Harden DBR umbrella: bound probe cost and pin connect to the major line - #27
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rugpanov wants to merge 3 commits into
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Harden DBR umbrella: bound probe cost and pin connect to the major line#27rugpanov wants to merge 3 commits into
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…he major line Follow-up hardening for the DBR 18+ umbrella scheme: - Cap the point-release probe for a bare major with no point-release pages (DBR 19 today). Gating the trailing-404 break on "a page was seen" let such a line scan the full 0..max_minor range (~52 requests). A separate max_leading_misses cap (5) ends the probe after a short run of leading 404s, keeping it above the 2-consecutive slack that bridges a removed early page. - Pin the bare-major umbrella's databricks-connect to the whole major line (18.x -> ~=18.0) instead of the latest point release's minor (~=18.2.0), matching the serverless whole-major convention. A cluster addressing the line by its bare major now resolves the newest connect in the major, and a new point release is covered without a regen. Point-release folders keep their exact-minor pin. Regenerates the 18.x / 19.x umbrella artifacts. - Simplify live_page to return just the classification (the page body was discarded at every call site) and note the transient no-live no-op window. 43 -> 46 unit tests: probe-count bound, leading-cap boundary, and an end-to-end DBR-19 umbrella-only assertion. Co-authored-by: Isaac <no-reply@databricks.com>
…he value Review follow-up. No behavior change: - Add a boundary test locking max_leading_misses=5 — a live release past a full run of leading 404s (18.0..18.4 deleted, 18.5 live) is not discovered, so a future change to the cap is a deliberate, visible edit. - Expand the comment: only genuine 404s count toward the cap (an EoS page is a hit that resets the counter, and upstream marks pages '(EoS)' rather than deleting them), and explain why 5. Co-authored-by: Isaac <no-reply@databricks.com>
Point releases are numbered contiguously from .0, so five leading 404s mean none were published (the empty case), not a gap. Comment + test docstring no longer conflate 'never existed' with 'deleted'. No behavior change. Co-authored-by: Isaac <no-reply@databricks.com>
rugpanov
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August 28, 2026 18:13
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Follow-up hardening for the DBR 18+ umbrella scheme merged in #26. Non-blocking review findings from that PR, addressed in one pass.
Changes
0..max_minorrange — ~52 HTTP requests per line. A separatemax_leading_missescap (5) ends the probe after a short run of leading 404s, kept above the 2-consecutive slack that bridges a removed early page. EoS pages don't count toward it (they reset the counter).databricks-connectto the whole major line —18.x→~=18.0instead of the latest point release's~=18.2.0— matching the serverless whole-major convention (dbconnect_pin). Point-release folders keep their exact-minor pin. Regenerates the18.x/19.xumbrella artifacts (~=18.0,~=19.0).live_pageto return just the classification; the page body was discarded at every call site.Why
A cluster addressing a line by its bare major should resolve the newest
databricks-connectin the major, and pick up a new point release without waiting on a regen. Verified withuv:18.xnow resolves to18.3.4(was capped at18.2.x) and19.xto19.1(the old~=19.0.0pin was already too tight to reach it). The probe cap keeps the weekly job from spending ~40s per bare major discovering pages that don't exist.Tests
43 → 47 unit tests: a probe-count bound for the no-point-release line, both leading-cap boundary cases (a live release within the slack is found; one past the cap is not), and an end-to-end
sync_dbrassertion for the DBR-19 umbrella-only path (wheredbr_metadefaults the minor). All green; artifacts regenerated bysync.py.