Development Versions: 13
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E.1. Release 13

Release date: 2020-XX-XX, CURRENT AS OF 2020-05-03

E.1.1. Overview

Major enhancements in PostgreSQL 13 include:

    The above items are explained in more detail in the sections below.

    E.1.2. Migration to Version 13

    A dump/restore using pg_dumpall or use of pg_upgrade or logical replication is required for those wishing to migrate data from any previous release. See Section 18.6 for general information on migrating to new major releases.

    Version 13 contains a number of changes that may affect compatibility with previous releases. Observe the following incompatibilities:

    • Change SIMILAR TO ... ESCAPE NULL to return NULL (Tom Lane)

      This new behavior matches the SQL specification. Previously this caused the escape to be set to the default backslash character. The previous behavior has been retained in old views by keeping the original function unchanged. This also applies to substring(text FROM pattern ESCAPE text).

    • Have jsonb_to_tsvector() properly check "string" parameter (Dominik Czarnota)

    • In ltree, when using adjacent asterisks with braces, e.g. ".*{2}.*{3}", properly interpret that as ".*{5}" (Nikita Glukhov)

    • Change the way non-default effective_io_concurrency values affect concurrency (Thomas Munro)

      Previously, this value was adjusted before effecting the number of concurrent requests. This value is now used directly. Conversion of old values to new ones can be done using:

      SELECT round(sum(OLD / n::float)) FROM generate_series(1, OLD) s(n);
    • Prevent display of auxiliary processes in pg_stat_ssl and pg_stat_gssapi system views (Euler Taveira)

      Queries that join these views to pg_stat_activity and wish to see auxiliary processes will need to use left joins.

    • Fix pageinspect's bt_metap() to return more appropriate data types that are less likely to overflow (Peter Geoghegan)

    • Rename some recovery-related wait events (Fujii Masao)

      Rename RecoveryWalAll to RecoveryWalStream and RecoveryWalStream to RecoveryRetrieveRetryInterval.

    • Fix ALTER FOREIGN TABLE ... RENAME COLUMN to return a more appropriate command tag (Fujii Masao)

      Previously it returned ALTER TABLE, but now returns ALTER FOREIGN TABLE.

    • Fix ALTER MATERIALIZED VIEW ... RENAME COLUMN to return a more appropriate command tag (Fujii Masao)

      Previously it returned ALTER TABLE, but now returns ALTER MATERIALIZED VIEW.

    • Remove support for defining operator classes using pre-PostgreSQL 8.0 syntax (Daniel Gustafsson)

    • Remove support for defining foreign key constraints using pre-PostgreSQL 7.3 syntax (Daniel Gustafsson)

    • Remove support for "opaque" pseudo-types used by pre-PostgreSQL 7.3 servers (Daniel Gustafsson)

    E.1.3. Changes

    Below you will find a detailed account of the changes between PostgreSQL 13 and the previous major release.

    E.1.3.1. Server

    E. Partitioning
    • Improve cases where pruning of partitions can happen (Yuzuko Hosoya, Amit Langote, Álvaro Herrera)

    • Allow partitionwise joins to happen in more cases (Ashutosh Bapat, Etsuro Fujita, Amit Langote, Tom Lane)

      For example, partitionwise joins can now happen between partitioned tables even when their partition bounds do not match exactly.

    • Allow BEFORE row-level triggers on partitioned tables (Álvaro Herrera)

      These triggers cannot change which partition is the destination.

    • Allow partitioned tables to be logically replicated via publications (Amit Langote)

      Previously, partitions had to be replicated individually. Now partitioned tables can be published explicitly causing all partitions to be automatically published. Addition/removal of partitions from partitioned tables are automatically added/removed from publications. The CREATE PUBLICATION option publish_via_partition_root controls whether changes to partitions are published as their own or their ancestor's.

    • Allow logical replication into partitioned tables on subscribers (Amit Langote)

      Previously, subscribers could only receive rows into non-partitioned tables.

    • Allow ROW values to be used as partitioning expressions (Amit Langote)

    E. Indexes
    • More efficiently store duplicates in btree indexes (Anastasia Lubennikova, Peter Geoghegan)

      This allows efficient btree indexing of low cardinality columns by storing duplicate keys only once. Users upgrading with pg_upgrade will need to use REINDEX to make use of this feature.

    • Allow GiST and SP-GiST indexes for box/point distance lookups (Nikita Glukhov)

    • Allow GIN indexes to more efficiently handle NOT restrictions (Nikita Glukhov, Alexander Korotkov, Tom Lane, Julien Rouhaud)

    • Allow index operator classes to take parameters (Nikita Glukhov)

    • Allow CREATE INDEX to specify the GiST signature length and maximum number of integer ranges (Nikita Glukhov)

      Indexes created on four and eight-byte integer array, tsvector, pg_trgm, ltree, and hstore columns can now control these GiST index parameters, rather than using the defaults.

    • Prevent indexes that use non-default collations from being added as a table's unique or primary key constraint (Tom Lane)

      The index and column collations must now match so the index's uniqueness matches the column's uniqueness.

    E. Optimizer
    • Improve the optimizer's selectivity estimation for containment/match operators (Tom Lane)

    • Allow setting statistics target for extended statistics (Tomas Vondra)

      This is controlled with the new command option ALTER STATISTICS ... SET STATISTICS. Previously this was computed based on more general statistics target settings.

    • Allow use of multiple extended statistics objects in a single query (Tomas Vondra)

    • Allow use of extended statistics objects for OR clauses and IN/ANY constant lists (Pierre Ducroquet, Tomas Vondra)

    • Allow functions in FROM clauses to be moved to their reference sites if they evaluate to constants (Alexander Kuzmenkov, Aleksandr Parfenov)

    E. General Performance
    • Implement incremental sorting (James Coleman, Alexander Korotkov, Tomas Vondra)

      If a result is already sorted by several leading keys, this allows for batch sorting of additional trailing keys because the previous keys are already equal. This is controlled by enable_incrementalsort.

    • Improve the performance of sorting inet values (Brandur Leach)

    • Allow hash aggregation to use disk storage for large aggregation result sets (Jeff Davis)

      Previously, hash aggregation was avoided if it was expected to use more than work_mem memory. This is controlled by hashagg_avoid_disk_plan.

    • Allow grouping sets to use hash aggregation with disk storage for large grouping set results (Jeff Davis)

    • Allow inserts to trigger autovacuum activity (Laurenz Albe, Darafei Praliaskouski)

      This new behavior reduces the work necessary when the table needs to be frozen and allows pages to be set as all-visible. All-visible pages allow index-only scans to access fewer heap rows.

    • Add maintenance_io_concurrency to control I/O concurrency for maintenance operations (Thomas Munro)

    • Allow skipping of WAL for full table writes if wal_level is minimal (Kyotaro Horiguchi)

      Relations larger than wal_skip_threshold will have their files fsync'ed rather than generating WAL. Previously this was done only for COPY operations, but the implementation had a bug that could cause data loss during crash recovery.

    • Enable Unix-domain sockets support on Windows (Peter Eisentraut)

    • Improve the performance when replaying DROP DATABASE commands when many tablespaces are in use (Fujii Masao)

    • Improve performance for truncation of very large relations (Kirk Jamison)

    • Improve speed of TOAST decompression and the retrieval of only the leading bytes of TOAST values (Binguo Bao, Andrey Borodin)

      Previously, TOAST values were fully fetched and only the requested leading bytes were decompressed and returned. Now, only the requested bytes are fetched.

    • Improve performance of LISTEN/NOTIFY (Martijn van Oosterhout)

    • Improve the efficiency of removing duplicate NOTIFY events (Tom Lane)

    • Use lookup tables to speed up integer to text conversion (David Fetter)

    • Reduce memory usage for query strings that contain multiple SQL statements (Amit Langote)

    E. Monitoring
    • Allow EXPLAIN, auto_explain, autovacuum, and pg_stat_statements to track WAL usage statistics (Kirill Bychik, Julien Rouhaud)

    • Allow a sample of statements to be logged (Adrien Nayrat)

      A log_statement_sample_rate ratio of statements taking over log_min_duration_sample duration will be logged.

    • Add the backend type to csvlog and optionally log_line_prefix log output (Peter Eisentraut)

    • Improve control of prepared statement parameter logging (Alexey Bashtanov, Álvaro Herrera)

      The GUC setting log_parameter_max_length controls the maximum length of parameter values output during statement non-error logging, and log_parameter_max_length_on_error does the same for error statement logging. Previously, prepared statement parameters were not logged during errors.

    • Make vacuum buffer counters 64-bits wide to avoid overflow (Álvaro Herrera)

    • Allow function call backtraces of errors to be logged (Peter Eisentraut, Álvaro Herrera)

      Server variable backtrace_functions specifies which C functions should generate backtraces on error.

    • Add min() and max() aggregates for pg_lsn (Fabrízio de Royes Mello)

      This is useful for monitoring queries.

    E. System Views
    E. Wait Events
    • Add wait event for posix_fallocate() (Thomas Munro)

    • Add wait event VacuumDelay to report on cost-based vacuum delay (Justin Pryzby)

    • Add wait events for WAL archive and recovery pause (Fujii Masao)

      The new events are BackupWaitWalArchive and RecoveryPause.

    • Add wait events RecoveryConflictSnapshot and RecoveryConflictTablespace to monitor recovery conflicts (Masahiko Sawada)

    • Improve performance of wait events on BSD-based systems (Thomas Munro)

    E. Authentication
    • Only allow superusers to view the ssl_passphrase_command setting (Insung Moon)

      This was changed as a security precaution.

    • Change the default minimum TLS version from 1.0 to 1.2 (Peter Eisentraut)

      This is controlled by ssl_min_protocol_version.

    E. Server Configuration
    • Tighten rules on which utility commands are possible in default_transaction_read_only mode (Robert Haas)

      This also increases the number of utility commands that can run in parallel queries.

    • Allow allow_system_table_mods to be changed after server start (Peter Eisentraut)

    • Disallow non-superusers from modifying system tables when allow_system_table_mods is set (Peter Eisentraut)

      Previously, if allow_system_table_mods was set at server start, non-superusers could issue INSERT/UPDATE/DELETE commands on system tables.

    E.1.3.2. Streaming Replication and Recovery

    • Allow streaming replication configuration settings to be changed by reload (Sergei Kornilov)

      Previously, a server restart was required to change primary_conninfo and primary_slot_name.

    • Allow WAL receivers use a temporary replication slot if a permanent one is not specified (Peter Eisentraut, Sergei Kornilov)

      This behavior can be enabled using wal_receiver_create_temp_slot.

    • Allow replication slot storage to be limited by max_slot_wal_keep_size (Kyotaro Horiguchi)

      Replication slots that exceed this value are invalidated.

    • Allow standby promotion to cancel any requested pause (Fujii Masao)

      Previously, promotion could not happen while the standby was in paused state.

    • Generate an error if recovery does not reach the specified recovery target (Leif Gunnar Erlandsen, Peter Eisentraut)

      Previously, the end of the WAL would promote the standby, even if the target was not reached.

    • Allow control over how much memory is used by logical decoding before it is spilled to disk (Tomas Vondra, Dilip Kumar, Amit Kapila)

      This is controlled by logical_decoding_work_mem.

    • Allow WAL recovery to continue even if invalid pages are referenced (Fujii Masao)

      This is enabled using ignore_invalid_pages.

    E.1.3.3. Utility Commands

    • Allow VACUUM to process indexes in parallel (Masahiko Sawada, Amit Kapila)

      The new PARALLEL option controls this.

    • Allow FETCH FIRST to use WITH TIES to return any additional rows that match the last result row (Surafel Temesgen)

    • Report planning-time buffer usage in EXPLAIN's BUFFER output (Julien Rouhaud)

    • Have CREATE TABLE LIKE propagate CHECK's NO INHERIT property to created tables (Ildar Musin, Chris Travers)

    • When using LOCK TABLE on a partitioned table, do not check permissions on the child tables (Amit Langote)

    • Allow OVERRIDING USER VALUE on inserts into identity columns (Dean Rasheed)

    • Add ALTER TABLE clause DROP EXPRESSION to remove generated properties from columns (Peter Eisentraut)

    • Fix bugs in ALTER TABLE when later clauses overlap changes made by earlier clauses in the same command (Tom Lane)

    • Add ALTER VIEW syntax to rename view columns (Fujii Masao)

      This was previously possible only using ALTER TABLE RENAME COLUMN.

    • Add ALTER TYPE options useful for extensions, like TOAST and I/O functions control (Tomas Vondra, Tom Lane)

    • Add CREATE DATABASE LOCALE option (Peter Eisentraut)

      This combines existing options LC_COLLATE and LC_CTYPE into a single option.

    • Allow DROP DATABASE to disconnect users so drop succeeds (Pavel Stehule, Amit Kapila)

      This is enabled by WITH FORCE.

    • Add C structure member tg_updatedcols to record updated columns to C triggers (Peter Eisentraut)

    • Add FOREIGN to ALTER statements, if appropriate (Luis Carril)


    E.1.3.4. Data Types

    • Add polymorphic data types for use by functions requiring compatible arguments (Pavel Stehule)

      The new data types are anycompatible, anycompatiblearray, anycompatiblenonarray, and anycompatiblerange.

    • Add SQL data type xid8 to expose FullTransactionId (Thomas Munro)

      The xid data type is only four bytes so does not show the transaction epoch.

    • Add data type regcollation and helper functions for system collations (Julien Rouhaud)

    • Use the glibc version in some cases as the collation version (Thomas Munro)

      If the glibc version changes, a warning will be issued when a mismatching collation is used.

    • Add support for collation versions on Windows (Thomas Munro)

    • Allow ROW values values to have their members extracted with suffix notation (Tom Lane)

      For example, (ROW(4, 5.0)).f1 returns 4.

    E.1.3.5. Functions

    • Add alternate version of jsonb_setI() with special NULL handling (Andrew Dunstan)

      The new function, jsonb_set_lax(), allows null new values to either set the specified key to JSON null, delete the key, raise exception, or ignore the operation. IS 'return_target' CLEAR?

    • Add jsonpath .datetime() method (Nikita Glukhov, Teodor Sigaev, Oleg Bartunov, Alexander Korotkov)

      This allows json values to be converted to timestamps, which can then be processed in jsonpath expressions. This also adds jsonpath functions that support time zone-aware output.

    • Add SQL functions NORMALIZE() to normalize Unicode strings, and IS NORMALIZED to check for normalization (Peter Eisentraut)

    • Allow Unicode escapes, e.g., E'\u####', U&'\####', to specify any character available in the database encoding, even when the database encoding is not UTF-8 (Tom Lane)

      The Unicode characters must be available in the database encoding.

    • Allow to_date() and to_timestamp() to recognize non-English month/day names (Juan José Santamaría Flecha, Tom Lane)

      The names recognized are the same as those output by to_char() with the same format codes.

    • Add format specifications FF1-FF6 to control display of 1-6 subsecond digits (Alexander Korotkov, Nikita Glukhov, Teodor Sigaev, Oleg Bartunov)

      These patterns can be used by to_char(), to_timestamp(), and jsonpath's .datetime().

    • Add SSSSS time format specification as an SQL standard alias for SSSS (Nikita Glukhov, Alexander Korotkov)

    • Add function gen_random_uuid() to generate version 4 UUIDs (Peter Eisentraut)

      Previously UUID generation functions were only available via external modules uuid-ossp and pgcrypto.

    • Add greatest-common-denominator (gcd) and least-common-multiple (lcm) functions (Vik Fearing)

    • Improve the performance and accuracy of square root and natural log (ln) output (Dean Rasheed)

    • Add function min_scale() that returns the number of digits to the right the decimal point that is required to represent the numeric value with full precision (Pavel Stehule)

    • Add function trim_scale() to reduce the scale of a number by removing trailing zeros (Pavel Stehule)

    • Add commutators of distance operators (Nikita Glukhov)

      For example, previously only point <-> line was supported, now line <-> point works too.

    • Create xid8 versions of all transaction id functions (Thomas Munro)

      The old function names were kept for backward compatibility. DO WE HAVE NEW NAMES?

    • Allow get_bit() and set_bit() to set bits beyond 256MB of bytea data (Movead Li)

    • Allow advisory-lock functions to be used in some parallel operations (Tom Lane)

    • Add the ability to remove an object's dependency on an extension (Álvaro Herrera)

      The object can be a function, materialized view, index, or trigger. The syntax is ALTER .. NO DEPENDS ON.

    E.1.3.6. PL/pgSQL

    • Improve performance of simple PL/pgSQL expressions (Tom Lane, Amit Langote)

    • Improve the performance of PL/pgSQL functions that use immutable expressions (Konstantin Knizhnik)

    E.1.3.7. Client Interfaces

    • Allow libpq clients to require channel binding (Jeff Davis)

      Using the libpq connection parameter channel_binding forces the other end of the TLS connection to prove it knows the user's password. This prevents man-in-the-middle attacks.

    • Add libpq connection parameters to control the min/max TLS version (Daniel Gustafsson)

      The settings are ssl_min_protocol_version and ssl_max_protocol_version.

    • Tighten line length and comment detection in .pgpass files (Fujii Masao)

    • Allow specification of passwords to unlock client certificates (Craig Ringer, Andrew Dunstan)

      This is specified by the sslpassword connection option.

    • Allow DER-encoded client certificates (Craig Ringer, Andrew Dunstan)

    E.1.3.8. Client Applications

    E. psql
    • Add the transaction status (%x) to the default psql prompts (Vik Fearing)

    • Allow the secondary psql prompt to be same number of spaces as the primary prompt (Thomas Munro)

      This is accomplished by setting PROMPT2 to %w.

    • Allow \g and \gx to change any \pset output options for a single command (Tom Lane)

      This allows syntax like \g (expand=on), which is equivalent to \gx.

    • Add psql commands to report operator classes and operator families (Sergey Cherkashin, Nikita Glukhov, Alexander Korotkov)

      The new commands are \dAc, \dAf, \dAo, and \dAp.

    • Show table persistence in psql's \dt+ and related commands (David Fetter)

      In verbose mode, the table/index/view shows if the object is permanent, temporary, or unlogged.

    • Improve output of psql \d for TOAST tables (Justin Pryzby)

    • Adjust display of psql's \e query (Tom Lane)

      When exiting the editor, if the query doesn't end with a semicolon or \g, the query buffer contents will now be displayed.

    • Add \warn command to psql (David Fetter)

      This is like \echo except that the text is sent to stderr instead of stdout.

    • Add the PostgreSQL home page to command-line --help output (Peter Eisentraut)

    E. pgbench
    • Allow pgbench to partition its 'accounts' table (Fabien Coelho)

      This allows performance testing of partitioning.

    • Add pgbench command \aset, which behaves like \gset, but for multiple queries (Fabien Coelho)

    • Allow pgbench to generate its data server-side, rather than client side (Fabien Coelho)

    • Allow pgbench to dump script contents using --show-script (Fabien Coelho)

    E.1.3.9. Server Applications

    • Generate backup manifests for base backups, and verify them (Robert Haas)

      A new tool pg_verifybackup" can verify backups.

    • Have pg_basebackup estimate the total backup size by default (Fujii Masao)

      This computation allows pg_stat_progress_basebackup to show progress, and can be disabled by using the --no-estimate-size option. Previously, this computation happened only if --progress was used.

    • Add pg_rewind option to configure standbys (Paul Guo, Jimmy Yih, Ashwin Agrawal)

      This matches pg_basebackup's --write-recovery-conf option.

    • Allow pg_rewind to use the target cluster's restore_command to retrieve needed WAL (Alexey Kondratov)

      This is enabled using the -c/--restore-target-wal option.

    • Have pg_rewind automatically run crash recovery before rewinding (Paul Guo, Jimmy Yih, Ashwin Agrawal)

      This can be disabled by using --no-ensure-shutdown.

    • Increase PREPARE TRANSACTION information reported by pg_waldump (Fujii Masao)

    • Add pg_waldump option --quiet to suppress non-error output (Andres Freund, Robert Haas)

    • Allow pg_dump --include-foreign-data to dump data from foreign servers (Luis Carril)

    • Allow vacuum commands run by vacuumdb to operate in parallel mode (Masahiko Sawada)

      This is enabled with the new --parallel option.

    • Allow reindexdb to operate in parallel (Julien Rouhaud)

      Parallel mode is enabled with the new --jobs option.

    • Allow dropdb to force disconnections so the drop succeeds (Pavel Stehule)

      This is enabled with the -f option.

    • Remove --adduser and --no-adduser from createuser (Alexander Lakhin)

      The long-supported options for this are called --superuser and --no-superuser.

    • Use the directory of the pg_upgrade binary as the default new 'bindir' location when running pg_upgrade (Daniel Gustafsson)

    E.1.3.10. Documentation

    • Add a glossary to the documentation (Corey Huinker, Jürgen Purtz, Roger Harkavy, Álvaro Herrera)

    • Reformat tables containing function information for better clarity (Tom Lane)

    • Upgrade to use DocBook 4.5 (Peter Eisentraut)

    E.1.3.11. Source Code

    • Add support for building on Visual Studio 2019 (Haribabu Kommi)

    • Add build support for MSYS2 (Peter Eisentraut)

    • Add compare_exchange and fetch_add assembly language code for Power PC compilers (Noah Misch)

    • Update Snowball stemmer dictionaries used by full text search (Panagiotis Mavrogiorgos)

      This adds Greek stemming and improves Danish and French stemming.

    • Remove support for Windows 2000 (Michael Paquier)

    • Remove support for non-ELF BSD systems (Peter Eisentraut)

    • Remove support for Python versions 2.5.X and earlier (Peter Eisentraut)

    • Remove support for OpenSSL 0.9.8 and 1.0.0 (Michael Paquier)

    • Remove support option --disable-float8-byval (Peter Eisentraut)

      This was needed for previously supported version-zero functions.

    • Remove configure option --disable-float4-byval (Peter Eisentraut)

      This was needed for previously supported version-zero functions.

    • Add the query string to planner hook functions (Pascal Legrand, Julien Rouhaud)

    • Add TRUNCATE command hook (Yuli Khodorkovskiy)

    • Add TLS init hook (Andrew Dunstan)

    • Allow building with no predefined Unix-domain socket directory (Peter Eisentraut)

    • Reduce the probability of SysV resource key collision on Unix platforms (Tom Lane)

    • Use operating system functions to cleanly erase memory that contains sensitive information (Peter Eisentraut)

      For example, this is used for clearing passwords stored in memory.

    • Add "headerscheck" script to test C header-file compatibility (Tom Lane)

    • Implement internal lists as arrays, rather than a chain of structures (Tom Lane)

      This improves performance for queries that access many object. The internal List API has also been improved.

    • Update Windows build scripts to use the modern --with-uuid flag for UUID libraries (Kyotaro Horiguchi)

    E.1.3.12. Additional Modules

    • Allow extensions to be specified as trusted (Tom Lane)

      Such extensions can be installed in a database by users with creation rights, even if they are not superusers. This change also removes the pg_pltemplate system catalog.

    • Remove support for upgrading "unpackaged" extensions (Tom Lane)

    • Allow non-superusers to connect to postgres_fdw foreign servers without using a password (Craig Ringer)

      Specifically, allow ALTER USER MAPPING to set password_required to false. Care must still be taken to avoid non-superusers from using superuser credentials to connect to the foreign server.

    • Allow postgres_fdw to use certificate authentication (Craig Ringer)

      Different users can use different certificates.

    • Allow sepgsql to control access to the TRUNCATE command (Yuli Khodorkovskiy)

    • Add extension bool_plperl which transforms SQL booleans to/from PL/Perl booleans (Ivan Panchenko)

    • Have pg_stat_statements treat SELECT ... FOR UPDATE as distinct from those without FOR UPDATE (Andrew Gierth, Vik Fearing)

    • Allow pg_stat_statements to optionally track the planning time of statements (Julien Rouhaud, Pascal Legrand, Thomas Munro, Fujii Masao)

      Previously only execution time was tracked.

    • Overhaul ltree's lquery syntax to treat NOT (!) more logically (Filip Rembialkowski, Tom Lane, Nikita Glukhov)

      Also allow non-* queries to use a numeric range ({}) of matches.

    • Add support for binary I/O of ltree, lquery, and ltxtquery types (Nino Floris)

    • Add option to dict_int extension to ignore the sign of integers (Jeff Janes)

    • Add adminpack function pg_file_sync() to allow fsync'ing a file (Fujii Masao)

    • Add pageinspect functions to output t_infomask/t_infomask2 values in human-readable format (Craig Ringer, Sawada Masahiko, Michael Paquier)

    • Add btree index deduplication processing columns to pageinspect output (Peter Geoghegan)

    E.1.4. Acknowledgments

    The following individuals (in alphabetical order) have contributed to this release as patch authors, committers, reviewers, testers, or reporters of issues.