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#hacking process

12 related sessions.

· 77:12 · youtube ↗

Agent hacking Postgres

Agent-assisted patch work around the wait-event timing submission.

The group reviewed Kirk Wolak's pg_dump patch for keeping loadable placeholders when table data is excluded, grounding the discussion in his large-table restore workflow. They debated a positive interface, filter-file actions, arbitrary dump queries, PII transformation, and referential-integrity risks, then posted supportive review feedback to pgsql-hackers. The final segment examined Salma El-Sayed's B-tree leaf-page merge design, including merged-page markers, scan correctness, vacuum cleanup, and review plans.

[timecodes · 8]
  1. Postgres 19 development opens and patches await review
  2. Kirk introduces the pg_dump placeholder patch
  3. Large-table dump and one-command restore use case
  4. Reviewing the option name and user interface
  5. Using AI to review design and mailing-list history
  6. Parallel chunks for restoring one large table
  7. Custom dump queries, filtering, and PII transformation
  8. B-tree leaf-page merge design and scan safety
#wait events#B-tree#AI-assisted hacking#hacking process@Nikolay Samokhvalov@Andrey Borodin@Kirk Wolak
-hackersCF #6984
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correlated mapping
· 55:36 · youtube ↗

Hacking Postgres with Kirk, Andrey, Nik

Custom command tags and logical decoding from an archive-fed recovery server.

The workshop first revisited customizable command tags, confirming legacy behavior remains the default and its added branch should be negligible, then explored extensible client protocols and better psql completion. The main direction was extracting data from managed Postgres without burdening production: decode archived WAL into a logical stream. They compared a full recovery server with a standalone tool, concluding the latter would need schema state at a starting LSN, checkpoint/full-page-image handling, and careful treatment of file swaps such as pg_repack.

[timecodes · 8]
  1. Command-tag customization and performance feedback
  2. Ideas for an extensible client/server protocol
  3. Language-server completion for psql
  4. Parallelizing logical-replication initialization
  5. Keeping an independent copy outside managed Postgres
  6. Turning archived WAL into a logical stream
  7. Designing a standalone offline decoder
  8. Checkpoints, full-page images, and pg_repack caveats
#logical decoding#recovery#WAL#hacking process@Nikolay Samokhvalov@Andrey Borodin@Kirk Wolak
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· 69:49 · youtube ↗

GSoC ideas for Postgres

Turn workshop ideas into scoped GSoC projects, including wait-event coverage, pg_stat_statements scalability, and B-tree page merge.

The group turned Postgres GSoC brainstorming into a draft set of core-development projects. After Nikolay recounted his 2006 SQL/XML GSoC experience, they evaluated planner, parallel GiST build, TOAST slicing, test coverage, logged/unlogged tables, global temporary tables, and autovacuum ideas. They then added wait-event coverage, pg_stat_statements scalability, and B-tree page merge, using an AI-generated wiki draft. The draft still needed expert validation, clearer mentor ownership, and manual editing before merging into the official ideas page.

[timecodes · 8]
  1. Nikolay's 2006 SQL/XML GSoC project
  2. Reviewing existing core project ideas
  3. How GSoC ideas, mentors, and proposals match
  4. Logged tables and other deceptively hard projects
  5. Global temporary tables and autonomous work
  6. Autovacuum control and scheduling ideas
  7. Generating the GSoC wiki draft
  8. Wait events, page merge, and observability projects
#hacking process@Nikolay Samokhvalov@Andrey Borodin@Kirk Wolak
GSoC 2026Andrey’s ideaswait coverage patchpgss scalabilityB-tree merge branchPR #15
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· 87:51 · youtube ↗

How to create Postgres patches with AI?

AI-assisted patch discovery, implementation, review, and submission.

The session developed a responsible AI-assisted patch workflow: treat prompts as engineering specifications, assign independent security, documentation, and testing reviewers, distrust praise, and use agents to summarize long CommitFest threads without surrendering judgment. They then applied that workflow to a patch that logs the LSN of DROP TABLE, enabling precise PITR after accidental deletion. The agent retrieved and rebased the patch, planned transaction, rollback, savepoint, and documentation tests, and continued adapting it to changed GUC infrastructure; final review remained pending.

[timecodes · 8]
  1. What AI changes in Postgres hacking
  2. Specifications and independent reviewer roles
  3. Maintenance work and critical AI feedback
  4. AI-assisted patch and CommitFest review
  5. Advice for learning Postgres development
  6. GSoC as an entry into core hacking
  7. Starting a live DROP TABLE logging review
  8. PITR use case, tests, and patch rebase
#AI-assisted hacking#hacking process@Nikolay Samokhvalov
tools PR #10
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· 70:24 · youtube ↗

Vibe Hacking Postgres

Review B-tree merge blockers and prototype commit-LSN logging for DROP TABLE.

After reviewing UUIDv7 and amcheck support for GIN in Postgres 18, the group discussed responsible AI-assisted hacking and briefly parked the B-tree merge work over unresolved scan concurrency. Most of the session revisited recovery from accidental DROP TABLE: they asked an agent to extend transaction callbacks with the commit LSN and build a logging extension. The prototype found table names through object-access hooks, but cleanup timing and an invalid commit LSN prevented a working result, leaving the design unfinished.

[timecodes · 8]
  1. Postgres 18 outcomes: UUIDv7 and GIN checks
  2. Responsible AI-assisted Postgres hacking
  3. Why the B-tree merge prototype was paused
  4. Revisiting a recovery landmark for DROP TABLE
  5. Prompting a callback and extension prototype
  6. Building and loading the DROP TABLE extension
  7. Combining object-access and commit callbacks
  8. Recovery-event catalogs and the invalid-LSN blocker
#recovery#B-tree#hacking process@Nikolay Samokhvalov@Andrey Borodin@Kirk Wolak
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· 51:42 · youtube ↗

Vibe Hacking Postgres

Test B-tree page merge against concurrent scans and expose correctness failures.

The group assessed the B-tree page-merge prototype after community feedback. They agreed benchmarks should emphasize extra buffer I/O, cache pollution, WAL, and sparse-page workloads rather than lookup latency alone. A new injection-point test then demonstrated the critical flaw: a concurrent forward scan returned duplicates while a backward scan missed tuples after pages were merged. Several recovery schemes were examined, but repeated vacuums and concurrent inserts defeated the simple designs. The session ended with correctness and concurrency still unresolved.

[timecodes · 8]
  1. Community feedback and the benchmark requirement
  2. Why sparse pages hurt buffers, WAL, and vacuum
  3. Scoping useful page-merge benchmarks
  4. Injection-point test exposes incorrect scans
  5. Visualizing the old-tree and new-tree race
  6. Concurrent inserts and possible query aborts
  7. When scans can recover from merged pages
  8. Why limited merges and repeated vacuums still fail
#B-tree#hacking process@Nikolay Samokhvalov@Andrey Borodin@Kirk Wolak
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· 87:17 · youtube ↗

Vibe Hacking Postgres

Rebase GiST amcheck and design useful corruption tests.

The group revived the long-running amcheck work for GiST indexes after shared infrastructure and the GIN checker had been committed. They manually rebased the remaining GiST patch, repaired build files and SQL upgrade scripts, and got its basic checks passing. They then asked Cursor to adapt newly committed GIN corruption tests. The generated tests initially assumed ordering that GiST does not have and later passed without actually corrupting indexes, leaving only a useful page-header corruption idea and more manual work.

[timecodes · 8]
  1. Reviving unfinished GiST amcheck work
  2. Applying the old patch to current Postgres
  3. Cursor overreaches while resolving rejects
  4. Manual rebase of build and extension files
  5. Compiling and running the basic GiST checks
  6. Recent GIN corruption tests as a template
  7. Reviewing AI's GiST corruption-test design
  8. Tests pass, but no corruption was injected
#hacking process@Nikolay Samokhvalov@Andrey Borodin@Kirk Wolak
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· 73:25 · youtube ↗

Vibe Hacking Postgres

Review commit-LSN logging for destructive DDL and its test strategy.

The workshop resumed the patch that logs a recovery LSN when destructive DDL commits. Review showed AI-generated schema support used the wrong hook, added an uncalled function, and supplied a nondeterministic regression test unsuitable for raw LSN output; a TAP test was deemed necessary. Rather than finish the substantial cleanup live, they switched to optimizing the regression-test schedule with Cursor. Its reordered groups caused failures and thermal throttling, demonstrating that faster scheduling must respect test dependencies and stable benchmarking conditions.

[timecodes · 8]
  1. Reality-checking AI-generated implementations
  2. Goal: log an LSN before destructive DDL
  3. Reviewing three patch iterations
  4. Why raw LSNs break regression-test output
  5. Finding unused schema-drop code
  6. Manual testing exposes missing schema logging
  7. Deferring patch cleanup and changing tasks
  8. Cursor rebalances the regression-test schedule
#recovery#hacking process@Nikolay Samokhvalov@Andrey Borodin@Kirk Wolak
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· 80:57 · youtube ↗

Vibe Hacking Postgres

Add a pg_resetwal system-identifier option and audit the agentic patch workflow.

Nik presented an AI-assisted pg_resetwal option for changing the system identifier, needed to replay archived WAL after DBLab created a replacement cluster. Review accepted the use case but called for removing interactive safeguards, shortening documentation, reducing redundant tests, and aligning option identifiers with other frontend tools. The session then demonstrated Nik's agentic patch workflow: small commits, specification-first documentation, compilation and manual tests, strict review by stronger models, and a final human review that caught issues the models missed.

[timecodes · 8]
  1. Opening review of the pg_resetwal patch
  2. What pg_resetwal changes and why it is dangerous
  3. DBLab recovery needs a different system identifier
  4. Mailing-list feedback on safeguards and docs
  5. AI-assisted Postgres patch workflow
  6. Indexing the tree and structuring small changes
  7. Strict review with a stronger model
  8. Human review finds option and parsing issues
#recovery#hacking process@Nikolay Samokhvalov@Andrey Borodin@Kirk Wolak
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· 74:57 · youtube ↗

Vibe Hacking Postgres

Merge improvements into commit-LSN logging for destructive DDL.

The session opened with AI-assisted Postgres development lessons from the committed pg_dump policy patch and a separate wal_compression-level prototype: write tests and documentation early, review every line, and use several strong models as independent critics. The practical task was merging Jim Jones's improvements into the patch that logs commit LSNs for destructive DDL. Cursor produced overbroad changes, but after resetting and supplying both patches, the group compiled and manually tested the result, found a callback-unregistration bug, and attempted test-driven repair.

[timecodes · 8]
  1. An AI-written pg_dump change reaches Postgres 18
  2. The hallucination that inspired wal_compression levels
  3. Tests and documentation in agentic development
  4. Returning to destructive-DDL LSN logging
  5. Comparing the original patch with Jim's version
  6. First Cursor attempt overreaches
  7. Supplying both patches for a focused merge
  8. Manual test exposes callback leakage
#recovery#hacking process@Nikolay Samokhvalov@Andrey Borodin@Kirk Wolak
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· 74:59 · youtube ↗

Hacking Postgres with Andrey and Nik

Redesign DROP TABLE recovery logging around the commit LSN.

The session opened with recent Postgres work on GIN amcheck, corruption detection, read streams, and pg_stat_statements sampling, then returned to the DROP TABLE recovery patch. The patch logged an attempted drop before commit, producing misleading landmarks after rollback. They redesigned transaction callbacks to receive the commit LSN, manually changed the commit path after an AI attempt stalled, and demonstrated commit-only logging. Remaining work included two-phase commit, schema/OID formatting, tests, and incorporating Jim Jones's review before a new version.

[timecodes · 8]
  1. GIN amcheck and corruption detection
  2. Recent read-stream and statistics work
  3. Revisiting DROP TABLE recovery logging
  4. Why attempted-drop logging is ambiguous
  5. Testing an AI coding agent on Postgres
  6. Passing the commit LSN to transaction callbacks
  7. Implementing the core changes manually
  8. Working result and remaining patch tasks
#recovery#hacking process@Nikolay Samokhvalov@Andrey Borodin
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· 93:53 · youtube ↗

Hacking Postgres — Andrey, Kirk, Nikolay

Review UUIDv7 and build deterministic transaction_timeout tests.

The first section reviewed UUIDv7's evolving RFC, monotonic counter, distributed generation, timestamp extraction, and blocked core support. They also surveyed transaction-timeout and SLRU-locking work. The hands-on section tackled flaky transaction-timeout tests by combining injection points with a background psql watch loop. Testing uncovered false success from malformed watch parameters and a broken-pipe cleanup problem when timeout killed psql. The harness remained unfinished, needing a reliable way to detect whether the background session is active.

[timecodes · 8]
  1. UUIDv7 status and the evolving RFC
  2. Monotonic counters and distributed generators
  3. Why UUIDv7 combines ordering and randomness
  4. Timestamp extraction and partitioning
  5. SLRU locking and subtransaction edge cases
  6. Transaction timeout lands, tests remain flaky
  7. Replacing fixed sleeps with injection points
  8. False success, broken pipes, and unfinished cleanup
#recovery#hacking process@Nikolay Samokhvalov@Andrey Borodin@Kirk Wolak
UUIDv7 committransaction_timeout commit
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