Add Block Range Indexes (BRIN) (Álvaro Herrera)

BRIN indexes store only summary data (such as minimum and maximum values) for ranges of heap blocks. They are therefore very compact and cheap to update; but if the data is naturally clustered, they can still provide substantial speedup of searches.

Allow queries to perform accurate distance filtering of bounding-box-indexed objects (polygons, circles) using GiST indexes (Alexander Korotkov, Heikki Linnakangas)

Previously, to exploit such an index a subquery had to be used to select a large number of rows ordered by bounding-box distance, and the result then had to be filtered further with a more accurate distance calculation.

Allow GiST indexes to perform index-only scans (Anastasia Lubennikova, Heikki Linnakangas, Andreas Karlsson)

Add configuration parameter gin_pending_list_limit to control the size of GIN pending lists (Fujii Masao)

This value can also be set on a per-index basis as an index storage parameter. Previously the pending-list size was controlled by work_mem, which was awkward because appropriate values for work_mem are often much too large for this purpose.

Issue a warning during the creation of hash indexes because they are not crash-safe (Bruce Momjian)

Improve the speed of sorting of varchar, text, and numeric fields via “abbreviated” keys (Peter Geoghegan, Andrew Gierth, Robert Haas)

Extend the infrastructure that allows sorting to be performed by inlined, non-SQL-callable comparison functions to cover CREATE INDEX, REINDEX, and CLUSTER (Peter Geoghegan)

Improve performance of hash joins (Tomas Vondra, Robert Haas)

Improve concurrency of shared buffer replacement (Robert Haas, Amit Kapila, Andres Freund)

Reduce the number of page locks and pins during index scans (Kevin Grittner)

The primary benefit of this is to allow index vacuums to be blocked less often.

Make per-backend tracking of buffer pins more memory-efficient (Andres Freund)

Improve lock scalability (Andres Freund)

This particularly addresses scalability problems when running on systems with multiple CPU sockets.

Allow the optimizer to remove unnecessary references to left-joined subqueries (David Rowley)

Allow pushdown of query restrictions into subqueries with window functions, where appropriate (David Rowley)

Allow a non-leakproof function to be pushed down into a security barrier view if the function does not receive any view output columns (Dean Rasheed)

Teach the planner to use statistics obtained from an expression index on a boolean-returning function, when a matching function call appears in WHERE (Tom Lane)

Make ANALYZE compute basic statistics (null fraction and average column width) even for columns whose data type lacks an equality function (Oleksandr Shulgin)

Speed up CRC (cyclic redundancy check) computations and switch to CRC-32C (Abhijit Menon-Sen, Heikki Linnakangas)

Improve bitmap index scan performance (Teodor Sigaev, Tom Lane)

Speed up CREATE INDEX by avoiding unnecessary memory copies (Robert Haas)

Increase the number of buffer mapping partitions (Amit Kapila, Andres Freund, Robert Haas)

This improves performance for highly concurrent workloads.

Add per-table autovacuum logging control via new log_autovacuum_min_duration storage parameter (Michael Paquier)

Add new configuration parameter cluster_name (Thomas Munro)

This string, typically set in postgresql.conf, allows clients to identify the cluster. This name also appears in the process title of all server processes, allowing for easier identification of processes belonging to the same cluster.

Prevent non-superusers from changing log_disconnections on connection startup (Fujii Masao)

Check “Subject Alternative Names” in SSL server certificates, if present (Alexey Klyukin)

When they are present, this replaces checks against the certificate's “Common Name”.

Add system view pg_stat_ssl to report SSL connection information (Magnus Hagander)

Add libpq functions to return SSL information in an implementation-independent way (Heikki Linnakangas)

While PQgetssl() can still be used to call OpenSSL functions, it is now considered deprecated because future versions of libpq might support other SSL implementations. When possible, use the new functions PQsslAttribute(), PQsslAttributeNames(), and PQsslInUse() to obtain SSL information in an SSL-implementation-independent way.

Make libpq honor any OpenSSL thread callbacks (Jan Urbanski)

Previously they were overwritten.

Replace configuration parameter checkpoint_segments with min_wal_size and max_wal_size (Heikki Linnakangas)

This change allows the allocation of a large number of WAL files without keeping them after they are no longer needed. Therefore the default for max_wal_size has been set to 1GB, much larger than the old default for checkpoint_segments. Also note that standby servers perform restartpoints to try to limit their WAL space consumption to max_wal_size; previously they did not pay any attention to checkpoint_segments.

Control the Linux OOM killer via new environment variables PG_OOM_ADJUST_FILE and PG_OOM_ADJUST_VALUE (Gurjeet Singh)

The previous OOM control infrastructure involved compile-time options LINUX_OOM_SCORE_ADJ and LINUX_OOM_ADJ, which are no longer supported. The new behavior is available in all builds.

Allow recording of transaction commit time stamps when configuration parameter track_commit_timestamp is enabled (Álvaro Herrera, Petr Jelínek)

Time stamp information can be accessed using functions pg_xact_commit_timestamp() and pg_last_committed_xact().

Allow local_preload_libraries to be set by ALTER ROLE SET (Peter Eisentraut, Kyotaro Horiguchi)

Allow autovacuum workers to respond to configuration parameter changes during a run (Michael Paquier)

Make configuration parameter debug_assertions read-only (Andres Freund)

This means that assertions can no longer be turned off if they were enabled at compile time, allowing for more efficient code optimization. This change also removes the postgres -A option.

Allow setting effective_io_concurrency on systems where it has no effect (Peter Eisentraut)

Add system view pg_file_settings to show the contents of the server's configuration files (Sawada Masahiko)

Add pending_restart to the system view pg_settings to indicate a change has been made but will not take effect until a database restart (Peter Eisentraut)

Allow ALTER SYSTEM values to be reset with ALTER SYSTEM RESET (Vik Fearing)

This command removes the specified setting from postgresql.auto.conf.

Allow REINDEX to reindex an entire schema using the SCHEMA option (Sawada Masahiko)

Add VERBOSE option to REINDEX (Sawada Masahiko)

Prevent REINDEX DATABASE and SCHEMA from outputting object names, unless VERBOSE is used (Simon Riggs)

Remove obsolete FORCE option from REINDEX (Fujii Masao)

Add support for IMPORT FOREIGN SCHEMA (Ronan Dunklau, Michael Paquier, Tom Lane)

This command allows automatic creation of local foreign tables that match the structure of existing tables on a remote server.

Allow CHECK constraints to be placed on foreign tables (Shigeru Hanada, Etsuro Fujita)

Such constraints are assumed to be enforced on the remote server, and are not enforced locally. However, they are assumed to hold for purposes of query optimization, such as constraint exclusion.

Allow foreign tables to participate in inheritance (Shigeru Hanada, Etsuro Fujita)

To let this work naturally, foreign tables are now allowed to have check constraints marked as not valid, and to set storage and OID characteristics, even though these operations are effectively no-ops for a foreign table.

Allow foreign data wrappers and custom scans to implement join pushdown (KaiGai Kohei)

Whenever a ddl_command_end event trigger is installed, capture details of DDL activity for it to inspect (Álvaro Herrera)

This information is available through a set-returning function pg_event_trigger_ddl_commands(), or by inspection of C data structures if that function doesn't provide enough detail.

Allow event triggers on table rewrites caused by ALTER TABLE (Dimitri Fontaine)

Add event trigger support for database-level COMMENT, SECURITY LABEL, and GRANT/REVOKE (Álvaro Herrera)

Add columns to the output of pg_event_trigger_dropped_objects (Álvaro Herrera)

This allows simpler processing of delete operations.

Add jsonb functions jsonb_set() and jsonb_pretty() (Dmitry Dolgov, Andrew Dunstan, Petr Jelínek)

Add jsonb generator functions to_jsonb(), jsonb_object(), jsonb_build_object(), jsonb_build_array(), jsonb_agg(), and jsonb_object_agg() (Andrew Dunstan)

Equivalent functions already existed for type json.

Reduce casting requirements to/from json and jsonb (Tom Lane)

Allow text, text array, and integer values to be subtracted from jsonb documents (Dmitry Dolgov, Andrew Dunstan)

Add jsonb || operator (Dmitry Dolgov, Andrew Dunstan)

Add json_strip_nulls() and jsonb_strip_nulls() functions to remove JSON null values from documents (Andrew Dunstan)

Add function pg_get_object_address() to return OIDs that uniquely identify an object, and function pg_identify_object_as_address() to return object information based on OIDs (Álvaro Herrera)

Loosen security checks for viewing queries in pg_stat_activity, executing pg_cancel_backend(), and executing pg_terminate_backend() (Stephen Frost)

Previously, only the specific role owning the target session could perform these operations; now membership in that role is sufficient.

Add pg_stat_get_snapshot_timestamp() to output the time stamp of the statistics snapshot (Matt Kelly)

This represents the last time the snapshot file was written to the file system.

Add mxid_age() to compute multi-xid age (Bruce Momjian)

Add min()/max() aggregates for inet/cidr data types (Haribabu Kommi)

Use 128-bit integers, where supported, as accumulators for some aggregate functions (Andreas Karlsson)

Improve PL/pgSQL array performance (Tom Lane)

Add an ASSERT statement in PL/pgSQL (Pavel Stehule)

Allow more PL/pgSQL keywords to be used as identifiers (Tom Lane)

Allow psql to produce AsciiDoc output (Szymon Guz)

Add an errors mode that displays only failed commands to psql's ECHO variable (Pavel Stehule)

This behavior can also be selected with psql's -b option.

Provide separate column, header, and border linestyle control in psql's unicode linestyle (Pavel Stehule)

Single or double lines are supported; the default is single.

Add new option %l in psql's PROMPT variables to display the current multiline statement line number (Sawada Masahiko)

Add \pset option pager_min_lines to control pager invocation (Andrew Dunstan)

Improve psql line counting used when deciding to invoke the pager (Andrew Dunstan)

psql now fails if the file specified by an --output or --log-file switch cannot be written (Tom Lane, Daniel Vérité)

Previously, it effectively ignored the switch in such cases.

Add psql tab completion when setting the search_path variable (Jeff Janes)

Currently only the first schema can be tab-completed.

Improve psql's tab completion for triggers and rules (Andreas Karlsson)

Allow pg_dump to share a snapshot taken by another session using --snapshot (Simon Riggs, Michael Paquier)

The remote snapshot must have been exported by pg_export_snapshot() or logical replication slot creation. This can be used to share a consistent snapshot across multiple pg_dump processes.

Support table sizes exceeding 8GB in tar archive format (Tom Lane)

The POSIX standard for tar format does not allow elements of a tar archive to exceed 8GB, but most modern implementations of tar support an extension that does allow it. Use the extension format when necessary, rather than failing.

Make pg_dump always print the server and pg_dump versions (Jing Wang)

Previously, version information was only printed in --verbose mode.

Remove the long-ignored -i/--ignore-version option from pg_dump, pg_dumpall, and pg_restore (Fujii Masao)

Support multiple pg_ctl -o options, concatenating their values (Bruce Momjian)

Allow control of pg_ctl's event source logging on MS Windows (MauMau)

This only controls pg_ctl, not the server, which has separate settings in postgresql.conf.

If the server's listen address is set to a wildcard value (0.0.0.0 in IPv4 or :: in IPv6), connect via the loopback address rather than trying to use the wildcard address literally (Kondo Yuta)

This fix primarily affects Windows, since on other platforms pg_ctl will prefer to use a Unix-domain socket.

Move pg_upgrade from contrib to src/bin (Peter Eisentraut)

In connection with this change, the functionality previously provided by the pg_upgrade_support module has been moved into the core server.

Support multiple pg_upgrade -o/-O options, concatenating their values (Bruce Momjian)

Improve database collation comparisons in pg_upgrade (Heikki Linnakangas)

Remove support for upgrading from 8.3 clusters (Bruce Momjian)

Move pgbench from contrib to src/bin (Peter Eisentraut)

Fix calculation of TPS number “excluding connections establishing” (Tatsuo Ishii, Fabien Coelho)

The overhead for connection establishment was miscalculated whenever the number of pgbench threads was less than the number of client connections. Although this is clearly a bug, we won't back-patch it into pre-9.5 branches since it makes TPS numbers not comparable to previous results.

Allow counting of pgbench transactions that take over a specified amount of time (Fabien Coelho)

This is controlled by a new --latency-limit option.

Allow pgbench to generate Gaussian/exponential distributions using \setrandom (Kondo Mitsumasa, Fabien Coelho)

Allow pgbench's \set command to handle arithmetic expressions containing more than one operator, and add % (modulo) to the set of operators it supports (Robert Haas, Fabien Coelho)

Allow higher-precision time stamp resolution on Windows 8, Windows Server 2012, and later Windows systems (Craig Ringer)

Install shared libraries to bin in MS Windows (Peter Eisentraut, Michael Paquier)

Install src/test/modules together with contrib on MSVC builds (Michael Paquier)

Allow configure's --with-extra-version option to be honored by the MSVC build (Michael Paquier)

Pass PGFILEDESC into MSVC contrib builds (Michael Paquier)

Add icons to all MSVC-built binaries and version information to all MS Windows binaries (Noah Misch)

MinGW already had such icons.

Add optional-argument support to the internal getopt_long() implementation (Michael Paquier, Andres Freund)

This is used by the MSVC build.