What's New in PostgreSQL 18 Support for PolarDB - PolarDB

PolarDB for PostgreSQL 18 is now available. This version is compatible with PostgreSQL 18 and includes performance improvements, streamlined operations, and new features.

Release date

January 10, 2026 (Singapore time)

Billing

This product supports subscription and pay-as-you-go billing models. which provide flexible billing options. For more information about billing, see Product Billing.

What's new in this version

Built on community PostgreSQL 18, PolarDB for PostgreSQL 18 includes exclusive features:

Feature	Description
GanosBase spatiotemporal engine	Geospatial and temporal data processing
Global plan cache	Query plan caching across sessions
GBK/GB18030 character sets	Chinese character encoding support

Supported extensions

This release supports the following 26 PostgreSQL extensions:

hypopg ip4r mysql_fdw pase pgaudit pg_bigm pg_cron pg_filedump pg_hint_plan pgjwt pg_net pg_similarity pgsodium pg_stat_kcache pgtap pgvector pldebugger postgres-decoderbufs prefix roaringbitmap sequential_uuids ganos varbitx vault wal2json zhparser

Performance optimizations

PolarDB for PostgreSQL 18 includes the following system-level optimizations:

Optimization	Description
Profile-Guided Optimization (PGO)	Compiler-level optimization based on runtime profiles
Binary Optimization and Layout Tool (BOLT)	Post-link binary optimization
Link-Time Optimization (LTO)	Cross-module optimization at link time
I/O optimizations	Batch file reads/writes and expansion, batch dirty page flushing

Note

For complete PostgreSQL 18 release information, see PostgreSQL 18 Release Notes.

Key improvements

System-level performance

Feature	Improvement
Asynchronous I/O	Backend can send multiple read requests in parallel, improving sequential scans, bitmap heap scans, and VACUUM efficiency.
Query optimization	Optimizer automatically removes unnecessary self-joins and converts `IN (VALUES ...)` clauses to `= ANY (array)` for better statistics usage.
B-tree skip scan	B-tree indexes now support skip scan for improved query performance.
GIN parallel builds	GIN indexes support parallel creation for faster index maintenance.
VACUUM optimization	`VACUUM` can freeze all-visible pages, reducing subsequent full-table freeze overhead. New `ONLY` option processes only the parent partitioned table.

Developer experience

Feature	Improvement
Virtual generated columns	Generated columns are now virtual by default—values are computed on read instead of stored on write, saving storage space.
RETURNING clause enhancements	Supports `OLD` and `NEW` keywords, enabling `INSERT`, `UPDATE`, `DELETE`, and `MERGE` to return data from before and after changes.

High availability and logical replication

Feature	Improvement
Generated column replication	Logical replication now supports generated columns.
Parallel streaming	The default value of the `streaming` parameter for `CREATE SUBSCRIPTION` is changed to `parallel`.
Conflict detection	New logical replication conflict log helps identify and resolve data synchronization issues.

Security and access control

Feature	Improvement
Authentication	MD5 password authentication is deprecated. OAuth authentication method is introduced for modern, secure identity verification.
Permission functions	New `pg_get_acl()` and `has_largeobject_privilege()` functions. Default permissions can now be defined for large objects.

Upgrade guide

We recommend upgrading to PolarDB for PostgreSQL 18 to stay current with PostgreSQL community updates and access the latest resources and best practices.

When upgrading from PolarDB for PostgreSQL 17, most data types, built-in functions, table columns, and objects remain unchanged. You can achieve nearly 100% compatibility using logical replication. We recommend using DTS for migrations between PolarDB for PostgreSQL versions.

Note

This topic covers differences between PolarDB for PostgreSQL 18 and 17. For other version differences, see Differences between PostgreSQL 17 and PostgreSQL 16, Differences between PostgreSQL 16 and PostgreSQL 15, and Differences between PostgreSQL 15 and PostgreSQL 14.

Behavior changes

Change	Description
Data checksums	`initdb` now enables data checksums by default.
Time zone abbreviations	Processing now prioritizes current session settings.
MD5 deprecation	Setting MD5 passwords with `CREATE ROLE` or `ALTER ROLE` now issues a deprecation warning.
Full-text search	Configuration file and dictionary reads now use the cluster's default collation provider.

System view changes

View	Change
`pg_backend_memory_contexts`	The `parent` column is removed. The `level` column index base changed from 0 to 1.
`pg_stat_all_tables`	Now includes statistics for time consumed by `VACUUM` and `ANALYZE` operations.
`pg_stat_wal`	The `wal_write`, `wal_sync`, `wal_write_time`, and `wal_sync_time` columns are removed.
`pg_log_backend_memory_contexts()`	The index base changed from 0 to 1.

New functions

Function	Purpose
`casefold()`	Case-insensitive string matching
`uuidv7()`	UUID version 7 generation (time-ordered)
`crc32()`, `crc32c()`	Cyclic redundancy check (CRC) calculation
`array_sort()`, `array_reverse()`	Array sorting and reversal
`pg_get_acl()`	Access control list details retrieval
`has_largeobject_privilege()`	Large object permission checking

Function changes

Function	Change
`MIN()`, `MAX()`	Support array and composite types.
`EXTRACT()`	New `WEEK` option is added.

Permission changes

Change	Description
`ALTER DEFAULT PRIVILEGES`	Supports defining default permissions for large objects.
`pg_signal_autovacuum_worker`	New predefined role is added
`GRANT`/`REVOKE`	Support for the obsolete Rule permission is removed.

Other changes

Change	Description
`VACUUM` and `ANALYZE`	Now process inherited child tables of a parent table by default.
`COPY FROM`	No longer treats `.` as an end marker when reading CSV files.
Unlogged partitioned tables	Creation is now prohibited.
`AFTER` triggers	Execute with the role that was active when the trigger event was queued.
`CREATE SUBSCRIPTION`	The default value of the `streaming` parameter changed to `parallel`.