Postgres 19 RC1 and what to test now

Postgres Weekly

Postgres 19: What Changed and What to Test Now — With RC1 out and GA due in under a month, Tom Kincaid walks through what survived the reverts and what to try before upgrading, including REPACK (CONCURRENTLY), pg_plan_advice, parallel autovacuum, and logical replication sequence synchronization, each with a 'what to test' checklist.

Tom Kincaid (EDB)

⭐ Postgres 19 RC1 was released last week, with an RC2 due November 12 and the final release expected on November 19.

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recovery_prefetch Considered Harmful and Causing Outages — Jeremy shows how recovery_prefetch, enabled by default since Postgres 15, can overwhelm standby storage after a write burst, causing hours of lag. With synchronous replication, a dropped connection then blocked primary writes for 35 minutes in his reproduction.

Jeremy Schneider

🩹 A patch to avoid redundant prefetches after full-page images is under review, which tackles part of the problem.

IN BRIEF:

• 🇺🇸 Postgres Conference 2027 takes place April 21–23, 2027 in San Jose, California. If you want to speak, its CFP is open until January 31.

• Who owns an abandoned extension? PGXN's David Wheeler asks pgsql-hackers what the policy should be, after receiving takeover requests and privilege escalation reports for unmaintained extensions.

• 🇧🇪 FOSDEM PGDay 2027 expands to two days, January 28–29, in Brussels. The CFP is open until December 1.

• 🇹🇭 FOSSASIA PGDay 2027 takes place on March 9, 2027 in Bangkok. Their CFP is open until November 30.

• Neon Realtime is now in public beta. You can subscribe to any deterministic SQL query and the result stays live as the data changes.

• 84% of surveyed Ruby on Rails developers run Postgres in production as per the results of the 2026 Rails Community Survey.

How hstore Can Beat jsonb for Audit Logs — depesz saw a post claiming that logging only changed columns from an audit trigger shrank the log 5x but slowed updates. But his own test, using hstore instead of jsonb, made diff logging the fastest variant.

Hubert 'depesz' Lubaczewski

Why is Postgres's numeric Type So Slow? — A deep dive into numeric's internals explaining why it's slow compared to double precision or DuckDB's integer-backed DECIMAL, and why "just use int128" doesn't fix it.

Andrei Lepikhov (pgEdge)

Citus Hits 10M QPS on Half Neki's Data Nodes — A month after PlanetScale's 118M QPS Neki post, Álvaro ran the same shape of workload on Citus with StackGres's new query routers and hit 10M QPS on 24 workers rather than Neki's 50 shards.

Álvaro Hernández (StackGres)

🎧 Postgres FM had Álvaro on the same day for an hour on Citus, StackGres and the thinking behind the benchmark.

📄 Why Materialize Dropped SERIALIZABLE for 3x Write Throughput – Hundreds of thousands of predicate locks sank their Postgres-backed metadata store, so they rebuilt it on READ COMMITTED and proved it correct in Lean. Petros Angelatos

📄 From Alert to Online Repack: A Playbook for Postgres Table Bloat – Build a bloat 'watchdog' with pg_cron and pgstattuple, then use pg_repack to take a 13GB table down to 3.4GB without taking it offline. Haider Z (Microsoft)

📄 Reducing Storage Initialization Impact in Amazon RDS After Snapshot Restore – Why queries on a freshly restored RDS Postgres can run 10–15x slower at first, and how to prewarm it. Modappady, Pattabiraman and Thakur (AWS)

📄 UUIDs Stored as text: What It Costs in Postgres 18 Hollis Varden

RELEASES AND CODE:

DocumentDB 1.0: A MongoDB-Compatible Document Database on Postgres — First open sourced by Microsoft last year but now a Linux Foundation project, DocumentDB is a set of extensions (plus a gateway) that speak the MongoDB wire protocol and store BSON natively. This first stable release comes with packages for Postgres 17 and 18.

DocumentDB

PGX: Run Thousands of Throwaway Databases in One Process — From the team behind pgbot, and built upon a Rust reimplementation of Postgres, PGX hosts large numbers of isolated databases in one process, each cloned from a template in milliseconds, for agent sandboxes and per-PR tests. Beta, AGPL-licensed, with fsync off, so for dev use only. (GitHub repo.)

PGRun

pgBackRest 2.60: Restores Now Stop on Invalid Page Checksums — The popular backup and restore tool now stops a restore with an error if any restored file has an invalid page checksum. Worth knowing before your next restore! (checksum-page-error=n can change it to a warning only.)

pgBackRest Community

• pg_hint_plan 1.9.0 – The long-standing query hinting extension, now built (only) for Postgres 19 using its new path generation strategies.

• PostgREST 16.5 – Popular REST API server layer for Postgres. Adds a client-side mitigation for a recent Postgres CVE.

• ⚠️ pgmq 1.13.1 – The Postgres-native message queue. Fixes two privilege issues, so upgrade if you use it.

• pg_ivm 1.17 – Incrementally maintained materialized views, which can now survive pg_upgrade if you use pg_ivm_dump_metadata --pg-upgrade.

• 🌐 PostGIS 3.7.0 RC3 – The geospatial data extension targets Postgres 19 RC1 – I'd expect a final 3.7 around the same time as Postgres 19 itself.

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