Cursor agent, audit-review skill).

Confirmed defects

No confirmed defects in reviewed scope.