Upgrading from 13.13 to 16.1 gives you 3.1 years worth of changes and fixes (765 of them)

List of changes:

• ⇑ Upgrade to 14 released on 2021-09-30 - docs

  • User-defined objects that reference certain built-in array functions along with their argument types must be recreated (Tom Lane)

    Specifically, array_append(), array_prepend(), array_cat(), array_position(), array_positions(), array_remove(), array_replace(), and width_bucket() used to take anyarray arguments but now take anycompatiblearray. Therefore, user-defined objects like aggregates and operators that reference those array function signatures must be dropped before upgrading, and recreated once the upgrade completes.

  • Remove deprecated containment operators @ and ~ for built-in geometric data types and contrib modules cube, hstore, intarray, and seg (Justin Pryzby)

    The more consistently named <@ and @> have been recommended for many years.

  • Fix to_tsquery() and websearch_to_tsquery() to properly parse query text containing discarded tokens (Alexander Korotkov)

    Certain discarded tokens, like underscore, caused the output of these functions to produce incorrect tsquery output, e.g., both websearch_to_tsquery('"pg_class pg"') and to_tsquery('pg_class <-> pg') used to output ( 'pg' & 'class' ) <-> 'pg', but now both output 'pg' <-> 'class' <-> 'pg'.

  • Fix websearch_to_tsquery() to properly parse multiple adjacent discarded tokens in quotes (Alexander Korotkov)

    Previously, quoted text that contained multiple adjacent discarded tokens was treated as multiple tokens, causing incorrect tsquery output, e.g., websearch_to_tsquery('"aaa: bbb"') used to output 'aaa' <2> 'bbb', but now outputs 'aaa' <-> 'bbb'.

  • Change EXTRACT() to return type numeric instead of float8 (Peter Eisentraut)

    This avoids loss-of-precision issues in some usages. The old behavior can still be obtained by using the old underlying function date_part().

    Also, EXTRACT(date) now throws an error for units that are not part of the date data type.

  • Change var_samp() and stddev_samp() with numeric parameters to return NULL when the input is a single NaN value (Tom Lane)

    Previously NaN was returned.

  • Return false for has_column_privilege() checks on non-existent or dropped columns when using attribute numbers (Joe Conway)

    Previously such attribute numbers returned an invalid-column error.

  • Fix handling of infinite window function ranges (Tom Lane)

    Previously window frame clauses like 'inf' PRECEDING AND 'inf' FOLLOWING returned incorrect results.

  • Remove factorial operators ! and !!, as well as function numeric_fac() (Mark Dilger)

    The factorial() function is still supported.

  • Disallow factorial() of negative numbers (Peter Eisentraut)

    Previously such cases returned 1.

  • Remove support for postfix (right-unary) operators (Mark Dilger)

    pg_dump and pg_upgrade will warn if postfix operators are being dumped.

  • Allow \D and \W shorthands to match newlines in regular expression newline-sensitive mode (Tom Lane)

    Previously they did not match newlines in this mode, but that disagrees with the behavior of other common regular expression engines. [^[:digit:]] or [^[:word:]] can be used to get the old behavior.

  • Disregard constraints when matching regular expression back-references (Tom Lane)

    For example, in (^\d+).*\1, the ^ constraint should be applied at the start of the string, but not when matching \1.

  • Disallow \w as a range start or end in regular expression character classes (Tom Lane)

    This previously was allowed but produced unexpected results.

  • Require custom server parameter names to use only characters that are valid in unquoted SQL identifiers (Tom Lane)

  • Change the default of the password_encryption server parameter to scram-sha-256 (Peter Eisentraut)

    Previously it was md5. All new passwords will be stored as SHA256 unless this server setting is changed or the password is specified in MD5 format. Also, the legacy (and undocumented) Boolean-like values which were previously synonyms for md5 are no longer accepted.

  • Remove server parameter vacuum_cleanup_index_scale_factor (Peter Geoghegan)

    This setting was ignored starting in PostgreSQL version 13.3.

  • Remove server parameter operator_precedence_warning (Tom Lane)

    This setting was used for warning applications about PostgreSQL 9.5 changes.

  • Overhaul the specification of clientcert in pg_hba.conf (Kyotaro Horiguchi)

    Values 1/0/no-verify are no longer supported; only the strings verify-ca and verify-full can be used. Also, disallow verify-ca if cert authentication is enabled since cert requires verify-full checking.

  • Remove support for SSL compression (Daniel Gustafsson, Michael Paquier)

    This was already disabled by default in previous PostgreSQL releases, and most modern OpenSSL and TLS versions no longer support it.

  • Remove server and libpq support for the version 2 wire protocol (Heikki Linnakangas)

    This was last used as the default in PostgreSQL 7.3 (released in 2002).

  • Disallow single-quoting of the language name in the CREATE/DROP LANGUAGE command (Peter Eisentraut)

  • Remove the composite types that were formerly created for sequences and toast tables (Tom Lane)

  • Process doubled quote marks in ecpg SQL command strings correctly (Tom Lane)

    Previously 'abc''def' was passed to the server as 'abc'def', and "abc""def" was passed as "abc"def", causing syntax errors.

  • Prevent the containment operators (<@ and @>) for intarray from using GiST indexes (Tom Lane)

    Previously a full GiST index scan was required, so just avoid that and scan the heap, which is faster. Indexes created for this purpose should be removed.

  • Remove contrib program pg_standby (Justin Pryzby)

  • Prevent tablefunc's function normal_rand() from accepting negative values (Ashutosh Bapat)

    Negative values produced undesirable results.

  • Add predefined roles pg_read_all_data and pg_write_all_data (Stephen Frost)

    These non-login roles can be used to give read or write permission to all tables, views, and sequences.

  • Add predefined role pg_database_owner that contains only the current database's owner (Noah Misch)

    This is especially useful in template databases.

  • Remove temporary files after backend crashes (Euler Taveira)

    Previously, such files were retained for debugging purposes. If necessary, deletion can be disabled with the new server parameter remove_temp_files_after_crash.

  • Allow long-running queries to be canceled if the client disconnects (Sergey Cherkashin, Thomas Munro)

    The server parameter client_connection_check_interval allows control over whether loss of connection is checked for intra-query. (This is supported on Linux and a few other operating systems.)

  • Add an optional timeout parameter to pg_terminate_backend()

  • Allow wide tuples to be always added to almost-empty heap pages (John Naylor, Floris van Nee)

    Previously tuples whose insertion would have exceeded the page's fill factor were instead added to new pages.

  • Add Server Name Indication (SNI) in SSL connection packets (Peter Eisentraut)

    This can be disabled by turning off client connection option sslsni.

  • Allow vacuum to skip index vacuuming when the number of removable index entries is insignificant (Masahiko Sawada, Peter Geoghegan)

    The vacuum parameter INDEX_CLEANUP has a new default of auto that enables this optimization.

  • Allow vacuum to more eagerly add deleted btree pages to the free space map (Peter Geoghegan)

    Previously vacuum could only add pages to the free space map that were marked as deleted by previous vacuums.

  • Allow vacuum to reclaim space used by unused trailing heap line pointers (Matthias van de Meent, Peter Geoghegan)

  • Allow vacuum to be more aggressive in removing dead rows during minimal-locking index operations (Álvaro Herrera)

    Specifically, CREATE INDEX CONCURRENTLY and REINDEX CONCURRENTLY no longer limit the dead row removal of other relations.

  • Speed up vacuuming of databases with many relations (Tatsuhito Kasahara)

  • Reduce the default value of vacuum_cost_page_miss to better reflect current hardware capabilities (Peter Geoghegan)

  • Add ability to skip vacuuming of TOAST tables (Nathan Bossart)

    VACUUM now has a PROCESS_TOAST option which can be set to false to disable TOAST processing, and vacuumdb has a --no-process-toast option.

  • Have COPY FREEZE appropriately update page visibility bits (Anastasia Lubennikova, Pavan Deolasee, Jeff Janes)

  • Cause vacuum operations to be more aggressive if the table is near xid or multixact wraparound (Masahiko Sawada, Peter Geoghegan)

    This is controlled by vacuum_failsafe_age and vacuum_multixact_failsafe_age.

  • Increase warning time and hard limit before transaction id and multi-transaction wraparound (Noah Misch)

    This should reduce the possibility of failures that occur without having issued warnings about wraparound.

  • Add per-index information to autovacuum logging output (Masahiko Sawada)

  • Improve the performance of updates and deletes on partitioned tables with many partitions (Amit Langote, Tom Lane)

    This change greatly reduces the planner's overhead for such cases, and also allows updates/deletes on partitioned tables to use execution-time partition pruning.

  • Allow partitions to be detached in a non-blocking manner (Álvaro Herrera)

    The syntax is ALTER TABLE ... DETACH PARTITION ... CONCURRENTLY, and FINALIZE.

  • Ignore COLLATE clauses in partition boundary values (Tom Lane)

    Previously any such clause had to match the collation of the partition key; but it's more consistent to consider that it's automatically coerced to the collation of the partition key.

  • Allow btree index additions to remove expired index entries to prevent page splits (Peter Geoghegan)

    This is particularly helpful for reducing index bloat on tables whose indexed columns are frequently updated.

  • Allow BRIN indexes to record multiple min/max values per range (Tomas Vondra)

    This is useful if there are groups of values in each page range.

  • Allow BRIN indexes to use bloom filters (Tomas Vondra)

    This allows BRIN indexes to be used effectively with data that is not well-localized in the heap.

  • Allow some GiST indexes to be built by presorting the data (Andrey Borodin)

    Presorting happens automatically and allows for faster index creation and smaller indexes.

  • Allow SP-GiST indexes to contain INCLUDE'd columns (Pavel Borisov)

  • Allow hash lookup for IN clauses with many constants (James Coleman, David Rowley)

    Previously the code always sequentially scanned the list of values.

  • Increase the number of places extended statistics can be used for OR clause estimation (Tomas Vondra, Dean Rasheed)

  • Allow extended statistics on expressions (Tomas Vondra)

    This allows statistics on a group of expressions and columns, rather than only columns like previously. System view pg_stats_ext_exprs reports such statistics.

  • Allow efficient heap scanning of a range of TIDs (Edmund Horner, David Rowley)

    Previously a sequential scan was required for non-equality TID specifications.

  • Fix EXPLAIN CREATE TABLE AS and EXPLAIN CREATE MATERIALIZED VIEW to honor IF NOT EXISTS (Bharath Rupireddy)

    Previously, if the object already existed, EXPLAIN would fail.

  • Improve the speed of computing MVCC visibility snapshots on systems with many CPUs and high session counts (Andres Freund)

    This also improves performance when there are many idle sessions.

  • Add executor method to memoize results from the inner side of a nested-loop join (David Rowley)

    This is useful if only a small percentage of rows is checked on the inner side. It can be disabled via server parameter enable_memoize.

  • Allow window functions to perform incremental sorts (David Rowley)

  • Improve the I/O performance of parallel sequential scans (Thomas Munro, David Rowley)

    This was done by allocating blocks in groups to parallel workers.

  • Allow a query referencing multiple foreign tables to perform foreign table scans in parallel (Robert Haas, Kyotaro Horiguchi, Thomas Munro, Etsuro Fujita)

    postgres_fdw supports this type of scan if async_capable is set.

  • Allow analyze to do page prefetching (Stephen Frost)

    This is controlled by maintenance_io_concurrency.

  • Improve performance of regular expression searches (Tom Lane)

  • Dramatically improve Unicode normalization (John Naylor)

    This speeds normalize() and IS NORMALIZED.

  • Add ability to use LZ4 compression on TOAST data (Dilip Kumar)

    This can be set at the column level, or set as a default via server parameter default_toast_compression. The server must be compiled with --with-lz4 to support this feature. The default setting is still pglz.

  • If server parameter compute_query_id is enabled, display the query id in pg_stat_activity, EXPLAIN VERBOSE, csvlog, and optionally in log_line_prefix (Julien Rouhaud)

    A query id computed by an extension will also be displayed.

  • Improve logging of auto-vacuum and auto-analyze (Stephen Frost, Jakub Wartak)

    This reports I/O timings for auto-vacuum and auto-analyze if track_io_timing is enabled. Also, report buffer read and dirty rates for auto-analyze.

  • Add information about the original user name supplied by the client to the output of log_connections (Jacob Champion)

  • Add system view pg_stat_progress_copy to report COPY progress (Josef Šimánek, Matthias van de Meent)

  • Add system view pg_stat_wal to report WAL activity (Masahiro Ikeda)

  • Add system view pg_stat_replication_slots to report replication slot activity (Sawada Masahiko, Amit Kapila, Vignesh C)

    The function pg_stat_reset_replication_slot() resets slot statistics.

  • Add system view pg_backend_memory_contexts to report session memory usage (Atsushi Torikoshi, Fujii Masao)

  • Add function pg_log_backend_memory_contexts() to output the memory contexts of arbitrary backends (Atsushi Torikoshi)

  • Add session statistics to the pg_stat_database system view (Laurenz Albe)

  • Add columns to pg_prepared_statements to report generic and custom plan counts (Atsushi Torikoshi, Kyotaro Horiguchi)

  • Add lock wait start time to pg_locks (Atsushi Torikoshi)

  • Make the archiver process visible in pg_stat_activity (Kyotaro Horiguchi)

  • Add wait event WalReceiverExit to report WAL receiver exit wait time (Fujii Masao)

  • Implement information schema view routine_column_usage to track columns referenced by function and procedure default expressions (Peter Eisentraut)

  • Allow an SSL certificate's distinguished name (DN) to be matched for client certificate authentication (Andrew Dunstan)

    The new pg_hba.conf option clientname=DN allows comparison with certificate attributes beyond the CN and can be combined with ident maps.

  • Allow pg_hba.conf and pg_ident.conf records to span multiple lines (Fabien Coelho)

    A backslash at the end of a line allows record contents to be continued on the next line.

  • Allow the specification of a certificate revocation list (CRL) directory (Kyotaro Horiguchi)

    This is controlled by server parameter ssl_crl_dir and libpq connection option sslcrldir. Previously only single CRL files could be specified.

  • Allow passwords of an arbitrary length (Tom Lane, Nathan Bossart)

  • Add server parameter idle_session_timeout to close idle sessions (Li Japin)

    This is similar to idle_in_transaction_session_timeout.

  • Change checkpoint_completion_target default to 0.9 (Stephen Frost)

    The previous default was 0.5.

  • Allow %P in log_line_prefix to report the parallel group leader's PID for a parallel worker (Justin Pryzby)

  • Allow unix_socket_directories to specify paths as individual, comma-separated quoted strings (Ian Lawrence Barwick)

    Previously all the paths had to be in a single quoted string.

  • Allow startup allocation of dynamic shared memory (Thomas Munro)

    This is controlled by min_dynamic_shared_memory. This allows more use of huge pages.

  • Add server parameter huge_page_size to control the size of huge pages used on Linux (Odin Ugedal)

  • Allow standby servers to be rewound via pg_rewind (Heikki Linnakangas)

  • Allow the restore_command setting to be changed during a server reload (Sergei Kornilov)

    You can also set restore_command to an empty string and reload to force recovery to only read from the pg_wal directory.

  • Add server parameter log_recovery_conflict_waits to report long recovery conflict wait times (Bertrand Drouvot, Masahiko Sawada)

  • Pause recovery on a hot standby server if the primary changes its parameters in a way that prevents replay on the standby (Peter Eisentraut)

    Previously the standby would shut down immediately.

  • Add function pg_get_wal_replay_pause_state() to report the recovery state (Dilip Kumar)

    It gives more detailed information than pg_is_wal_replay_paused(), which still exists.

  • Add new read-only server parameter in_hot_standby (Haribabu Kommi, Greg Nancarrow, Tom Lane)

    This allows clients to easily detect whether they are connected to a hot standby server.

  • Speed truncation of small tables during recovery on clusters with a large number of shared buffers (Kirk Jamison)

  • Allow file system sync at the start of crash recovery on Linux (Thomas Munro)

    By default, PostgreSQL opens and fsyncs each data file in the database cluster at the start of crash recovery. A new setting, recovery_init_sync_method=syncfs, instead syncs each filesystem used by the cluster. This allows for faster recovery on systems with many database files.

  • Add function pg_xact_commit_timestamp_origin() to return the commit timestamp and replication origin of the specified transaction (Movead Li)

  • Add the replication origin to the record returned by pg_last_committed_xact() (Movead Li)

  • Allow replication origin functions to be controlled using standard function permission controls (Martín Marqués)

    Previously these functions could only be executed by superusers, and this is still the default.

  • Allow logical replication to stream long in-progress transactions to subscribers (Dilip Kumar, Amit Kapila, Ajin Cherian, Tomas Vondra, Nikhil Sontakke, Stas Kelvich)

    Previously transactions that exceeded logical_decoding_work_mem were written to disk until the transaction completed.

  • Enhance the logical replication API to allow streaming large in-progress transactions (Tomas Vondra, Dilip Kumar, Amit Kapila)

    The output functions begin with stream. test_decoding also supports these.

  • Allow multiple transactions during table sync in logical replication (Peter Smith, Amit Kapila, and Takamichi Osumi)

  • Immediately WAL-log subtransaction and top-level XID association (Tomas Vondra, Dilip Kumar, Amit Kapila)

    This is useful for logical decoding.

  • Enhance logical decoding APIs to handle two-phase commits (Ajin Cherian, Amit Kapila, Nikhil Sontakke, Stas Kelvich)

    This is controlled via pg_create_logical_replication_slot().

  • Generate WAL invalidation messages during command completion when using logical replication (Dilip Kumar, Tomas Vondra, Amit Kapila)

    When logical replication is disabled, WAL invalidation messages are generated at transaction completion. This allows logical streaming of in-progress transactions.

  • Allow logical decoding to more efficiently process cache invalidation messages (Dilip Kumar)

    This allows logical decoding to work efficiently in presence of a large amount of DDL.

  • Allow control over whether logical decoding messages are sent to the replication stream (David Pirotte, Euler Taveira)

  • Allow logical replication subscriptions to use binary transfer mode (Dave Cramer)

    This is faster than text mode, but slightly less robust.

  • Allow logical decoding to be filtered by xid (Markus Wanner)

  • Reduce the number of keywords that can't be used as column labels without AS (Mark Dilger)

    There are now 90% fewer restricted keywords.

  • Allow an alias to be specified for JOIN's USING clause (Peter Eisentraut)

    The alias is created by writing AS after the USING clause. It can be used as a table qualification for the merged USING columns.

  • Allow DISTINCT to be added to GROUP BY to remove duplicate GROUPING SET combinations (Vik Fearing)

    For example, GROUP BY CUBE (a,b), CUBE (b,c) will generate duplicate grouping combinations without DISTINCT.

  • Properly handle DEFAULT entries in multi-row VALUES lists in INSERT (Dean Rasheed)

    Such cases used to throw an error.

  • Add SQL-standard SEARCH and CYCLE clauses for common table expressions (Peter Eisentraut)

    The same results could be accomplished using existing syntax, but much less conveniently.

  • Allow column names in the WHERE clause of ON CONFLICT to be table-qualified (Tom Lane)

    Only the target table can be referenced, however.

  • Allow REFRESH MATERIALIZED VIEW to use parallelism (Bharath Rupireddy)

  • Allow REINDEX to change the tablespace of the new index (Alexey Kondratov, Michael Paquier, Justin Pryzby)

    This is done by specifying a TABLESPACE clause. A --tablespace option was also added to reindexdb to control this.

  • Allow REINDEX to process all child tables or indexes of a partitioned relation (Justin Pryzby, Michael Paquier)

  • Allow index commands using CONCURRENTLY to avoid waiting for the completion of other operations using CONCURRENTLY (Álvaro Herrera)

  • Improve the performance of COPY FROM in binary mode (Bharath Rupireddy, Amit Langote)

  • Preserve SQL standard syntax for SQL-defined functions in view definitions (Tom Lane)

    Previously, calls to SQL-standard functions such as EXTRACT() were shown in plain function-call syntax. The original syntax is now preserved when displaying a view or rule.

  • Add the SQL-standard clause GRANTED BY to GRANT and REVOKE (Peter Eisentraut)

  • Add OR REPLACE option for CREATE TRIGGER (Takamichi Osumi)

    This allows pre-existing triggers to be conditionally replaced.

  • Allow TRUNCATE to operate on foreign tables (Kazutaka Onishi, Kohei KaiGai)

    The postgres_fdw module also now supports this.

  • Allow publications to be more easily added to and removed from a subscription (Japin Li)

    The new syntax is ALTER SUBSCRIPTION ... ADD/DROP PUBLICATION. This avoids having to specify all publications to add/remove entries.

  • Add primary keys, unique constraints, and foreign keys to system catalogs (Peter Eisentraut)

    These changes help GUI tools analyze the system catalogs. The existing unique indexes of catalogs now have associated UNIQUE or PRIMARY KEY constraints. Foreign key relationships are not actually stored or implemented as constraints, but can be obtained for display from the function pg_get_catalog_foreign_keys().

  • Allow CURRENT_ROLE every place CURRENT_USER is accepted (Peter Eisentraut)

  • Allow extensions and built-in data types to implement subscripting (Dmitry Dolgov)

    Previously subscript handling was hard-coded into the server, so that subscripting could only be applied to array types. This change allows subscript notation to be used to extract or assign portions of a value of any type for which the concept makes sense.

  • Allow subscripting of JSONB (Dmitry Dolgov)

    JSONB subscripting can be used to extract and assign to portions of JSONB documents.

  • Add support for multirange data types (Paul Jungwirth, Alexander Korotkov)

    These are like range data types, but they allow the specification of multiple, ordered, non-overlapping ranges. An associated multirange type is automatically created for every range type.

  • Add support for the stemming of languages Armenian, Basque, Catalan, Hindi, Serbian, and Yiddish (Peter Eisentraut)

  • Allow tsearch data files to have unlimited line lengths (Tom Lane)

    The previous limit was 4K bytes. Also remove function t_readline().

  • Add support for Infinity and -Infinity values in the numeric data type (Tom Lane)

    Floating-point data types already supported these.

  • Add point operators <<| and |>> representing strictly above/below tests (Emre Hasegeli)

    Previously these were called >^ and <^, but that naming is inconsistent with other geometric data types. The old names remain available, but may someday be removed.

  • Add operators to add and subtract LSN and numeric (byte) values (Fujii Masao)

  • Allow binary data transfer to be more forgiving of array and record OID mismatches (Tom Lane)

  • Create composite array types for system catalogs (Wenjing Zeng)

    User-defined relations have long had composite types associated with them, and also array types over those composite types. System catalogs now do as well. This change also fixes an inconsistency that creating a user-defined table in single-user mode would fail to create a composite array type.

  • Allow SQL-language functions and procedures to use SQL-standard function bodies (Peter Eisentraut)

    Previously only string-literal function bodies were supported. When writing a function or procedure in SQL-standard syntax, the body is parsed immediately and stored as a parse tree. This allows better tracking of function dependencies, and can have security benefits.

  • Allow procedures to have OUT parameters (Peter Eisentraut)

  • Allow some array functions to operate on a mix of compatible data types (Tom Lane)

    The functions array_append(), array_prepend(), array_cat(), array_position(), array_positions(), array_remove(), array_replace(), and width_bucket() now take anycompatiblearray instead of anyarray arguments. This makes them less fussy about exact matches of argument types.

  • Add SQL-standard trim_array() function (Vik Fearing)

    This could already be done with array slices, but less easily.

  • Add bytea equivalents of ltrim() and rtrim() (Joel Jacobson)

  • Support negative indexes in split_part() (Nikhil Benesch)

    Negative values start from the last field and count backward.

  • Add string_to_table() function to split a string on delimiters (Pavel Stehule)

    This is similar to the regexp_split_to_table() function.

  • Add unistr() function to allow Unicode characters to be specified as backslash-hex escapes in strings (Pavel Stehule)

    This is similar to how Unicode can be specified in literal strings.

  • Add bit_xor() XOR aggregate function (Alexey Bashtanov)

  • Add function bit_count() to return the number of bits set in a bit or byte string (David Fetter)

  • Add date_bin() function (John Naylor)

    This function “bins” input timestamps, grouping them into intervals of a uniform length aligned with a specified origin.

  • Allow make_timestamp()/make_timestamptz() to accept negative years (Peter Eisentraut)

    Negative values are interpreted as BC years.

  • Add newer regular expression substring() syntax (Peter Eisentraut)

    The new SQL-standard syntax is SUBSTRING(text SIMILAR pattern ESCAPE escapechar). The previous standard syntax was SUBSTRING(text FROM pattern FOR escapechar), which is still accepted by PostgreSQL.

  • Allow complemented character class escapes \D, \S, and \W within regular expression brackets (Tom Lane)

  • Add [[:word:]] as a regular expression character class, equivalent to \w (Tom Lane)

  • Allow more flexible data types for default values of lead() and lag() window functions (Vik Fearing)

  • Make non-zero floating-point values divided by infinity return zero (Kyotaro Horiguchi)

    Previously such operations produced underflow errors.

  • Make floating-point division of NaN by zero return NaN (Tom Lane)

    Previously this returned an error.

  • Cause exp() and power() for negative-infinity exponents to return zero (Tom Lane)

    Previously they often returned underflow errors.

  • Improve the accuracy of geometric computations involving infinity (Tom Lane)

  • Mark built-in type coercion functions as leakproof where possible (Tom Lane)

    This allows more use of functions that require type conversion in security-sensitive situations.

  • Change pg_describe_object(), pg_identify_object(), and pg_identify_object_as_address() to always report helpful error messages for non-existent objects (Michael Paquier)

  • Improve PL/pgSQL's expression and assignment parsing (Tom Lane)

    This change allows assignment to array slices and nested record fields.

  • Allow plpgsql's RETURN QUERY to execute its query using parallelism (Tom Lane)

  • Improve performance of repeated CALLs within plpgsql procedures (Pavel Stehule, Tom Lane)

  • Add pipeline mode to libpq (Craig Ringer, Matthieu Garrigues, Álvaro Herrera)

    This allows multiple queries to be sent, only waiting for completion when a specific synchronization message is sent.

  • Enhance libpq's target_session_attrs parameter options (Haribabu Kommi, Greg Nancarrow, Vignesh C, Tom Lane)

    The new options are read-only, primary, standby, and prefer-standby.

  • Improve the output format of libpq's PQtrace() (Aya Iwata, Álvaro Herrera)

  • Allow an ECPG SQL identifier to be linked to a specific connection (Hayato Kuroda)

    This is done via DECLARE ... STATEMENT.

  • Allow vacuumdb to skip index cleanup and truncation (Nathan Bossart)

    The options are --no-index-cleanup and --no-truncate.

  • Allow pg_dump to dump only certain extensions (Guillaume Lelarge)

    This is controlled by option --extension.

  • Add pgbench permute() function to randomly shuffle values (Fabien Coelho, Hironobu Suzuki, Dean Rasheed)

  • Include disconnection times in the reconnection overhead measured by pgbench with -C (Yugo Nagata)

  • Allow multiple verbose option specifications (-v) to increase the logging verbosity (Tom Lane)

    This behavior is supported by pg_dump, pg_dumpall, and pg_restore.

  • Allow psql's \df and \do commands to specify function and operator argument types (Greg Sabino Mullane, Tom Lane)

    This helps reduce the number of matches printed for overloaded names.

  • Add an access method column to psql's \d[i|m|t]+ output (Georgios Kokolatos)

  • Allow psql's \dt and \di to show TOAST tables and their indexes (Justin Pryzby)

  • Add psql command \dX to list extended statistics objects (Tatsuro Yamada)

  • Fix psql's \dT to understand array syntax and backend grammar aliases, like int for integer (Greg Sabino Mullane, Tom Lane)

  • When editing the previous query or a file with psql's \e, or using \ef and \ev, ignore the results if the editor exits without saving (Laurenz Albe)

    Previously, such edits would load the previous query into the query buffer, and typically execute it immediately. This was deemed to be probably not what the user wants.

  • Improve tab completion (Vignesh C, Michael Paquier, Justin Pryzby, Georgios Kokolatos, Julien Rouhaud)

  • Add command-line utility pg_amcheck to simplify running contrib/amcheck tests on many relations (Mark Dilger)

  • Add --no-instructions option to initdb (Magnus Hagander)

    This suppresses the server startup instructions that are normally printed.

  • Stop pg_upgrade from creating analyze_new_cluster script (Magnus Hagander)

    Instead, give comparable vacuumdb instructions.

  • Remove support for the postmaster -o option (Magnus Hagander)

    This option was unnecessary since all passed options could already be specified directly.

  • Rename "Default Roles" to "Predefined Roles" (Bruce Momjian, Stephen Frost)

  • Add documentation for the factorial() function (Peter Eisentraut)

    With the removal of the ! operator in this release, factorial() is the only built-in way to compute a factorial.

  • Add configure option --with-ssl={openssl} to allow future choice of the SSL library to use (Daniel Gustafsson, Michael Paquier)

    The spelling --with-openssl is kept for compatibility.

  • Add support for abstract Unix-domain sockets (Peter Eisentraut)

    This is currently supported on Linux and Windows.

  • Allow Windows to properly handle files larger than four gigabytes (Juan José Santamaría Flecha)

    For example this allows COPY, WAL files, and relation segment files to be larger than four gigabytes.

  • Add server parameter debug_discard_caches to control cache flushing for test purposes (Craig Ringer)

    Previously this behavior could only be set at compile time. To invoke it during initdb, use the new option --discard-caches.

  • Various improvements in valgrind error detection ability (Álvaro Herrera, Peter Geoghegan)

  • Add a test module for the regular expression package (Tom Lane)

  • Add support for LLVM version 12 (Andres Freund)

  • Change SHA1, SHA2, and MD5 hash computations to use the OpenSSL EVP API (Michael Paquier)

    This is more modern and supports FIPS mode.

  • Remove separate build-time control over the choice of random number generator (Daniel Gustafsson)

    This is now always determined by the choice of SSL library.

  • Add direct conversion routines between EUC_TW and Big5 encodings (Heikki Linnakangas)

  • Add collation version support for FreeBSD (Thomas Munro)

  • Add amadjustmembers to the index access method API (Tom Lane)

    This allows an index access method to provide validity checking during creation of a new operator class or family.

  • Provide feature-test macros in libpq-fe.h for recently-added libpq features (Tom Lane, Álvaro Herrera)

    Historically, applications have usually used compile-time checks of PG_VERSION_NUM to test whether a feature is available. But that's normally the server version, which might not be a good guide to libpq's version. libpq-fe.h now offers #define symbols denoting application-visible features added in v14; the intent is to keep adding symbols for such features in future versions.

  • Allow subscripting of hstore values (Tom Lane, Dmitry Dolgov)

  • Allow GiST/GIN pg_trgm indexes to do equality lookups (Julien Rouhaud)

    This is similar to LIKE except no wildcards are honored.

  • Allow the cube data type to be transferred in binary mode (KaiGai Kohei)

  • Allow pgstattuple_approx() to report on TOAST tables (Peter Eisentraut)

  • Add contrib module pg_surgery which allows changes to row visibility (Ashutosh Sharma)

    This is useful for correcting database corruption.

  • Add contrib module old_snapshot to report the XID/time mapping used by an active old_snapshot_threshold (Robert Haas)

  • Allow amcheck to also check heap pages (Mark Dilger)

    Previously it only checked B-Tree index pages.

  • Allow pageinspect to inspect GiST indexes (Andrey Borodin, Heikki Linnakangas)

  • Change pageinspect block numbers to be bigints (Peter Eisentraut)

  • Mark btree_gist functions as parallel safe (Steven Winfield)

  • Move query hash computation from pg_stat_statements to the core server (Julien Rouhaud)

    The new server parameter compute_query_id's default of auto will automatically enable query id computation when this extension is loaded.

  • Cause pg_stat_statements to track top and nested statements separately (Julien Rohaud)

    Previously, when tracking all statements, identical top and nested statements were tracked as a single entry; but it seems more useful to separate such usages.

  • Add row counts for utility commands to pg_stat_statements (Fujii Masao, Katsuragi Yuta, Seino Yuki)

  • Add pg_stat_statements_info system view to show pg_stat_statements activity (Katsuragi Yuta, Yuki Seino, Naoki Nakamichi)

  • Allow postgres_fdw to INSERT rows in bulk (Takayuki Tsunakawa, Tomas Vondra, Amit Langote)

  • Allow postgres_fdw to import table partitions if specified by IMPORT FOREIGN SCHEMA ... LIMIT TO (Matthias van de Meent)

    By default, only the root of a partitioned table is imported.

  • Add postgres_fdw function postgres_fdw_get_connections() to report open foreign server connections (Bharath Rupireddy)

  • Allow control over whether foreign servers keep connections open after transaction completion (Bharath Rupireddy)

    This is controlled by keep_connections and defaults to on.

  • Allow postgres_fdw to reestablish foreign server connections if necessary (Bharath Rupireddy)

    Previously foreign server restarts could cause foreign table access errors.

  • Add postgres_fdw functions to discard cached connections (Bharath Rupireddy)

• ⇑ Upgrade to 14.1 released on 2021-11-11 - docs

  • Ensure that parallel VACUUM doesn't miss any indexes (Peter Geoghegan, Masahiko Sawada)

    A parallel VACUUM would fail to process indexes that are below the min_parallel_index_scan_size cutoff, if the table also has at least two indexes that are above that size. This could result in those indexes becoming corrupt, since they'd still contain references to any heap entries removed by the VACUUM; subsequent queries using such indexes would be likely to return rows they shouldn't. This problem does not affect autovacuum, since it doesn't use parallel vacuuming. However, it is advisable to reindex any manually-vacuumed tables that have the right mix of index sizes.

  • Fix incorrect creation of shared dependencies when cloning a database that contains non-builtin objects (Aleksander Alekseev)

    The effects of this error are probably limited in practice. In principle, it could allow a role to be dropped while it still owns objects; but most installations would never want to drop a role that had been used for objects they'd added to template1.

  • Fix corruption of parse tree while creating a range type (Alex Kozhemyakin, Sergey Shinderuk)

    CREATE TYPE incorrectly freed an element of the parse tree, which could cause problems for a later event trigger, or if the CREATE TYPE command was stored in the plan cache and used again later.

  • Avoid choosing the wrong hash equality operator for Memoize plans (David Rowley)

    This error could result in crashes or incorrect query results.

  • Fix “could not find RecursiveUnion” error when EXPLAIN tries to print a filter condition attached to a WorkTableScan node (Tom Lane)

  • Avoid assertion failure when inserting NaN into a BRIN float8 or float4 minmax_multi_ops index (Tomas Vondra)

    In production builds, such cases would result in a somewhat inefficient, but not actually incorrect, index.

  • Allow the autovacuum launcher process to respond to pg_log_backend_memory_contexts() requests more quickly (Koyu Tanigawa)

  • Fix memory leak in HMAC hash calculations (Sergey Shinderuk)

  • Fix checking of query type in PL/pgSQL's RETURN QUERY statement (Tom Lane)

    RETURN QUERY should accept any query that can return tuples, e.g. UPDATE RETURNING. v14 accidentally disallowed anything but SELECT; moreover, the RETURN QUERY EXECUTE variant failed to apply any query-type check at all.

  • Prevent pg_amcheck from checking temporary relations, as well as indexes that are invalid or not ready (Mark Dilger)

    This avoids unhelpful checks of relations that will almost certainly appear inconsistent.

  • Make contrib/amcheck skip unlogged tables when running on a standby server (Mark Dilger)

    It's appropriate to do this since such tables will be empty, and unlogged indexes were already handled similarly.

  • When running a TAP test, include the module's own directory in PATH (Andrew Dunstan)

    This allows tests to find built programs that are not installed, such as custom test drivers.

• ⇑ Upgrade to 14.2 released on 2022-02-10 - docs

  • Fix corruption of HOT chains when a RECENTLY_DEAD tuple changes state to fully DEAD during page pruning (Andres Freund)

    It was possible for VACUUM to remove a recently-dead tuple while leaving behind a redirect item that pointed to it. When the tuple's item slot is later re-used by some new tuple, that tuple would be seen as part of the pre-existing HOT chain, creating a form of index corruption. If this has happened, reindexing the table should repair the damage. However, this is an extremely low-probability scenario, so we do not recommend reindexing just on the chance that it might have happened.

  • Fix crash in EvalPlanQual rechecks for tables with a mix of local and foreign partitions (Etsuro Fujita)

  • Fix dangling pointer in COPY TO (Bharath Rupireddy)

    This oversight could cause an incorrect error message or a crash after an error in COPY.

  • Correctly handle alignment padding when extracting a range from a multirange (Alexander Korotkov)

    This error could cause crashes when handling multiranges over variable-length data types.

  • Fix over-optimistic use of hashing for anonymous RECORD data types (Tom Lane)

    This prevents some cases of “could not identify a hash function for type record” errors.

  • Fix Memoize plan nodes to handle subplans that use parameters coming from above the Memoize (David Rowley)

  • Fix Memoize plan nodes to work correctly with non-hashable join operators (David Rowley)

  • Ensure that replication origin timestamp is set while replicating a ROLLBACK PREPARED operation (Masahiko Sawada)

  • Fix failure of SP-GiST indexes when the indexed column's data type is binary-compatible with the declared input type of the operator class (Tom Lane)

    Such cases should work, but failed with “compress method must be defined when leaf type is different from input type”.

  • Fix memory leak when updating expression indexes (Peter Geoghegan)

    An UPDATE affecting many rows could consume significant amounts of memory.

  • Ensure that the session targeted by pg_log_backend_memory_contexts() sends its results only to the server's log (Fujii Masao)

    Previously, a sufficiently high setting of client_min_messages could result in the log message also being sent to the connected client. Since that client hadn't requested it, that would be surprising (and possibly a wire protocol violation).

  • When reverse-listing a SQL-standard function body, display function parameters appropriately within INSERT ... SELECT (Tom Lane)

    Previously, they'd come out as $N even when the parameter had a name.

  • Make psql's \d command sort a table's extended statistics objects by name not OID (Justin Pryzby)

  • Fix failures on Windows when using the terminal as data source or destination (Dmitry Koval, Juan José Santamaría Flecha, Michael Paquier)

    This affects psql's \copy command, as well as pg_recvlogical with -f -.

  • Fix edge cases in postgres_fdw's handling of asynchronous queries (Etsuro Fujita)

    These errors could lead to crashes or incorrect results when attempting to parallelize scans of foreign tables.

  • Re-allow cross-compilation without OpenSSL (Tom Lane)

    configure should assume that /dev/urandom will be available on the target system, but it failed instead.

• ⇑ Upgrade to 14.3 released on 2022-05-12 - docs

  • Fix incorrect roundoff when extracting epoch values from intervals (Peter Eisentraut)

    The new numeric-based code for EXTRACT() failed to yield results equivalent to the old float-based code, as a result of accidentally truncating the DAYS_PER_YEAR value to an integer.

  • Defend against pg_stat_get_replication_slot(NULL) (Andres Freund)

    This function should be marked strict in the catalog data, but it was not in v14, so add a run-time check instead.

  • Fix planner failure when a Result plan node appears immediately underneath an Append node (Etsuro Fujita)

    Recently-added code to support asynchronous remote queries failed to handle this case, leading to crashes or errors about unrecognized node types.

  • Fix planner failure if a query using SEARCH or CYCLE features contains a duplicate CTE name (Tom Lane, Kyotaro Horiguchi)

    When the name of the recursive WITH query is re-used within itself, the planner could crash or report odd errors such as “could not find attribute 2 in subquery targetlist”.

  • Tighten lookup of the index “owned by” a constraint (Tom Lane, Japin Li)

    Some code paths mistook the index depended on by a foreign key constraint for one owned by a unique or primary key constraint, resulting in odd errors during certain ALTER TABLE operations on tables having foreign key constraints.

  • Prevent data loss if a system crash occurs shortly after a sorted GiST index build (Heikki Linnakangas)

    The code path for building GiST indexes using sorting neglected to fsync the file upon completion. This could result in a corrupted index if the operating system crashed shortly later.

  • Re-allow underscore as the first character in a custom parameter name (Japin Li)

    Such names were unintentionally disallowed in v14.

  • Add regress option for the compute_query_id parameter (Michael Paquier)

    This is intended to facilitate testing, by allowing query IDs to be computed but not shown in EXPLAIN output.

  • Wake up for latch events when the checkpointer is waiting between writes (Thomas Munro)

    This improves responsiveness to backends sending sync requests. The change also creates a proper wait event class for these waits.

  • Make the server more robust against missed timer interrupts (Michael Harris, Tom Lane)

    An optimization added in v14 meant that if a server process somehow missed a timer interrupt, it would never again ask the kernel for another one, thus breaking timeout detection for the remainder of the session. This seems unduly fragile, so add a recovery path.

  • Re-allow database.schema.table patterns in psql, pg_dump, and pg_amcheck (Mark Dilger)

    Versions before v14 silently ignored all but the schema and table fragments of a pattern containing more than one dot. Refactoring in v14 accidentally broke that use-case. Reinstate it, but now complain if the first fragment is not the name of the current database.

  • In contrib/postgres_fdw, disable batch insertion when BEFORE INSERT ... FOR EACH ROW triggers exist on the foreign table (Etsuro Fujita)

    Such a trigger might query the table it's on and expect to see previously-inserted rows. With batch insertion, those rows might not be visible yet, so disable the feature to avoid unexpected behavior.

  • Fix configure to handle platforms that have sys/epoll.h but not sys/signalfd.h (Tom Lane)

  • Do not add OpenSSL dependencies to libpq's pkg-config file when building without OpenSSL (Fabrice Fontaine)

• ⇑ Upgrade to 14.4 released on 2022-06-16 - docs

  • Prevent possible corruption of indexes created or rebuilt with the CONCURRENTLY option (Álvaro Herrera)

    An optimization added in v14 caused CREATE INDEX ... CONCURRENTLY and REINDEX ... CONCURRENTLY to sometimes miss indexing rows that were updated during the index build. Revert that optimization. It is recommended that any indexes made with the CONCURRENTLY option be rebuilt after installing this update. (Alternatively, rebuild them without CONCURRENTLY.)

  • Harden Memoize plan node against non-deterministic equality functions (David Rowley)

    Memoize could crash if a data type's equality or hash functions gave inconsistent results across different calls. Throw a runtime error instead.

  • Fix incorrect cost estimates for Memoize plans (David Rowley)

    This mistake could lead to Memoize being used when it isn't really the best plan, or to very long executor startup times due to initializing an overly-large hash table for a Memoize node.

  • Fix COPY FROM's error checking in the case where the database encoding is SQL_ASCII while the client's encoding is a multi-byte encoding (Heikki Linnakangas)

    This mistake could lead to false complaints of invalidly-encoded input data.

  • Prevent crash after server connection loss in pg_amcheck (Tom Lane)

    Misprocessing of a libpq-generated error result, such as a report of lost connection, would lead to a crash.

• ⇑ Upgrade to 14.5 released on 2022-08-11 - docs

  • Fix incorrect permissions-checking code for extended statistics (Richard Guo)

    If there are extended statistics on a table that the user has only partial SELECT permissions on, some queries would fail with “unrecognized node type” errors.

  • Fix extended statistics machinery to handle MCV-type statistics on boolean-valued expressions (Tom Lane)

    Statistics collection worked fine, but a query containing such an expression in WHERE would fail with “unknown clause type”.

  • Allow cancellation of ANALYZE while it is computing extended statistics (Tom Lane, Justin Pryzby)

    In some scenarios with high statistics targets, it was possible to spend many seconds in an un-cancellable sort operation.

  • Fix trim_array() to handle a zero-dimensional array argument sanely (Martin Kalcher)

  • Avoid assertion failure when min_dynamic_shared_memory is set to a non-default value (Thomas Munro)

  • Improve libpq's handling of idle states in pipeline mode (Álvaro Herrera, Kyotaro Horiguchi)

    This fixes “message type 0x33 arrived from server while idle” warnings, as well as possible loss of end-of-query NULL results from PQgetResult().

  • Fix pg_upgrade to detect non-upgradable usages of functions taking anyarray (Justin Pryzby)

    Version 14 changed some built-in functions to take type anycompatiblearray instead of anyarray. While this is mostly transparent, user-defined aggregates and operators built atop these functions have to be declared with exactly matching types. The presence of an object referencing the old signature will cause pg_upgrade to fail, so change it to detect and report such cases before beginning the upgrade.

  • In contrib/postgres_fdw, prevent batch insertion when there are WITH CHECK OPTION constraints (Etsuro Fujita)

    Such constraints cannot be checked properly if more than one row is inserted at a time.

  • Fix contrib/postgres_fdw to detect failure to send an asynchronous data fetch query (Fujii Masao)

  • Avoid using signalfd() on illumos systems (Thomas Munro)

    This appears to trigger hangs and kernel panics, so avoid the function until a fix is available.

• ⇑ Upgrade to 15 released on 2022-10-13 - docs

  • Remove PUBLIC creation permission on the public schema (Noah Misch)

    The new default is one of the secure schema usage patterns that Section 5.9.6 has recommended since the security release for CVE-2018-1058. The change applies to new database clusters and to newly-created databases in existing clusters. Upgrading a cluster or restoring a database dump will preserve public's existing permissions.

    For existing databases, especially those having multiple users, consider revoking CREATE permission on the public schema to adopt this new default. For new databases having no need to defend against insider threats, granting CREATE permission will yield the behavior of prior releases.

  • Change the owner of the public schema to be the new pg_database_owner role (Noah Misch)

    This allows each database's owner to have ownership privileges on the public schema within their database. Previously it was owned by the bootstrap superuser, so that non-superuser database owners could not do anything with it.

    This change applies to new database clusters and to newly-created databases in existing clusters. Upgrading a cluster or restoring a database dump will preserve public's existing ownership specification.

  • Remove long-deprecated exclusive backup mode (David Steele, Nathan Bossart)

    If the database server stops abruptly while in this mode, the server could fail to start. The non-exclusive backup mode is considered superior for all purposes. Functions pg_start_backup()/pg_stop_backup() have been renamed to pg_backup_start()/pg_backup_stop(), and the functions pg_backup_start_time() and pg_is_in_backup() have been removed.

  • Increase hash_mem_multiplier default to 2.0 (Peter Geoghegan)

    This allows query hash operations to use more work_mem memory than other operations.

  • Remove server-side language plpython2u and generic Python language plpythonu (Andres Freund)

    Python 2.x is no longer supported. While the original intent of plpythonu was that it could eventually refer to plpython3u, changing it now seems more likely to cause problems than solve them, so it's just been removed.

  • Generate an error if array_to_tsvector() is passed an empty-string array element (Jean-Christophe Arnu)

    This is prohibited because lexemes should never be empty. Users of previous Postgres releases should verify that no empty lexemes are stored because they can lead to dump/restore failures and inconsistent results.

  • Generate an error when chr() is supplied with a negative argument (Peter Eisentraut)

  • Prevent CREATE OR REPLACE VIEW from changing the collation of an output column (Tom Lane)

  • Disallow zero-length Unicode identifiers, e.g., U&"" (Peter Eisentraut)

    Non-Unicode zero-length identifiers were already disallowed.

  • Prevent numeric literals from having non-numeric trailing characters (Peter Eisentraut)

    Previously, query text like 123abc would be interpreted as 123 followed by a separate token abc.

  • Adjust JSON numeric literal processing to match the SQL/JSON-standard (Peter Eisentraut)

    This accepts numeric formats like .1 and 1., and disallows trailing junk after numeric literals, like 1.type().

  • When interval input provides a fractional value for a unit greater than months, round to the nearest month (Bruce Momjian)

    For example, convert 1.99 years to 2 years, not 1 year 11 months as before.

  • Improve consistency of interval parsing with trailing periods (Tom Lane)

    Numbers with trailing periods were rejected on some platforms.

  • Mark the interval output function as stable, not immutable, since it depends on IntervalStyle (Tom Lane)

    This will, for example, cause creation of indexes relying on the text output of interval values to fail.

  • Detect integer overflow in interval justification functions (Joe Koshakow)

    The affected functions are justify_interval(), justify_hours(), and justify_days().

  • Change the I/O format of type "char" for non-ASCII characters (Tom Lane)

    Bytes with the high bit set are now output as a backslash and three octal digits, to avoid encoding issues.

  • Remove the default ADMIN OPTION privilege a login role has on its own role membership (Robert Haas)

    Previously, a login role could add/remove members of its own role, even without ADMIN OPTION privilege.

  • Allow logical replication to run as the owner of the subscription (Mark Dilger)

    Because row-level security policies are not checked, only superusers, roles with bypassrls, and table owners can replicate into tables with row-level security policies.

  • Prevent UPDATE and DELETE logical replication operations on tables where the subscription owner does not have SELECT permission on the table (Jeff Davis)

    UPDATE and DELETE commands typically involve reading the table as well, so require the subscription owner to have table SELECT permission.

  • When EXPLAIN references the session's temporary object schema, refer to it as pg_temp (Amul Sul)

    Previously the actual schema name was reported, leading to inconsistencies across sessions.

  • Fix pg_statio_all_tables to sum values for the rare case of TOAST tables with multiple indexes (Andrei Zubkov)

    Previously such cases would show one row for each index.

  • Disallow setting custom options that match the name of an installed extension, but are not one of the extension's declared variables (Florin Irion, Tom Lane)

    This change causes any such pre-existing variables to be deleted during extension load, and then prevents new ones from being created later in the session. The intent is to prevent confusion about whether a variable is associated with an extension or not.

  • Remove obsolete server variable stats_temp_directory (Andres Freund, Kyotaro Horiguchi)

  • Improve the algorithm used to compute random() (Fabien Coelho)

    This will cause random()'s results to differ from what was emitted by prior versions, even for the same seed value.

  • libpq's PQsendQuery() function is no longer supported in pipeline mode (Álvaro Herrera)

    Applications that are using that combination will need to be modified to use PQsendQueryParams() instead.

  • On non-Windows platforms, consult the HOME environment variable to find the user's home directory (Anders Kaseorg)

    If HOME is empty or unset, fall back to the previous method of checking the <pwd.h> database. This change affects libpq (for example, while looking up ~/.pgpass) as well as various client application programs.

  • Remove pg_dump's --no-synchronized-snapshots option (Tom Lane)

    All still-supported server versions support synchronized snapshots, so there's no longer a need for this option.

  • After an error is detected in psql's --single-transaction mode, change the final COMMIT command to ROLLBACK only if ON_ERROR_STOP is set (Michael Paquier)

  • Avoid unnecessary casting of constants in queries sent by postgres_fdw (Dian Fay)

    When column types are intentionally different between local and remote databases, such casts could cause errors.

  • Remove xml2's xml_is_well_formed() function (Tom Lane)

    This function has been implemented in the core backend since Postgres 9.1.

  • Allow custom scan providers to indicate if they support projections (Sven Klemm)

    The default is now that custom scan providers are assumed to not support projections; those that do will need to be updated for this release.

  • Record and check the collation version of each database (Peter Eisentraut)

    This feature is designed to detect collation version changes to avoid index corruption. Function pg_database_collation_actual_version() reports the underlying operating system collation version, and ALTER DATABASE ... REFRESH sets the recorded database collation version to match the operating system collation version.

  • Allow ICU collations to be set as the default for clusters and databases (Peter Eisentraut)

    Previously, only libc-based collations could be selected at the cluster and database levels. ICU collations could only be used via explicit COLLATE clauses.

  • Add system view pg_ident_file_mappings to report pg_ident.conf information (Julien Rouhaud)

  • Improve planning time for queries referencing partitioned tables (David Rowley)

    This change helps when only a few of many partitions are relevant.

  • Allow ordered scans of partitions to avoid sorting in more cases (David Rowley)

    Previously, a partitioned table with a DEFAULT partition or a LIST partition containing multiple values could not be used for ordered partition scans. Now they can be used if such partitions are pruned during planning.

  • Improve foreign key behavior of updates on partitioned tables that move rows between partitions (Amit Langote)

    Previously, such updates ran a delete action on the source partition and an insert action on the target partition. PostgreSQL will now run an update action on the partition root, providing cleaner semantics.

  • Allow CLUSTER on partitioned tables (Justin Pryzby)

  • Fix ALTER TRIGGER RENAME on partitioned tables to properly rename triggers on all partitions (Arne Roland, Álvaro Herrera)

    Also prohibit cloned triggers from being renamed.

  • Allow btree indexes on system and TOAST tables to efficiently store duplicates (Peter Geoghegan)

    Previously de-duplication was disabled for these types of indexes.

  • Improve lookup performance of GiST indexes that were built using sorting (Aliaksandr Kalenik, Sergei Shoulbakov, Andrey Borodin)

  • Allow unique constraints and indexes to treat NULL values as not distinct (Peter Eisentraut)

    Previously NULL entries were always treated as distinct values, but this can now be changed by creating constraints and indexes using UNIQUE NULLS NOT DISTINCT.

  • Allow the ^@ starts-with operator and the starts_with() function to use btree indexes if using the C collation (Tom Lane)

    Previously these could only use SP-GiST indexes.

  • Allow extended statistics to record statistics for a parent with all its children (Tomas Vondra, Justin Pryzby)

    Regular statistics already tracked parent and parent-plus-all-children statistics separately.

  • Add server variable recursive_worktable_factor to allow the user to specify the expected size of the working table of a recursive query (Simon Riggs)

  • Allow hash lookup for NOT IN clauses with many constants (David Rowley, James Coleman)

    Previously the code always sequentially scanned the list of values.

  • Allow SELECT DISTINCT to be parallelized (David Rowley)

  • Speed up encoding validation of UTF-8 text by processing 16 bytes at a time (John Naylor, Heikki Linnakangas)

    This will improve text-heavy operations like COPY FROM.

  • Improve performance for sorts that exceed work_mem (Heikki Linnakangas)

    When the sort data no longer fits in work_mem, switch to a batch sorting algorithm that uses more output streams than before.

  • Improve performance and reduce memory consumption of in-memory sorts (Ronan Dunklau, David Rowley, Thomas Munro, John Naylor)

  • Allow WAL full page writes to use LZ4 and Zstandard compression (Andrey Borodin, Justin Pryzby)

    This is controlled by the wal_compression server setting.

  • Add support for writing WAL using direct I/O on macOS (Thomas Munro)

    This only works if max_wal_senders = 0 and wal_level = minimal.

  • Allow vacuum to be more aggressive in setting the oldest frozen and multi transaction id (Peter Geoghegan)

  • Allow a query referencing multiple foreign tables to perform parallel foreign table scans in more cases (Andrey Lepikhov, Etsuro Fujita)

  • Improve the performance of window functions that use row_number(), rank(), dense_rank() and count() (David Rowley)

  • Improve the performance of spinlocks on high-core-count ARM64 systems (Geoffrey Blake)

  • Enable default logging of checkpoints and slow autovacuum operations (Bharath Rupireddy)

    This changes the default of log_checkpoints to on and that of log_autovacuum_min_duration to 10 minutes. This will cause even an idle server to generate some log output, which might cause problems on resource-constrained servers without log file rotation. These defaults should be changed in such cases.

  • Generate progress messages in the server log during slow server starts (Nitin Jadhav, Robert Haas)

    The messages report the cause of the delay. The time interval for notification is controlled by the new server variable log_startup_progress_interval.

  • Store cumulative statistics system data in shared memory (Kyotaro Horiguchi, Andres Freund, Melanie Plageman)

    Previously this data was sent to a statistics collector process via UDP packets, and could only be read by sessions after transferring it via the file system. There is no longer a separate statistics collector process.

  • Add additional information to VACUUM VERBOSE and autovacuum logging messages (Peter Geoghegan)

  • Add EXPLAIN (BUFFERS) output for temporary file block I/O (Masahiko Sawada)

  • Allow log output in JSON format (Sehrope Sarkuni, Michael Paquier)

    The new setting is log_destination = jsonlog.

  • Allow pg_stat_reset_single_table_counters() to reset the counters of relations shared across all databases (Sadhuprasad Patro)

  • Add wait events for local shell commands (Fujii Masao)

    The new wait events are used when calling archive_command, archive_cleanup_command, restore_command and recovery_end_command.

  • Allow table accesses done by a view to optionally be controlled by privileges of the view's caller (Christoph Heiss)

    Previously, view accesses were always treated as being done by the view's owner. That's still the default.

  • Allow members of the pg_write_server_files predefined role to perform server-side base backups (Dagfinn Ilmari Mannsåker)

    Previously only superusers could perform such backups.

  • Allow GRANT to grant permissions to change individual server variables via SET and ALTER SYSTEM (Mark Dilger)

    The new function has_parameter_privilege() reports on this privilege.

  • Add predefined role pg_checkpoint that allows members to run CHECKPOINT (Jeff Davis)

    Previously checkpoints could only be run by superusers.

  • Allow members of the pg_read_all_stats predefined role to access the views pg_backend_memory_contexts and pg_shmem_allocations (Bharath Rupireddy)

    Previously these views could only be accessed by superusers.

  • Allow GRANT to grant permissions on pg_log_backend_memory_contexts() (Jeff Davis)

    Previously this function could only be run by superusers.

  • Add server variable shared_memory_size to report the size of allocated shared memory (Nathan Bossart)

  • Add server variable shared_memory_size_in_huge_pages to report the number of huge memory pages required (Nathan Bossart)

    This is only supported on Linux.

  • Honor server variable shared_preload_libraries in single-user mode (Jeff Davis)

    This change supports use of shared_preload_libraries to load custom access methods and WAL resource managers, which would be essential for database access even in single-user mode.

  • On Solaris, make the default setting of dynamic_shared_memory_type be sysv (Thomas Munro)

    The previous default choice, posix, can result in spurious failures on this platform.

  • Allow postgres -C to properly report runtime-computed values (Nathan Bossart)

    Previously runtime-computed values data_checksums, wal_segment_size, and data_directory_mode would report values that would not be accurate on the running server. However, this does not work on a running server.

  • Add support for LZ4 and Zstandard compression of server-side base backups (Jeevan Ladhe, Robert Haas)

  • Run the checkpointer and bgwriter processes during crash recovery (Thomas Munro)

    This helps to speed up long crash recoveries.

  • Allow WAL processing to pre-fetch needed file contents (Thomas Munro)

    This is controlled by the server variable recovery_prefetch.

  • Allow archiving via loadable modules (Nathan Bossart)

    Previously, archiving was only done by calling shell commands. The new server variable archive_library can be set to specify a library to be called for archiving.

  • No longer require IDENTIFY_SYSTEM to be run before START_REPLICATION (Jeff Davis)

  • Allow publication of all tables in a schema (Vignesh C, Hou Zhijie, Amit Kapila)

    For example, this syntax is now supported: CREATE PUBLICATION pub1 FOR TABLES IN SCHEMA s1,s2. ALTER PUBLICATION supports a similar syntax. Tables added later to the listed schemas will also be replicated.

  • Allow publication content to be filtered using a WHERE clause (Hou Zhijie, Euler Taveira, Peter Smith, Ajin Cherian, Tomas Vondra, Amit Kapila)

    Rows not satisfying the WHERE clause are not published.

  • Allow publication content to be restricted to specific columns (Tomas Vondra, Álvaro Herrera, Rahila Syed)

  • Allow skipping of transactions on a subscriber using ALTER SUBSCRIPTION ... SKIP (Masahiko Sawada)

  • Add support for prepared (two-phase) transactions to logical replication (Peter Smith, Ajin Cherian, Amit Kapila, Nikhil Sontakke, Stas Kelvich)

    The new CREATE_REPLICATION_SLOT option is called TWO_PHASE. pg_recvlogical now supports a new --two-phase option during slot creation.

  • Prevent logical replication of empty transactions (Ajin Cherian, Hou Zhijie, Euler Taveira)

    Previously, publishers would send empty transactions to subscribers if subscribed tables were not modified.

  • Add SQL functions to monitor the directory contents of logical replication slots (Bharath Rupireddy)

    The new functions are pg_ls_logicalsnapdir(), pg_ls_logicalmapdir(), and pg_ls_replslotdir(). They can be run by members of the predefined pg_monitor role.

  • Allow subscribers to stop the application of logical replication changes on error (Osumi Takamichi, Mark Dilger)

    This is enabled with the subscriber option disable_on_error and avoids possible infinite error loops during stream application.

  • Adjust subscriber server variables to match the publisher so datetime and float8 values are interpreted consistently (Japin Li)

    Some publishers might be relying on inconsistent behavior.

  • Add system view pg_stat_subscription_stats to report on subscriber activity (Masahiko Sawada)

    The new function pg_stat_reset_subscription_stats() allows resetting these statistics counters.

  • Suppress duplicate entries in the pg_publication_tables system view (Hou Zhijie)

    In some cases a partition could appear more than once.

  • Add SQL MERGE command to adjust one table to match another (Simon Riggs, Pavan Deolasee, Álvaro Herrera, Amit Langote)

    This is similar to INSERT ... ON CONFLICT but more batch-oriented.

  • Add support for HEADER option in COPY text format (Rémi Lapeyre)

    The new option causes the column names to be output, and optionally verified on input.

  • Add new WAL-logged method for database creation (Dilip Kumar)

    This is the new default method for copying the template database, as it avoids the need for checkpoints during database creation. However, it might be slow if the template database is large, so the old method is still available.

  • Allow CREATE DATABASE to set the database OID (Shruthi Gowda, Antonin Houska)

  • Prevent DROP DATABASE, DROP TABLESPACE, and ALTER DATABASE SET TABLESPACE from occasionally failing during concurrent use on Windows (Thomas Munro)

  • Allow foreign key ON DELETE SET actions to affect only specified columns (Paul Martinez)

    Previously, all of the columns in the foreign key were always affected.

  • Allow ALTER TABLE to modify a table's ACCESS METHOD (Justin Pryzby, Jeff Davis)

  • Properly call object access hooks when ALTER TABLE causes table rewrites (Michael Paquier)

  • Allow creation of unlogged sequences (Peter Eisentraut)

  • Track dependencies on individual columns in the results of functions returning composite types (Tom Lane)

    Previously, if a view or rule contained a reference to a specific column within the result of a composite-returning function, that was not noted as a dependency; the view or rule was only considered to depend on the composite type as a whole. This meant that dropping the individual column would be allowed, causing problems in later use of the view or rule. The column-level dependency is now also noted, so that dropping such a column will be rejected unless the view is changed or dropped.

  • Allow the scale of a numeric value to be negative, or greater than its precision (Dean Rasheed, Tom Lane)

    This allows rounding of values to the left of the decimal point, e.g., '1234'::numeric(4, -2) returns 1200.

  • Improve overflow detection when casting values to interval (Joe Koshakow)

  • Change the I/O format of type "char" for non-ASCII characters (Tom Lane)

  • Update the display width information of modern Unicode characters, like emojis (Jacob Champion)

    Also update from Unicode 5.0 to 14.0.0. There is now an automated way to keep Postgres updated with Unicode releases.

  • Add multirange input to range_agg() (Paul Jungwirth)

  • Add MIN() and MAX() aggregates for the xid8 data type (Ken Kato)

  • Add regular expression functions for compatibility with other relational systems (Gilles Darold, Tom Lane)

    The new functions are regexp_count(), regexp_instr(), regexp_like(), and regexp_substr(). Some new optional arguments were also added to regexp_replace().

  • Add the ability to compute the distance between polygons (Tom Lane)

  • Add to_char() format codes of, tzh, and tzm (Nitin Jadhav)

    The upper-case equivalents of these were already supported.

  • When applying AT TIME ZONE to a time with time zone value, use the transaction start time rather than wall clock time to determine whether DST applies (Aleksander Alekseev, Tom Lane)

    This allows the conversion to be considered stable rather than volatile, and it saves a kernel call per invocation.

  • Ignore NULL array elements in ts_delete() and setweight() functions with array arguments (Jean-Christophe Arnu)

    These functions effectively ignore empty-string array elements (since those could never match a valid lexeme). It seems consistent to let them ignore NULL elements too, instead of failing.

  • Add support for petabyte units to pg_size_pretty() and pg_size_bytes() (David Christensen)

  • Change pg_event_trigger_ddl_commands() to output references to other sessions' temporary schemas using the actual schema name (Tom Lane)

    Previously this function reported all temporary schemas as pg_temp, but it's misleading to use that for any but the current session's temporary schema.

  • Fix enforcement of PL/pgSQL variable CONSTANT markings (Tom Lane)

    Previously, a variable could be used as a CALL output parameter or refcursor OPEN variable despite being marked CONSTANT.

  • Allow IP address matching against a server certificate's Subject Alternative Name (Jacob Champion)

  • Allow PQsslAttribute() to report the SSL library type without requiring a libpq connection (Jacob Champion)

  • Change query cancellations sent by the client to use the same TCP settings as normal client connections (Jelte Fennema)

    This allows configured TCP timeouts to apply to query cancel connections.

  • Prevent libpq event callback failures from forcing an error result (Tom Lane)

  • Allow pgbench to retry after serialization and deadlock failures (Yugo Nagata, Marina Polyakova)

  • Improve performance of psql's \copy command, by sending data in larger chunks (Heikki Linnakangas)

  • Add \dconfig command to report server variables (Mark Dilger, Tom Lane)

    This is similar to the server-side SHOW command, but it can process patterns to show multiple variables conveniently.

  • Add \getenv command to assign the value of an environment variable to a psql variable (Tom Lane)

  • Add + option to the \lo_list and \dl commands to show large-object privileges (Pavel Luzanov)

  • Add a pager option for the \watch command (Pavel Stehule, Thomas Munro)

    This is only supported on Unix and is controlled by the PSQL_WATCH_PAGER environment variable.

  • Make psql include intra-query double-hyphen comments in queries sent to the server (Tom Lane, Greg Nancarrow)

    Previously such comments were removed from the query before being sent. Double-hyphen comments that are before any query text are not sent, and are not recorded as separate psql history entries.

  • Adjust psql so that Readline's meta-# command will insert a double-hyphen comment marker (Tom Lane)

    Previously a pound marker was inserted, unless the user had taken the trouble to configure a non-default comment marker.

  • Make psql output all results when multiple queries are passed to the server at once (Fabien Coelho)

    Previously, only the last query result was displayed. The old behavior can be restored by setting the SHOW_ALL_RESULTS psql variable to off.

  • After an error is detected in --single-transaction mode, change the final COMMIT command to ROLLBACK only if ON_ERROR_STOP is set (Michael Paquier)

    Previously, detection of an error in a -c command or -f script file would lead to issuing ROLLBACK at the end, regardless of the value of ON_ERROR_STOP.

  • Improve psql's tab completion (Shinya Kato, Dagfinn Ilmari Mannsåker, Peter Smith, Koyu Tanigawa, Ken Kato, David Fetter, Haiying Tang, Peter Eisentraut, Álvaro Herrera, Tom Lane, Masahiko Sawada)

  • Limit support of psql's backslash commands to servers running PostgreSQL 9.2 or later (Tom Lane)

    Remove code that was only used when running with an older server. Commands that do not require any version-specific adjustments compared to 9.2 will still work.

  • Make pg_dump dump public schema ownership changes and security labels (Noah Misch)

  • Improve performance of dumping databases with many objects (Tom Lane)

    This will also improve the performance of pg_upgrade.

  • Improve parallel pg_dump's performance for tables with large TOAST tables (Tom Lane)

  • Add dump/restore option --no-table-access-method to force restore to only use the default table access method (Justin Pryzby)

  • Limit support of pg_dump and pg_dumpall to servers running PostgreSQL 9.2 or later (Tom Lane)

  • Add new pg_basebackup option --target to control the base backup location (Robert Haas)

    The new options are server to write the backup locally and blackhole to discard the backup (for testing).

  • Allow pg_basebackup to do server-side gzip, LZ4, and Zstandard compression and client-side LZ4 and Zstandard compression of base backup files (Dipesh Pandit, Jeevan Ladhe)

    Client-side gzip compression was already supported.

  • Allow pg_basebackup to compress on the server side and decompress on the client side before storage (Dipesh Pandit)

    This is accomplished by specifying compression on the server side and plain output format.

  • Allow pg_basebackup's --compress option to control the compression location (server or client), compression method, and compression options (Michael Paquier, Robert Haas)

  • Add the LZ4 compression method to pg_receivewal (Georgios Kokolatos)

    This is enabled via --compress=lz4 and requires binaries to be built using --with-lz4.

  • Add additional capabilities to pg_receivewal's --compress option (Georgios Kokolatos)

  • Improve pg_receivewal's ability to restart at the proper WAL location (Ronan Dunklau)

    Previously, pg_receivewal would start based on the WAL file stored in the local archive directory, or at the sending server's current WAL flush location. With this change, if the sending server is running Postgres 15 or later, the local archive directory is empty, and a replication slot is specified, the replication slot's restart point will be used.

  • Add pg_rewind option --config-file to simplify use when server configuration files are stored outside the data directory (Gunnar Bluth)

  • Store pg_upgrade's log and temporary files in a subdirectory of the new cluster called pg_upgrade_output.d (Justin Pryzby)

    Previously such files were left in the current directory, requiring manual cleanup. Now they are automatically removed on successful completion of pg_upgrade.

  • Disable default status reporting during pg_upgrade operation if the output is not a terminal (Andres Freund)

    The status reporting output can be enabled for non-tty usage by using --verbose.

  • Make pg_upgrade report all databases with invalid connection settings (Jeevan Ladhe)

    Previously only the first database with an invalid connection setting was reported.

  • Make pg_upgrade preserve tablespace and database OIDs, as well as relation relfilenode numbers (Shruthi Gowda, Antonin Houska)

  • Add a --no-sync option to pg_upgrade (Michael Paquier)

    This is recommended only for testing.

  • Limit support of pg_upgrade to old servers running PostgreSQL 9.2 or later (Tom Lane)

  • Allow pg_waldump output to be filtered by relation file node, block number, fork number, and full page images (David Christensen, Thomas Munro)

  • Make pg_waldump report statistics before an interrupted exit (Bharath Rupireddy)

    For example, issuing a control-C in a terminal running pg_waldump --stats --follow will report the current statistics before exiting. This does not work on Windows.

  • Improve descriptions of some transaction WAL records reported by pg_waldump (Masahiko Sawada, Michael Paquier)

  • Allow pg_waldump to dump information about multiple resource managers (Heikki Linnakangas)

    This is enabled by specifying the --rmgr option multiple times.

  • Add documentation for pg_encoding_to_char() and pg_char_to_encoding() (Ian Lawrence Barwick)

  • Document the ^@ starts-with operator (Tom Lane)

  • Add support for continuous integration testing using cirrus-ci (Andres Freund, Thomas Munro, Melanie Plageman)

  • Add configure option --with-zstd to enable Zstandard builds (Jeevan Ladhe, Robert Haas, Michael Paquier)

  • Add an ABI identifier field to the magic block in loadable libraries, allowing non-community PostgreSQL distributions to identify libraries that are not compatible with other builds (Peter Eisentraut)

    An ABI field mismatch will generate an error at load time.

  • Create a new pg_type.typcategory value for "char" (Tom Lane)

    Some other internal-use-only types have also been assigned to this category.

  • Add new protocol message TARGET to specify a new COPY method to be used for base backups (Robert Haas)

    pg_basebackup now uses this method.

  • Add new protocol message COMPRESSION and COMPRESSION_DETAIL to specify the compression method and options (Robert Haas)

  • Remove server support for old BASE_BACKUP command syntax and base backup protocol (Robert Haas)

  • Add support for extensions to set custom backup targets (Robert Haas)

  • Allow extensions to define custom WAL resource managers (Jeff Davis)

  • Add function pg_settings_get_flags() to get the flags of server variables (Justin Pryzby)

  • On Windows, export all the server's global variables using PGDLLIMPORT markers (Robert Haas)

    Previously, only specific variables were accessible to extensions on Windows.

  • Require GNU make version 3.81 or later to build PostgreSQL (Tom Lane)

  • Require OpenSSL to build the pgcrypto extension (Peter Eisentraut)

  • Require Perl version 5.8.3 or later (Dagfinn Ilmari Mannsåker)

  • Require Python version 3.2 or later (Andres Freund)

  • Allow amcheck to check sequences (Mark Dilger)

  • Improve amcheck sanity checks for TOAST tables (Mark Dilger)

  • Add new module basebackup_to_shell as an example of a custom backup target (Robert Haas)

  • Add new module basic_archive as an example of performing archiving via a library (Nathan Bossart)

  • Allow btree_gist indexes on boolean columns (Emre Hasegeli)

    These can be used for exclusion constraints.

  • Fix pageinspect's page_header() to handle 32-kilobyte page sizes (Quan Zongliang)

    Previously, improper negative values could be returned in certain cases.

  • Add counters for temporary file block I/O to pg_stat_statements (Masahiko Sawada)

  • Add JIT counters to pg_stat_statements (Magnus Hagander)

  • Add new module pg_walinspect (Bharath Rupireddy)

    This gives SQL-level output similar to pg_waldump.

  • Indicate the permissive/enforcing state in sepgsql log messages (Dave Page)

  • Allow postgres_fdw to push down CASE expressions (Alexander Pyhalov)

  • Add server variable postgres_fdw.application_name to control the application name of postgres_fdw connections (Hayato Kuroda)

    Previously the remote session's application_name could only be set on the remote server or via a postgres_fdw connection specification. postgres_fdw.application_name supports some escape sequences for customization, making it easier to tell such connections apart on the remote server.

  • Allow parallel commit on postgres_fdw servers (Etsuro Fujita)

    This is enabled with the CREATE SERVER option parallel_commit.

• ⇑ Upgrade to 15.1 released on 2022-11-10 - docs

  • Fix failure to remove non-first segments of large tables (Tom Lane)

    PostgreSQL splits large tables into multiple files (normally with 1GB per file). The logic for dropping a table was broken and would miss removing all but the first such file, in two cases: drops of temporary tables and WAL replay of drops of regular tables. Applications that routinely create multi-gigabyte temporary tables could suffer significant disk space leakage.

    Orphaned temporary-table files are removed during postmaster start, so the mere act of updating to 15.1 is sufficient to clear any leaked temporary-table storage. However, if you suffered any database crashes while using 15.0, and there might have been large tables dropped just before such crashes, it's advisable to check the database directories for files named according to the pattern NNNN.NN. If there is no matching file named just NNNN (without the .NN suffix), these files should be removed manually.

  • Avoid failure in EXPLAIN VERBOSE for a query using SEARCH BREADTH FIRST with constant initial values (Tom Lane)

  • Prevent use of MERGE on a partitioned table with foreign-table partitions (Álvaro Herrera)

    The case isn't supported, and previously threw an incomprehensible error.

  • Fix planner failure with extended statistics on partitioned or inherited tables (Richard Guo, Justin Pryzby)

    Some cases failed with “cache lookup failed for statistics object”.

  • Avoid double call of the shutdown callback of an archiver module (Nathan Bossart, Bharath Rupireddy)

  • In libpq, handle single-row mode correctly when pipelining (Denis Laxalde)

    The single-row flag was not reset at the correct time if pipeline mode was also active.

  • Fix psql's exit status when a command-line query is canceled (Peter Eisentraut)

    psql -c query would exit successfully if the query was canceled. Fix it to exit with nonzero status, as in other error cases.

  • Fix pg_dump's failure to dump comments attached to some CHECK constraints (Tom Lane)

  • Fix CREATE DATABASE to allow its oid parameter to exceed 2³¹ (Tom Lane)

    This oversight prevented pg_upgrade from succeeding when the source installation contained databases with OIDs larger than that.

• ⇑ Upgrade to 15.2 released on 2023-02-09 - docs

  • Fix possible failure of MERGE to compute GENERATED columns (Dean Rasheed)

    When the first row-level action of the MERGE was an UPDATE, any subsequent INSERT actions would fail to compute GENERATED columns that were deemed unnecessary to compute for the UPDATE action (due to not depending on any of the UPDATE target columns).

  • Fix MERGE's check for unreachable WHEN clauses (Dean Rasheed)

    A WHEN clause following an unconditional WHEN clause should be rejected as unreachable, but this case was not always detected.

  • Fix MERGE's rule-detection test (Dean Rasheed)

    MERGE is not supported on tables with rules; but it also failed on tables that once had rules but no longer do.

  • In MERGE, don't count a DO NOTHING action as a processed tuple (Álvaro Herrera)

    This makes the code's behavior match the documentation.

  • Allow a WITH RECURSIVE ... CYCLE CTE to access its output column (Tom Lane)

    A reference to the SET column from within the CTE would fail with “cache lookup failed for type 0”.

  • Fix handling of pending inserts when doing a bulk insertion to a foreign table (Etsuro Fujita)

    In some cases pending insertions were not flushed to the FDW soon enough, leading to logical inconsistencies, for example BEFORE ROW triggers not seeing rows they should be able to see.

  • Fix jsonb subscripting to cope with toasted subscript values (Tom Lane, David G. Johnston)

    Using a text value fetched directly from a table as a jsonb subscript was likely to fail. Fetches would usually not find any matching element. Assignments could store the value with a garbage key, although keys long enough to cause that problem are probably rare in the field.

  • Remove arbitrary limit on number of elements in int2vector and oidvector (Tom Lane)

    The input functions for these types previously rejected more than 100 elements. With the introduction of the logical replication column list feature, it's necessary to accept int2vectors having up to 1600 columns, otherwise long column lists cause logical-replication failures.

  • Fix planner preprocessing oversights for window function run-condition expressions (Richard Guo, David Rowley)

    This could lead to planner errors such as “WindowFunc not found in subplan target lists”.

  • Fix possible dangling-pointer access during execution of window function run-condition expressions (David Rowley)

    In practice, because the run-condition optimization is only applied to certain window functions that happen to all return int8, this only manifested as a problem on 32-bit builds.

  • Fix planner issues when combining Memoize nodes with partitionwise joins or parameterized nestloops (Richard Guo)

    These errors could lead to not using Memoize in contexts where it would be useful, or possibly to wrong query plans.

  • Prevent the statistics machinery from getting confused when a relation's relkind changes (Andres Freund)

    Converting a table to a view could lead to crashes or assertion failures.

  • Fix under-parenthesized display of AT TIME ZONE constructs (Tom Lane)

    This could result in dump/restore failures for rules or views in which an argument of AT TIME ZONE is itself an expression.

  • Prevent clobbering of cached parsetrees for utility statements in SQL functions (Tom Lane, Daniel Gustafsson)

    If a SQL-language function executes the same utility command more than once within a single calling query, it could crash or report strange errors such as “unrecognized node type”.

  • Fix deadlock between DROP DATABASE and logical replication worker process (Hou Zhijie)

    This was caused by an ill-advised choice to block interrupts while creating a logical replication slot in the worker. In version 15 that could lead to an undetected deadlock. In version 14, no deadlock has been observed, but it's still a bad idea to block interrupts while waiting for network I/O.

  • In logical decoding, notify the remote node when a transaction is detected to have crashed (Hou Zhijie)

    After a server restart, we'll re-stream the changes for transactions occurring shortly before the restart. Some of these transactions probably never completed; when we realize that one didn't we throw away the relevant decoding state locally, but we neglected to tell the subscriber about it. That led to the subscriber keeping useless streaming files until it's next restarted.

  • Acquire spinlock while updating shared state during logical decoding context creation (Masahiko Sawada)

    We neglected to acquire the appropriate lock while updating data about two-phase transactions, potentially allowing other processes to see inconsistent data.

  • Fix pgoutput replication plug-in to not send columns not listed in a table's replication column list (Hou Zhijie)

    UPDATE and DELETE events did not pay attention to the configured column list, thus sending more data than expected. This did not cause a problem when the receiver is our built-in logical replication code, but it might confuse other receivers, and in any case it wasted network bandwidth.

  • Fix int64_div_fast_to_numeric() to work for a wider range of inputs (Dean Rasheed)

    This function misbehaved with some values of its second argument. No such usages exist in core PostgreSQL, but it's clearly a hazard for external modules, so repair.

  • Fix assertion failure in BRIN minmax-multi opclasses (Tomas Vondra)

    The assertion was overly strict, so this mistake was harmless in non-assert builds.

  • Fix possible corruption of very large tablespace map files in pg_basebackup (Antonin Houska)

  • Avoid harmless warning from pg_dump in --if-exists mode (Tom Lane)

    If the public schema has a non-default owner then use of pg_dump's --if-exists option resulted in a warning message “warning: could not find where to insert IF EXISTS in statement "-- *not* dropping schema, since initdb creates it"”. The dump output was okay, though.

  • Fix psql's \sf and \ef commands to handle SQL-language functions that have SQL-standard function bodies (Tom Lane)

    These commands misidentified the start of the function body when it used new-style syntax.

  • Update contrib/pageinspect to mark its disk-accessing functions as PARALLEL RESTRICTED (Tom Lane)

    This avoids possible failure if one of these functions is used to examine a temporary table, since a session's temporary tables are not accessible from parallel workers.

• ⇑ Upgrade to 15.3 released on 2023-05-11 - docs

  • Fix potential corruption of the template (source) database after CREATE DATABASE with the STRATEGY WAL_LOG option (Nathan Bossart, Ryo Matsumura)

    Improper buffer handling created a risk that any later modification of the template's pg_class catalog would be lost.

  • Fix memory leakage and unnecessary disk reads during CREATE DATABASE with the STRATEGY WAL_LOG option (Andres Freund)

  • Fix various planner failures with MERGE commands (Tom Lane)

    Planning could fail with errors like “variable not found in subplan target list” or “PlaceHolderVar found where not expected”.

  • Fix the row count reported by MERGE for some corner cases (Dean Rasheed)

    The row count reported in the command tag counted rows that actually hadn't been modified due to a BEFORE ROW trigger returning NULL. This is inconsistent with what happens in plain UPDATE or DELETE, so change it to not count such rows. Also, avoid counting a row twice when MERGE moves it into a different partition of a partitioned table.

  • Fix MERGE problems with concurrent updates (Dean Rasheed, Álvaro Herrera)

    Some cases misbehaved if a row to be updated or deleted by MERGE had just been updated by a concurrent transaction. This could lead to a crash, or the wrong merge action being executed, or no action at all.

  • Add support for decompiling MERGE commands (Álvaro Herrera)

    This was overlooked when MERGE was added, but it's essential support for MERGE in new-style SQL functions.

  • Fix enabling/disabling of foreign-key triggers in partitioned tables (Tom Lane)

    ALTER TABLE ... ENABLE/DISABLE TRIGGER failed if applied to a partitioned table's foreign-key enforcement triggers, because it tried to locate the clone triggers for the partitions by name, and they do not have the same name. Locate them by parent-trigger OID instead.

  • Adjust text-search-related character classification logic to correctly detect whether the prevailing locale is C (Jeff Davis)

    This code got confused if the database's default collation uses ICU.

  • Avoid possible crash on empty input for type interval (Tom Lane)

  • Re-allow exponential notation in ISO-8601 interval fields (Tom Lane)

    Interval input like P0.1e10D isn't officially sanctioned by ISO-8601, but we accepted it for a long time before version 15, so re-allow it.

  • Avoid failure with PlaceHolderVars in extended-statistics code (Tom Lane)

    Use of dependency-type extended statistics could fail with “PlaceHolderVar found where not expected”.

  • Fix incorrect tests for whether a qual clause applied to a subquery can be transformed into a window aggregate “run condition” within the subquery (David Rowley)

    A SubPlan within such a clause would cause assertion failures or incorrect answers, as would some other unusual cases.

  • Fix memory leak in Memoize plan execution (David Rowley)

  • Fix buffer refcount leak when using batched inserts for a foreign table included in a partitioned tree (Alexander Pyhalov)

  • Restore support for sub-millisecond vacuum_cost_delay settings (Thomas Munro)

  • Avoid useless work while scanning a multi-column BRIN index with multiple scan keys (Tomas Vondra)

    The existing code effectively considered only the last scan key while deciding whether a range matched, thus usually scanning more of the index than it needed to.

  • Fix netmask handling in BRIN inet_minmax_multi_ops opclass (Tomas Vondra)

    This error triggered an assertion failure in assert-enabled builds, but is mostly harmless in production builds.

  • Re-activate reporting of wait event SLRUFlushSync (Thomas Munro)

    Reporting of this type of wait was accidentally removed in code refactoring.

  • Disable startup progress reporting overhead in standby mode (Bharath Rupireddy)

    In standby mode, we don't actually report progress of recovery, but we were doing work to track it anyway.

  • Fix list_copy_head() to work correctly on an empty List (David Rowley)

    This case is not known to be reached by any core PostgreSQL code, but extensions might rely on it working.

  • Fix assertion failure for MERGE into a partitioned table with row-level security enabled (Dean Rasheed)

  • Correctly detect non-seekable files on Windows (Juan José Santamaría Flecha, Michael Paquier, Daniel Watzinger)

    This bug led to misbehavior when pg_dump writes to a pipe or pg_restore reads from one.

  • In pgbench's “prepared” mode, prepare all the commands in a pipeline before starting the pipeline (Álvaro Herrera)

    This avoids a failure when a pgbench script tries to start a serializable transaction inside a pipeline.

  • In contrib/amcheck's heap checking code, deal correctly with tuples having zero xmin or xmax (Robert Haas)

  • In contrib/amcheck, deal sanely with xids that appear to be before epoch zero (Andres Freund)

    In cases of corruption we might see a wrapped-around 32-bit xid that appears to be before the first xid epoch. Promoting such a value to 64-bit form produced a value far in the future, resulting in wrong reports. Return FirstNormalFullTransactionId in such cases so that things work reasonably sanely.

  • In contrib/basebackup_to_shell, properly detect failure to open a pipe (Robert Haas)

  • In contrib/pageinspect, add defenses against incorrect input for the gist_page_items() function (Dmitry Koval)

  • Fix handling of escape sequences in contrib/postgres_fdw's application_name parameter (Kyotaro Horiguchi, Michael Paquier)

    The code to expand these could fail if executed in a background process, as for example during auto-analyze of a foreign table.

  • In contrib/pg_walinspect, limit memory usage of pg_get_wal_records_info() (Bharath Rupireddy)

• ⇑ Upgrade to 15.4 released on 2023-08-10 - docs

  • Fix MERGE to enforce row security policies properly (Dean Rasheed)

    When MERGE performs an UPDATE action, it should enforce any UPDATE or SELECT RLS policies defined on the target table, to be consistent with the way that a plain UPDATE with a WHERE clause works. Instead it was enforcing INSERT RLS policies for both INSERT and UPDATE actions.

    In addition, when MERGE performs a DO NOTHING action, it applied the target table's DELETE RLS policies to existing rows, even though those rows are not being deleted. While it's not a security problem, this could result in unwanted errors.

    The PostgreSQL Project thanks Dean Rasheed for reporting this problem. (CVE-2023-39418)

  • Fix tracking of tables' access method dependencies (Michael Paquier)

    ALTER TABLE ... SET ACCESS METHOD failed to update relevant pg_depend entries when changing a table's access method. When using non-built-in access methods, this creates a risk that an access method could be dropped even though tables still depend on it. This fix corrects the logic in ALTER TABLE, but it will not adjust any already-missing pg_depend entries.

  • Don't Memoize lateral joins with volatile join conditions (Richard Guo)

    Applying Memoize to a sub-plan that contains volatile filter conditions is likely to lead to wrong answers. The check to avoid doing this missed some cases that can arise when using LATERAL.

  • Fix misbehavior of EvalPlanQual checks with inherited or partitioned target tables (Tom Lane)

    This oversight could lead to update or delete actions in READ COMMITTED isolation mode getting performed when they should have been skipped because of a conflicting concurrent update.

  • Ensure that all existing placeholders are checked for matches when an extension declares its GUC prefix to be reserved (Karina Litskevich, Ekaterina Sokolova)

    Faulty loop logic could cause some entries to be skipped.

  • Avoid leaking a stats entry for a subscription when it is dropped (Masahiko Sawada)

  • Silence bogus “missing contrecord” errors (Thomas Munro)

    Treat this case as plain end-of-WAL to avoid logging inaccurate complaints from pg_waldump and walsender.

  • Avoid assertion failure when the stats_fetch_consistency setting is changed intra-transaction (Kyotaro Horiguchi)

  • Fix contrib/pageinspect's gist_page_items() function to work when there are included index columns (Alexander Lakhin, Michael Paquier)

    Previously, if the index has included columns, gist_page_items() would fail to display those values on index leaf pages, or crash outright on non-leaf pages.

  • In psql, ignore the PSQL_WATCH_PAGER environment variable when stdin/stdout are not a terminal (Tom Lane)

    This corresponds to the treatment of PSQL_PAGER in commands besides \watch.

  • Fix pg_dump to correctly handle new-style SQL-language functions whose bodies require parse-time dependencies on unique indexes (Tom Lane)

    Such cases can arise from GROUP BY and ON CONFLICT clauses, for example. The function must then be postponed until after the unique index in the dump output, but pg_dump did not do that and instead printed a warning about “could not resolve dependency loop”.

  • Improve pg_dump's display of details about dependency-loop problems (Tom Lane)

  • Avoid crash in pgbench with an empty pipeline and prepared mode (Álvaro Herrera)

  • Fix make_etags script to work with non-Exuberant ctags (Masahiko Sawada)

• ⇑ Upgrade to 16 released on 2023-09-14 - docs

  • Change assignment rules for PL/pgSQL bound cursor variables (Tom Lane)

    Previously, the string value of such variables was set to match the variable name during cursor assignment; now it will be assigned during OPEN, and will not match the variable name. To restore the previous behavior, assign the desired portal name to the cursor variable before OPEN.

  • Disallow NULLS NOT DISTINCT indexes for primary keys (Daniel Gustafsson)

  • Change REINDEX DATABASE and reindexdb to not process indexes on system catalogs (Simon Riggs)

    Processing such indexes is still possible using REINDEX SYSTEM and reindexdb --system.

  • Tighten GENERATED expression restrictions on inherited and partitioned tables (Amit Langote, Tom Lane)

    Columns of parent/partitioned and child/partition tables must all have the same generation status, though now the actual generation expressions can be different.

  • Remove pg_walinspect functions pg_get_wal_records_info_till_end_of_wal() and pg_get_wal_stats_till_end_of_wal() (Bharath Rupireddy)

  • Rename server variable force_parallel_mode to debug_parallel_query (David Rowley)

  • Remove the ability to create views manually with ON SELECT rules (Tom Lane)

  • Remove the server variable vacuum_defer_cleanup_age (Andres Freund)

    This has been unnecessary since hot_standby_feedback and replication slots were added.

  • Remove server variable promote_trigger_file (Simon Riggs)

    This was used to promote a standby to primary, but is now easier accomplished with pg_ctl promote or pg_promote().

  • Remove read-only server variables lc_collate and lc_ctype (Peter Eisentraut)

    Collations and locales can vary between databases so having them as read-only server variables was unhelpful.

  • Role inheritance now controls the default inheritance status of member roles added during GRANT (Robert Haas)

    The role's default inheritance behavior can be overridden with the new GRANT ... WITH INHERIT clause. This allows inheritance of some roles and not others because the members' inheritance status is set at GRANT time. Previously the inheritance status of member roles was controlled only by the role's inheritance status, and changes to a role's inheritance status affected all previous and future member roles.

  • Restrict the privileges of CREATEROLE and its ability to modify other roles (Robert Haas)

    Previously roles with CREATEROLE privileges could change many aspects of any non-superuser role. Such changes, including adding members, now require the role requesting the change to have ADMIN OPTION permission. For example, they can now change the CREATEDB, REPLICATION, and BYPASSRLS properties only if they also have those permissions.

  • Remove symbolic links for the postmaster binary (Peter Eisentraut)

  • Allow incremental sorts in more cases, including DISTINCT (David Rowley)

  • Add the ability for aggregates having ORDER BY or DISTINCT to use pre-sorted data (David Rowley)

    The new server variable enable_presorted_aggregate can be used to disable this.

  • Allow memoize atop a UNION ALL (Richard Guo)

  • Allow anti-joins to be performed with the non-nullable input as the inner relation (Richard Guo)

  • Allow parallelization of FULL and internal right OUTER hash joins (Melanie Plageman, Thomas Munro)

  • Improve the accuracy of GIN index access optimizer costs (Ronan Dunklau)

  • Allow more efficient addition of heap and index pages (Andres Freund)

  • During non-freeze operations, perform page freezing where appropriate (Peter Geoghegan)

    This makes full-table freeze vacuums less necessary.

  • Allow window functions to use the faster ROWS mode internally when RANGE mode is active but unnecessary (David Rowley)

  • Allow optimization of always-increasing window functions ntile(), cume_dist() and percent_rank() (David Rowley)

  • Allow aggregate functions string_agg() and array_agg() to be parallelized (David Rowley)

  • Improve performance by caching RANGE and LIST partition lookups (Amit Langote, Hou Zhijie, David Rowley)

  • Allow control of the shared buffer usage by vacuum and analyze (Melanie Plageman)

    The VACUUM/ANALYZE option is BUFFER_USAGE_LIMIT, and the vacuumdb option is --buffer-usage-limit. The default value is set by server variable vacuum_buffer_usage_limit, which also controls autovacuum.

  • Support wal_sync_method=fdatasync on Windows (Thomas Munro)

  • Allow HOT updates if only BRIN-indexed columns are updated (Matthias van de Meent, Josef Simanek, Tomas Vondra)

  • Improve the speed of updating the process title (David Rowley)

  • Allow xid/subxid searches and ASCII string detection to use vector operations (Nathan Bossart, John Naylor)

    ASCII detection is particularly useful for COPY FROM. Vector operations are also used for some C array searches.

  • Reduce overhead of memory allocations (Andres Freund, David Rowley)

  • Add system view pg_stat_io view to track I/O statistics (Melanie Plageman)

  • Record statistics on the last sequential and index scans on tables (Dave Page)

    This information appears in pg_stat_*_tables and pg_stat_*_indexes.

  • Record statistics on the occurrence of updated rows moving to new pages (Corey Huinker)

    The pg_stat_*_tables column is n_tup_newpage_upd.

  • Add speculative lock information to the pg_locks system view (Masahiko Sawada, Noriyoshi Shinoda)

    The transaction id is displayed in the transactionid column and the speculative insertion token is displayed in the objid column.

  • Add the display of prepared statement result types to the pg_prepared_statements view (Dagfinn Ilmari Mannsåker)

  • Create subscription statistics entries at subscription creation time so stats_reset is accurate (Andres Freund)

    Previously entries were created only when the first statistics were reported.

  • Correct the I/O accounting for temp relation writes shown in pg_stat_database (Melanie Plageman)

  • Add function pg_stat_get_backend_subxact() to report on a session's subtransaction cache (Dilip Kumar)

  • Have pg_stat_get_backend_idset(), pg_stat_get_backend_activity(), and related functions use the unchanging backend id (Nathan Bossart)

    Previously the index values might change during the lifetime of the session.

  • Report stand-alone backends with a special backend type (Melanie Plageman)

  • Add wait event SpinDelay to report spinlock sleep delays (Andres Freund)

  • Create new wait event DSMAllocate to indicate waiting for dynamic shared memory allocation (Thomas Munro)

    Previously this type of wait was reported as DSMFillZeroWrite, which was also used by mmap() allocations.

  • Add the database name to the process title of logical WAL senders (Tatsuhiro Nakamori)

    Physical WAL senders do not display a database name.

  • Add checkpoint and REDO LSN information to log_checkpoints messages (Bharath Rupireddy, Kyotaro Horiguchi)

  • Provide additional details during client certificate failures (Jacob Champion)

  • Add predefined role pg_create_subscription with permission to create subscriptions (Robert Haas)

  • Allow subscriptions to not require passwords (Robert Haas)

    This is accomplished with the option password_required=false.

  • Simplify permissions for LOCK TABLE (Jeff Davis)

    Previously a user's ability to perform LOCK TABLE at various lock levels was limited to the lock levels required by the commands they had permission to execute on the table. For example, someone with UPDATE permission could perform all lock levels except ACCESS SHARE, even though it was a lesser lock level. Now users can issue lesser lock levels if they already have permission for greater lock levels.

  • Allow GRANT group_name TO user_name to be performed with ADMIN OPTION (Robert Haas)

    Previously CREATEROLE permission was required.

  • Allow GRANT to use WITH ADMIN TRUE/FALSE syntax (Robert Haas)

    Previously only the WITH ADMIN OPTION syntax was supported.

  • Allow roles that create other roles to automatically inherit the new role's rights or the ability to SET ROLE to the new role (Robert Haas, Shi Yu)

    This is controlled by server variable createrole_self_grant.

  • Prevent users from changing the default privileges of non-inherited roles (Robert Haas)

    This is now only allowed for inherited roles.

  • When granting role membership, require the granted-by role to be a role that has appropriate permissions (Robert Haas)

    This is a requirement even when a non-bootstrap superuser is granting role membership.

  • Allow non-superusers to grant permissions using a granted-by user that is not the current user (Robert Haas)

    The current user still must have sufficient permissions given by the specified granted-by user.

  • Add GRANT to control permission to use SET ROLE (Robert Haas)

    This is controlled by a new GRANT ... SET option.

  • Add dependency tracking to roles which have granted privileges (Robert Haas)

    For example, removing ADMIN OPTION will fail if there are privileges using that option; CASCADE must be used to revoke dependent permissions.

  • Add dependency tracking of grantors for GRANT records (Robert Haas)

    This guarantees that pg_auth_members.grantor values are always valid.

  • Allow multiple role membership records (Robert Haas)

    Previously a new membership grant would remove a previous matching membership grant, even if other aspects of the grant did not match.

  • Prevent removal of superuser privileges for the bootstrap user (Robert Haas)

    Restoring such users could lead to errors.

  • Allow makeaclitem() to accept multiple privilege names (Robins Tharakan)

    Previously only a single privilege name, like SELECT, was accepted.

  • Add support for Kerberos credential delegation (Stephen Frost)

    This is enabled with server variable gss_accept_delegation and libpq connection parameter gssdelegation.

  • Allow the SCRAM iteration count to be set with server variable scram_iterations (Daniel Gustafsson)

  • Improve performance of server variable management (Tom Lane)

  • Tighten restrictions on which server variables can be reset (Masahiko Sawada)

    Previously, while certain variables, like transaction_isolation, were not affected by RESET ALL, they could be individually reset in inappropriate situations.

  • Move various postgresql.conf items into new categories (Shinya Kato)

    This also affects the categories displayed in the pg_settings view.

  • Prevent configuration file recursion beyond 10 levels (Julien Rouhaud)

  • Allow autovacuum to more frequently honor changes to delay settings (Melanie Plageman)

    Rather than honor changes only at the start of each relation, honor them at the start of each block.

  • Remove restrictions that archive files be durably renamed (Nathan Bossart)

    The archive_command command is now more likely to be called with already-archived files after a crash.

  • Prevent archive_library and archive_command from being set at the same time (Nathan Bossart)

    Previously archive_library would override archive_command.

  • Allow the postmaster to terminate children with an abort signal (Tom Lane)

    This allows collection of a core dump for a stuck child process. This is controlled by send_abort_for_crash and send_abort_for_kill. The postmaster's -T switch is now the same as setting send_abort_for_crash.

  • Remove the non-functional postmaster -n option (Tom Lane)

  • Allow the server to reserve backend slots for roles with pg_use_reserved_connections membership (Nathan Bossart)

    The number of reserved slots is set by server variable reserved_connections.

  • Allow huge pages to work on newer versions of Windows 10 (Thomas Munro)

    This adds the special handling required to enable huge pages on newer versions of Windows 10.

  • Add debug_io_direct setting for developer usage (Thomas Munro, Andres Freund, Bharath Rupireddy)

    While primarily for developers, wal_sync_method=open_sync/open_datasync has been modified to not use direct I/O with wal_level=minimal; this is now enabled with debug_io_direct=wal.

  • Add function pg_split_walfile_name() to report the segment and timeline values of WAL file names (Bharath Rupireddy)

  • Add support for regular expression matching on database and role entries in pg_hba.conf (Bertrand Drouvot)

    Regular expression patterns are prefixed with a slash. Database and role names that begin with slashes need to be double-quoted if referenced in pg_hba.conf.

  • Improve user-column handling of pg_ident.conf to match pg_hba.conf (Jelte Fennema)

    Specifically, add support for all, role membership with +, and regular expressions with a leading slash. Any user name that matches these patterns must be double-quoted.

  • Allow include files in pg_hba.conf and pg_ident.conf (Julien Rouhaud)

    These are controlled by include, include_if_exists, and include_dir. System views pg_hba_file_rules and pg_ident_file_mappings now display the file name.

  • Allow pg_hba.conf tokens to be of unlimited length (Tom Lane)

  • Add rule and map numbers to the system view pg_hba_file_rules (Julien Rouhaud)

  • Determine the default encoding from the locale when using ICU (Jeff Davis)

    Previously the default was always UTF-8.

  • Have CREATE DATABASE and CREATE COLLATION's LOCALE options, and initdb and createdb --locale options, control non-libc collation providers (Jeff Davis)

    Previously they only controlled libc providers.

  • Add predefined collations unicode and ucs_basic (Peter Eisentraut)

    This only works if ICU support is enabled.

  • Allow custom ICU collation rules to be created (Peter Eisentraut)

    This is done using CREATE COLLATION's new RULES clause, as well as new options for CREATE DATABASE, createdb, and initdb.

  • Allow Windows to import system locales automatically (Juan José Santamaría Flecha)

    Previously, only ICU locales could be imported on Windows.

  • Allow logical decoding on standbys (Bertrand Drouvot, Andres Freund, Amit Khandekar)

    Snapshot WAL records are required for logical slot creation but cannot be created on standbys. To avoid delays, the new function pg_log_standby_snapshot() allows creation of such records.

  • Add server variable to control how logical decoding publishers transfer changes and how subscribers apply them (Shi Yu)

    The variable is debug_logical_replication_streaming.

  • Allow logical replication initial table synchronization to copy rows in binary format (Melih Mutlu)

    This is only possible for subscriptions marked as binary.

  • Allow parallel application of logical replication (Hou Zhijie, Wang Wei, Amit Kapila)

    The CREATE SUBSCRIPTION STREAMING option now supports parallel to enable application of large transactions by parallel workers. The number of parallel workers is controlled by the new server variable max_parallel_apply_workers_per_subscription. Wait events LogicalParallelApplyMain, LogicalParallelApplyStateChange, and LogicalApplySendData were also added. Column leader_pid was added to system view pg_stat_subscription to track parallel activity.

  • Improve performance for logical replication apply without a primary key (Onder Kalaci, Amit Kapila)

    Specifically, REPLICA IDENTITY FULL can now use btree indexes rather than sequentially scanning the table to find matches.

  • Allow logical replication subscribers to process only changes that have no origin (Vignesh C, Amit Kapila)

    This can be used to avoid replication loops. This is controlled by the new CREATE SUBSCRIPTION ... ORIGIN option.

  • Perform logical replication SELECT and DML actions as the table owner (Robert Haas)

    This improves security and now requires subscription owners to be either superusers or to have SET ROLE permission on all roles owning tables in the replication set. The previous behavior of performing all operations as the subscription owner can be enabled with the subscription run_as_owner option.

  • Have wal_retrieve_retry_interval operate on a per-subscription basis (Nathan Bossart)

    Previously the retry time was applied globally. This also adds wait events >LogicalRepLauncherDSA and LogicalRepLauncherHash.

  • Add EXPLAIN option GENERIC_PLAN to display the generic plan for a parameterized query (Laurenz Albe)

  • Allow a COPY FROM value to map to a column's DEFAULT (Israel Barth Rubio)

  • Allow COPY into foreign tables to add rows in batches (Andrey Lepikhov, Etsuro Fujita)

    This is controlled by the postgres_fdw option batch_size.

  • Allow the STORAGE type to be specified by CREATE TABLE (Teodor Sigaev, Aleksander Alekseev)

    Previously only ALTER TABLE could control this.

  • Allow truncate triggers on foreign tables (Yugo Nagata)

  • Allow VACUUM and vacuumdb to only process TOAST tables (Nathan Bossart)

    This is accomplished by having VACUUM turn off PROCESS_MAIN or by vacuumdb using the --no-process-main option.

  • Add VACUUM options to skip or update all frozen statistics (Tom Lane, Nathan Bossart)

    The options are SKIP_DATABASE_STATS and ONLY_DATABASE_STATS.

  • Change REINDEX DATABASE and REINDEX SYSTEM to no longer require an argument (Simon Riggs)

    Previously the database name had to be specified.

  • Allow CREATE STATISTICS to generate a statistics name if none is specified (Simon Riggs)

  • Allow non-decimal integer literals (Peter Eisentraut)

    For example, 0x42F, 0o273, and 0b100101.

  • Allow NUMERIC to process hexadecimal, octal, and binary integers of any size (Dean Rasheed)

    Previously only unquoted eight-byte integers were supported with these non-decimal bases.

  • Allow underscores in integer and numeric constants (Peter Eisentraut, Dean Rasheed)

    This can improve readability for long strings of digits.

  • Accept the spelling +infinity in datetime input (Vik Fearing)

  • Prevent the specification of epoch and infinity together with other fields in datetime strings (Joseph Koshakow)

  • Remove undocumented support for date input in the form YyearMmonthDday (Joseph Koshakow)

  • Add functions pg_input_is_valid() and pg_input_error_info() to check for type conversion errors (Tom Lane)

  • Allow subqueries in the FROM clause to omit aliases (Dean Rasheed)

  • Add support for enhanced numeric literals in SQL/JSON paths (Peter Eisentraut)

    For example, allow hexadecimal, octal, and binary integers and underscores between digits.

  • Add SQL/JSON constructors (Nikita Glukhov, Teodor Sigaev, Oleg Bartunov, Alexander Korotkov, Amit Langote)

    The new functions JSON_ARRAY(), JSON_ARRAYAGG(), JSON_OBJECT(), and JSON_OBJECTAGG() are part of the SQL standard.

  • Add SQL/JSON object checks (Nikita Glukhov, Teodor Sigaev, Oleg Bartunov, Alexander Korotkov, Amit Langote, Andrew Dunstan)

    The IS JSON checks include checks for values, arrays, objects, scalars, and unique keys.

  • Allow JSON string parsing to use vector operations (John Naylor)

  • Improve the handling of full text highlighting function ts_headline() for OR and NOT expressions (Tom Lane)

  • Add functions to add, subtract, and generate timestamptz values in a specified time zone (Przemyslaw Sztoch, Gurjeet Singh)

    The functions are date_add(), date_subtract(), and generate_series().

  • Change date_trunc(unit, timestamptz, time_zone) to be an immutable function (Przemyslaw Sztoch)

    This allows the creation of expression indexes using this function.

  • Add server variable SYSTEM_USER (Bertrand Drouvot)

    This reports the authentication method and its authenticated user.

  • Add functions array_sample() and array_shuffle() (Martin Kalcher)

  • Add aggregate function ANY_VALUE() which returns any value from a set (Vik Fearing)

  • Add function random_normal() to supply normally-distributed random numbers (Paul Ramsey)

  • Add error function erf() and its complement erfc() (Dean Rasheed)

  • Improve the accuracy of numeric power() for integer exponents (Dean Rasheed)

  • Add XMLSERIALIZE() option INDENT to pretty-print its output (Jim Jones)

  • Change pg_collation_actual_version() to return a reasonable value for the default collation (Jeff Davis)

    Previously it returned NULL.

  • Allow pg_read_file() and pg_read_binary_file() to ignore missing files (Kyotaro Horiguchi)

  • Add byte specification (B) to pg_size_bytes() (Peter Eisentraut)

  • Allow to_reg* functions to accept numeric OIDs as input (Tom Lane)

  • Add the ability to get the current function's OID in PL/pgSQL (Pavel Stehule)

    This is accomplished with GET DIAGNOSTICS variable = PG_ROUTINE_OID.

  • Add libpq connection option require_auth to specify a list of acceptable authentication methods (Jacob Champion)

    This can also be used to disallow certain authentication methods.

  • Allow multiple libpq-specified hosts to be randomly selected (Jelte Fennema)

    This is enabled with load_balance_hosts=random and can be used for load balancing.

  • Add libpq option sslcertmode to control transmission of the client certificate (Jacob Champion)

    The option values are disable, allow, and require.

  • Allow libpq to use the system certificate pool for certificate verification (Jacob Champion, Thomas Habets)

    This is enabled with sslrootcert=system, which also enables sslmode=verify-full.

  • Allow ECPG variable declarations to use typedef names that match unreserved SQL keywords (Tom Lane)

    This change does prevent keywords which match C typedef names from being processed as keywords in later EXEC SQL blocks.

  • Allow psql to control the maximum width of header lines in expanded format (Platon Pronko)

    This is controlled by xheader_width.

  • Add psql command \drg to show role membership details (Pavel Luzanov)

    The Member of output column has been removed from \du and \dg because this new command displays this informaion in more detail.

  • Allow psql's access privilege commands to show system objects (Nathan Bossart)

    The options are \dpS and \zS.

  • Add FOREIGN designation to psql \d+ for foreign table children and partitions (Ian Lawrence Barwick)

  • Prevent \df+ from showing function source code (Isaac Morland)

    Function bodies are more easily viewed with \sf.

  • Allow psql to submit queries using the extended query protocol (Peter Eisentraut)

    Passing arguments to such queries is done using the new psql \bind command.

  • Allow psql \watch to limit the number of executions (Andrey Borodin)

    The \watch options can now be named when specified.

  • Detect invalid values for psql \watch, and allow zero to specify no delay (Andrey Borodin)

  • Allow psql scripts to obtain the exit status of shell commands and queries (Corey Huinker, Tom Lane)

    The new psql control variables are SHELL_ERROR and SHELL_EXIT_CODE.

  • Various psql tab completion improvements (Vignesh C, Aleksander Alekseev, Dagfinn Ilmari Mannsåker, Shi Yu, Michael Paquier, Ken Kato, Peter Smith)

  • Add pg_dump control of dumping child tables and partitions (Gilles Darold)

    The new options are --table-and-children, --exclude-table-and-children, and --exclude-table-data-and-children.

  • Add LZ4 and Zstandard compression to pg_dump (Georgios Kokolatos, Justin Pryzby)

  • Allow pg_dump and pg_basebackup to use long mode for compression (Justin Pryzby)

  • Improve pg_dump to accept a more consistent compression syntax (Georgios Kokolatos)

    Options like --compress=gzip:5.

  • Add initdb option to set server variables for the duration of initdb and all future server starts (Tom Lane)

    The option is -c name=value.

  • Add options to createuser to control more user options (Shinya Kato)

    Specifically, the new options control the valid-until date, bypassing of row-level security, and role membership.

  • Deprecate createuser option --role (Nathan Bossart)

    This option could be easily confused with new createuser role membership options, so option --member-of has been added with the same functionality. The --role option can still be used.

  • Allow control of vacuumdb schema processing (Gilles Darold)

    These are controlled by options --schema and --exclude-schema.

  • Use new VACUUM options to improve the performance of vacuumdb (Tom Lane, Nathan Bossart)

  • Have pg_upgrade set the new cluster's locale and encoding (Jeff Davis)

    This removes the requirement that the new cluster be created with the same locale and encoding settings.

  • Add pg_upgrade option to specify the default transfer mode (Peter Eisentraut)

    The option is --copy.

  • Improve pg_basebackup to accept numeric compression options (Georgios Kokolatos, Michael Paquier)

    Options like --compress=server-5 are now supported.

  • Fix pg_basebackup to handle tablespaces stored in the PGDATA directory (Robert Haas)

  • Add pg_waldump option --save-fullpage to dump full page images (David Christensen)

  • Allow pg_waldump options -t/--timeline to accept hexadecimal values (Peter Eisentraut)

  • Add support for progress reporting to pg_verifybackup (Masahiko Sawada)

  • Allow pg_rewind to properly track timeline changes (Heikki Linnakangas)

    Previously if pg_rewind was run after a timeline switch but before a checkpoint was issued, it might incorrectly determine that a rewind was unnecessary.

  • Have pg_receivewal and pg_recvlogical cleanly exit on SIGTERM (Christoph Berg)

    This signal is often used by systemd.

  • Build ICU support by default (Jeff Davis)

    This removes build flag --with-icu and adds flag --without-icu.

  • Add support for SSE2 (Streaming SIMD Extensions 2) vector operations on x86-64 architectures (John Naylor)

  • Add support for Advanced SIMD (Single Instruction Multiple Data) (NEON) instructions on ARM architectures (Nathan Bossart)

  • Have Windows binaries built with MSVC use RandomizedBaseAddress (ASLR) (Michael Paquier)

    This was already enabled on MinGW builds.

  • Prevent extension libraries from exporting their symbols by default (Andres Freund, Tom Lane)

    Functions that need to be called from the core backend or other extensions must now be explicitly marked PGDLLEXPORT.

  • Require Windows 10 or newer versions (Michael Paquier, Juan José Santamaría Flecha)

    Previously Windows Vista and Windows XP were supported.

  • Require Perl version 5.14 or later (John Naylor)

  • Require Bison version 2.3 or later (John Naylor)

  • Require Flex version 2.5.35 or later (John Naylor)

  • Require MIT Kerberos for GSSAPI support (Stephen Frost)

  • Remove support for Visual Studio 2013 (Michael Paquier)

  • Remove support for HP-UX (Thomas Munro)

  • Remove support for HP/Intel Itanium (Thomas Munro)

  • Remove support for M68K, M88K, M32R, and SuperH CPU architectures (Thomas Munro)

  • Remove libpq support for SCM credential authentication (Michael Paquier)

    Backend support for this authentication method was removed in PostgresSQL 9.1.

  • Add meson build system (Andres Freund, Nazir Bilal Yavuz, Peter Eisentraut)

    This eventually will replace the Autoconf and Windows-based MSVC build systems.

  • Allow control of the location of the openssl binary used by the build system (Peter Eisentraut)

    Make finding openssl program a configure or meson option

  • Add build option to allow testing of small WAL segment sizes (Andres Freund)

    The build options are --with-segsize-blocks and -Dsegsize_blocks.

  • Add pgindent options (Andrew Dunstan)

    The new options are --show-diff, --silent-diff, --commit, and --help, and allow multiple --exclude options. Also require the typedef file to be explicitly specified. Options --code-base and --build were also removed.

  • Add pg_bsd_indent source code to the main tree (Tom Lane)

  • Improve make_ctags and make_etags (Yugo Nagata)

  • Adjust pg_attribute columns for efficiency (Peter Eisentraut)

  • Improve use of extension-based indexes on boolean columns (Zongliang Quan, Tom Lane)

  • Add support for Daitch-Mokotoff Soundex to fuzzystrmatch (Dag Lem)

  • Allow auto_explain to log values passed to parameterized statements (Dagfinn Ilmari Mannsåker)

    This affects queries using server-side PREPARE/EXECUTE and client-side parse/bind. Logging is controlled by auto_explain.log_parameter_max_length; by default query parameters will be logged with no length restriction.

  • Have auto_explain's log_verbose mode honor the value of compute_query_id (Atsushi Torikoshi)

    Previously even if compute_query_id was enabled, log_verbose was not showing the query identifier.

  • Change the maximum length of ltree labels from 256 to 1000 and allow hyphens (Garen Torikian)

  • Have pg_stat_statements normalize constants used in utility commands (Michael Paquier)

    Previously constants appeared instead of placeholders, e.g., $1.

  • Add pg_walinspect function pg_get_wal_block_info() to report WAL block information (Michael Paquier, Melanie Plageman, Bharath Rupireddy)

  • Change how pg_walinspect functions pg_get_wal_records_info() and pg_get_wal_stats() interpret ending LSNs (Bharath Rupireddy)

    Previously ending LSNs which represent nonexistent WAL locations would generate an error, while they will now be interpreted as the end of the WAL.

  • Add detailed descriptions of WAL records in pg_walinspect and pg_waldump (Melanie Plageman, Peter Geoghegan)

  • Add pageinspect function bt_multi_page_stats() to report statistics on multiple pages (Hamid Akhtar)

    This is similar to bt_page_stats() except it can report on a range of pages.

  • Add empty range output column to pageinspect function brin_page_items() (Tomas Vondra)

  • Redesign archive modules to be more flexible (Nathan Bossart)

    Initialization changes will require modules written for older versions of Postgres to be updated.

  • Correct inaccurate pg_stat_statements row tracking extended query protocol statements (Sami Imseih)

  • Add pg_buffercache function pg_buffercache_usage_counts() to report usage totals (Nathan Bossart)

  • Add pg_buffercache function pg_buffercache_summary() to report summarized buffer statistics (Melih Mutlu)

  • Allow the schemas of required extensions to be referenced in extension scripts using the new syntax @extschema:referenced_extension_name@ (Regina Obe)

  • Allow required extensions to be marked as non-relocatable using no_relocate (Regina Obe)

    This allows @extschema:referenced_extension_name@ to be treated as a constant for the lifetime of the extension.

  • Allow postgres_fdw to do aborts in parallel (Etsuro Fujita)

    This is enabled with postgres_fdw option parallel_abort.

  • Make ANALYZE on foreign postgres_fdw tables more efficient (Tomas Vondra)

    The postgres_fdw option analyze_sampling controls the sampling method.

  • Restrict shipment of reg* type constants in postgres_fdw to those referencing built-in objects or extensions marked as shippable (Tom Lane)

  • Have postgres_fdw and dblink handle interrupts during connection establishment (Andres Freund)

• ⇑ Upgrade to 16.1 released on 2023-11-09 - docs

  • Process date values more sanely in BRIN datetime_minmax_multi_ops indexes (Tomas Vondra)

    The distance calculation for dates was backward, causing poor decisions about which entries to merge. The index still produces correct results, but is much less efficient than it should be. Reindexing BRIN minmax_multi indexes on date columns is advisable.

  • Process large timestamp and timestamptz values more sanely in BRIN datetime_minmax_multi_ops indexes (Tomas Vondra)

    Infinities were mistakenly treated as having distance zero rather than a large distance from other values, causing poor decisions about which entries to merge. Also, finite-but-very-large values (near the endpoints of the representable timestamp range) could result in internal overflows, again causing poor decisions. The index still produces correct results, but is much less efficient than it should be. Reindexing BRIN minmax_multi indexes on timestamp and timestamptz columns is advisable if the column contains, or has contained, infinities or large finite values.

  • Avoid calculation overflows in BRIN interval_minmax_multi_ops indexes with extreme interval values (Tomas Vondra)

    This bug might have caused unexpected failures while trying to insert large interval values into such an index.

  • Fix inconsistent rechecking of concurrently-updated rows during MERGE (Dean Rasheed)

    In READ COMMITTED mode, an update that finds that its target row was just updated by a concurrent transaction will recheck the query's WHERE conditions on the updated row. MERGE failed to ensure that the proper rows of other joined tables were used during this recheck, possibly resulting in incorrect decisions about whether the newly-updated row should be updated again by MERGE.

  • Correctly identify the target table in an inherited UPDATE/DELETE/MERGE even when the parent table is excluded by constraints (Amit Langote, Tom Lane)

    If the initially-named table is excluded by constraints, but not all its inheritance descendants are, the first non-excluded descendant was identified as the primary target table. This would lead to firing statement-level triggers associated with that table, rather than the initially-named table as should happen. In v16, the same oversight could also lead to “invalid perminfoindex 0 in RTE with relid NNNN” errors.

  • Fix intra-query memory leak in Memoize execution (Orlov Aleksej, David Rowley)

  • Fix improper sharing of origin filter condition across successive pg_logical_slot_get_changes() calls (Hou Zhijie)

    The origin condition set by one call of this function would be re-used by later calls that did not specify the origin argument. This was not intended.

  • Fix ALTER SUBSCRIPTION so that a commanded change in the run_as_owner option is actually applied (Hou Zhijie)

  • Fix bulk table insertion into partitioned tables (Andres Freund)

    Improper sharing of insertion state across partitions could result in failures during COPY FROM, typically manifesting as “could not read block NNNN in file XXXX: read only 0 of 8192 bytes” errors.

  • In COPY FROM, avoid evaluating column default values that will not be needed by the command (Laurenz Albe)

    This avoids a possible error if the default value isn't actually valid for the column, or if the default's expression would fail in the current execution context. Such edge cases sometimes arise while restoring dumps, for example. Previous releases did not fail in this situation, so prevent v16 from doing so.

  • In COPY FROM, fail cleanly when an unsupported encoding conversion is needed (Tom Lane)

    Recent refactoring accidentally removed the intended error check for this, such that it ended in “cache lookup failed for function 0” instead of a useful error message.

  • Fix “could not find pathkey item to sort” errors occurring while planning aggregate functions with ORDER BY or DISTINCT options (David Rowley)

  • Fix the background writer to report any WAL writes it makes to the statistics counters (Nazir Bilal Yavuz)

  • Fix confusion about forced-flush behavior in pgstat_report_wal() (Ryoga Yoshida, Michael Paquier)

    This could result in some statistics about WAL I/O being forgotten in a shutdown.

  • Fix statistics tracking of temporary-table extensions (Karina Litskevich, Andres Freund)

    These were counted as normal-table writes when they should be counted as temp-table writes.

  • When track_io_timing is enabled, include the time taken by relation extension operations as write time (Nazir Bilal Yavuz)

  • Avoid a possible pfree-a-NULL-pointer crash after an error in OpenSSL connection setup (Sergey Shinderuk)

  • Track hash function and negator function dependencies of ScalarArrayOpExpr plan nodes (David Rowley)

    In most cases this oversight was harmless, since these functions would be unlikely to disappear while the node's original operator remains present.

  • Fix “could not duplicate handle” error occurring on Windows when min_dynamic_shared_memory is set above zero (Thomas Munro)

  • Fix pg_dump to dump the new run_as_owner option of subscriptions (Philip Warner)

    Due to this oversight, subscriptions would always be restored with run_as_owner set to false, which is not equivalent to their behavior in pre-v16 releases.

  • Fix vacuumdb's handling of multiple -N switches (Nathan Bossart, Kuwamura Masaki)

    Multiple -N switches should exclude tables in multiple schemas, but in fact excluded nothing due to faulty construction of a generated query.

  • Fix vacuumdb to honor its --buffer-usage-limit option in analyze-only mode (Ryoga Yoshida, David Rowley)

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