PostgreSQL 12 enhancements include notable improvements to query performance,
particularly over larger data sets, and overall space utilization. This
release provides application developers with new capabilities such as SQL/JSON
path expression support, optimizations for how common table expression
WITH) queries are executed, and generated columns. The
PostgreSQL community continues to support the extensibility and robustness of
PostgreSQL, with further additions to internationalization, authentication,
and providing easier ways to administrate PostgreSQL. This release also
introduces the pluggable table storage interface, which allows developers to
create their own methods for storing data.
"The development community behind PostgreSQL contributed features for PostgreSQL 12 that offer performance and space management gains that our users can achieve with minimal effort, as well as improvements in enterprise authentication, administration functionality, and SQL/JSON support." said Dave Page, a core team member of the PostgreSQL Global Development Group. "This release continues the trend of making it easier to manage database workloads large and small while building on PostgreSQL's reputation of flexibility, reliability and stability in production environments."
PostgreSQL benefits from over 20 years of open source development and has become the preferred open source relational database for organizations of all sizes. The project continues to receive recognition across the industry, including being featured for the second year in a row as the "DBMS of the Year" in 2018 by DB-Engines and receiving the "Lifetime Achievement" open source award at OSCON 2019.
PostgreSQL 12 provides significant performance and maintenance enhancements to its indexing system and to partitioning.
B-tree Indexes, the standard type of indexing in PostgreSQL, have been optimized in PostgreSQL 12 to better handle workloads where the indexes are frequently modified. Using a fair use implementation of the TPC-C benchmark, PostgreSQL 12 demonstrated on average a 40% reduction in space utilization and an overall gain in query performance.
Queries on partitioned tables have also seen demonstrable improvements,
particularly for tables with thousands of partitions that only need to
retrieve data from a limited subset. PostgreSQL 12 also improves the
performance of adding data to partitioned tables with
COPY, and includes the
ability to attach a new partition to a table without blocking queries.
There are additional enhancements to indexing in PostgreSQL 12 that affect
overall performance, including lower overhead in write-ahead log generation
for the GiST, GIN, and SP-GiST index types, the ability to create covering
on GiST indexes, the ability to perform K-nearest neighbor queries with the distance operator
<->) using SP-GiST indexes, and
now supporting most-common value (MCV) statistics to help generate better
query plans when using columns that are nonuniformly distributed.
Just-in-time (JIT) compilation
using LLVM, introduced in PostgreSQL 11, is now enabled by default. JIT
compilation can provide performance benefits to the execution of expressions in
WHERE clauses, target lists, aggregates, and some internal operations, and is
available if your PostgreSQL installation is compiled or packaged with LLVM.
PostgreSQL is known for its conformance to the SQL standard - one reason why it was renamed from "POSTGRES" to "PostgreSQL" - and PostgreSQL 12 adds several features to continue its implementation of the SQL standard with enhanced functionality.
PostgreSQL 12 introduces the ability to run queries over JSON documents using
JSON path expressions
defined in the SQL/JSON standard. Such queries may utilize the existing indexing
mechanisms for documents stored in the
format to efficiently retrieve data.
Common table expressions, also known as
WITH queries, can now be
automatically inlined by PostgreSQL 12, which in turn can help increase the
performance of many existing queries. In this release, a
query can be inlined if it is not recursive, does not have any side-effects,
and is only referenced once in a later part of a query.
PostgreSQL 12 introduces "generated columns." Defined in the SQL standard, this type of column computes its value from the contents of other columns in the same table. In this version, PostgreSQL supports "stored generated columns," where the computed value is stored on the disk.
PostgreSQL 12 extends its support of ICU collations by allowing users to define "nondeterministic collations" that can, for example, allow case-insensitive or accent-insensitive comparisons.
PostgreSQL expands on its robust authentication method support with several enhancements that provide additional security and functionality. This release introduces both client and server-side encryption for authentication over GSSAPI interfaces, as well as the ability for PostgreSQL to discover LDAP servers if PostgreSQL is compiled with OpenLDAP.
Additionally, PostgreSQL 12 now supports a form of multi-factor authentication.
A PostgreSQL server can now require an authenticating client to provide a
valid SSL certificate with their username using the
option and combine this with the requirement of a separate authentication
PostgreSQL 12 introduces the ability to rebuild indexes without blocking
writes to an index via the
command, allowing users to avoid downtime scenarios for lengthy index rebuilds.
Additionally, PostgreSQL 12 can now enable or disable page checksums in an
offline cluster using the
command. Previously page checksums, a feature to help verify the integrity of
data stored to disk, could only be enabled at the time a PostgreSQL cluster was
For a full list of features included in this release, please read the release notes, which can be found at: https://www.postgresql.org/docs/12/release-12.html
PostgreSQL is the world's most advanced open source database, with a global community of thousands of users, contributors, companies and organizations. The PostgreSQL Project builds on over 30 years of engineering, starting at the University of California, Berkeley, and 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.