Upgrading from 11.13 to 13 gives you 1.9 years worth of changes and fixes (430 of them)

List of changes:

• ⇑ Upgrade to 12 released on 2019-10-03 - docs

  • Remove the special behavior of oid columns (Andres Freund, John Naylor)

    Previously, a normally-invisible oid column could be specified during table creation using WITH OIDS; that ability has been removed. Columns can still be explicitly declared as type oid. Operations on tables that have columns created using WITH OIDS will need adjustment.

    The system catalogs that previously had hidden oid columns now have ordinary oid columns. Hence, SELECT * will now output those columns, whereas previously they would be displayed only if selected explicitly.

  • Remove data types abstime, reltime, and tinterval (Andres Freund)

    These are obsoleted by SQL-standard types such as timestamp.

  • Remove the timetravel extension (Andres Freund)

  • Move recovery.conf settings into postgresql.conf (Masao Fujii, Simon Riggs, Abhijit Menon-Sen, Sergei Kornilov)

    recovery.conf is no longer used, and the server will not start if that file exists. recovery.signal and standby.signal files are now used to switch into non-primary mode. The trigger_file setting has been renamed to promote_trigger_file. The standby_mode setting has been removed.

  • Do not allow multiple conflicting recovery_target* specifications (Peter Eisentraut)

    Specifically, only allow one of recovery_target, recovery_target_lsn, recovery_target_name, recovery_target_time, and recovery_target_xid. Previously, multiple different instances of these parameters could be specified, and the last one was honored. Now, only one can be specified, though the same one can be specified multiple times and the last specification is honored.

  • Cause recovery to advance to the latest timeline by default (Peter Eisentraut)

    Specifically, recovery_target_timeline now defaults to latest. Previously, it defaulted to current.

  • Refactor code for geometric functions and operators (Emre Hasegeli)

    This could lead to more accurate, but slightly different, results compared to previous releases. Notably, cases involving NaN, underflow, overflow, and division by zero are handled more consistently than before.

  • Improve performance by using a new algorithm for output of real and double precision values (Andrew Gierth)

    Previously, displayed floating-point values were rounded to 6 (for real) or 15 (for double precision) digits by default, adjusted by the value of extra_float_digits. Now, whenever extra_float_digits is more than zero (as it now is by default), only the minimum number of digits required to preserve the exact binary value are output. The behavior is the same as before when extra_float_digits is set to zero or less.

    Also, formatting of floating-point exponents is now uniform across platforms: two digits are used unless three are necessary. In previous releases, Windows builds always printed three digits.

  • random() and setseed() now behave uniformly across platforms (Tom Lane)

    The sequence of random() values generated following a setseed() call with a particular seed value is likely to be different now than before. However, it will also be repeatable, which was not previously guaranteed because of interference from other uses of random numbers inside the server. The SQL random() function now has its own private per-session state to forestall that.

  • Change SQL-style substring() to have standard-compliant greediness behavior (Tom Lane)

    In cases where the pattern can be matched in more than one way, the initial sub-pattern is now treated as matching the least possible amount of text rather than the greatest; for example, a pattern such as %#"aa*#"% now selects the first group of a's from the input, not the last group.

  • Do not pretty-print the result of xpath() or the XMLTABLE construct (Tom Lane)

    In some cases, these functions would insert extra whitespace (newlines and/or spaces) in nodeset values. This is undesirable since depending on usage, the whitespace might be considered semantically significant.

  • Rename command-line tool pg_verify_checksums to pg_checksums (Michaël Paquier)

  • In pg_restore, require specification of -f - to send the dump contents to standard output (Euler Taveira)

    Previously, this happened by default if no destination was specified, but that was deemed to be unfriendly.

  • Disallow non-unique abbreviations in psql's \pset format command (Daniel Vérité)

    Previously, for example, \pset format a chose aligned; it will now fail since that could equally well mean asciidoc.

  • In new btree indexes, the maximum index entry length is reduced by eight bytes, to improve handling of duplicate entries (Peter Geoghegan)

    This means that a REINDEX operation on an index pg_upgrade'd from a previous release could potentially fail.

  • Cause DROP IF EXISTS FUNCTION/PROCEDURE/AGGREGATE/ROUTINE to generate an error if no argument list is supplied and there are multiple matching objects (David Rowley)

    Also improve the error message in such cases.

  • Split the pg_statistic_ext catalog into two catalogs, and add the pg_stats_ext view of it (Dean Rasheed, Tomas Vondra)

    This change supports hiding potentially-sensitive statistics data from unprivileged users.

  • Remove obsolete pg_constraint.consrc column (Peter Eisentraut)

  • Remove obsolete pg_attrdef.adsrc column (Peter Eisentraut)

  • Mark table columns of type name as having “C” collation by default (Tom Lane, Daniel Vérité)

    The comparison operators for data type name can now use any collation, rather than always using “C” collation. To preserve the previous semantics of queries, columns of type name are now explicitly marked as having “C” collation. A side effect of this is that regular-expression operators on name columns will now use the “C” collation by default, not the database collation, to determine the behavior of locale-dependent regular expression patterns (such as \w). If you want non-C behavior for a regular expression on a name column, attach an explicit COLLATE clause. (For user-defined name columns, another possibility is to specify a different collation at table creation time; but that just moves the non-backwards-compatibility to the comparison operators.)

  • Treat object-name columns in the information_schema views as being of type name, not varchar (Tom Lane)

    Per the SQL standard, object-name columns in the information_schema views are declared as being of domain type sql_identifier. In PostgreSQL, the underlying catalog columns are really of type name. This change makes sql_identifier be a domain over name, rather than varchar as before. This eliminates a semantic mismatch in comparison and sorting behavior, which can greatly improve the performance of queries on information_schema views that restrict an object-name column. Note however that inequality restrictions, for example

    SELECT ... FROM information_schema.tables WHERE table_name < 'foo';
    

    will now use “C”-locale comparison semantics by default, rather than the database's default collation as before. Sorting on these columns will also follow “C” ordering rules. The previous behavior (and inefficiency) can be enforced by adding a COLLATE "default" clause.

  • Remove the ability to disable dynamic shared memory (Kyotaro Horiguchi)

    Specifically, dynamic_shared_memory_type can no longer be set to none.

  • Parse libpq integer connection parameters more strictly (Fabien Coelho)

    In previous releases, using an incorrect integer value for connection parameters connect_timeout, keepalives, keepalives_count, keepalives_idle, keepalives_interval and port resulted in libpq either ignoring those values or failing with incorrect error messages.

  • 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.

  • Allow 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)

  • Improve psql \d and \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)

  • Support INCLUDE columns in GiST indexes (Andrey Borodin)

  • 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 LEAST and 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 (array) clauses.

  • Compute 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 ctid columns.

  • 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.

  • Allow 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.

  • Allow ALTER TABLE ... SET DATA TYPE changing between timestamp and 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 int2 or int4 integers (Andres Freund)

  • Allow parallelized queries when in SERIALIZABLE isolation mode (Thomas Munro)

    Previously, parallelism was disabled when in this mode.

  • Use pread() and 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 CLUSTER and 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 --progress.

  • 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 pg_stat_database.datid value of zero.

  • Add the ability to list the contents of the archive directory (Christoph Moench-Tegeder)

    The function is pg_ls_archive_statusdir().

  • Add the ability to list the contents of temporary directories (Nathan Bossart)

    The function, 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 client_serial and issuer_dn. Column 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.

  • Include the application_name, if set, in log_connections log messages (Don Seiler)

  • 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 hostgssenc and hostnogssenc record types in pg_hba.conf for selecting connections that do or do not use GSSAPI encryption, corresponding to the existing hostssl and hostnossl record types. There is also a new gssencmode libpq option, and a pg_stat_gssapi system view.

  • Allow the clientcert 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 clientcert=verify-full.

  • 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)

    For example, 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)

  • Add wal_recycle and wal_init_zero server parameters to control WAL file recycling (Jerry Jelinek)

    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)

    The server parameters are ssl_min_protocol_version and ssl_max_protocol_version.

  • 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)

    These parameters are archive_cleanup_command, promote_trigger_file, recovery_end_command, and recovery_min_apply_delay.

  • Allow the streaming replication timeout (wal_sender_timeout) to be set per connection (Takayuki Tsunakawa)

    Previously, this could only be set cluster-wide.

  • Add function 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 pg_copy_physical_replication_slot() and pg_copy_logical_replication_slot().

  • Make max_wal_senders not count as part of max_connections (Alexander Kukushkin)

  • 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.

  • Add REINDEX CONCURRENTLY option to allow reindexing without locking out writes (Michaël Paquier, Andreas Karlsson, Peter Eisentraut)

    This is also controlled by the reindexdb application's --concurrently option.

  • 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 INSERT or UPDATE commands.

  • Add a 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)

    Previously, 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)

    The commands are COMMIT AND CHAIN and ROLLBACK AND CHAIN.

  • Add VACUUM and CREATE TABLE options to prevent VACUUM from truncating trailing empty pages (Takayuki Tsunakawa)

    These options are vacuum_truncate and toast.vacuum_truncate. Use of these options reduces VACUUM's locking requirements, but prevents returning disk space to the operating system.

  • Allow 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 VACUUM and ANALYZE operations on tables that cannot be locked immediately (Nathan Bossart)

    This option is called SKIP_LOCKED.

  • Allow VACUUM and ANALYZE to take optional Boolean argument specifications (Masahiko Sawada)

  • Prevent TRUNCATE, VACUUM and 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 auto_explain.log_settings.

  • Add 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)

    Type 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)

    Also add log10() as an alias for log(), for standards compliance.

  • Improve the accuracy of statistical aggregates like variance() by using more precise algorithms (Dean Rasheed)

  • Allow 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.

  • Adjust to_timestamp()/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)

    Specifically, in XMLTABLE, xpath(), and 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.

  • Allow the BY VALUE clause in XMLEXISTS and XMLTABLE (Chapman Flack)

    This SQL-standard clause has no effect in PostgreSQL's implementation, but it was unnecessarily being rejected.

  • Prevent current_schema() and current_schemas() from being run by parallel workers, as they are not parallel-safe (Michaël Paquier)

  • Allow RECORD and 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.

  • Add PREPARE AS support to ECPG (Ryo Matsumura)

  • Allow vacuumdb to select tables for vacuum based on their wraparound horizon (Nathan Bossart)

    The options are --min-xid-age and --min-mxid-age.

  • Allow vacuumdb to disable waiting for locks or skipping all-visible pages (Nathan Bossart)

    The options are --skip-locked and --disable-page-skipping.

  • Add colorization to the output of command-line utilities (Peter Eisentraut)

    This is enabled by setting the environment variable PG_COLOR to always or 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 PG_COLORS="error=01;31:warning=01;35:locus=01".

  • Add CSV table output mode in psql (Daniel Vérité)

    This is controlled by \pset format csv or the command-line --csv option.

  • 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 TABLE, CREATE TRIGGER, CREATE EVENT TRIGGER, ANALYZE, EXPLAIN, VACUUM, ALTER TABLE, ALTER INDEX, 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 \gset.

  • 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)

    The --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 --no-sync option.

  • 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 --rows-per-insert.

  • Allow pg_dump to emit INSERT ... ON CONFLICT DO NOTHING (Surafel Temesgen)

    This avoids conflict failures during restore. The option is --on-conflict-do-nothing.

  • 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.

  • Add --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 4xxx 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 7xxx 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 and strerror_r, now behave uniformly across platforms within Postgres code (Tom Lane)

    Notably, printf understands %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)

  • Allow 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)

  • Properly honor WITH CHECK OPTION on views that reference postgres_fdw tables (Etsuro Fujita)

    While 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 INSERTs and UPDATEs with RETURNING clauses that returned CHECK OPTION values were validated.

  • Allow 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 LOG.

  • 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)

  • Improve oid2name and vacuumlo option handling to match other commands (Tatsuro Yamada)

• ⇑ Upgrade to 12.1 released on 2019-11-14 - docs

  • Fix crash when ALTER TABLE adds a column without a default value along with making other changes that require a table rewrite (Andres Freund)

  • Fix lock handling in REINDEX CONCURRENTLY (Michael Paquier)

    REINDEX CONCURRENTLY neglected to take a session-level lock on the new index version, potentially allowing other sessions to manipulate it too soon. Also, a query-cancel or session-termination interrupt arriving at the wrong time could result in failure to release the session-level locks that REINDEX CONCURRENTLY does hold.

  • Avoid crash due to race condition when reporting the progress of a CREATE INDEX CONCURRENTLY or REINDEX CONCURRENTLY command (Álvaro Herrera)

  • Avoid creating duplicate dependency entries during REINDEX CONCURRENTLY (Michael Paquier)

    This bug resulted in bloat in pg_depend, but no worse consequences than that.

  • Fix “wrong type of slot” error when trying to CLUSTER on an expression index (Andres Freund)

  • Fix dropping of indexed columns in partitioned tables (Amit Langote, Michael Paquier)

    Previously this might fail with an error message complaining about the dependencies of the indexes. It should automatically drop the indexes, instead.

  • Ensure that a partition index can be dropped after a failure to reindex it concurrently (Michael Paquier)

    The index's pg_class.relispartition flag was left in the wrong state in such a case, causing DROP INDEX to fail.

  • Fix handling of equivalence class members for partition-wise joins (Amit Langote)

    This oversight could lead either to failure to use a feasible partition-wise join plan, or to a “could not find pathkey item to sort” planner failure.

  • Fix crash triggered by an EvalPlanQual recheck on a table with a BEFORE UPDATE trigger (Andres Freund)

  • Ignore restore_command, recovery_end_command, and recovery_min_apply_delay settings during crash recovery (Fujii Masao)

    Now that these settings can be specified in postgresql.conf, they could be turned on during crash recovery, but honoring them then is undesirable. Ignore these settings until crash recovery is complete.

  • Fix result of text position() function (also known as strpos()) for an empty search string (Tom Lane)

    Historically, and per the SQL standard, the result should be one in such cases, but 12.0 returned zero.

  • Avoid memory leak while vacuuming a GiST index (Dilip Kumar)

  • Fix libpq to allow trailing whitespace in the string values of integer parameters (Michael Paquier)

    Version 12 tightened libpq's validation of integer parameters, but disallowing trailing whitespace seems undesirable.

  • In libpq, correctly report CONNECTION_BAD connection status after a failure caused by a syntactically invalid connect_timeout parameter value (Lars Kanis)

  • Fix scheduling of parallel restore of a foreign key constraint on a partitioned table (Álvaro Herrera)

    pg_dump failed to emit full dependency information for partitioned tables' foreign keys. This could allow parallel pg_restore to try to recreate a foreign key constraint too soon.

  • In pg_upgrade, reject tables with columns of type sql_identifier, as that has changed representation in version 12 (Tomas Vondra)

  • In pg_rewind with the --dry-run option, avoid updating pg_control (Alexey Kondratov)

    This could lead to failures in subsequent pg_rewind attempts.

  • Put back pqsignal() as an exported libpq symbol (Tom Lane)

    This function was removed on the grounds that no clients should be using it, but that turns out to break usage of current libpq with very old versions of psql, and perhaps other applications.

• ⇑ Upgrade to 12.2 released on 2020-02-13 - docs

  • Fix TRUNCATE ... CASCADE to ensure all relevant partitions are truncated (Jehan-Guillaume de Rorthais)

    If a partition of a partitioned table is truncated with the CASCADE option, and the partitioned table has a foreign-key reference from another table, that table must also be truncated. The need to check this was missed if the referencing table was itself partitioned, possibly allowing rows to survive that violate the foreign-key constraint.

    Hence, if you have foreign key constraints between partitioned tables, and you have done any partition-level TRUNCATE on the referenced table, you should check to see if any foreign key violations exist. The simplest way is to add a new instance of the foreign key constraint (and, once that succeeds, drop it or the original constraint). That may be prohibitive from a locking standpoint, however, in which case you might prefer to manually query for unmatched rows.

  • Fix failure to attach foreign key constraints to sub-partitions (Jehan-Guillaume de Rorthais)

    When adding a partition to a level below the first level of a multi-level partitioned table, foreign key constraints referencing the top partitioned table were not cloned to the new partition, leading to possible constraint violations later. Detaching and re-attaching the new partition is the cheapest way to fix this. However, if there are many partitions to be fixed, adding a new instance of the foreign key constraint might be preferable.

  • Fix possible crash during concurrent update on a partitioned table or inheritance tree (Tom Lane)

  • Fix base backup to handle database OIDs larger than INT32_MAX (Peter Eisentraut)

  • Fix crash during recursive page split in GiST index build (Heikki Linnakangas)

  • Fix failure in ALTER TABLE when a column referenced in a GENERATED expression has been added or changed in type earlier in the same ALTER command (Tom Lane)

  • Fix unlikely panic in the checkpointer process, caused by opening relation segments that might already have been removed (Thomas Munro)

  • Fix handling of multiple AFTER ROW triggers on a foreign table (Etsuro Fujita)

  • Ensure that the <> operator for type char reports indeterminate-collation errors as such, rather than as “cache lookup failed for collation 0” (Tom Lane)

  • Avoid treating TID scans as sequential scans (Tatsuhito Kasahara)

    A refactoring oversight caused TID scans (selection by CTID) to be counted as sequential scans in the statistics views, and to take whole-table predicate locks as sequential scans do. The latter behavior could cause unnecessary serialization errors in serializable transaction mode.

  • Reduce spinlock contention when there are many active walsender processes (Pierre Ducroquet)

  • Fix EXPLAIN's SETTINGS option to print as empty in non-text output formats (Tom Lane)

    In the non-text output formats, fields are supposed to appear when requested, even if they have empty or zero values.

  • Fix planner errors induced by overly-aggressive collapsing of joins to single-row subqueries (Tom Lane)

    This mistake led to errors such as “failed to construct the join relation”.

  • Fix “no = operator for opfamily NNNN” planner error when trying to match a LIKE or regex pattern-match operator to a binary-compatible index opclass (Tom Lane)

  • Fix incorrect estimation for OR clauses when using most-common-value extended statistics (Tomas Vondra)

  • Fix bugs in handling of non-blocking I/O when using GSSAPI encryption (Tom Lane)

    These errors could result in dropping data (usually leading to subsequent wire-protocol-violation errors) or in a “livelock” situation where a sending process goes to sleep although not all its data has been sent. Moreover, libpq failed to keep separate encryption state for each connection, creating the possibility for failures in applications using multiple encrypted database connections.

  • Avoid crash after an out-of-memory failure in ecpglib (Tom Lane)

  • Fix handling of a corner-case error result from Windows' ReadFile() function (Thomas Munro, Juan José Santamaría Flecha)

    So far as is known, this oversight just resulted in noisy log messages, not any actual query misbehavior.

  • On Windows, work around sharing violations for the postmaster's log file when pg_ctl is used to start the postmaster very shortly after it's been stopped, for example by pg_ctl restart (Alexander Lakhin)

• ⇑ Upgrade to 12.3 released on 2020-05-14 - docs

  • Fix possible failure with GENERATED columns (David Rowley)

    If a GENERATED column's value is an exact copy of another column of the table (and it is a pass-by-reference data type), it was possible to crash or insert corrupted data into the table. While it would be rather pointless for a GENERATED expression to just duplicate another column, an expression using a function that sometimes returns its input unchanged could create the situation.

  • Handle inheritance of generated columns better (Peter Eisentraut)

    When a table column is inherited during CREATE TABLE ... INHERITS, disallow changing any generation properties when the parent column is already marked GENERATED; but allow a child column to be marked GENERATED when its parent is not.

  • Fix cross-column references in CREATE TABLE LIKE INCLUDING GENERATED (Peter Eisentraut)

    CREATE TABLE ... LIKE failed when trying to copy a GENERATED expression that references a physically-later column.

  • Preserve the indisclustered setting of indexes rebuilt by REINDEX CONCURRENTLY (Justin Pryzby)

  • Fix crash when COLLATE is applied to a non-collatable type in a partition bound expression (Dmitry Dolgov)

  • Repair performance regression in floating point overflow/underflow detection (Emre Hasegeli)

    Previous refactoring had resulted in isinf() being called extra times in some hot code paths.

  • Fix server's connection-startup logic for case where a GSSAPI connection is rejected because support is not compiled in, and the client then tries SSL instead (Andrew Gierth)

    This led to a bogus “unsupported frontend protocol” failure.

  • Fix memory leakage during GSSAPI encryption (Tom Lane)

    Both the backend and libpq would leak memory equivalent to the total amount of data sent during the session, if GSSAPI encryption is in use.

  • Fix query-lifespan memory leak for a set-returning function used in a query's FROM clause (Andres Freund)

  • Improve planner's handling of no-op domain coercions (Tom Lane)

    Fix some cases where a domain coercion that does nothing was not completely removed from expressions.

  • Avoid race condition when ANALYZE replaces the catalog tuple for extended statistics data (Dean Rasheed)

  • Remove ill-considered skip of “redundant” anti-wraparound vacuums (Michael Paquier)

    This avoids a corner case where autovacuum could get into a loop of repeatedly trying and then skipping the same vacuum job.

  • Ensure INCLUDE'd columns are always removed from B-tree pivot tuples (Peter Geoghegan)

    This mistake wasted space in some rare cases, but was otherwise harmless.

  • Cope with invalid TOAST indexes that could be left over after a failed REINDEX CONCURRENTLY (Julien Rouhaud)

  • Ensure that valid index dependencies are left behind after a failed REINDEX CONCURRENTLY (Michael Paquier)

    Previously the old index could be left with no pg_depend links at all, so that for example it would not get dropped if the parent table is dropped.

  • Avoid possible failure after a replication slot copy, due to premature removal of WAL data (Masahiko Sawada, Arseny Sher)

  • Ensure that generated columns are correctly handled during updates issued by logical replication (Peter Eisentraut)

  • Fix crash in psql when attempting to re-establish a failed connection (Michael Paquier)

  • Ensure that pg_basebackup generates valid tar files (Robert Haas)

    In some cases a partial block of zeroes would be added to the end of the file. While this seems to be harmless with common versions of tar, it's not OK per the POSIX file format spec.

  • Make pg_checksums skip tablespace subdirectories that belong to a different PostgreSQL major version (Michael Banck, Bernd Helmle)

    Such subdirectories don't really belong to our database cluster, and so must not be processed.

  • Ignore temporary copies of pg_internal.init in pg_checksums and related programs (Michael Paquier)

  • On Windows, avoid premature creation of postmaster's log file during pg_ctl start (Alexander Lakhin)

    The previous coding could allow the file to be created with permissions that wouldn't allow the postmaster to write on it.

  • On Windows, set console VT100 compatibility mode in programs that support PG_COLOR colorization (Juan José Santamaría Flecha)

    Without this, the colorization option doesn't actually work.

  • Stop requiring extra parentheses in ereport() calls (Andres Freund, Tom Lane)

  • Fix Makefile dependencies for libpq and ecpg (Dagfinn Ilmari Mannsåker)

• ⇑ Upgrade to 12.4 released on 2020-08-13 - docs

  • Fix incorrect plan execution when a partitioned table is subject to both static and run-time partition pruning in the same query, and a new partition is added concurrently with the query (Amit Langote, Tom Lane)

  • Forbid numeric NaN values in jsonpath computations (Alexander Korotkov)

    Neither SQL nor JSON have the concept of NaN (not-a-number), but the jsonpath code attempted to allow such values anyway. This necessarily leads to nonstandard behavior, so it seems better to reject such values at the outset.

  • Handle single Inf or NaN inputs correctly in floating-point aggregates (Tom Lane)

    The affected aggregates are corr(), covar_pop(), regr_intercept(), regr_r2(), regr_slope(), regr_sxx(), regr_sxy(), regr_syy(), stddev_pop(), and var_pop(). The correct answer in such cases is NaN, but an algorithmic change introduced in PostgreSQL v12 had caused these aggregates to produce zero instead.

  • Fix REINDEX CONCURRENTLY to preserve the index's replication identity flag (Michael Paquier)

    Previously, reindexing a table's replica identity index caused the setting to be lost, preventing old tuple values from being included in future logical-decoding output.

  • Use the query-specified collation for operators invoked during selectivity estimation (Tom Lane)

    Previously, the collation of the underlying database column was used. But using the query's collation is arguably more correct. More importantly, now that we have nondeterministic collations, there are cases where an operator will fail outright if given a nondeterministic collation. We don't want planning to fail in cases where the query itself would work, so this means that we must use the query's collation when invoking operators for estimation purposes.

  • Fix checkpointer process to discard file sync requests when fsync is off (Heikki Linnakangas)

    Such requests are treated as no-ops if fsync is off, but we forgot to remove them from the checkpointer's table of pending actions. This would lead to bloat of that table, as well as possible assertion failures if fsync is later re-enabled.

  • Ensure that libpq continues to try to read from the database connection socket after a write failure (Tom Lane)

    This is important not only to ensure that we collect any final error message from a dying server process, but because we do not consider the connection lost until we see a read failure. This oversight allowed libpq to continue trying to send COPY data indefinitely after a mid-transfer loss of connection, rather than reporting failure to the application.

  • Fix bugs in libpq's management of GSS encryption state (Tom Lane)

    A connection using GSS encryption could freeze up when attempting to reset it after a server restart, or when moving on to the next one of a list of candidate servers.

  • Fix ecpg crash with bytea and cursor variables (Jehan-Guillaume de Rorthais)

  • Make pg_restore cope with data-offset-less custom-format archive files when it needs to restore data items out of order (David Gilman, Tom Lane)

    pg_dump will produce such files if it cannot seek its output (for example, if the output is piped to something). This fix primarily improves the ability to do a parallel restore from such a file.

• ⇑ Upgrade to 13 released on 2020-09-24 - docs

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

    This new behavior matches the SQL specification. Previously a null ESCAPE value was taken to mean using the default escape string (a backslash character). This also applies to substring(text FROM pattern ESCAPE text). The previous behavior has been retained in old views by keeping the original function unchanged.

  • Make json[b]_to_tsvector() fully check the spelling of its string option (Dominik Czarnota)

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

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

    SELECT round(sum(OLDVALUE / n::float)) AS newvalue FROM generate_series(1, OLDVALUE) 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.

  • Rename various wait events to improve consistency (Fujii Masao, Tom Lane)

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

    Previously it returned ALTER TABLE; now it returns ALTER FOREIGN TABLE.

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

    Previously it returned ALTER TABLE; now it returns ALTER MATERIALIZED VIEW.

  • Rename configuration parameter wal_keep_segments to wal_keep_size (Fujii Masao)

    This determines how much WAL to retain for standby servers. It is specified in megabytes, rather than number of files as with the old parameter. If you previously used wal_keep_segments, the following formula will give you an approximately equivalent setting:

    wal_keep_size = wal_keep_segments * wal_segment_size (typically 16MB)
    

  • 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)

  • Remove support for upgrading unpackaged (pre-9.1) extensions (Tom Lane)

    The FROM option of CREATE EXTENSION is no longer supported. Any installations still using unpackaged extensions should upgrade them to a packaged version before updating to PostgreSQL 13.

  • Remove support for posixrules files in the timezone database (Tom Lane)

    IANA's timezone group has deprecated this feature, meaning that it will gradually disappear from systems' timezone databases over the next few years. Rather than have a behavioral change appear unexpectedly with a timezone data update, we have removed PostgreSQL's support for this feature as of version 13. This affects only the behavior of POSIX-style time zone specifications that lack an explicit daylight savings transition rule; formerly the transition rule could be determined by installing a custom posixrules file, but now it is hard-wired. The recommended fix for any affected installations is to start using a geographical time zone name.

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

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

  • Allow pruning of partitions to happen in more cases (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.

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

    However, such a trigger is not allowed to 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 a partitioned table can be published explicitly, causing all its partitions to be published automatically. Addition/removal of a partition causes it to be likewise added to or removed from the publication. The CREATE PUBLICATION option publish_via_partition_root controls whether changes to partitions are published as their own changes or their parent's.

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

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

  • Allow whole-row variables (that is, table.*) to be used in partitioning expressions (Amit Langote)

  • More efficiently store duplicates in B-tree indexes (Anastasia Lubennikova, Peter Geoghegan)

    This allows efficient B-tree indexing of low-cardinality columns by storing duplicate keys only once. Users upgrading with pg_upgrade will need to use REINDEX to make an existing index use this feature.

  • Allow GiST and SP-GiST indexes on box columns to support ORDER BY box <-> point queries (Nikita Glukhov)

  • Allow GIN indexes to more efficiently handle ! (NOT) clauses in tsquery searches (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's collation must match that of the underlying column, but ALTER TABLE previously failed to check this.

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

  • Allow setting the 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 pulled up (inlined) if they evaluate to constants (Alexander Kuzmenkov, Aleksandr Parfenov)

  • Implement incremental sorting (James Coleman, Alexander Korotkov, Tomas Vondra)

    If an intermediate query result is known to be sorted by one or more leading keys of a required sort ordering, the additional sorting can be done considering only the remaining keys, if the rows are sorted in batches that have equal leading keys.

    If necessary, this can be controlled using enable_incremental_sort.

  • 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. Now, a hash aggregation plan can be chosen despite that. The hash table will be spilled to disk if it exceeds work_mem times hash_mem_multiplier.

    This behavior is normally preferable to the old behavior, in which once hash aggregation had been chosen, the hash table would be kept in memory no matter how large it got — which could be very large if the planner had misestimated. If necessary, behavior similar to that can be obtained by increasing hash_mem_multiplier.

  • Allow inserts, not only updates and deletes, to trigger vacuuming activity in autovacuum (Laurenz Albe, Darafei Praliaskouski)

    Previously, insert-only activity would trigger auto-analyze but not auto-vacuum, on the grounds that there could not be any dead tuples to remove. However, a vacuum scan has other useful side-effects such as setting page-all-visible bits, which improves the efficiency of index-only scans. Also, allowing an insert-only table to receive periodic vacuuming helps to spread out the work of “freezing” old tuples, so that there is not suddenly a large amount of freezing work to do when the entire table reaches the anti-wraparound threshold all at once.

    If necessary, this behavior can be adjusted with the new parameters autovacuum_vacuum_insert_threshold and autovacuum_vacuum_insert_scale_factor, or the equivalent table storage options.

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

  • Allow WAL writes to be skipped during a transaction that creates or rewrites a relation, 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.

  • Improve 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 retrieval of the leading bytes of TOAST'ed values (Binguo Bao, Andrey Borodin)

    Previously, compressed out-of-line TOAST values were fully fetched even when it's known that only some leading bytes are needed. Now, only enough data to produce the result is fetched.

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

  • Speed up conversions of integers to text (David Fetter)

  • Reduce memory usage for query strings and extension scripts that contain many SQL statements (Amit Langote)

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

  • Allow a sample of SQL statements, rather than all statements, to be logged (Adrien Nayrat)

    A log_statement_sample_rate fraction of those statements taking more than 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 logging of non-error statements, while log_parameter_max_length_on_error does the same for logging of statements with errors. Previously, prepared statement parameters were never logged during errors.

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

    The new parameter backtrace_functions specifies which C functions should generate backtraces on error.

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

  • Add leader_pid to pg_stat_activity to report a parallel worker's leader process (Julien Rouhaud)

  • Add system view pg_stat_progress_basebackup to report the progress of streaming base backups (Fujii Masao)

  • Add system view pg_stat_progress_analyze to report ANALYZE progress (Álvaro Herrera, Tatsuro Yamada, Vinayak Pokale)

  • Add system view pg_shmem_allocations to display shared memory usage (Andres Freund, Robert Haas)

  • Add system view pg_stat_slru to monitor internal SLRU caches (Tomas Vondra)

  • Allow track_activity_query_size to be set as high as 1MB (Vyacheslav Makarov)

    The previous maximum was 100kB.

  • Report a wait event while creating a DSM segment with 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)

  • Allow only superusers to view the ssl_passphrase_command setting (Insung Moon)

    This was changed as a security precaution.

  • Change the server's default minimum TLS version for encrypted connections from 1.0 to 1.2 (Peter Eisentraut)

    This choice can be controlled by ssl_min_protocol_version.

  • Tighten rules on which utility commands are allowed in read-only transaction mode (Robert Haas)

    This change 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.

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

  • 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 to use a temporary replication slot when a permanent one is not specified (Peter Eisentraut, Sergei Kornilov)

    This behavior can be enabled using wal_receiver_create_temp_slot.

  • Allow WAL storage for replication slots to be limited by max_slot_wal_keep_size (Kyotaro Horiguchi)

    Replication slots that would require exceeding this value are marked invalid.

  • 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, a standby would promote itself upon reaching the end of WAL, 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 recovery to continue even if invalid pages are referenced by WAL (Fujii Masao)

    This is enabled using ignore_invalid_pages.

  • Allow VACUUM to process a table's 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)

  • Make CREATE TABLE LIKE propagate a CHECK constraint's NO INHERIT property to the created table (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 ... DROP EXPRESSION to allow removing the GENERATED property from a column (Peter Eisentraut)

  • Fix bugs in multi-step ALTER TABLE commands (Tom Lane)

    IF NOT EXISTS clauses now work as expected, in that derived actions (such as index creation) do not execute if the column already exists. Also, certain cases of combining related actions into one ALTER TABLE now work when they did not before.

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

    Renaming view columns was already possible, but one had to write ALTER TABLE RENAME COLUMN, which is confusing.

  • Add ALTER TYPE options to modify a base type's TOAST properties and support functions (Tomas Vondra, Tom Lane)

  • Add CREATE DATABASE LOCALE option (Peter Eisentraut)

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

  • Allow DROP DATABASE to disconnect sessions using the target database, allowing the drop to succeed (Pavel Stehule, Amit Kapila)

    This is enabled by the FORCE option.

  • Add structure member tg_updatedcols to allow C-language update triggers to know which column(s) were updated (Peter Eisentraut)

  • 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 existing xid data type is only four bytes so it does not provide the transaction epoch.

  • Add data type regcollation and associated functions, to represent OIDs of collation objects (Julien Rouhaud)

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

    If the glibc version changes, a warning will be issued about possible corruption of collation-dependent indexes.

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

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

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

  • Add alternate version of jsonb_set() with improved NULL handling (Andrew Dunstan)

    The new function, jsonb_set_lax(), handles a NULL new value by either setting the specified key to a JSON null, deleting the key, raising an exception, or returning the jsonb value unmodified, as requested.

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

    This function allows JSON values to be converted to timestamps, which can then be processed in jsonpath expressions. This change 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)

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

    These are particularly useful in monitoring queries.

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

  • 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 patterns.

  • Add datetime format patterns FF1 – FF6 to specify input or output of 1 to 6 fractional-second 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 datetime format pattern 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 in the 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 the numeric type's square root (sqrt) and natural log (ln) functions (Dean Rasheed)

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

  • Add function trim_scale() to reduce the scale of a numeric value 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 xid-based functions still exist, for backward compatibility.

  • Allow get_bit() and set_bit() to set bits beyond the first 256MB of a bytea value (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.

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

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

  • Allow libpq clients to require channel binding for encrypted connections (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 minimum and maximum TLS version allowed for an encrypted connection (Daniel Gustafsson)

    The settings are ssl_min_protocol_version and ssl_max_protocol_version. By default, the minimum TLS version is 1.2 (this represents a behavioral change from previous releases).

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

    This is enabled by libpq's sslpassword connection parameter.

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

  • Fix ecpg's EXEC SQL elif directive to work correctly (Tom Lane)

    Previously it behaved the same as endif followed by ifdef, so that a successful previous branch of the same if construct did not prevent expansion of the elif branch or following branches.

  • Add transaction status (%x) to psql's default prompts (Vik Fearing)

  • Allow the secondary psql prompt to be blank but the same width as the primary prompt (Thomas Munro)

    This is accomplished by setting PROMPT2 to %w.

  • Allow psql's \g and \gx commands to change \pset output options for the duration of that single command (Tom Lane)

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

  • Add psql commands to display 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's \d for TOAST tables (Justin Pryzby)

  • Fix redisplay after psql's \e command (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)

  • 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 initial data server-side, rather than client-side (Fabien Coelho)

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

  • 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. If that is not needed, it can be disabled by using the --no-estimate-size option. Previously, this computation happened only if the --progress option was used.

  • Add an option to pg_rewind 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 the PREPARE TRANSACTION-related information reported by pg_waldump (Fujii Masao)

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

  • Add pg_dump option --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 disconnect sessions using the target database, allowing the drop to succeed (Pavel Stehule)

    This is enabled with the -f option.

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

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

  • Use the directory of the pg_upgrade program as the default --new-bindir setting when running pg_upgrade (Daniel Gustafsson)

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

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

  • Upgrade to use DocBook 4.5 (Peter Eisentraut)

  • 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 configure options --disable-float8-byval and --disable-float4-byval (Peter Eisentraut)

    These were needed for compatibility with some version-zero C functions, but those are no longer supported.

  • Pass 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 reliably 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 cells (Tom Lane)

    This improves performance for queries that access many objects.

  • Change the API for TS_execute() (Tom Lane, Pavel Borisov)

    TS_execute callbacks must now provide ternary (yes/no/maybe) logic. Calculating NOT queries accurately is now the default.

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

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

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

    Specifically, allow a superuser to set password_required to false for a user mapping. Care must still be taken to prevent 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 commands 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 an option to dict_int 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 B-tree index de-duplication processing columns to pageinspect output (Peter Geoghegan)

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