Snapshot Management | Agent Skills Atlas

About this skill

PostgreSQL's MVCC snapshot infrastructure — src/backend/utils/time/snapmgr.c — GetTransactionSnapshot / GetLatestSnapshot / PushActiveSnapshot / RegisterSnapshot and the tuple-visibility machinery in heapamvisibility.c. Covers the ActiveSnapshot stack, RegisteredSnapshots heap, snapshot export for parallel workers, historic snapshots for logical decoding, and the interaction with xmin horizon. Loads when the user asks about Snapshot semantics, MVCC visibility (HeapTupleSatisfiesMVCC), catalog snapshots vs transaction snapshots, isolation levels, exported snapshots for pgdump, or SET LOCAL transactionisolation. Skip when the ask is about xact.c commit/abort mechanics or about xid horizons for freezing (see vacuum-autovacuum).

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0 potential findings · Scanned 11/4/2026 · Scanner 0.2.1

Content SHA-256: ce9d90a36fc0eecbcda4e38c02d47053256270f74e510ca0eaf6c845c8344f0c

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Original listing metadata

Original name

snapshot-management

Original description

PostgreSQL's MVCC snapshot infrastructure — `src/backend/utils/time/snapmgr.c` — `GetTransactionSnapshot` / `GetLatestSnapshot` / `PushActiveSnapshot` / `RegisterSnapshot` and the tuple-visibility machinery in `heapam_visibility.c`. Covers the ActiveSnapshot stack, RegisteredSnapshots heap, snapshot export for parallel workers, historic snapshots for logical decoding, and the interaction with xmin horizon. Loads when the user asks about `Snapshot` semantics, MVCC visibility (`HeapTupleSatisfiesMVCC`), catalog snapshots vs transaction snapshots, isolation levels, exported snapshots for pg_dump, or `SET LOCAL transaction_isolation`. Skip when the ask is about xact.c commit/abort mechanics or about xid horizons for freezing (see `vacuum-autovacuum`).

About this listing

Category: Engineering
Reported license: PostgreSQL
Listing language (estimated): English
Review status: Not individually reviewed
Agent compatibility: Atlas installation supports Claude Code, Codex, and Cursor. Skill-specific dependencies and features are checked during setup.