Fencing a Postgres primary that might still be alive
Comments on “Fencing a Postgres primary that might still be alive”
Claim-checked. Scored by all three judges, and its checkable claims were compared with the sources it cites. How far stories are checked
ClickHouse describes how its managed Postgres, built on the open source Ubicloud control plane, fences a possibly live primary before promoting a standby. It runs several methods in parallel: stopping Postgres, locking pg_hba.conf, and cutting the network. On bare metal it downs a veth interface, on AWS it force-detaches a second NIC, and on GCP it deletes a Dynamic NIC. If every method fails, it promotes anyway, favoring availability. The GCP timings (0.7 to 2.5 seconds to last packet) are the authors' own measurements.
Why it ranked
No. 18 of 139 with a score of 0.66. The panel rated it highest on technical depth (0.93) and new information (0.92), lowest on audience breadth (0.50). Placed No. 18, No. 42 by score alone: the placement terms moved other stories past it.
- AI judgeJudge 2claude-haiku-5-5
- Detailed, measured engineering write-up on fencing a Postgres primary across bare metal, AWS and GCP, with specific mechanisms and timings. Strong technical depth; appeals mainly to infrastructure and database builders, not broadly new.
- AI judgeJudge 3gpt-5.6-luna
- A detailed, evidence-backed engineering account of PostgreSQL failover fencing across bare metal, AWS, and GCP, including failure modes, measured delays, implementation details, and the consequential fail-open availability trade-off.
Each judge wrote its line after answering the rubric, with the site and the author still hidden. Every answer behind this is in the table under Score.
Score
0.66total under rubric v2.3
- Significance0.55
- Reader interest0.79
- Audience breadth0.50
- Practical relevance0.71
- Substantiated0.84
- Technical depth0.93
- New information0.92
- Counts against: Promotional0.11
- Counts against: Overclaim0.14
Each judge’s answer per question (0–1), their mean and spread, and what the question adds to the score (weight × mean).
| Question | Judge 1 | Judge 2 | Judge 3 | Mean | Spread | Weight | Contribution (weight times mean) |
|---|---|---|---|---|---|---|---|
| SignificanceHow much does this change what people in tech know or can do? | 0.53 | 0.40 | 0.72 | 0.55 | 0.32 | +0.24 | +0.132 |
| Reader interestWould a well-informed senior engineer or tech founder want to read this today, and likely pass it on? | 0.68 | 0.80 | 0.88 | 0.79 | 0.20 | +0.26 | +0.205 |
| Audience breadthHow many people who build technology does it concern? | 0.47 | 0.50 | 0.52 | 0.50 | 0.05 | +0.13 | +0.065 |
| Practical relevanceHow useful is it to someone who builds software or tech products? | 0.72 | 0.60 | 0.82 | 0.71 | 0.22 | +0.22 | +0.157 |
| SubstantiatedHow well is it backed? Consider whether it is the primary source, and whether its main claims come with data, code, a demo, a reproducible method or citations. | 0.87 | 0.75 | 0.91 | 0.84 | 0.16 | +0.05 | +0.042 |
| Technical depthHow technically substantive is it? | 1.00 | 0.90 | 0.90 | 0.93 | 0.10 | +0.05 | +0.047 |
| New informationDoes it contain information absent from the stories covered in the last 7 days (list provided)? | 0.87 | 0.90 | 0.98 | 0.92 | 0.11 | +0.05 | +0.046 |
| PromotionalIs it mainly marketing with little substance (a press release, ad or sponsored post with no real information)? A launch post that carries real news is not promotional. | 0.06 | 0.20 | 0.08 | 0.11 | 0.14 | −0.19 | −0.022 |
| OverclaimDo the headline or conclusions claim more than the body supports? | 0.17 | 0.15 | 0.10 | 0.14 | 0.07 | −0.11 | −0.015 |
| Sum of contributions | +0.656 | ||||||
| Claim-check penalty | 0.000 | ||||||
| Total, as published | 0.656 | ||||||
Spread is the highest minus the lowest judge answer. marks a spread above 0.40: the judges disagree, and the story is marked contested.
The badge for this ranking, for the author's page or anyone's: one line of HTML, and it links back here.
<a href="https://rubric.hrih.si/editions/2026-11-05/18/"><img src="https://rubric.hrih.si/badge/2026-11-05/18.svg" alt="Ranked #18 on Rubric, 5 Nov 2026" width="238" height="28"></a>Claim check
Claim check: 4 matches source · 1 no source given · 3 couldn’t check. Each claim is compared with the source the article itself cites; a flag is published only when both checkers agree.
Couldn’t checkQuote
The Postgres documentation says a pg_hba.conf record type matches connection attempts, so rules apply only to new connections and not to sessions that are already open.
The source was unreachable, paywalled or too long, or the two checkers disagreed.
The article says “The Postgres documentation says for each record type that the record "matches connection attempts”
The source says No passage could be compared.
Source cited by the article: postgresql.org/docs/18/auth-pg-hba-conf.html
Matches sourceQuote
The veth(4) man page states that when either device of a veth pair is down, the link state of the pair is down.
The cited source says the same thing.
The article says “When either device is down, the link state of the pair is down”
The source says “When either device is down, the link state of the pair is down”
Source cited by the article: man7.org/linux/man-pages/man4/veth.4.html
Couldn’t checkDate
Since July 2025, the AWS StopInstances API has a skipOsShutdown parameter that skips the OS shutdown.
The source was unreachable, paywalled or too long, or the two checkers disagreed.
The article says “Since July 2025, StopInstances has a skipOsShutdown parameter that skips the OS shutdown”
The source says No passage could be compared.
Source cited by the article: docs.aws.amazon.com/AWSEC2/latest/APIReference/API_StopInstances.html
Couldn’t checkGeneralization
On AWS a primary network interface at device index 0 cannot be detached while the instance is running, but secondary interfaces can be.
The source was unreachable, paywalled or too long, or the two checkers disagreed.
The article says “it is not possible to detach primary network interface while the instance is running. However, it is possible to detach secondary network interfaces even while the instance is running”
The source says No passage could be compared.
Source cited by the article: docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-eni.html
Matches sourceQuote
The AWS DetachNetworkInterface API reference says to use the Force parameter only as a last resort to detach a network interface from a failed instance.
The cited source says the same thing.
The article says “Use the Force parameter only as a last resort to detach a network interface from a failed instance”
The source says “Use the Force parameter only as a last resort to detach a network interface from a failed instance”
Source cited by the article: docs.aws.amazon.com/AWSEC2/latest/APIReference/API_DetachNetworkInterface.html
Matches sourceQuote
A GCP firewall deny rule leaves existing connections persisting with their traffic unaffected.
The cited source says the same thing.
The article says “Existing connections persist, and their associated traffic remains unaffected”
The source says “Cloud NGFW enforces this change only on new connections. Existing connections persist, and their associated traffic remains unaffected”
Source cited by the article: docs.cloud.google.com/firewall/docs/firewalls
Matches sourceDate
Dynamic NICs became generally available on GCP on October 30, 2025.
The cited source says the same thing.
The article says “Dynamic NICs have become generally available on GCP on October 30, 2025”
The source says “Dynamic Network Interfaces (NICs) are available in General Availability”
Source cited by the article: docs.cloud.google.com/vpc/docs/release-notes
No source givenNumber
In the authors' trials on GCP, the last user-flow packet came 0.7 to 2.5 seconds after deleting the Dynamic NIC, and Google marked the operation done 5.0 to 7.0 seconds after.
The article gives no link or citation for it.
The article says “the last packet on any user flow came 0.7 to 2.5 seconds after the request, and Google marked the operation as done 5.0 to 7.0 seconds after it”
The source says No source to compare with.
Also covered by
No other coverage was clustered with this story.
Elsewhere
Elsewhere: HN 3 pts, not on front page
Recorded for context only, checked 5 Nov 2026, 05:46 UTC. It played no part in the ranking.