Posted on 2023-09-14 by PostgreSQL Global Development Group

PostgreSQL Project

September 14, 2023 – The PostgreSQL Global Development Group today announced the
release of PostgreSQL 16, the latest version of the world’s most advanced open
source database.

PostgreSQL 16 raises its
performance, with notable improvements to query parallelism, bulk data loading,
and logical replication. There are many features in this release for developers
and administrators alike, including more SQL/JSON syntax, new monitoring stats
for your workloads, and greater flexibility in defining access control rules for
management of policies across large fleets.

“As relational database patterns evolve, PostgreSQL continues to make
performance gains in searching and managing data at scale,” said Dave Page, a
PostgreSQL Core Team member. “PostgreSQL 16 gives users more methods to scale-up
and scale-out their workloads, while giving them new ways to gain insights and
optimize how they manage their data.”

PostgreSQL, an innovative data management system known for its reliability and
robustness, benefits from over 25 years of open source development from a global
developer community and has become the preferred open source relational database
for organizations of all sizes.

Performance Improvements

PostgreSQL 16 improves the performance of existing PostgreSQL functionality
through new query planner optimizations. In this latest release, the
query planner can parallelize
FULL and RIGHT
joins,
generate better optimized plans for queries that use
aggregate functions
with a DISTINCT or ORDER BY clause, utilize incremental sorts for
SELECT DISTINCT
queries, and optimize
window functions
so they execute more efficiently. It also improves RIGHT and OUTER
“anti-joins”, which enables users to identify rows not present in a joined
table.

This release includes improvements for bulk loading using
COPY in both single
and concurrent operations, with tests showing up to a 300% performance
improvement in some cases. PostgreSQL 16 adds support for
load balancing
in clients that use libpq, and improvements to vacuum strategy that reduce the
necessity of full-table freezes. Additionally, PostgreSQL 16 introduces CPU
acceleration using SIMD in both x86 and ARM architectures, resulting in
performance gains when processing ASCII and JSON strings, and performing array
and subtransaction searches.

Logical replication

Logical replication
lets users stream data to other PostgreSQL instances or subscribers that can
interpret the PostgreSQL logical replication protocol. In PostgreSQL 16, users
can perform logical replication from a standby instance, meaning a standby can
publish logical changes to other servers. This provides developers with new
workload distribution options, for example, using a standby rather than the
busier primary to logically replicate changes to downstream systems.

Additionally, there are several performance improvements in PostgreSQL 16 to
logical replication. Subscribers can now apply large transactions using parallel
workers. For tables that do not have a primary key, subscribers can use B-tree
indexes instead of sequential scans to find rows. Under certain conditions,
users can also speed up initial table synchronization using the binary format.

There are several access control improvements to logical replication in
PostgreSQL 16, including the new
predefined role
pg_create_subscription, which grants users the ability to create new logical
subscriptions. Finally, this release begins adding support for bidirectional
logical replication, introducing functionality to replicate data between two
tables from different publishers.

Developer Experience

PostgreSQL 16 adds more syntax from the
SQL/JSON standard,
including constructors and predicates such as JSON_ARRAY(), JSON_ARRAYAGG(),
and IS JSON. This release also introduces the ability to use underscores for
thousands separators (e.g. 5_432_000) and non-decimal integer literals, such
as 0x1538, 0o12470, and 0b1010100111000.

Developers using PostgreSQL 16 also benefit from new commands in psql. This
includes
bind,
which allows users to prepare parameterized queries and use bind to
substitute the variables (e.g SELECT $1::int + $2::int bind 1 2 g).

PostgreSQL 16 improves general support for
text collations, which
provide rules for how text is sorted. PostgreSQL 16 builds with ICU support by
default, determines the default ICU locale from the environment, and allows
users to define custom ICU collation rules.

Monitoring

A key aspect of tuning the performance of database workloads is understanding
the impact of your I/O operations on your system. PostgreSQL 16 introduces
pg_stat_io,
a new source of key I/O metrics for granular analysis of I/O access patterns.

Additionally, this release adds a new field to the
pg_stat_all_tables
view that records a timestamp representing when a table or index was last
scanned. PostgreSQL 16 also makes
auto_explain more
readable by logging values passed into parameterized statements, and improves
the accuracy of the query tracking algorithm used by
pg_stat_statements
and pg_stat_activity.

Access Control & Security

PostgreSQL 16 provides finer-grained options for access control and enhances
other security features. The release improves management of
pg_hba.conf and
pg_ident.conf
files, including allowing regular expression matching for user and database
names and include directives for external configuration files.

This release adds several security-oriented client connection parameters,
including require_auth, which allows clients to specify which authentication
parameters they are willing to accept from a server, and
sslrootcert="system",
which indicates that PostgreSQL should use the trusted certificate authority
(CA) store provided by the client’s operating system. Additionally, the release
adds support for Kerberos credential delegation, allowing extensions such as
postgres_fdw and
dblink to use authenticated
credentials to connect to trusted services.

About PostgreSQL

PostgreSQL is the world’s most advanced open
source database, with a global community of thousands of users, contributors,
companies and organizations. Built on over 35 years of engineering, starting at
the University of California, Berkeley, PostgreSQL has continued with an
unmatched pace of development. PostgreSQL’s mature feature set not only matches
top proprietary database systems, but exceeds them in advanced database
features, extensibility, security, and stability.

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