doc: TLS (and SNI / ALPN routing) now supported with PostgreSQL 17!

[coolaj86]

Note: ALPN must be set to postgresql, as per the docs, and IANA.

New client-side connection option, sslnegotiation=direct, that performs a direct TLS handshake to avoid a round-trip negotiation.

E.1.1. Overview 

(from https://www.postgresql.org/docs/17/release-17.html#RELEASE-17-HIGHLIGHTS)

PostgreSQL 17 contains many new features and enhancements, including:

• New memory management system for VACUUM, which reduces memory consumption and can improve overall vacuuming performance.

• New SQL/JSON capabilities, including constructors, identity functions, and the JSON_TABLE() function, which converts JSON data into a table representation.

• Various query performance improvements, including for sequential reads using streaming I/O, write throughput under high concurrency, and searches over multiple values in a btree index.

• Logical replication enhancements, including:

  • Failover control

  • pg_createsubscriber, a utility that creates logical replicas from physical standbys

  • pg_upgrade now preserves replication slots on both publishers and subscribers

• New client-side connection option, sslnegotiation=direct, that performs a direct TLS handshake to avoid a round-trip negotiation.

• pg_basebackup now supports incremental backup.

• COPY adds a new option, ON_ERROR ignore, that allows a copy operation to continue in the event of an error.

The above items and other new features of PostgreSQL 17 are explained in more detail in the sections below.

More options for managing security and operations

(from https://www.postgresql.org/about/news/postgresql-17-released-2936/)

PostgreSQL 17 further extends how users can manage the overall lifecycle of their database systems. PostgreSQL has a new TLS option, sslnegotiation, that lets users perform a direct TLS handshakes when using ALPN (registered as postgresql in the ALPN directory). PostgreSQL 17 also adds the pg_maintain predefined role, which gives users permission to perform maintenance operations.

pg_basebackup, the backup utility included in PostgreSQL, now supports incremental backups and adds the pg_combinebackup utility to reconstruct a full backup. Additionally, pg_dump includes a new option called --filter that lets you select what objects to include when generating a dump file.

PostgreSQL 17 also includes enhancements to monitoring and analysis features. EXPLAIN now shows the time spent for local I/O block reads and writes, and includes two new options: SERIALIZE and MEMORY, useful for seeing the time spent in data conversion for network transmission, and how much memory was used. PostgreSQL 17 now reports the progress of vacuuming indexes, and adds the pg_wait_events system view that, when combined with pg_stat_activity, gives more insight into why an active session is waiting.