Improve performance of many operations on partitioned tables (Amit Langote, David Rowley, Tom Lane, Álvaro Herrera)
Allow tables with thousands of child partitions to be processed efficiently by operations that only affect a small number of partitions.
Allow foreign keys to reference partitioned tables (Álvaro Herrera)
Improve speed of
COPY into partitioned tables (David Rowley)
Allow partition bounds to be any expression (Kyotaro Horiguchi, Tom Lane, Amit Langote)
Such expressions are evaluated at partitioned-table creation time. Previously, only simple constants were allowed as partition bounds.
CREATE TABLE's tablespace specification for a partitioned table to affect the tablespace of its children (David Rowley, Álvaro Herrera)
Avoid sorting when partitions are already being scanned in the necessary order (David Rowley)
ALTER TABLE ATTACH PARTITION is now performed with reduced locking requirements (Robert Haas)
Add partition introspection functions (Michaël Paquier, Álvaro Herrera, Amit Langote)
The new function
pg_partition_root() returns the top-most parent of a partition tree,
pg_partition_ancestors() reports all ancestors of a partition, and
pg_partition_tree() displays information about partitions.
Include partitioned indexes in the system view
pg_indexes (Suraj Kharage)
Add psql command
\dP to list partitioned tables and indexes (Pavel Stehule)
\z display of partitioned tables (Pavel Stehule, Michaël Paquier, Álvaro Herrera)
Fix bugs that could cause
ALTER TABLE DETACH PARTITION to leave behind incorrect dependency state, allowing subsequent operations to misbehave, for example by not dropping a former partition child index when its table is dropped (Tom Lane)
Improve performance and space utilization of btree indexes with many duplicates (Peter Geoghegan, Heikki Linnakangas)
Previously, duplicate index entries were stored unordered within their duplicate groups. This caused overhead during index inserts, wasted space due to excessive page splits, and it reduced
VACUUM's ability to recycle entire pages. Duplicate index entries are now sorted in heap-storage order.
Indexes pg_upgrade'd from previous releases will not have these benefits.
Allow multi-column btree indexes to be smaller (Peter Geoghegan, Heikki Linnakangas)
Internal pages and min/max leaf page indicators now only store index keys until the change key, rather than all indexed keys. This also improves the locality of index access.
Indexes pg_upgrade'd from previous releases will not have these benefits.
Improve speed of btree index insertions by reducing locking overhead (Alexander Korotkov)
Add support for nearest-neighbor (KNN) searches of SP-GiST indexes (Nikita Glukhov, Alexander Korotkov, Vlad Sterzhanov)
Reduce the WAL write overhead of GiST, GIN, and SP-GiST index creation (Anastasia Lubennikova, Andrey V. Lepikhov)
Allow index-only scans to be more efficient on indexes with many columns (Konstantin Knizhnik)
Improve the performance of vacuum scans of GiST indexes (Andrey Borodin, Konstantin Kuznetsov, Heikki Linnakangas)
Delete empty leaf pages during GiST
VACUUM (Andrey Borodin)
Reduce locking requirements for index renaming (Peter Eisentraut)
Allow CREATE STATISTICS to create most-common-value statistics for multiple columns (Tomas Vondra)
This improves optimization for queries that test several columns, requiring an estimate of the combined effect of several
WHERE clauses. If the columns are correlated and have non-uniform distributions then multi-column statistics will allow much better estimates.
Allow common table expressions (CTEs) to be inlined into the outer query (Andreas Karlsson, Andrew Gierth, David Fetter, Tom Lane)
Specifically, CTEs are automatically inlined if they have no side-effects, are not recursive, and are referenced only once in the query. Inlining can be prevented by specifying
MATERIALIZED, or forced for multiply-referenced CTEs by specifying
NOT MATERIALIZED. Previously, CTEs were never inlined and were always evaluated before the rest of the query.
Allow control over when generic plans are used for prepared statements (Pavel Stehule)
This is controlled by the plan_cache_mode server parameter.
Improve optimization of partition and
UNION ALL queries that have only a single child (David Rowley)
Improve processing of domains that have no check constraints (Tom Lane)
Domains that are being used purely as type aliases no longer cause optimization difficulties.
Pre-evaluate calls of
GREATEST when their arguments are constants (Vik Fearing)
Improve optimizer's ability to verify that partial indexes with
IS NOT NULL conditions are usable in queries (Tom Lane, James Coleman)
Usability can now be recognized in more cases where the calling query involves casts or large
x IN (
ANALYZE statistics using the collation defined for each column (Tom Lane)
Previously, the database's default collation was used for all statistics. This potentially gives better optimizer behavior for columns with non-default collations.
Improve selectivity estimates for inequality comparisons on
ctid columns (Edmund Horner)
Improve optimization of joins on columns of type
tid (Tom Lane)
These changes primarily improve the efficiency of self-joins on
Fix the leakproofness designations of some btree comparison operators and support functions (Tom Lane)
This allows some optimizations that previously would not have been applied in the presence of security barrier views or row-level security.
Enable Just-in-Time (JIT) compilation by default, if the server has been built with support for it (Andres Freund)
Note that this support is not built by default, but has to be selected explicitly while configuring the build.
Speed up keyword lookup (John Naylor, Joerg Sonnenberger, Tom Lane)
Improve search performance for multi-byte characters in
position() and related functions (Heikki Linnakangas)
Allow toasted values to be minimally decompressed (Paul Ramsey)
This is useful for routines that only need to examine the initial portion of a toasted field.
ALTER TABLE ... SET NOT NULL to avoid unnecessary table scans (Sergei Kornilov)
This can be optimized when the table's column constraints can be recognized as disallowing nulls.
ALTER TABLE ... SET DATA TYPE changing between
timestamptz to avoid a table rewrite when the session time zone is UTC (Noah Misch)
In the UTC time zone, these two data types are binary compatible.
Improve speed in converting strings to
int4 integers (Andres Freund)
Allow parallelized queries when in
SERIALIZABLE isolation mode (Thomas Munro)
Previously, parallelism was disabled when in this mode.
pwrite() for random I/O (Oskari Saarenmaa, Thomas Munro)
This reduces the number of system calls required for I/O.
Improve the speed of setting the process title on FreeBSD (Thomas Munro)
Allow logging of statements from only a percentage of transactions (Adrien Nayrat)
The parameter log_transaction_sample_rate controls this.
Add progress reporting to
CREATE INDEX and
REINDEX operations (Álvaro Herrera, Peter Eisentraut)
Progress is reported in the
pg_stat_progress_create_index system view.
Add progress reporting to
VACUUM FULL (Tatsuro Yamada)
Progress is reported in the
pg_stat_progress_cluster system view.
Add progress reporting to pg_checksums (Michael Banck, Bernd Helmle)
This is enabled with the option
Add counter of checksum failures to
pg_stat_database (Magnus Hagander)
Add tracking of global objects in system view
pg_stat_database (Julien Rouhaud)
Global objects are shown with a
datid value of zero.
Add the ability to list the contents of the archive directory (Christoph Moench-Tegeder)
The function is
Add the ability to list the contents of temporary directories (Nathan Bossart)
pg_ls_tmpdir(), optionally allows specification of a tablespace.
Add information about the client certificate to the system view
pg_stat_ssl (Peter Eisentraut)
The new columns are
clientdn has been renamed to
client_dn for clarity.
Restrict visibility of rows in
pg_stat_ssl for unprivileged users (Peter Eisentraut)
At server start, emit a log message including the server version number (Christoph Berg)
Prevent logging “incomplete startup packet” if a new connection is immediately closed (Tom Lane)
This avoids log spam from certain forms of monitoring.
Make the walreceiver set its application name to the cluster name, if set (Peter Eisentraut)
Add the timestamp of the last received standby message to
pg_stat_replication (Lim Myungkyu)
Add a wait event for fsync of WAL segments (Konstantin Knizhnik)
Add GSSAPI encryption support (Robbie Harwood, Stephen Frost)
This feature allows TCP/IP connections to be encrypted when using GSSAPI authentication, without having to set up a separate encryption facility such as SSL. In support of this, add
hostnogssenc record types in
pg_hba.conf for selecting connections that do or do not use GSSAPI encryption, corresponding to the existing
hostnossl record types. There is also a new gssencmode libpq option, and a pg_stat_gssapi system view.
pg_hba.conf option to check that the database user name matches the client certificate's common name (Julian Markwort, Marius Timmer)
This new check is enabled with
Allow discovery of an LDAP server using DNS SRV records (Thomas Munro)
This avoids the requirement of specifying
ldapserver. It is only supported if PostgreSQL is compiled with OpenLDAP.
Add ability to enable/disable cluster checksums using pg_checksums (Michael Banck, Michaël Paquier)
The cluster must be shut down for these operations.
Reduce the default value of autovacuum_vacuum_cost_delay to 2ms (Tom Lane)
This allows autovacuum operations to proceed faster by default.
Allow vacuum_cost_delay to specify sub-millisecond delays, by accepting fractional values (Tom Lane)
Allow time-based server parameters to use units of microseconds (
us) (Tom Lane)
Allow fractional input for integer server parameters (Tom Lane)
SET work_mem = '30.1GB' is now allowed, even though
work_mem is an integer parameter. The value will be rounded to an integer after any required units conversion.
Allow units to be defined for floating-point server parameters (Tom Lane)
Avoiding file recycling can be beneficial on copy-on-write file systems like ZFS.
Add server parameter tcp_user_timeout to control the server's TCP timeout (Ryohei Nagaura)
Allow control of the minimum and maximum SSL protocol versions (Peter Eisentraut)
Add server parameter ssl_library to report the SSL library version used by the server (Peter Eisentraut)
Add server parameter shared_memory_type to control the type of shared memory to use (Andres Freund)
This allows selection of System V shared memory, if desired.
Allow some recovery parameters to be changed with reload (Peter Eisentraut)
Allow the streaming replication timeout (wal_sender_timeout) to be set per connection (Takayuki Tsunakawa)
Previously, this could only be set cluster-wide.
pg_promote() to promote standbys to primaries (Laurenz Albe, Michaël Paquier)
Previously, this operation was only possible by using pg_ctl or creating a trigger file.
Allow replication slots to be copied (Masahiko Sawada)
The functions for this are
Add an explicit value of
current for recovery_target_timeline (Peter Eisentraut)
Make recovery fail if a two-phase transaction status file is corrupt (Michaël Paquier)
Previously, a warning was logged and recovery continued, allowing the transaction to be lost.
CONCURRENTLY option to allow reindexing without locking out writes (Michaël Paquier, Andreas Karlsson, Peter Eisentraut)
This is also controlled by the reindexdb application's
Add support for generated columns (Peter Eisentraut)
The content of generated columns are computed from expressions (including references to other columns in the same table) rather than being specified by
WHERE clause to
COPY FROM to control which rows are accepted (Surafel Temesgen)
This provides a simple way to filter incoming data.
Allow enumerated values to be added more flexibly (Andrew Dunstan, Tom Lane, Thomas Munro)
ALTER TYPE ... ADD VALUE could not be called in a transaction block, unless it was part of the same transaction that created the enumerated type. Now it can be called in a later transaction, so long as the new enumerated value is not referenced until after it is committed.
Add commands to end a transaction and start a new one (Peter Eisentraut)
Add VACUUM and
CREATE TABLE options to prevent
VACUUM from truncating trailing empty pages (Takayuki Tsunakawa)
These options are
toast.vacuum_truncate. Use of these options reduces
VACUUM's locking requirements, but prevents returning disk space to the operating system.
VACUUM to skip index cleanup (Masahiko Sawada)
This change adds a
VACUUM command option
INDEX_CLEANUP as well as a table storage option
vacuum_index_cleanup. Use of this option reduces the ability to reclaim space and can lead to index bloat, but it is helpful when the main goal is to freeze old tuples.
Add the ability to skip
ANALYZE operations on tables that cannot be locked immediately (Nathan Bossart)
This option is called
ANALYZE to take optional Boolean argument specifications (Masahiko Sawada)
ANALYZE from requesting a lock on tables for which the user lacks permission (Michaël Paquier)
This prevents unauthorized locking, which could interfere with user queries.
Add EXPLAIN option
SETTINGS to output non-default optimizer settings (Tomas Vondra)
This output can also be obtained when using auto_explain by setting
OR REPLACE option to CREATE AGGREGATE (Andrew Gierth)
Allow modifications of system catalogs' options using ALTER TABLE (Peter Eisentraut)
Modifications of catalogs'
reloptions and autovacuum settings are now supported. (Setting allow_system_table_mods is still required.)
Use all key columns' names when selecting default constraint names for foreign keys (Peter Eisentraut)
Previously, only the first column name was included in the constraint name, resulting in ambiguity for multi-column foreign keys.
Update assorted knowledge about Unicode to match Unicode 12.1.0 (Peter Eisentraut)
This fixes, for example, cases where psql would misformat output involving combining characters.
Update Snowball stemmer dictionaries with support for new languages (Arthur Zakirov)
This adds word stemming support for Arabic, Indonesian, Irish, Lithuanian, Nepali, and Tamil to full text search.
Allow creation of collations that report string equality for strings that are not bit-wise equal (Peter Eisentraut)
This feature supports “nondeterministic” collations that can define case- and accent-agnostic equality comparisons. Thus, for example, a case-insensitive uniqueness constraint on a text column can be made more easily than before. This is only supported for ICU collations.
Add support for ICU collation attributes on older ICU versions (Peter Eisentraut)
This allows customization of the collation rules in a consistent way across all ICU versions.
Allow data type name to more seamlessly be compared to other text types (Tom Lane)
name now behaves much like a domain over type
text that has default collation “C”. This allows cross-type comparisons to be processed more efficiently.
Add support for the SQL/JSON path language (Nikita Glukhov, Teodor Sigaev, Alexander Korotkov, Oleg Bartunov, Liudmila Mantrova)
This allows execution of complex queries on
JSON values using an SQL-standard language.
Add support for hyperbolic functions (Lætitia Avrot)
log10() as an alias for
log(), for standards compliance.
Improve the accuracy of statistical aggregates like
variance() by using more precise algorithms (Dean Rasheed)
date_trunc() to have an additional argument to control the time zone (Vik Fearing, Tom Lane)
This is faster and simpler than using the
AT TIME ZONE clause.
to_date() functions to be more forgiving of template mismatches (Artur Zakirov, Alexander Korotkov, Liudmila Mantrova)
This new behavior more closely matches the Oracle functions of the same name.
Fix assorted bugs in XML functions (Pavel Stehule, Markus Winand, Chapman Flack)
xmlexists(), fix some cases where nothing was output for a node, or an unexpected error was thrown, or necessary escaping of XML special characters was omitted.
BY VALUE clause in
XMLTABLE (Chapman Flack)
This SQL-standard clause has no effect in PostgreSQL's implementation, but it was unnecessarily being rejected.
current_schemas() from being run by parallel workers, as they are not parallel-safe (Michaël Paquier)
RECORD to be used as column types in a query's column definition list for a table function that is declared to return
RECORD (Elvis Pranskevichus)
Allow SQL commands and variables with the same names as those commands to be used in the same PL/pgSQL function (Tom Lane)
For example, allow a variable called
comment to exist in a function that calls the
COMMENT SQL command. Previously this combination caused a parse error.
Add new optional warning and error checks to PL/pgSQL (Pavel Stehule)
The new checks allow for run-time validation of
INTO column counts and single-row results.
Add connection parameter tcp_user_timeout to control libpq's TCP timeout (Ryohei Nagaura)
Allow libpq (and thus psql) to report only the
SQLSTATE value in error messages (Didier Gautheron)
Add libpq function
PQresultMemorySize() to report the memory used by a query result (Lars Kanis, Tom Lane)
Remove the no-display/debug flag from libpq's
options connection parameter (Peter Eisentraut)
This allows this parameter to be set by postgres_fdw.
Allow ecpg to create variables of data type
bytea (Ryo Matsumura)
This allows ECPG clients to interact with
bytea data directly, rather than using an encoded form.
PREPARE AS support to ECPG (Ryo Matsumura)
Allow vacuumdb to select tables for vacuum based on their wraparound horizon (Nathan Bossart)
The options are
Allow vacuumdb to disable waiting for locks or skipping all-visible pages (Nathan Bossart)
The options are
Add colorization to the output of command-line utilities (Peter Eisentraut)
This is enabled by setting the environment variable
auto. The specific colors used can be adjusted by setting the environment variable
PG_COLORS, using ANSI escape codes for colors. For example, the default behavior is equivalent to
Add CSV table output mode in psql (Daniel Vérité)
This is controlled by
\pset format csv or the command-line
Show the manual page URL in psql's
\help output for a SQL command (Peter Eisentraut)
Display the IP address in psql's
\conninfo (Fabien Coelho)
Improve tab completion of
CREATE EVENT TRIGGER,
ALTER DATABASE, and
ALTER INDEX ALTER COLUMN (Dagfinn Ilmari Mannsåker, Tatsuro Yamada, Michaël Paquier, Tom Lane, Justin Pryzby)
Allow values produced by queries to be assigned to pgbench variables (Fabien Coelho, Álvaro Herrera)
The command for this is
Improve precision of pgbench's
--rate option (Tom Lane)
Improve pgbench's error reporting with clearer messages and return codes (Peter Eisentraut)
Allow control of log file rotation via pg_ctl (Kyotaro Horiguchi, Alexander Kuzmenkov, Alexander Korotkov)
Previously, this was only possible via an SQL function or a process signal.
Properly detach the new server process during
pg_ctl start (Paul Guo)
This prevents the server from being shut down if the shell script that invoked pg_ctl is interrupted later.
Allow pg_upgrade to use the file system's cloning feature, if there is one (Peter Eisentraut)
--clone option has the advantages of
--link, while preventing the old cluster from being changed after the new cluster has started.
Allow specification of the socket directory to use in pg_upgrade (Daniel Gustafsson)
This is controlled by
--socketdir; the default is the current directory.
Allow pg_checksums to disable fsync operations (Michaël Paquier)
This is controlled by the
Allow pg_rewind to disable fsync operations (Michaël Paquier)
Fix pg_test_fsync to report accurate
open_datasync durations on Windows (Laurenz Albe)
When pg_dump emits data with
INSERT commands rather than
COPY, allow more than one data row to be included in each
INSERT (Surafel Temesgen, David Rowley)
The option controlling this is
Allow pg_dump to emit
INSERT ... ON CONFLICT DO NOTHING (Surafel Temesgen)
This avoids conflict failures during restore. The option is
Decouple the order of operations in a parallel pg_dump from the order used by a subsequent parallel pg_restore (Tom Lane)
This allows pg_restore to perform more-fully-parallelized parallel restores, especially in cases where the original dump was not done in parallel. Scheduling of a parallel pg_dump is also somewhat improved.
Allow the extra_float_digits setting to be specified for pg_dump and pg_dumpall (Andrew Dunstan)
This is primarily useful for making dumps that are exactly comparable across different source server versions. It is not recommended for normal use, as it may result in loss of precision when the dump is restored.
--exclude-database option to pg_dumpall (Andrew Dunstan)
Add CREATE ACCESS METHOD command to create new table types (Andres Freund, Haribabu Kommi, Álvaro Herrera, Alexander Korotkov, Dmitry Dolgov)
This enables the development of new table access methods, which can optimize storage for different use cases. The existing
heap access method remains the default.
Add planner support function interfaces to improve optimizer estimates, inlining, and indexing for functions (Tom Lane)
This allows extensions to create planner support functions that can provide function-specific selectivity, cost, and row-count estimates that can depend on the function's arguments. Support functions can also supply simplified representations and index conditions, greatly expanding optimization possibilities.
Simplify renumbering manually-assigned OIDs, and establish a new project policy for management of such OIDs (John Naylor, Tom Lane)
Patches that manually assign OIDs for new built-in objects (such as new functions) should now randomly choose OIDs in the range 8000—9999. At the end of a development cycle, the OIDs used by committed patches will be renumbered down to lower numbers, currently somewhere in the 4
xxx range, using the new
renumber_oids.pl script. This approach should greatly reduce the odds of OID collisions between different in-process patches.
While there is no specific policy reserving any OIDs for external use, it is recommended that forks and other projects needing private manually-assigned OIDs use numbers in the high 7
xxx range. This will avoid conflicts with recently-merged patches, and it should be a long time before the core project reaches that range.
Build Cygwin binaries using dynamic instead of static libraries (Marco Atzeri)
Remove configure switch
--disable-strong-random (Michaël Paquier)
A strong random-number source is now required.
printf-family functions, as well as
strerror_r, now behave uniformly across platforms within Postgres code (Tom Lane)
%m everywhere; on Windows,
strerror copes with Winsock error codes (it used to do so in backend but not frontend code); and
strerror_r always follows the GNU return convention.
Require a C99-compliant compiler, and MSVC 2013 or later on Windows (Andres Freund)
Use pandoc, not lynx, for generating plain-text documentation output files (Peter Eisentraut)
This affects only the
INSTALL file generated during
make dist and the seldom-used plain-text
postgres.txt output file. Pandoc produces better output than lynx and avoids some locale/encoding issues. Pandoc version 1.13 or later is required.
Support use of images in the PostgreSQL documentation (Jürgen Purtz)
ORDER BY sorts and
LIMIT clauses to be pushed to postgres_fdw foreign servers in more cases (Etsuro Fujita)
Improve optimizer cost accounting for postgres_fdw queries (Etsuro Fujita)
WITH CHECK OPTION on views that reference postgres_fdw tables (Etsuro Fujita)
CHECK OPTIONs on postgres_fdw tables are ignored (because the reference is foreign), views on such tables are considered local, so this change enforces
CHECK OPTIONs on them. Previously, only
RETURNING clauses that returned
CHECK OPTION values were validated.
pg_stat_statements_reset() to be more granular (Haribabu Kommi, Amit Kapila)
The function now allows reset of statistics for specific databases, users, and queries.
Allow control of the auto_explain log level (Tom Dunstan, Andrew Dunstan)
The default is
Update unaccent rules with new punctuation and symbols (Hugh Ranalli, Michaël Paquier)
Allow unaccent to handle some accents encoded as combining characters (Hugh Ranalli)
Allow unaccent to remove accents from Greek characters (Tasos Maschalidis)
Add a parameter to amcheck's
bt_index_parent_check() function to check each index tuple from the root of the tree (Peter Geoghegan)