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özkan pakdil
özkan pakdil

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PostgreSQL 18 Beta 1 Summary

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PostgreSQL 18 Beta 1 - New Features and Breaking Changes

Source : GitHub - PostgreSQL 18 Beta 1 New Features

Overview

PostgreSQL 18 introduces over 200 new features and changes. This document summarizes all significant new features, improvements, and breaking changes introduced in the Beta 1 release. Meaning these features can disappear too, this is just a beta.

1. Highlights of Major New Features

1.1 Adaptation to Large Scale Environments

  • Virtual Columns : Support for virtual (non-stored) columns in tables.
  • ONLY Clause for VACUUM/ANALYZE : Now supports partitioned tables to avoid recursive partition scans.

1.2 Reliability Enhancements

  • pg_dumpall Output Format : Supports formats other than plain text.
  • pg_verifybackup Tar Format : Adds support for tar format verification.

1.3 Maintainability Improvements

  • Statistics Migration : pg_dump and pg_dumpall can now include optimizer statistics.
  • Functions for Stats Management : Added functions to set or clear optimizer stats per table/column.
    • pg_restore_relation_stats, pg_clear_relation_stats, pg_restore_attribute_stats, pg_clear_attribute_stats
    • Commits: d32d146

1.4 Programming Improvements

  • Access to OLD and NEW in RETURNING clause.
  • New Function : UUID v7 support.

1.5 Preparations for Future Features

  • Asynchronous I/O Infrastructure : Introduced with io_method and io_workers.
  • NUMA Support : Basic infrastructure and views (pg_shmem_allocations_numa).

2. Breaking Changes & Incompatibilities

2.1 Platform & Tool Support

  • Dropped support for: PA-RISC, LLVM < 14, OpenSSL < 1.1.1, Python < 3.6.8.
  • Added support: Tcl 9.

2.2 Passwords

  • MD5 passwords : Now deprecated; warning shown by default.

2.3 Configuration

  • Removed --disable-spin-locks and --disable-atomics.
  • initdb now enables data checksums by default.

2.4 SQL & DDL Statements

  • COPY FREEZE : Disallowed on foreign tables.
  • EXPLAIN : BUFFERS enabled by default.
  • CREATE SUBSCRIPTION : Default streaming = parallel.

3. Architecture Changes

3.1 Catalog Changes

  • New Views : pg_aios, pg_shmem_allocations_numa
  • Added Columns : Many views now include additional metadata, such as constraint enforcement flags, VACUUM/ANALYZE timing, and I/O stats.

3.2 Logical Replication

  • Logs detailed conflict types like insert_exists, update_differ, delete_missing.
  • Propagation of generated columns via publish_generated_columns.

3.3 Storage I/O Enhancements

  • Streaming I/O : Broadened scope to VACUUM, CREATE DATABASE, GiST/SP-GiST, etc.
  • Async I/O : Controlled with io_method, can use io_uring.

4. SQL Enhancements

4.1 ALTER Enhancements

  • ALTER CONSTRAINT SET INHERIT/NO INHERIT
  • ADD CONSTRAINT ... NOT VALID
  • ALTER TABLE ONLY DROP CONSTRAINT

4.2 ANALYZE Improvements

  • ONLY Clause : Skip partitions.
  • Verbose Stats : Includes I/O, WAL, and delay stats.

5. Utilities & Tooling

  • pg_combinebackup, pg_createsubscriber: New utilities.
  • pg_stat_io: Combines WAL and I/O metrics.
  • psql \conninfo: More detailed output.

6. Contrib Modules

Highlights:

  • amcheck: Enhanced with streaming I/O.
  • Enhancements to: pgcrypto, pg_stat_statements, postgres_fdw.

Summary

PostgreSQL 18 Beta 1 introduces significant architectural upgrades and functional improvements while laying the groundwork for upcoming innovations like async I/O and NUMA-aware processing. Compatibility testing is essential for a smooth transition.

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