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PlanetScale Postgres supports versions 17 and 18 of Postgres. Specifically, the following versions are currently supported:
  • 17.9
  • 18.3
New databases will be created using the latest version by default and we recommend sticking to that default, but you can choose an older version if you need to.

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Major version upgrades

PlanetScale doesn’t currently offer in-place upgrades between major versions of Postgres. To upgrade from Postgres 17 to 18, create a new Postgres 18 database and perform an online migration from your existing PlanetScale Postgres 17 database using our import guides. The same import process also applies if you’re migrating from another provider such as RDS, Aurora, or a self-hosted Postgres instance. You can import into any supported major version regardless of where the source database is hosted.

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Benchmarking Postgres 17 vs 18

Our Benchmarking Postgres 17 vs 18 blog post covers sysbench oltp_read_only results across multiple EC2 instance types and I/O configurations.
  • Postgres 18’s new io_method=worker default delivers the best overall read performance, outperforming both io_uring and the legacy synchronous I/O in most scenarios.
  • Local NVMe disks dramatically outperform network-attached storage (gp3, io2) regardless of Postgres version or I/O setting.

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What’s new in Postgres 18

Postgres 18 builds on Postgres 17 with new features, changed defaults, and some deprecations. For full details, see the official Postgres 18 release notes.
AreaWhat Postgres 18 adds
I/O architectureNew asynchronous I/O (AIO) subsystem with io_method setting (worker, io_uring, sync); up to 3× faster reads in benchmarks
VacuumProactive page-freezing during regular vacuums, reducing the need for aggressive vacuum passes
WAL / write throughputPer-connection WAL and I/O statistics for finer-grained monitoring
IndexesSkip-scan lookups on multicolumn B-tree indexes; parallel GIN index builds; broader OR-clause index usage
pg_upgradeRetains optimizer statistics through upgrades, reducing post-upgrade performance dips; parallel checks via --jobs; --swap flag
SQL / developer featuresVirtual generated columns (default); uuidv7() / uuidv4() functions; OLD/NEW in RETURNING for DML statements; temporal PRIMARY KEY/UNIQUE/FOREIGN KEY constraints (WITHOUT OVERLAPS, PERIOD)
AuthenticationOAuth 2.0 authentication; FIPS mode validation; TLS v1.3 cipher suite allowlisting; SCRAM passthrough for postgres_fdw/dblink; md5 auth deprecated
Logical replicationWrite-conflict logging; parallel streaming for subscriptions by default; pg_createsubscriber --all for all databases; auto-invalidation of idle replication slots
ObservabilityEXPLAIN ANALYZE auto-shows buffer access and index-lookup counts; ANALYZE (VERBOSE) now reports WAL, CPU, and average read stats
Text processingPG_UNICODE_FAST collation; casefold() function; LIKE over nondeterministic collations; full-text search uses cluster default collation provider
Wire protocolProtocol version 3.2 (first update since 2003); libpq still defaults to 3.0 for backward compatibility
Data checksumsOn by default at initdb (off by default in 17)