2020-08-13 This release contains a variety of fixes from 12.3. For information about new features in major release 12, see . A dump/restore is not required for those running 12.X. However, if you are upgrading from a version earlier than 12.2, see . Set a secure search_path in logical replication walsenders and apply workers (Noah Misch) A malicious user of either the publisher or subscriber database could potentially cause execution of arbitrary SQL code by the role running replication, which is often a superuser. Some of the risks here are equivalent to those described in CVE-2018-1058, and are mitigated in this patch by ensuring that the replication sender and receiver execute with empty search_path settings. (As with CVE-2018-1058, that change might cause problems for under-qualified names used in replicated tables' DDL.) Other risks are inherent in replicating objects that belong to untrusted roles; the most we can do is document that there is a hazard to consider. (CVE-2020-14349) Make contrib modules' installation scripts more secure (Tom Lane) Attacks similar to those described in CVE-2018-1058 could be carried out against an extension installation script, if the attacker can create objects in either the extension's target schema or the schema of some prerequisite extension. Since extensions often require superuser privilege to install, this can open a path to obtaining superuser privilege. To mitigate this risk, be more careful about the search_path used to run an installation script; disable check_function_bodies within the script; and fix catalog-adjustment queries used in some contrib modules to ensure they are secure. Also provide documentation to help third-party extension authors make their installation scripts secure. This is not a complete solution; extensions that depend on other extensions can still be at risk if installed carelessly. (CVE-2020-14350) Fix edge cases in partition pruning (Etsuro Fujita, Dmitry Dolgov) When there are multiple partition key columns, generation of pruning tests could misbehave if some columns had no constraining WHERE clauses or multiple constraining clauses. This could lead to server crashes, incorrect query results, or assertion failures. Fix construction of parameterized BitmapAnd and BitmapOr index scans on the inside of partition-wise nestloop joins (Tom Lane) A plan in which such a scan needed to use a value from the outside of the join would usually crash at execution. Fix incorrect plan execution when a partitioned table is subject to both static and run-time partition pruning in the same query, and a new partition is added concurrently with the query (Amit Langote, Tom Lane) In logical replication walsender, fix failure to send feedback messages after sending a keepalive message (Álvaro Herrera) This is a relatively minor problem when using built-in logical replication, because the built-in walreceiver will send a feedback reply (which clears the incorrect state) fairly frequently anyway. But with some other replication systems, such as pglogical, it causes significant performance issues. Fix firing of column-specific UPDATE triggers in logical replication subscribers (Tom Lane) The code neglected to account for the possibility of column numbers being different between the publisher and subscriber tables, so that if those were indeed different, wrong decisions might be made about which triggers to fire. Update oldest xmin and LSN values during pg_replication_slot_advance() (Michael Paquier) This function previously failed to do that, possibly preventing resource cleanup (such as removal of no-longer-needed WAL segments) after manual advancement of a replication slot. Fix slow execution of ts_headline() (Tom Lane) The phrase-search fix added in our previous set of minor releases could cause ts_headline() to take unreasonable amounts of time for long documents; to make matters worse, the query was not cancellable within the troublesome loop. Ensure the repeat() function can be interrupted by query cancel (Joe Conway) Fix pg_current_logfile() to not include a carriage return (\r) in its result on Windows (Tom Lane) Ensure that pg_read_file() and related functions read until EOF is reached (Joe Conway) Previously, if not given a specific data length to read, these functions would stop at whatever file length was reported by stat(). That's unhelpful for pipes and other sorts of virtual files. Forbid numeric NaN values in jsonpath computations (Alexander Korotkov) Neither SQL nor JSON have the concept of NaN (not-a-number), but the jsonpath code attempted to allow such values anyway. This necessarily leads to nonstandard behavior, so it seems better to reject such values at the outset. Handle single Inf or NaN inputs correctly in floating-point aggregates (Tom Lane) The affected aggregates are corr(), covar_pop(), regr_intercept(), regr_r2(), regr_slope(), regr_sxx(), regr_sxy(), regr_syy(), stddev_pop(), and var_pop(). The correct answer in such cases is NaN, but an algorithmic change introduced in PostgreSQL v12 had caused these aggregates to produce zero instead. Fix mis-handling of NaN inputs during parallel aggregation on numeric-type columns (Tom Lane) If some partial aggregation workers found only NaNs while others found only non-NaNs, the results were combined incorrectly, possibly leading to the wrong overall result (i.e., not NaN when it should be). Reject time-of-day values greater than 24 hours (Tom Lane) The intention of the datetime input code is to allow 24:00:00 or equivalently 23:59:60, but no larger value. However, the range check was miscoded so that it would accept 23:59:60.nnn with nonzero fractional-second nnn. In timestamp values this would result in wrapping into the first second of the next day. In time and timetz values, the stored value would actually be more than 24 hours, causing dump/reload failures and possibly other misbehavior. Undo double-quoting of index names in EXPLAIN's non-text output formats (Tom Lane, Euler Taveira) Fix EXPLAIN's accounting for resource usage, particularly buffer accesses, in parallel workers in a plan using Gather Merge nodes (Jehan-Guillaume de Rorthais) Fix timing of constraint revalidation in ALTER TABLE (David Rowley) If ALTER TABLE needs to fully rewrite the table's contents (for example, due to change of a column's data type) and also needs to scan the table to re-validate foreign keys or CHECK constraints, it sometimes did things in the wrong order, leading to odd errors such as could not read block 0 in file "base/nnnnn/nnnnn": read only 0 of 8192 bytes. Fix REINDEX CONCURRENTLY to preserve the index's replication identity flag (Michael Paquier) Previously, reindexing a table's replica identity index caused the setting to be lost, preventing old tuple values from being included in future logical-decoding output. Work around incorrect not-null markings for pg_subscription.subslotname and pg_subscription_rel.srsublsn (Tom Lane) The bootstrap catalog data incorrectly marks these two catalog columns as always non-null. There's no easy way to correct that mistake in existing installations (though v13 and later will have the correct markings). The main place that depends on that marking being correct is JIT-enabled tuple deconstruction, so teach it to explicitly ignore the marking for these two columns. Also adjust some C code that accessed srsublsn without checking to see if it's null; a crash from that is improbable but perhaps not impossible. Cope with LATERAL references in restriction clauses attached to an un-flattened sub-SELECT in the FROM clause (Tom Lane) This oversight could result in assertion failures or crashes at query execution. Use the query-specified collation for operators invoked during selectivity estimation (Tom Lane) Previously, the collation of the underlying database column was used. But using the query's collation is arguably more correct. More importantly, now that we have nondeterministic collations, there are cases where an operator will fail outright if given a nondeterministic collation. We don't want planning to fail in cases where the query itself would work, so this means that we must use the query's collation when invoking operators for estimation purposes. Avoid believing that a never-analyzed foreign table has zero tuples (Tom Lane) This primarily affected the planner's estimate of the number of groups that would be obtained by GROUP BY. Remove bogus warning about leftover placeholder tuple in BRIN index de-summarization (Álvaro Herrera) The case can occur legitimately after a cancelled vacuum, so warning about it is overly noisy. Fix selection of tablespaces for shared fileset temporary files (Magnus Hagander, Tom Lane) If temp_tablespaces is empty or explicitly names the database's primary tablespace, such files got placed into the pg_default tablespace rather than the database's primary tablespace as expected. Fix corner-case error in masking of SP-GiST index pages during WAL consistency checking (Alexander Korotkov) This could cause false failure reports when wal_consistency_checking is enabled. Improve error handling in the server's buffile module (Thomas Munro) Fix some cases where I/O errors were indistinguishable from reaching EOF, or were not reported at all. Also add details such as block numbers and byte counts where appropriate. Fix conflict-checking anomalies in SERIALIZABLE isolation mode (Peter Geoghegan) If a concurrently-inserted tuple was updated by a different concurrent transaction, and neither tuple version was visible to the current transaction's snapshot, serialization conflict checking could draw the wrong conclusions about whether the tuple was relevant to the results of the current transaction. This could allow a serializable transaction to commit when it should have failed with a serialization error. Avoid repeated marking of dead btree index entries as dead (Masahiko Sawada) While functionally harmless, this led to useless WAL traffic when checksums are enabled or wal_log_hints is on. Fix checkpointer process to discard file sync requests when fsync is off (Heikki Linnakangas) Such requests are treated as no-ops if fsync is off, but we forgot to remove them from the checkpointer's table of pending actions. This would lead to bloat of that table, as well as possible assertion failures if fsync is later re-enabled. Avoid trouble during cleanup of a non-exclusive backup when JIT compilation has been activated during the backup (Robert Haas) Fix failure of some code paths to acquire the correct lock before modifying pg_control (Nathan Bossart, Fujii Masao) This oversight could allow pg_control to be written out with an inconsistent checksum, possibly causing trouble later, including inability to restart the database if it crashed before the next pg_control update. Fix errors in currtid() and currtid2() (Michael Paquier) These functions (which are undocumented and used only by ancient versions of the ODBC driver) contained coding errors that could result in crashes, or in confusing error messages such as could not open file when applied to a relation having no storage. Avoid calling elog() or palloc() while holding a spinlock (Michael Paquier, Tom Lane) Logic associated with replication slots had several violations of this coding rule. While the odds of trouble are quite low, an error in the called function would lead to a stuck spinlock. Fix assertion in logical replication subscriber to allow use of REPLICA IDENTITY FULL (Euler Taveira) This was just an incorrect assertion, so it has no impact on standard production builds. Ensure that libpq continues to try to read from the database connection socket after a write failure (Tom Lane) This is important not only to ensure that we collect any final error message from a dying server process, but because we do not consider the connection lost until we see a read failure. This oversight allowed libpq to continue trying to send COPY data indefinitely after a mid-transfer loss of connection, rather than reporting failure to the application. Fix bugs in libpq's management of GSS encryption state (Tom Lane) A connection using GSS encryption could freeze up when attempting to reset it after a server restart, or when moving on to the next one of a list of candidate servers. Fix ecpg crash with bytea and cursor variables (Jehan-Guillaume de Rorthais) Report out-of-disk-space errors properly in pg_dump and pg_basebackup (Justin Pryzby, Tom Lane, Álvaro Herrera) Some code paths could produce silly reports like could not write file: Success. Make pg_restore cope with data-offset-less custom-format archive files when it needs to restore data items out of order (David Gilman, Tom Lane) pg_dump will produce such files if it cannot seek its output (for example, if the output is piped to something). This fix primarily improves the ability to do a parallel restore from such a file. Fix parallel restore of tables having both table-level privileges and per-column privileges (Tom Lane) The table-level privilege grants have to be applied first, but a parallel restore did not reliably order them that way; this could lead to tuple concurrently updated errors, or to disappearance of some per-column privilege grants. The fix for this is to include dependency links between such entries in the archive file, meaning that a new dump has to be taken with a corrected pg_dump to ensure that the problem will not recur. Ensure that pg_upgrade runs with vacuum_defer_cleanup_age set to zero in the target cluster (Bruce Momjian) If the target cluster's configuration has been modified to set vacuum_defer_cleanup_age to a nonzero value, that prevented freezing of the system catalogs from working properly, which caused the upgrade to fail in confusing ways. Ensure that any such setting is overridden for the duration of the upgrade. Fix pg_recvlogical to drain pending messages before exiting (Noah Misch) Without this, the replication sender might detect a send failure and exit without making the expected final update to the replication slot's LSN position. That led to re-transmitting data after the next connection. It was also possible to miss error messages sent after the last data that pg_recvlogical wants to consume. Fix pg_rewind's handling of just-deleted files in the source data directory (Justin Pryzby, Michael Paquier) When working with an on-line source database, concurrent file deletions are possible, but pg_rewind would get confused if deletion happened between seeing a file's directory entry and examining it with stat(). Make pg_test_fsync use binary I/O mode on Windows (Michael Paquier) Previously it wrote the test file in text mode, which is not an accurate reflection of PostgreSQL's actual usage. Fix contrib/amcheck to not complain about deleted index pages that are empty (Alexander Korotkov) This state of affairs is normal during WAL replay. Fix failure to initialize local state correctly in contrib/dblink (Joe Conway) With the right combination of circumstances, this could lead to dblink_close() issuing an unexpected remote COMMIT. Fix contrib/pgcrypto's misuse of deflate() (Tom Lane) The pgp_sym_encrypt functions could produce incorrect compressed data due to mishandling of zlib's API requirements. We have no reports of this error manifesting with stock zlib, but it can be seen when using IBM's zlibNX implementation. Fix corner case in decompression logic in contrib/pgcrypto's pgp_sym_decrypt functions (Kyotaro Horiguchi, Michael Paquier) A compressed stream can validly end with an empty packet, but the decompressor failed to handle this and would complain about corrupt data. Support building our NLS code with Microsoft Visual Studio 2015 or later (Juan José Santamaría Flecha, Davinder Singh, Amit Kapila) Avoid possible failure of our MSVC install script when there is a file named configure several levels above the source code tree (Arnold Müller) This could confuse some logic that looked for configure to identify the top level of the source tree. 2020-05-14 This release contains a variety of fixes from 12.2. For information about new features in major release 12, see . A dump/restore is not required for those running 12.X. However, if you are upgrading from a version earlier than 12.2, see . Fix possible failure with GENERATED columns (David Rowley) If a GENERATED column's value is an exact copy of another column of the table (and it is a pass-by-reference data type), it was possible to crash or insert corrupted data into the table. While it would be rather pointless for a GENERATED expression to just duplicate another column, an expression using a function that sometimes returns its input unchanged could create the situation. Handle inheritance of generated columns better (Peter Eisentraut) When a table column is inherited during CREATE TABLE ... INHERITS, disallow changing any generation properties when the parent column is already marked GENERATED; but allow a child column to be marked GENERATED when its parent is not. Fix cross-column references in CREATE TABLE LIKE INCLUDING GENERATED (Peter Eisentraut) CREATE TABLE ... LIKE failed when trying to copy a GENERATED expression that references a physically-later column. Propagate ALTER TABLE ... SET STORAGE to indexes (Peter Eisentraut) Non-expression index columns have always copied the attstorage property of their table column at creation. Update them when ALTER TABLE ... SET STORAGE is done, to maintain consistency. Preserve the indisclustered setting of indexes rewritten by ALTER TABLE (Amit Langote, Justin Pryzby) Previously, ALTER TABLE lost track of which index had been used for CLUSTER. Preserve the replica identity properties of indexes rewritten by ALTER TABLE (Quan Zongliang, Peter Eisentraut) Preserve the indisclustered setting of indexes rebuilt by REINDEX CONCURRENTLY (Justin Pryzby) Lock objects sooner during DROP OWNED BY (Álvaro Herrera) This avoids failures in race-condition cases where another session is deleting some of the same objects. Fix error-case processing for CREATE ROLE ... IN ROLE (Andrew Gierth) Some error cases would be reported as unexpected node type or the like, instead of the intended message. Ensure that when a partition is detached, any triggers cloned from its formerly-parent table are removed (Justin Pryzby) Fix crash when COLLATE is applied to a non-collatable type in a partition bound expression (Dmitry Dolgov) Ensure that unique indexes over partitioned tables match the equality semantics of the partitioning key (Guancheng Luo) This would only be an issue with index opclasses that have unusual notions of equality, but it's wrong in theory, so check. Ensure that members of the pg_read_all_stats role can read all statistics views, as expected (Magnus Hagander) The functions underlying the pg_stat_progress_* views had not gotten this memo. Repair performance regression in information_schema.triggers view (Tom Lane) This patch redefines that view so that an outer WHERE clause constraining the table name can be pushed down into the view, allowing its calculations to be done only for triggers belonging to the table of interest rather than all triggers in the database. In a database with many triggers this would make a significant speed difference for queries of that form. Since things worked that way before v11, this is a potential performance regression. Users who find this to be a problem can fix it by replacing the view definition (or, perhaps, just deleting and reinstalling the whole information_schema schema). Repair performance regression in floating point overflow/underflow detection (Emre Hasegeli) Previous refactoring had resulted in isinf() being called extra times in some hot code paths. Fix full text search to handle NOT above a phrase search correctly (Tom Lane) Queries such as !(foo<->bar) failed to find matching rows when implemented as a GiST or GIN index search. Fix full text search for cases where a phrase search includes an item with both prefix matching and a weight restriction (Tom Lane) Fix ts_headline() to make better headline selections when working with phrase queries (Tom Lane) Fix bugs in gin_fuzzy_search_limit processing (Adé Heyward, Tom Lane) A small value of gin_fuzzy_search_limit could result in unexpected slowness due to unintentionally rescanning the same index page many times. Another code path failed to apply the intended filtering at all, possibly returning too many values. Allow input of type circle to accept the format (x,y),r as the documentation says it does (David Zhang) Make the get_bit() and set_bit() functions cope with bytea strings longer than 256MB (Movead Li) Since the bit number argument is only int4, it's impossible to use these functions to access bits beyond the first 256MB of a long bytea. We'll widen the argument to int8 in v13, but in the meantime, allow these functions to work on the initial substring of a long bytea. Ignore file-not-found errors in pg_ls_waldir() and allied functions (Tom Lane) This prevents a race condition failure if a file is removed between when we see its directory entry and when we attempt to stat() it. Avoid possibly leaking an open-file descriptor for a directory in pg_ls_dir(), pg_timezone_names(), pg_tablespace_databases(), and allied functions (Justin Pryzby) Fix polymorphic-function type resolution to correctly infer the actual type of an anyarray output when given only an anyrange input (Tom Lane) Fix server's connection-startup logic for case where a GSSAPI connection is rejected because support is not compiled in, and the client then tries SSL instead (Andrew Gierth) This led to a bogus unsupported frontend protocol failure. Fix memory leakage during GSSAPI encryption (Tom Lane) Both the backend and libpq would leak memory equivalent to the total amount of data sent during the session, if GSSAPI encryption is in use. Fix query-lifespan memory leak for a set-returning function used in a query's FROM clause (Andres Freund) Avoid leakage of a hashed subplan's hash tables across multiple executions (Andreas Karlsson, Tom Lane) This mistake could result in severe memory bloat if a query re-executed a hashed subplan enough times. Improve planner's handling of no-op domain coercions (Tom Lane) Fix some cases where a domain coercion that does nothing was not completely removed from expressions. Avoid unlikely crash when REINDEX is terminated by a session-shutdown signal (Tom Lane) Prevent printout of possibly-incorrect hash join table statistics in EXPLAIN (Konstantin Knizhnik, Tom Lane, Thomas Munro) Fix reporting of elapsed time for heap truncation steps in VACUUM VERBOSE (Tatsuhito Kasahara) Fix possible undercounting of deleted B-tree index pages in VACUUM VERBOSE output (Peter Geoghegan) Fix wrong bookkeeping for oldest deleted page in a B-tree index (Peter Geoghegan) This could cause subtly wrong decisions about when VACUUM can skip an index cleanup scan; although it appears there may be no significant user-visible effects from that. Ensure that TimelineHistoryRead and TimelineHistoryWrite wait states are reported in all code paths that read or write timeline history files (Masahiro Ikeda) Avoid possibly showing waiting twice in a process's PS status (Masahiko Sawada) Avoid race condition when ANALYZE replaces the catalog tuple for extended statistics data (Dean Rasheed) Remove ill-considered skip of redundant anti-wraparound vacuums (Michael Paquier) This avoids a corner case where autovacuum could get into a loop of repeatedly trying and then skipping the same vacuum job. Ensure INCLUDE'd columns are always removed from B-tree pivot tuples (Peter Geoghegan) This mistake wasted space in some rare cases, but was otherwise harmless. Cope with invalid TOAST indexes that could be left over after a failed REINDEX CONCURRENTLY (Julien Rouhaud) Ensure that valid index dependencies are left behind after a failed REINDEX CONCURRENTLY (Michael Paquier) Previously the old index could be left with no pg_depend links at all, so that for example it would not get dropped if the parent table is dropped. Avoid failure if autovacuum tries to access a just-dropped temporary schema (Tom Lane) This hazard only arises if a superuser manually drops a temporary schema; which isn't normal practice, but should work. Avoid premature recycling of WAL segments during crash recovery (Jehan-Guillaume de Rorthais) WAL segments that become ready to be archived during crash recovery were potentially recycled without being archived. Avoid scanning irrelevant timelines during archive recovery (Kyotaro Horiguchi) This can eliminate many attempts to fetch non-existent WAL files from archive storage, which is helpful if archive access is slow. Remove bogus subtransaction logged without previous top-level txn record error check in logical decoding (Arseny Sher, Amit Kapila) This condition is legitimately reachable in various scenarios, so remove the check. Avoid possible failure after a replication slot copy, due to premature removal of WAL data (Masahiko Sawada, Arseny Sher) Ensure that a replication slot's io_in_progress_lock is released in failure code paths (Pavan Deolasee) This could result in a walsender later becoming stuck waiting for the lock. Ensure that generated columns are correctly handled during updates issued by logical replication (Peter Eisentraut) Fix race conditions in synchronous standby management (Tom Lane) During a change in the synchronous_standby_names setting, there was a window in which wrong decisions could be made about whether it is OK to release transactions that are waiting for synchronous commit. Another hazard for similarly wrong decisions existed if a walsender process exited and was immediately replaced by another. Add missing SQLSTATE values to a few error reports (Sawada Masahiko) Fix PL/pgSQL to reliably refuse to execute an event trigger function as a plain function (Tom Lane) Fix memory leak in libpq when using sslmode=verify-full (Roman Peshkurov) Certificate verification during connection startup could leak some memory. This would become an issue if a client process opened many database connections during its lifetime. Fix ecpg to treat an argument of just - as meaning read from stdin on all platforms (Tom Lane) Fix crash in psql when attempting to re-establish a failed connection (Michael Paquier) Allow tab-completion of the filename argument to psql's \gx command (Vik Fearing) Add pg_dump support for ALTER ... DEPENDS ON EXTENSION (Álvaro Herrera) pg_dump previously ignored dependencies added this way, causing them to be forgotten during dump/restore or pg_upgrade. Fix pg_dump to dump comments on RLS policy objects (Tom Lane) In pg_dump, postpone restore of event triggers till the end (Fabrízio de Royes Mello, Hamid Akhtar, Tom Lane) This minimizes the risk that an event trigger could interfere with the restoration of other objects. Ensure that pg_basebackup generates valid tar files (Robert Haas) In some cases a partial block of zeroes would be added to the end of the file. While this seems to be harmless with common versions of tar, it's not OK per the POSIX file format spec. Make pg_checksums skip tablespace subdirectories that belong to a different PostgreSQL major version (Michael Banck, Bernd Helmle) Such subdirectories don't really belong to our database cluster, and so must not be processed. Ignore temporary copies of pg_internal.init in pg_checksums and related programs (Michael Paquier) Fix quoting of --encoding, --lc-ctype and --lc-collate values in createdb utility (Michael Paquier) contrib/lo's lo_manage() function crashed if called directly rather than as a trigger (Tom Lane) In contrib/ltree, protect against overflow of ltree and lquery length fields (Nikita Glukhov) Work around failure in contrib/pageinspect's bt_metap() function when an oldest_xact value exceeds 2^31-1 (Peter Geoghegan) Such XIDs will now be reported as negative integers, which isn't great but it beats throwing an error. v13 will widen the output argument to int8 to provide saner reporting. Fix cache reference leak in contrib/sepgsql (Michael Luo) On Windows, avoid premature creation of postmaster's log file during pg_ctl start (Alexander Lakhin) The previous coding could allow the file to be created with permissions that wouldn't allow the postmaster to write on it. Avoid failures when dealing with Unix-style locale names on Windows (Juan José Santamaría Flecha) On Windows, set console VT100 compatibility mode in programs that support PG_COLOR colorization (Juan José Santamaría Flecha) Without this, the colorization option doesn't actually work. Stop requiring extra parentheses in ereport() calls (Andres Freund, Tom Lane) Use pkg-config, if available, to locate libxml2 during configure (Hugh McMaster, Tom Lane, Peter Eisentraut) If pkg-config is not present or lacks knowledge of libxml2, we still query xml2-config as before. This change could break build processes that try to make PostgreSQL use a non-default version of libxml2 by putting that version's xml2-config into the PATH. Instead, set XML2_CONFIG to point to the non-default xml2-config. That method will work with either older or newer PostgreSQL releases. Fix Makefile dependencies for libpq and ecpg (Dagfinn Ilmari Mannsåker) In MSVC builds, cope with spaces in the path name for Python (Victor Wagner) In MSVC builds, fix detection of Visual Studio version to work with more language settings (Andrew Dunstan) In MSVC builds, use -Wno-deprecated with bison versions newer than 3.0, as non-Windows builds already do (Andrew Dunstan) Update time zone data files to tzdata release 2020a for DST law changes in Morocco and the Canadian Yukon, plus historical corrections for Shanghai. The America/Godthab zone has been renamed to America/Nuuk to reflect current English usage; however, the old name remains available as a compatibility link. Also, update initdb's list of known Windows time zone names to include recent additions, improving the odds that it will correctly translate the system time zone setting on that platform. 2020-02-13 This release contains a variety of fixes from 12.1. For information about new features in major release 12, see . A dump/restore is not required for those running 12.X. However, if you have any foreign key constraints referencing partitioned tables, see the two entries below about bugs in that feature. Add missing permissions checks for ALTER ... DEPENDS ON EXTENSION (Álvaro Herrera) Marking an object as dependent on an extension did not have any privilege check whatsoever. This oversight allowed any user to mark routines, triggers, materialized views, or indexes as droppable by anyone able to drop an extension. Require that the calling user own the specified object (and hence have privilege to drop it). (CVE-2020-1720) Fix TRUNCATE ... CASCADE to ensure all relevant partitions are truncated (Jehan-Guillaume de Rorthais) If a partition of a partitioned table is truncated with the CASCADE option, and the partitioned table has a foreign-key reference from another table, that table must also be truncated. The need to check this was missed if the referencing table was itself partitioned, possibly allowing rows to survive that violate the foreign-key constraint. Hence, if you have foreign key constraints between partitioned tables, and you have done any partition-level TRUNCATE on the referenced table, you should check to see if any foreign key violations exist. The simplest way is to add a new instance of the foreign key constraint (and, once that succeeds, drop it or the original constraint). That may be prohibitive from a locking standpoint, however, in which case you might prefer to manually query for unmatched rows. Fix failure to attach foreign key constraints to sub-partitions (Jehan-Guillaume de Rorthais) When adding a partition to a level below the first level of a multi-level partitioned table, foreign key constraints referencing the top partitioned table were not cloned to the new partition, leading to possible constraint violations later. Detaching and re-attaching the new partition is the cheapest way to fix this. However, if there are many partitions to be fixed, adding a new instance of the foreign key constraint might be preferable. Fix possible crash during concurrent update on a partitioned table or inheritance tree (Tom Lane) Ensure that row triggers on partitioned tables are correctly cloned to sub-partitions when appropriate (Álvaro Herrera) User-defined triggers (but not triggers for foreign key or deferred unique constraints) might be missed when creating or attaching a partition. Fix logical replication subscriber code to execute per-column UPDATE triggers when appropriate (Peter Eisentraut) Avoid failure in logical decoding when a large transaction must be spilled into many separate temporary files (Amit Khandekar) Fix possible crash or data corruption when a logical replication subscriber processes a row update (Tom Lane, Tomas Vondra) This bug caused visible problems only if the subscriber's table contained columns that were not being copied from the publisher and had pass-by-reference data types. Fix crash in logical replication subscriber after DDL changes on a subscribed relation (Jehan-Guillaume de Rorthais, Vignesh C) Fix failure in logical replication publisher after a database crash and restart (Vignesh C) Ensure that the effect of pg_replication_slot_advance() on a physical replication slot will persist across restarts (Alexey Kondratov, Michael Paquier) Improve efficiency of logical replication with REPLICA IDENTITY FULL (Konstantin Knizhnik) When searching for an existing tuple during an update or delete operation, return the first matching tuple not the last one. Fix base backup to handle database OIDs larger than INT32_MAX (Peter Eisentraut) Ensure parallel plans are always shut down at the correct time (Kyotaro Horiguchi) This oversight is known to result in temporary file leak warnings from multi-batch parallel hash joins. Prevent premature shutdown of a Gather or GatherMerge plan node that is underneath a Limit node (Amit Kapila) This avoids failure if such a plan node needs to be scanned more than once, as for instance if it is on the inside of a nestloop. Improve efficiency of parallel hash join on CPUs with many cores (Gang Deng, Thomas Munro) Avoid crash in parallel CREATE INDEX when there are no free dynamic shared memory slots (Thomas Munro) Fall back to a non-parallel index build, instead. Avoid memory leak when there are no free dynamic shared memory slots (Thomas Munro) Ignore the CONCURRENTLY option when performing an index creation, drop, or rebuild on a temporary table (Michael Paquier, Heikki Linnakangas, Andres Freund) This avoids strange failures if the temporary table has an ON COMMIT action. There is no benefit in using CONCURRENTLY for a temporary table anyway, since other sessions cannot access the table, making the extra processing pointless. Fix possible failure when resetting expression indexes on temporary tables that are marked ON COMMIT DELETE ROWS (Tom Lane) Fix possible crash in BRIN index operations with box, range and inet data types (Heikki Linnakangas) Fix crash during recursive page split in GiST index build (Heikki Linnakangas) Fix handling of deleted pages in GIN indexes (Alexander Korotkov) Avoid possible deadlocks, incorrect updates of a deleted page's state, and failure to traverse through a recently-deleted page. Fix possible crash with a SubPlan (sub-SELECT) within a multi-row VALUES list (Tom Lane) Fix failure in ALTER TABLE when a column referenced in a GENERATED expression has been added or changed in type earlier in the same ALTER command (Tom Lane) Fix failure to insert default values for missing attributes during tuple conversion (Vik Fearing, Andrew Gierth) This could result in values incorrectly reading as NULL, when they come from columns that had been added by ALTER TABLE ADD COLUMN with a constant default. Fix unlikely panic in the checkpointer process, caused by opening relation segments that might already have been removed (Thomas Munro) Fix crash after FileClose() failure (Noah Misch) This issue could only be observed with data_sync_retry enabled, since otherwise FileClose() failure would be reported as a PANIC. Fix handling of multiple AFTER ROW triggers on a foreign table (Etsuro Fujita) Fix unlikely crash with pass-by-reference aggregate transition states (Andres Freund, Teodor Sigaev) Improve error reporting in to_date() and to_timestamp() (Tom Lane, Álvaro Herrera) Reports about incorrect month or day names in input strings could truncate the input in the middle of a multi-byte character, leading to an improperly encoded error message that could cause follow-on failures. Truncate at the next whitespace instead. Fix off-by-one result for EXTRACT(ISOYEAR FROM timestamp) for BC dates (Tom Lane) Ensure that the <> operator for type char reports indeterminate-collation errors as such, rather than as cache lookup failed for collation 0 (Tom Lane) Avoid treating TID scans as sequential scans (Tatsuhito Kasahara) A refactoring oversight caused TID scans (selection by CTID) to be counted as sequential scans in the statistics views, and to take whole-table predicate locks as sequential scans do. The latter behavior could cause unnecessary serialization errors in serializable transaction mode. Avoid stack overflow in information_schema views when a self-referential view exists in the system catalogs (Tom Lane) A self-referential view can't work; it will always result in infinite recursion. We handled that situation correctly when trying to execute the view, but not when inquiring whether it is automatically updatable. Ensure that walsender processes always show NULL for transaction start time in pg_stat_activity (Álvaro Herrera) Previously, the xact_start column would sometimes show the process start time. Improve performance of hash joins with very large inner relations (Thomas Munro) Reduce spinlock contention when there are many active walsender processes (Pierre Ducroquet) Fix placement of Subplans Removed field in EXPLAIN output (Daniel Gustafsson, Tom Lane) In non-text output formats, this field was emitted inside the Plans sub-group, resulting in syntactically invalid output. Attach it to the parent Append or MergeAppend plan node as intended. This causes the field to change position in text output format too: if there are any InitPlans attached to the same plan node, Subplans Removed will now appear before those. Fix EXPLAIN's SETTINGS option to print as empty in non-text output formats (Tom Lane) In the non-text output formats, fields are supposed to appear when requested, even if they have empty or zero values. Allow the planner to apply potentially-leaky tests to child-table statistics, if the user can read the corresponding column of the table that's actually named in the query (Dilip Kumar, Amit Langote) This change fixes a performance problem for partitioned tables that was created by the fix for CVE-2017-7484. That security fix disallowed applying leaky operators to statistics for columns that the current user doesn't have permission to read directly. However, it's somewhat common to grant permissions only on the parent partitioned table and not bother to do so on individual partitions. In such cases, the user can read the column via the parent, so there's no point in this security restriction; it only results in poorer planner estimates than necessary. Fix planner errors induced by overly-aggressive collapsing of joins to single-row subqueries (Tom Lane) This mistake led to errors such as failed to construct the join relation. Fix no = operator for opfamily NNNN planner error when trying to match a LIKE or regex pattern-match operator to a binary-compatible index opclass (Tom Lane) Fix edge-case crashes and misestimations in selectivity calculations for the <@ and @> range operators (Michael Paquier, Andrey Borodin, Tom Lane) Fix incorrect estimation for OR clauses when using most-common-value extended statistics (Tomas Vondra) Ignore system columns when applying most-common-value extended statistics (Tomas Vondra) This prevents negative bitmapset member not allowed planner errors for affected queries. Fix BRIN index logic to support hypothetical BRIN indexes (Julien Rouhaud, Heikki Linnakangas) Previously, if an index adviser extension tried to get the planner to produce a plan involving a hypothetical BRIN index, that would fail, because the BRIN cost estimation code would always try to physically access the index's metapage. Now it checks to see if the index is only hypothetical, and uses default assumptions about the index parameters if so. Improve error reporting for attempts to use automatic updating of views with conditional INSTEAD rules (Dean Rasheed) This has never been supported, but previously the error was thrown only at execution time, so that it could be masked by planner errors. Prevent a composite type from being included in itself indirectly via a range type (Tom Lane, Julien Rouhaud) Disallow partition key expressions that return pseudo-types, such as record (Tom Lane) Fix error reporting for index expressions of prohibited types (Amit Langote) Fix dumping of views that contain only a VALUES list to handle cases where a view output column has been renamed (Tom Lane) Ensure that data types and collations used in XMLTABLE constructs are accounted for when computing dependencies of a view or rule (Tom Lane) Previously it was possible to break a view using XMLTABLE by dropping a type, if the type was not otherwise referenced in the view. This fix does not correct the dependencies already recorded for existing views, only for newly-created ones. Prevent unwanted downcasing and truncation of RADIUS authentication parameters (Marcos David) The pg_hba.conf parser mistakenly treated these fields as SQL identifiers, which in general they aren't. Transmit incoming NOTIFY messages to the client before sending ReadyForQuery, rather than after (Tom Lane) This change ensures that, with libpq and other client libraries that act similarly to it, any notifications received during a transaction will be available by the time the client thinks the transaction is complete. This probably makes no difference in practical applications (which would need to cope with asynchronous notifications in any case); but it makes it easier to build test cases with reproducible behavior. Fix bugs in handling of non-blocking I/O when using GSSAPI encryption (Tom Lane) These errors could result in dropping data (usually leading to subsequent wire-protocol-violation errors) or in a livelock situation where a sending process goes to sleep although not all its data has been sent. Moreover, libpq failed to keep separate encryption state for each connection, creating the possibility for failures in applications using multiple encrypted database connections. Allow libpq to parse all GSS-related connection parameters even when the GSSAPI code hasn't been compiled in (Tom Lane) This makes the behavior similar to our SSL support, where it was long ago deemed to be a good idea to always accept all the related parameters, even if some are ignored or restricted due to lack of the feature in a particular build. Fix incorrect handling of %b and %B format codes in ecpg's PGTYPEStimestamp_fmt_asc() function (Tomas Vondra) Due to an off-by-one error, these codes would print the wrong month name, or possibly crash. Avoid crash after an out-of-memory failure in ecpglib (Tom Lane) Fix parallel pg_dump/pg_restore to more gracefully handle failure to create worker processes (Tom Lane) Prevent possible crash or lockup when attempting to terminate a parallel pg_dump/pg_restore run via a signal (Tom Lane) In pg_upgrade, look inside arrays and ranges while searching for non-upgradable data types in tables (Tom Lane) Apply more thorough syntax checking to createuser's --connection-limit option (Álvaro Herrera) Cope with changes of the specific type referenced by a PL/pgSQL composite-type variable in more cases (Ashutosh Sharma, Tom Lane) Dropping and re-creating the composite type referenced by a PL/pgSQL variable could lead to could not open relation with OID NNNN errors. Avoid crash in postgres_fdw when trying to send a command like UPDATE remote_tab SET (x,y) = (SELECT ...) to the remote server (Tom Lane) In contrib/dict_int, reject maxlen settings less than one (Tomas Vondra) This prevents a possible crash with silly settings for that parameter. Disallow NULL category values in contrib/tablefunc's crosstab() function (Joe Conway) This case never worked usefully, and it would crash on some platforms. Fix configure's probe for OpenSSL's SSL_clear_options() function so that it works with OpenSSL versions before 1.1.0 (Michael Paquier, Daniel Gustafsson) This problem could lead to failure to set the SSL compression option as desired, when PostgreSQL is built against an old version of OpenSSL. Mark some timeout and statistics-tracking GUC variables as PGDLLIMPORT, to allow extensions to access them on Windows (Pascal Legrand) This applies to idle_in_transaction_session_timeout, lock_timeout, statement_timeout, track_activities, track_counts, and track_functions. Avoid memory leak in sanity checks for slab memory contexts (Tomas Vondra) This isn't an issue for production builds, since they wouldn't ordinarily have memory context checking enabled; but the leak could be quite severe in a debug build. Fix multiple statistics entries reported by the LWLock statistics mechanism (Fujii Masao) The LWLock statistics code (which is not built by default; it requires compiling with -DLWLOCK_STATS) could report multiple entries for the same LWLock and backend process, as a result of faulty hashtable key creation. Fix race condition that led to delayed delivery of interprocess signals on Windows (Amit Kapila) This caused visible timing oddities in NOTIFY, and perhaps other misbehavior. Fix handling of a corner-case error result from Windows' ReadFile() function (Thomas Munro, Juan José Santamaría Flecha) So far as is known, this oversight just resulted in noisy log messages, not any actual query misbehavior. On Windows, retry a few times after an ERROR_ACCESS_DENIED file access failure (Alexander Lakhin, Tom Lane) This helps cope with cases where a file open attempt fails because the targeted file is flagged for deletion but not yet actually gone. pg_ctl, for example, frequently failed with such an error when probing to see if the postmaster had shut down yet. On Windows, work around sharing violations for the postmaster's log file when pg_ctl is used to start the postmaster very shortly after it's been stopped, for example by pg_ctl restart (Alexander Lakhin) 2019-11-14 This release contains a variety of fixes from 12.0. For information about new features in major release 12, see . A dump/restore is not required for those running 12.X. Fix crash when ALTER TABLE adds a column without a default value along with making other changes that require a table rewrite (Andres Freund) Fix lock handling in REINDEX CONCURRENTLY (Michael Paquier) REINDEX CONCURRENTLY neglected to take a session-level lock on the new index version, potentially allowing other sessions to manipulate it too soon. Also, a query-cancel or session-termination interrupt arriving at the wrong time could result in failure to release the session-level locks that REINDEX CONCURRENTLY does hold. Avoid crash due to race condition when reporting the progress of a CREATE INDEX CONCURRENTLY or REINDEX CONCURRENTLY command (Álvaro Herrera) Avoid creating duplicate dependency entries during REINDEX CONCURRENTLY (Michael Paquier) This bug resulted in bloat in pg_depend, but no worse consequences than that. Prevent VACUUM from trying to freeze an old multixact ID involving a still-running transaction (Nathan Bossart, Jeremy Schneider) This case would lead to VACUUM failing until the old transaction terminates. Fix wrong type of slot error when trying to CLUSTER on an expression index (Andres Freund) SET CONSTRAINTS ... DEFERRED failed on partitioned tables, incorrectly complaining about lack of triggers (Álvaro Herrera) Fix failure when creating indexes for a partition, if the parent partitioned table contains any dropped columns (Michael Paquier) Fix dropping of indexed columns in partitioned tables (Amit Langote, Michael Paquier) Previously this might fail with an error message complaining about the dependencies of the indexes. It should automatically drop the indexes, instead. Ensure that a partition index can be dropped after a failure to reindex it concurrently (Michael Paquier) The index's pg_class.relispartition flag was left in the wrong state in such a case, causing DROP INDEX to fail. Fix handling of equivalence class members for partition-wise joins (Amit Langote) This oversight could lead either to failure to use a feasible partition-wise join plan, or to a could not find pathkey item to sort planner failure. Ensure that offset expressions in WINDOW clauses are processed when a query's expressions are manipulated (Andrew Gierth) This oversight could result in assorted failures when the offsets are nontrivial expressions. One example is that a function parameter reference in such an expression would fail if the function was inlined. Avoid postmaster failure if a parallel query requests a background worker when no postmaster child process array slots remain free (Tom Lane) Fix crash triggered by an EvalPlanQual recheck on a table with a BEFORE UPDATE trigger (Andres Freund) Fix unexpected relkind error when a query tries to access a TOAST table (John Hsu, Michael Paquier, Tom Lane) The error should say that permission is denied, but this case got broken during code refactoring. Provide a relevant error context line when an error occurs while setting GUC parameters during parallel worker startup (Thomas Munro) Ensure that fsync() is applied only to files that are opened read/write (Andres Freund, Michael Paquier) Some code paths tried to do this after opening a file read-only, but on some platforms that causes bad file descriptor or similar errors. Allow encoding conversion to succeed on longer strings than before (Álvaro Herrera, Tom Lane) Previously, there was a hard limit of 0.25GB on the input string, but now it will work as long as the converted output is not over 1GB. Avoid creating unnecessarily-bulky tuple stores for window functions (Andrew Gierth) In some cases the tuple storage would include all columns of the source table(s), not just the ones that are needed by the query. Allow repalloc() to give back space when a large chunk is reduced in size (Tom Lane) Ensure that temporary WAL and history files are removed at the end of archive recovery (Sawada Masahiko) Avoid failure in archive recovery if recovery_min_apply_delay is enabled (Fujii Masao) recovery_min_apply_delay is not typically used in this configuration, but it should work. Ignore restore_command, recovery_end_command, and recovery_min_apply_delay settings during crash recovery (Fujii Masao) Now that these settings can be specified in postgresql.conf, they could be turned on during crash recovery, but honoring them then is undesirable. Ignore these settings until crash recovery is complete. Fix logical replication failure when publisher and subscriber have different ideas about a table's replica identity columns (Jehan-Guillaume de Rorthais, Peter Eisentraut) Declaring a column as part of the replica identity on the subscriber, when it does not exist at all on the publisher, led to negative bitmapset member not allowed errors. Avoid unwanted delay during shutdown of a logical replication walsender (Craig Ringer, Álvaro Herrera) Fix timeout handling in logical replication walreceiver processes (Julien Rouhaud) Erroneous logic prevented wal_receiver_timeout from working in logical replication deployments. Correctly time-stamp replication messages for logical decoding (Jeff Janes) This oversight resulted, for example, in pg_stat_subscription.last_msg_send_time usually reading as NULL. Fix race condition during backend exit, when the backend process has previously waited for synchronous replication to occur (Dongming Liu) Avoid logging complaints about abandoned connections when using PAM authentication (Tom Lane) libpq-based clients will typically make two connection attempts when a password is required, since they don't prompt their user for a password until their first connection attempt fails. Therefore the server is coded not to generate useless log spam when a client closes the connection upon being asked for a password. However, the PAM authentication code hadn't gotten that memo, and would generate several messages about a phantom authentication failure. Fix misbehavior of bitshiftright() (Tom Lane) The bitstring right shift operator failed to zero out padding space that exists in the last byte of the result when the bitstring length is not a multiple of 8. While invisible to most operations, any nonzero bits there would result in unexpected comparison behavior, since bitstring comparisons don't bother to ignore the extra bits, expecting them to always be zero. If you have inconsistent data as a result of saving the output of bitshiftright() in a table, it's possible to fix it with something like UPDATE mytab SET bitcol = ~(~bitcol) WHERE bitcol != ~(~bitcol); Fix result of text position() function (also known as strpos()) for an empty search string (Tom Lane) Historically, and per the SQL standard, the result should be one in such cases, but 12.0 returned zero. Fix detection of edge-case integer overflow in interval multiplication (Yuya Watari) Avoid crashes if ispell text search dictionaries contain wrong affix data (Arthur Zakirov) Avoid memory leak while vacuuming a GiST index (Dilip Kumar) On Windows, recognize additional spellings of the Norwegian (Bokmål) locale name (Tom Lane) Fix libpq to allow trailing whitespace in the string values of integer parameters (Michael Paquier) Version 12 tightened libpq's validation of integer parameters, but disallowing trailing whitespace seems undesirable. In libpq, correctly report CONNECTION_BAD connection status after a failure caused by a syntactically invalid connect_timeout parameter value (Lars Kanis) Avoid compile failure if an ECPG client includes ecpglib.h while having ENABLE_NLS defined (Tom Lane) This risk was created by a misplaced declaration: ecpg_gettext() should not be visible to client code. Fix scheduling of parallel restore of a foreign key constraint on a partitioned table (Álvaro Herrera) pg_dump failed to emit full dependency information for partitioned tables' foreign keys. This could allow parallel pg_restore to try to recreate a foreign key constraint too soon. In pg_dump, ensure stable output order for similarly-named triggers and row-level-security policy objects (Benjie Gillam) Previously, if two triggers on different tables had the same names, they would be sorted in OID-based order, which is less desirable than sorting them by table name. Likewise for RLS policies. In pg_upgrade, reject tables with columns of type sql_identifier, as that has changed representation in version 12 (Tomas Vondra) Improve pg_upgrade's checks for the use of a data type that has changed representation, such as line (Tomas Vondra) The previous coding could be fooled by cases where the data type of interest underlies a stored column of a domain or composite type. In pg_rewind with the --dry-run option, avoid updating pg_control (Alexey Kondratov) This could lead to failures in subsequent pg_rewind attempts. Fix failure in pg_waldump with the -s option, when a continuation WAL record ends exactly at a page boundary (Andrey Lepikhov) In pg_waldump with the --bkp-details option, avoid emitting extra newlines for WAL records involving full-page writes (Andres Freund) Fix small memory leak in pg_waldump (Andres Freund) Put back pqsignal() as an exported libpq symbol (Tom Lane) This function was removed on the grounds that no clients should be using it, but that turns out to break usage of current libpq with very old versions of psql, and perhaps other applications. Fix configure's test for presence of libperl so that it works on recent Red Hat releases (Tom Lane) Previously, it could fail if the user sets CFLAGS to -O0. Ensure correct code generation for spinlocks on PowerPC (Noah Misch) The previous spinlock coding allowed the compiler to select register zero for use with an assembly instruction that does not accept that register, causing a build failure. We have seen only one long-ago report that matches this bug, but it could cause problems for people trying to build modified PostgreSQL code or use atypical compiler options. On AIX, don't use the compiler option -qsrcmsg (Noah Misch) This avoids an internal compiler error with xlc v16.1.0, with little consequence other than changing the format of compiler error messages. Fix MSVC build process to cope with spaces in the file path of OpenSSL (Andrew Dunstan) 2019-10-03 Major enhancements in PostgreSQL 12 include: General performance improvements, including: Optimizations to space utilization and read/write performance for B-tree indexes Partitioning performance enhancements, including improved query performance on tables with thousands of partitions, improved insertion performance with and , and the ability to execute ALTER TABLE ATTACH PARTITION without blocking queries Automatic (but overridable) inlining of common table expressions (CTEs) Reduction of WAL overhead for creation of GiST, GIN, and SP-GiST indexes Support for covering GiST indexes, via the INCLUDE clause Multi-column most-common-value (MCV) statistics can be defined via , to support better plans for queries that test several non-uniformly-distributed columns Enhancements to administrative functionality, including: REINDEX CONCURRENTLY can rebuild an index without blocking writes to its table can enable/disable page checksums (used for detecting data corruption) in an offline cluster Progress reporting statistics for , , , VACUUM FULL, and Support for the SQL/JSON path language Stored generated columns Nondeterministic ICU collations, enabling case-insensitive and accent-insensitive grouping and ordering New authentication features, including: Encryption of TCP/IP connections when using GSSAPI authentication Discovery of LDAP servers using DNS SRV records Multi-factor authentication, using the clientcert=verify-full option combined with an additional authentication method in pg_hba.conf The above items are explained in more detail in the sections below. A dump/restore using or use of or logical replication is required for those wishing to migrate data from any previous release. See for general information on migrating to new major releases. Version 12 contains a number of changes that may affect compatibility with previous releases. Observe the following incompatibilities: Remove the special behavior of oid columns (Andres Freund, John Naylor) Previously, a normally-invisible oid column could be specified during table creation using WITH OIDS; that ability has been removed. Columns can still be explicitly declared as type oid. Operations on tables that have columns created using WITH OIDS will need adjustment. The system catalogs that previously had hidden oid columns now have ordinary oid columns. Hence, SELECT * will now output those columns, whereas previously they would be displayed only if selected explicitly. Remove data types abstime, reltime, and tinterval (Andres Freund) These are obsoleted by SQL-standard types such as timestamp. Remove the timetravel extension (Andres Freund) Move recovery.conf settings into postgresql.conf (Masao Fujii, Simon Riggs, Abhijit Menon-Sen, Sergei Kornilov) recovery.conf is no longer used, and the server will not start if that file exists. recovery.signal and standby.signal files are now used to switch into non-primary mode. The trigger_file setting has been renamed to . The standby_mode setting has been removed. Do not allow multiple conflicting recovery_target* specifications (Peter Eisentraut) Specifically, only allow one of , , , , and . Previously, multiple different instances of these parameters could be specified, and the last one was honored. Now, only one can be specified, though the same one can be specified multiple times and the last specification is honored. Cause recovery to advance to the latest timeline by default (Peter Eisentraut) Specifically, now defaults to latest. Previously, it defaulted to current. Refactor code for geometric functions and operators (Emre Hasegeli) This could lead to more accurate, but slightly different, results compared to previous releases. Notably, cases involving NaN, underflow, overflow, and division by zero are handled more consistently than before. Improve performance by using a new algorithm for output of real and double precision values (Andrew Gierth) Previously, displayed floating-point values were rounded to 6 (for real) or 15 (for double precision) digits by default, adjusted by the value of . Now, whenever extra_float_digits is more than zero (as it now is by default), only the minimum number of digits required to preserve the exact binary value are output. The behavior is the same as before when extra_float_digits is set to zero or less. Also, formatting of floating-point exponents is now uniform across platforms: two digits are used unless three are necessary. In previous releases, Windows builds always printed three digits. random() and setseed() now behave uniformly across platforms (Tom Lane) The sequence of random() values generated following a setseed() call with a particular seed value is likely to be different now than before. However, it will also be repeatable, which was not previously guaranteed because of interference from other uses of random numbers inside the server. The SQL random() function now has its own private per-session state to forestall that. Change SQL-style substring() to have standard-compliant greediness behavior (Tom Lane) In cases where the pattern can be matched in more than one way, the initial sub-pattern is now treated as matching the least possible amount of text rather than the greatest; for example, a pattern such as %#"aa*#"% now selects the first group of a's from the input, not the last group. Do not pretty-print the result of xpath() or the XMLTABLE construct (Tom Lane) In some cases, these functions would insert extra whitespace (newlines and/or spaces) in nodeset values. This is undesirable since depending on usage, the whitespace might be considered semantically significant. Rename command-line tool pg_verify_checksums to (Michaël Paquier) In , require specification of -f - to send the dump contents to standard output (Euler Taveira) Previously, this happened by default if no destination was specified, but that was deemed to be unfriendly. Disallow non-unique abbreviations in psql's \pset format command (Daniel Vérité) Previously, for example, \pset format a chose aligned; it will now fail since that could equally well mean asciidoc. In new btree indexes, the maximum index entry length is reduced by eight bytes, to improve handling of duplicate entries (Peter Geoghegan) This means that a operation on an index pg_upgrade'd from a previous release could potentially fail. Cause DROP IF EXISTS FUNCTION/PROCEDURE/AGGREGATE/ROUTINE to generate an error if no argument list is supplied and there are multiple matching objects (David Rowley) Also improve the error message in such cases. Split the pg_statistic_ext catalog into two catalogs, and add the pg_stats_ext view of it (Dean Rasheed, Tomas Vondra) This change supports hiding potentially-sensitive statistics data from unprivileged users. Remove obsolete pg_constraint.consrc column (Peter Eisentraut) This column has been deprecated for a long time, because it did not update in response to other catalog changes (such as column renamings). The recommended way to get a text version of a check constraint's expression from pg_constraint is pg_get_expr(conbin, conrelid). pg_get_constraintdef() is also a useful alternative. Remove obsolete pg_attrdef.adsrc column (Peter Eisentraut) This column has been deprecated for a long time, because it did not update in response to other catalog changes (such as column renamings). The recommended way to get a text version of a default-value expression from pg_attrdef is pg_get_expr(adbin, adrelid). Mark table columns of type name as having C collation by default (Tom Lane, Daniel Vérité) The comparison operators for data type name can now use any collation, rather than always using C collation. To preserve the previous semantics of queries, columns of type name are now explicitly marked as having C collation. A side effect of this is that regular-expression operators on name columns will now use the C collation by default, not the database collation, to determine the behavior of locale-dependent regular expression patterns (such as \w). If you want non-C behavior for a regular expression on a name column, attach an explicit COLLATE clause. (For user-defined name columns, another possibility is to specify a different collation at table creation time; but that just moves the non-backwards-compatibility to the comparison operators.) Treat object-name columns in the information_schema views as being of type name, not varchar (Tom Lane) Per the SQL standard, object-name columns in the information_schema views are declared as being of domain type sql_identifier. In PostgreSQL, the underlying catalog columns are really of type name. This change makes sql_identifier be a domain over name, rather than varchar as before. This eliminates a semantic mismatch in comparison and sorting behavior, which can greatly improve the performance of queries on information_schema views that restrict an object-name column. Note however that inequality restrictions, for example SELECT ... FROM information_schema.tables WHERE table_name < 'foo'; will now use C-locale comparison semantics by default, rather than the database's default collation as before. Sorting on these columns will also follow C ordering rules. The previous behavior (and inefficiency) can be enforced by adding a COLLATE "default" clause. Remove the ability to disable dynamic shared memory (Kyotaro Horiguchi) Specifically, can no longer be set to none. Parse libpq integer connection parameters more strictly (Fabien Coelho) In previous releases, using an incorrect integer value for connection parameters connect_timeout, keepalives, keepalives_count, keepalives_idle, keepalives_interval and port resulted in libpq either ignoring those values or failing with incorrect error messages. Below you will find a detailed account of the changes between PostgreSQL 12 and the previous major release. Improve performance of many operations on partitioned tables (Amit Langote, David Rowley, Tom Lane, Álvaro Herrera) Allow tables with thousands of child partitions to be processed efficiently by operations that only affect a small number of partitions. Allow foreign keys to reference partitioned tables (Álvaro Herrera) Improve speed of COPY into partitioned tables (David Rowley) Allow partition bounds to be any expression (Kyotaro Horiguchi, Tom Lane, Amit Langote) Such expressions are evaluated at partitioned-table creation time. Previously, only simple constants were allowed as partition bounds. Allow CREATE TABLE's tablespace specification for a partitioned table to affect the tablespace of its children (David Rowley, Álvaro Herrera) Avoid sorting when partitions are already being scanned in the necessary order (David Rowley) ALTER TABLE ATTACH PARTITION is now performed with reduced locking requirements (Robert Haas) Add partition introspection functions (Michaël Paquier, Álvaro Herrera, Amit Langote) The new function pg_partition_root() returns the top-most parent of a partition tree, pg_partition_ancestors() reports all ancestors of a partition, and pg_partition_tree() displays information about partitions. Include partitioned indexes in the system view pg_indexes (Suraj Kharage) Add psql command \dP to list partitioned tables and indexes (Pavel Stehule) Improve psql \d and \z display of partitioned tables (Pavel Stehule, Michaël Paquier, Álvaro Herrera) Fix bugs that could cause ALTER TABLE DETACH PARTITION to leave behind incorrect dependency state, allowing subsequent operations to misbehave, for example by not dropping a former partition child index when its table is dropped (Tom Lane) Improve performance and space utilization of btree indexes with many duplicates (Peter Geoghegan, Heikki Linnakangas) Previously, duplicate index entries were stored unordered within their duplicate groups. This caused overhead during index inserts, wasted space due to excessive page splits, and it reduced VACUUM's ability to recycle entire pages. Duplicate index entries are now sorted in heap-storage order. Indexes pg_upgrade'd from previous releases will not have these benefits. Allow multi-column btree indexes to be smaller (Peter Geoghegan, Heikki Linnakangas) Internal pages and min/max leaf page indicators now only store index keys until the change key, rather than all indexed keys. This also improves the locality of index access. Indexes pg_upgrade'd from previous releases will not have these benefits. Improve speed of btree index insertions by reducing locking overhead (Alexander Korotkov) Support INCLUDE columns in GiST indexes (Andrey Borodin) Add support for nearest-neighbor (KNN) searches of SP-GiST indexes (Nikita Glukhov, Alexander Korotkov, Vlad Sterzhanov) Reduce the WAL write overhead of GiST, GIN, and SP-GiST index creation (Anastasia Lubennikova, Andrey V. Lepikhov) Allow index-only scans to be more efficient on indexes with many columns (Konstantin Knizhnik) Improve the performance of vacuum scans of GiST indexes (Andrey Borodin, Konstantin Kuznetsov, Heikki Linnakangas) Delete empty leaf pages during GiST VACUUM (Andrey Borodin) Reduce locking requirements for index renaming (Peter Eisentraut) Allow to create most-common-value statistics for multiple columns (Tomas Vondra) This improves optimization for queries that test several columns, requiring an estimate of the combined effect of several WHERE clauses. If the columns are correlated and have non-uniform distributions then multi-column statistics will allow much better estimates. Allow common table expressions (CTEs) to be inlined into the outer query (Andreas Karlsson, Andrew Gierth, David Fetter, Tom Lane) Specifically, CTEs are automatically inlined if they have no side-effects, are not recursive, and are referenced only once in the query. Inlining can be prevented by specifying MATERIALIZED, or forced for multiply-referenced CTEs by specifying NOT MATERIALIZED. Previously, CTEs were never inlined and were always evaluated before the rest of the query. Allow control over when generic plans are used for prepared statements (Pavel Stehule) This is controlled by the server parameter. Improve optimization of partition and UNION ALL queries that have only a single child (David Rowley) Improve processing of domains that have no check constraints (Tom Lane) Domains that are being used purely as type aliases no longer cause optimization difficulties. Pre-evaluate calls of LEAST and GREATEST when their arguments are constants (Vik Fearing) Improve optimizer's ability to verify that partial indexes with IS NOT NULL conditions are usable in queries (Tom Lane, James Coleman) Usability can now be recognized in more cases where the calling query involves casts or large x IN (array) clauses. Compute ANALYZE statistics using the collation defined for each column (Tom Lane) Previously, the database's default collation was used for all statistics. This potentially gives better optimizer behavior for columns with non-default collations. Improve selectivity estimates for inequality comparisons on ctid columns (Edmund Horner) Improve optimization of joins on columns of type tid (Tom Lane) These changes primarily improve the efficiency of self-joins on ctid columns. Fix the leakproofness designations of some btree comparison operators and support functions (Tom Lane) This allows some optimizations that previously would not have been applied in the presence of security barrier views or row-level security. Enable Just-in-Time (JIT) compilation by default, if the server has been built with support for it (Andres Freund) Note that this support is not built by default, but has to be selected explicitly while configuring the build. Speed up keyword lookup (John Naylor, Joerg Sonnenberger, Tom Lane) Improve search performance for multi-byte characters in position() and related functions (Heikki Linnakangas) Allow toasted values to be minimally decompressed (Paul Ramsey) This is useful for routines that only need to examine the initial portion of a toasted field. Allow ALTER TABLE ... SET NOT NULL to avoid unnecessary table scans (Sergei Kornilov) This can be optimized when the table's column constraints can be recognized as disallowing nulls. Allow ALTER TABLE ... SET DATA TYPE changing between timestamp and timestamptz to avoid a table rewrite when the session time zone is UTC (Noah Misch) In the UTC time zone, these two data types are binary compatible. Improve speed in converting strings to int2 or int4 integers (Andres Freund) Allow parallelized queries when in SERIALIZABLE isolation mode (Thomas Munro) Previously, parallelism was disabled when in this mode. Use pread() and pwrite() for random I/O (Oskari Saarenmaa, Thomas Munro) This reduces the number of system calls required for I/O. Improve the speed of setting the process title on FreeBSD (Thomas Munro) Allow logging of statements from only a percentage of transactions (Adrien Nayrat) The parameter controls this. Add progress reporting to CREATE INDEX and REINDEX operations (Álvaro Herrera, Peter Eisentraut) Progress is reported in the pg_stat_progress_create_index system view. Add progress reporting to CLUSTER and VACUUM FULL (Tatsuro Yamada) Progress is reported in the pg_stat_progress_cluster system view. Add progress reporting to (Michael Banck, Bernd Helmle) This is enabled with the option --progress. Add counter of checksum failures to pg_stat_database (Magnus Hagander) Add tracking of global objects in system view pg_stat_database (Julien Rouhaud) Global objects are shown with a pg_stat_database.datid value of zero. Add the ability to list the contents of the archive directory (Christoph Moench-Tegeder) The function is pg_ls_archive_statusdir(). Add the ability to list the contents of temporary directories (Nathan Bossart) The function, pg_ls_tmpdir(), optionally allows specification of a tablespace. Add information about the client certificate to the system view pg_stat_ssl (Peter Eisentraut) The new columns are client_serial and issuer_dn. Column clientdn has been renamed to client_dn for clarity. Restrict visibility of rows in pg_stat_ssl for unprivileged users (Peter Eisentraut) At server start, emit a log message including the server version number (Christoph Berg) Prevent logging incomplete startup packet if a new connection is immediately closed (Tom Lane) This avoids log spam from certain forms of monitoring. Include the , if set, in log messages (Don Seiler) Make the walreceiver set its application name to the cluster name, if set (Peter Eisentraut) Add the timestamp of the last received standby message to pg_stat_replication (Lim Myungkyu) Add a wait event for fsync of WAL segments (Konstantin Knizhnik) Add GSSAPI encryption support (Robbie Harwood, Stephen Frost) This feature allows TCP/IP connections to be encrypted when using GSSAPI authentication, without having to set up a separate encryption facility such as SSL. In support of this, add hostgssenc and hostnogssenc record types in pg_hba.conf for selecting connections that do or do not use GSSAPI encryption, corresponding to the existing hostssl and hostnossl record types. There is also a new libpq option, and a system view. Allow the clientcert pg_hba.conf option to check that the database user name matches the client certificate's common name (Julian Markwort, Marius Timmer) This new check is enabled with clientcert=verify-full. Allow discovery of an LDAP server using DNS SRV records (Thomas Munro) This avoids the requirement of specifying ldapserver. It is only supported if PostgreSQL is compiled with OpenLDAP. Add ability to enable/disable cluster checksums using (Michael Banck, Michaël Paquier) The cluster must be shut down for these operations. Reduce the default value of to 2ms (Tom Lane) This allows autovacuum operations to proceed faster by default. Allow to specify sub-millisecond delays, by accepting fractional values (Tom Lane) Allow time-based server parameters to use units of microseconds (us) (Tom Lane) Allow fractional input for integer server parameters (Tom Lane) For example, SET work_mem = '30.1GB' is now allowed, even though work_mem is an integer parameter. The value will be rounded to an integer after any required units conversion. Allow units to be defined for floating-point server parameters (Tom Lane) Add and server parameters to control WAL file recycling (Jerry Jelinek) Avoiding file recycling can be beneficial on copy-on-write file systems like ZFS. Add server parameter to control the server's TCP timeout (Ryohei Nagaura) Allow control of the minimum and maximum SSL protocol versions (Peter Eisentraut) The server parameters are and . Add server parameter to report the SSL library version used by the server (Peter Eisentraut) Add server parameter to control the type of shared memory to use (Andres Freund) This allows selection of System V shared memory, if desired. Allow some recovery parameters to be changed with reload (Peter Eisentraut) These parameters are , , , and . Allow the streaming replication timeout () to be set per connection (Takayuki Tsunakawa) Previously, this could only be set cluster-wide. Add function pg_promote() to promote standbys to primaries (Laurenz Albe, Michaël Paquier) Previously, this operation was only possible by using or creating a trigger file. Allow replication slots to be copied (Masahiko Sawada) The functions for this are pg_copy_physical_replication_slot() and pg_copy_logical_replication_slot(). Make not count as part of (Alexander Kukushkin) Add an explicit value of current for (Peter Eisentraut) Make recovery fail if a two-phase transaction status file is corrupt (Michaël Paquier) Previously, a warning was logged and recovery continued, allowing the transaction to be lost. Add CONCURRENTLY option to allow reindexing without locking out writes (Michaël Paquier, Andreas Karlsson, Peter Eisentraut) This is also controlled by the application's --concurrently option. Add support for generated columns (Peter Eisentraut) The content of generated columns are computed from expressions (including references to other columns in the same table) rather than being specified by INSERT or UPDATE commands. Add a WHERE clause to COPY FROM to control which rows are accepted (Surafel Temesgen) This provides a simple way to filter incoming data. Allow enumerated values to be added more flexibly (Andrew Dunstan, Tom Lane, Thomas Munro) Previously, ALTER TYPE ... ADD VALUE could not be called in a transaction block, unless it was part of the same transaction that created the enumerated type. Now it can be called in a later transaction, so long as the new enumerated value is not referenced until after it is committed. Add commands to end a transaction and start a new one (Peter Eisentraut) The commands are COMMIT AND CHAIN and ROLLBACK AND CHAIN. Add and CREATE TABLE options to prevent VACUUM from truncating trailing empty pages (Takayuki Tsunakawa) These options are vacuum_truncate and toast.vacuum_truncate. Use of these options reduces VACUUM's locking requirements, but prevents returning disk space to the operating system. Allow VACUUM to skip index cleanup (Masahiko Sawada) This change adds a VACUUM command option INDEX_CLEANUP as well as a table storage option vacuum_index_cleanup. Use of this option reduces the ability to reclaim space and can lead to index bloat, but it is helpful when the main goal is to freeze old tuples. Add the ability to skip VACUUM and ANALYZE operations on tables that cannot be locked immediately (Nathan Bossart) This option is called SKIP_LOCKED. Allow VACUUM and ANALYZE to take optional Boolean argument specifications (Masahiko Sawada) Prevent , VACUUM and ANALYZE from requesting a lock on tables for which the user lacks permission (Michaël Paquier) This prevents unauthorized locking, which could interfere with user queries. Add option SETTINGS to output non-default optimizer settings (Tomas Vondra) This output can also be obtained when using by setting auto_explain.log_settings. Add OR REPLACE option to (Andrew Gierth) Allow modifications of system catalogs' options using (Peter Eisentraut) Modifications of catalogs' reloptions and autovacuum settings are now supported. (Setting is still required.) Use all key columns' names when selecting default constraint names for foreign keys (Peter Eisentraut) Previously, only the first column name was included in the constraint name, resulting in ambiguity for multi-column foreign keys. Update assorted knowledge about Unicode to match Unicode 12.1.0 (Peter Eisentraut) This fixes, for example, cases where psql would misformat output involving combining characters. Update Snowball stemmer dictionaries with support for new languages (Arthur Zakirov) This adds word stemming support for Arabic, Indonesian, Irish, Lithuanian, Nepali, and Tamil to full text search. Allow creation of collations that report string equality for strings that are not bit-wise equal (Peter Eisentraut) This feature supports nondeterministic collations that can define case- and accent-agnostic equality comparisons. Thus, for example, a case-insensitive uniqueness constraint on a text column can be made more easily than before. This is only supported for ICU collations. Add support for ICU collation attributes on older ICU versions (Peter Eisentraut) This allows customization of the collation rules in a consistent way across all ICU versions. Allow data type name to more seamlessly be compared to other text types (Tom Lane) Type name now behaves much like a domain over type text that has default collation C. This allows cross-type comparisons to be processed more efficiently. Add support for the SQL/JSON path language (Nikita Glukhov, Teodor Sigaev, Alexander Korotkov, Oleg Bartunov, Liudmila Mantrova) This allows execution of complex queries on JSON values using an SQL-standard language. Add support for hyperbolic functions (Lætitia Avrot) Also add log10() as an alias for log(), for standards compliance. Improve the accuracy of statistical aggregates like variance() by using more precise algorithms (Dean Rasheed) Allow date_trunc() to have an additional argument to control the time zone (Vik Fearing, Tom Lane) This is faster and simpler than using the AT TIME ZONE clause. Adjust to_timestamp()/to_date() functions to be more forgiving of template mismatches (Artur Zakirov, Alexander Korotkov, Liudmila Mantrova) This new behavior more closely matches the Oracle functions of the same name. Fix assorted bugs in XML functions (Pavel Stehule, Markus Winand, Chapman Flack) Specifically, in XMLTABLE, xpath(), and xmlexists(), fix some cases where nothing was output for a node, or an unexpected error was thrown, or necessary escaping of XML special characters was omitted. Allow the BY VALUE clause in XMLEXISTS and XMLTABLE (Chapman Flack) This SQL-standard clause has no effect in PostgreSQL's implementation, but it was unnecessarily being rejected. Prevent current_schema() and current_schemas() from being run by parallel workers, as they are not parallel-safe (Michaël Paquier) Allow RECORD and RECORD[] to be used as column types in a query's column definition list for a table function that is declared to return RECORD (Elvis Pranskevichus) Allow SQL commands and variables with the same names as those commands to be used in the same PL/pgSQL function (Tom Lane) For example, allow a variable called comment to exist in a function that calls the COMMENT SQL command. Previously this combination caused a parse error. Add new optional warning and error checks to PL/pgSQL (Pavel Stehule) The new checks allow for run-time validation of INTO column counts and single-row results. Add connection parameter to control libpq's TCP timeout (Ryohei Nagaura) Allow libpq (and thus psql) to report only the SQLSTATE value in error messages (Didier Gautheron) Add libpq function PQresultMemorySize() to report the memory used by a query result (Lars Kanis, Tom Lane) Remove the no-display/debug flag from libpq's options connection parameter (Peter Eisentraut) This allows this parameter to be set by postgres_fdw. Allow to create variables of data type bytea (Ryo Matsumura) This allows ECPG clients to interact with bytea data directly, rather than using an encoded form. Add PREPARE AS support to ECPG (Ryo Matsumura) Allow to select tables for vacuum based on their wraparound horizon (Nathan Bossart) The options are --min-xid-age and --min-mxid-age. Allow vacuumdb to disable waiting for locks or skipping all-visible pages (Nathan Bossart) The options are --skip-locked and --disable-page-skipping. Add colorization to the output of command-line utilities (Peter Eisentraut) This is enabled by setting the environment variable PG_COLOR to always or auto. The specific colors used can be adjusted by setting the environment variable PG_COLORS, using ANSI escape codes for colors. For example, the default behavior is equivalent to PG_COLORS="error=01;31:warning=01;35:locus=01". Add CSV table output mode in psql (Daniel Vérité) This is controlled by \pset format csv or the command-line --csv option. Show the manual page URL in psql's \help output for a SQL command (Peter Eisentraut) Display the IP address in psql's \conninfo (Fabien Coelho) Improve tab completion of CREATE TABLE, CREATE TRIGGER, CREATE EVENT TRIGGER, ANALYZE, EXPLAIN, VACUUM, ALTER TABLE, ALTER INDEX, ALTER DATABASE, and ALTER INDEX ALTER COLUMN (Dagfinn Ilmari Mannsåker, Tatsuro Yamada, Michaël Paquier, Tom Lane, Justin Pryzby) Allow values produced by queries to be assigned to pgbench variables (Fabien Coelho, Álvaro Herrera) The command for this is \gset. Improve precision of pgbench's --rate option (Tom Lane) Improve pgbench's error reporting with clearer messages and return codes (Peter Eisentraut) Allow control of log file rotation via (Kyotaro Horiguchi, Alexander Kuzmenkov, Alexander Korotkov) Previously, this was only possible via an SQL function or a process signal. Properly detach the new server process during pg_ctl start (Paul Guo) This prevents the server from being shut down if the shell script that invoked pg_ctl is interrupted later. Allow to use the file system's cloning feature, if there is one (Peter Eisentraut) The --clone option has the advantages of --link, while preventing the old cluster from being changed after the new cluster has started. Allow specification of the socket directory to use in pg_upgrade (Daniel Gustafsson) This is controlled by --socketdir; the default is the current directory. Allow to disable fsync operations (Michaël Paquier) This is controlled by the --no-sync option. Allow to disable fsync operations (Michaël Paquier) Fix to report accurate open_datasync durations on Windows (Laurenz Albe) When pg_dump emits data with INSERT commands rather than COPY, allow more than one data row to be included in each INSERT (Surafel Temesgen, David Rowley) The option controlling this is --rows-per-insert. Allow pg_dump to emit INSERT ... ON CONFLICT DO NOTHING (Surafel Temesgen) This avoids conflict failures during restore. The option is --on-conflict-do-nothing. Decouple the order of operations in a parallel pg_dump from the order used by a subsequent parallel pg_restore (Tom Lane) This allows pg_restore to perform more-fully-parallelized parallel restores, especially in cases where the original dump was not done in parallel. Scheduling of a parallel pg_dump is also somewhat improved. Allow the setting to be specified for pg_dump and pg_dumpall (Andrew Dunstan) This is primarily useful for making dumps that are exactly comparable across different source server versions. It is not recommended for normal use, as it may result in loss of precision when the dump is restored. Add --exclude-database option to pg_dumpall (Andrew Dunstan) Add command to create new table types (Andres Freund, Haribabu Kommi, Álvaro Herrera, Alexander Korotkov, Dmitry Dolgov) This enables the development of new table access methods, which can optimize storage for different use cases. The existing heap access method remains the default. Add planner support function interfaces to improve optimizer estimates, inlining, and indexing for functions (Tom Lane) This allows extensions to create planner support functions that can provide function-specific selectivity, cost, and row-count estimates that can depend on the function's arguments. Support functions can also supply simplified representations and index conditions, greatly expanding optimization possibilities. Simplify renumbering manually-assigned OIDs, and establish a new project policy for management of such OIDs (John Naylor, Tom Lane) Patches that manually assign OIDs for new built-in objects (such as new functions) should now randomly choose OIDs in the range 8000—9999. At the end of a development cycle, the OIDs used by committed patches will be renumbered down to lower numbers, currently somewhere in the 4xxx range, using the new renumber_oids.pl script. This approach should greatly reduce the odds of OID collisions between different in-process patches. While there is no specific policy reserving any OIDs for external use, it is recommended that forks and other projects needing private manually-assigned OIDs use numbers in the high 7xxx range. This will avoid conflicts with recently-merged patches, and it should be a long time before the core project reaches that range. Build Cygwin binaries using dynamic instead of static libraries (Marco Atzeri) Remove configure switch --disable-strong-random (Michaël Paquier) A strong random-number source is now required. printf-family functions, as well as strerror and strerror_r, now behave uniformly across platforms within Postgres code (Tom Lane) Notably, printf understands %m everywhere; on Windows, strerror copes with Winsock error codes (it used to do so in backend but not frontend code); and strerror_r always follows the GNU return convention. Require a C99-compliant compiler, and MSVC 2013 or later on Windows (Andres Freund) Use pandoc, not lynx, for generating plain-text documentation output files (Peter Eisentraut) This affects only the INSTALL file generated during make dist and the seldom-used plain-text postgres.txt output file. Pandoc produces better output than lynx and avoids some locale/encoding issues. Pandoc version 1.13 or later is required. Support use of images in the PostgreSQL documentation (Jürgen Purtz) Allow ORDER BY sorts and LIMIT clauses to be pushed to foreign servers in more cases (Etsuro Fujita) Improve optimizer cost accounting for postgres_fdw queries (Etsuro Fujita) Properly honor WITH CHECK OPTION on views that reference postgres_fdw tables (Etsuro Fujita) While CHECK OPTIONs on postgres_fdw tables are ignored (because the reference is foreign), views on such tables are considered local, so this change enforces CHECK OPTIONs on them. Previously, only INSERTs and UPDATEs with RETURNING clauses that returned CHECK OPTION values were validated. Allow pg_stat_statements_reset() to be more granular (Haribabu Kommi, Amit Kapila) The function now allows reset of statistics for specific databases, users, and queries. Allow control of the log level (Tom Dunstan, Andrew Dunstan) The default is LOG. Update rules with new punctuation and symbols (Hugh Ranalli, Michaël Paquier) Allow unaccent to handle some accents encoded as combining characters (Hugh Ranalli) Allow unaccent to remove accents from Greek characters (Tasos Maschalidis) Add a parameter to 's bt_index_parent_check() function to check each index tuple from the root of the tree (Peter Geoghegan) Improve and option handling to match other commands (Tatsuro Yamada) The following individuals (in alphabetical order) have contributed to this release as patch authors, committers, reviewers, testers, or reporters of issues. Abhijit Menon-Sen Achilleas Mantzios Adam Berlin Adam Bielanski Aditya Toshniwal Adrien Nayrat Alan Jackson Albert Schabhuetl Aleksander Alekseev Alex Aktsipetrov Alex Kliukin Alex Macy Alexander Korotkov Alexander Kukushkin Alexander Kuzmenkov Alexander Lakhin Alexandra Ryzhevich Alexey Bashtanov Alexey Ermakov Alexey Kondratov Alexey Kryuchkov Alexey Stepanov Allison Kaptur Álvaro Herrera Alyssa Ross Amit Kapila Amit Khandekar Amit Langote Amul Sul Anastasia Lubennikova André Hänsel Andrea Gelmini Andreas Joseph Krogh Andreas Karlsson Andreas Kunert Andreas Scherbaum Andreas Seltenreich Andrei Yahorau Andres Freund Andrew Dunstan Andrew Fletcher Andrew Gierth Andrew Krasichkov Andrey Borodin Andrey Klychkov Andrey Lepikhov Andy Abelisto Anthony Greene Anthony Skorski Antonin Houska Arne Roland Arseny Sher Arthur Zakirov Ash Marath Ashutosh Bapat Ashutosh Sharma Ashwin Agrawal Aya Iwata Bartosz Polnik Basil Bourque Bernd Helmle Brad DeJong Brigitte Blanc-Lafay Bruce Klein Bruce Momjian Bruno Wolff Chapman Flack Chen Huajun Chris Travers Chris Wilson Christian Hofstaedtler Christoph Berg Christoph Moench-Tegeder Clemens Ladisch Colm McHugh Corey Huinker Craig Ringer Dagfinn Ilmari Mannsåker Daisuke Higuchi Daniel Fiori Daniel Gustafsson Daniel Vérité Daniel Westermann Daniel Wilches Darafei Praliaskouski Daryl Waycott Dave Cramer David Binderman David Fetter David G. Johnston David Rowley David Steele Davy Machado Dean Rasheed Derek Hans Derek Nelson Devrim Gündüz Dian Fay Didier Gautheron Dilip Kumar Dmitry Dolgov Dmitry Marakasov Dmitry Molotkov Dmitry Shalashov Don Seiler Donald Dong Doug Rady Edmund Horner Eduards Bezverhijs Elvis Pranskevichus Emanuel Araújo Emre Hasegeli Eric Cyr Erik Rijkers Ertugrul Kahveci Etsuro Fujita Eugen Konkov Euler Taveira Fabien Coelho Fabrízio de Royes Mello Feike Steenbergen Filip Rembialkowski Gaby Schilders Geert Lobbestael George Tarasov Georgios Kokolatos Gianni Ciolli Gilles Darold Greg Stark Grigory Smolkin Guillaume Lelarge Gunnlaugur Thor Briem Gurjeet Singh Hadi Moshayedi Hailong Li Hans Buschmann Haribabu Kommi Haruka Takatsuka Hayato Kuroda Heikki Linnakangas Hironobu Suzuki Hubert Lubaczewski Hugh Ranalli Ian Barwick Ibrar Ahmed Ildar Musin Insung Moon Ioseph Kim Isaac Morland Ivan Panchenko Jack Kelly Jacob Champion Jaime Casanova Jakob Egger Jakub Glapa Jakub Janecek James Coleman James Inform James Robinson James Sewell James Tomson Jan Chochol Jaroslav Sivy Jean-Christophe Arnu Jean-Marc Voillequin Jean-Pierre Pelletier Jeevan Chalke Jeevan Ladhe Jeff Davis Jeff Janes Jeremy Evans Jeremy Schneider Jeremy Smith Jerry Jelinek Jesper Pedersen Jianing Yang Jie Zhang Jim Nasby Jimmy Yih Joe Conway Joe Wildish Joerg Sonnenberger John Klann John Naylor Jonah Harris Jonathan S. Katz Jorge Gustavo Rocha José Arthur Benetasso Villanova Joshua D. Drake Juan José Santamaría Flecha Julian Hsiao Julian Markwort Julian Schauder Julien Rouhaud Jürgen Purtz Jürgen Strobel Justin Pryzby Kaiting Chen Karen Huddleston Karl Czajkowski Karl O. Pinc Keiichi Hirobe Keith Fiske Ken Tanzer Kenji Uno Kevin Grittner Kevin Hale Boyes Kieran McCusker Kirk Jamison Kohei KaiGai Konstantin Knizhnik Konstantin Kuznetsov Kristjan Tammekivi Kuntal Ghosh Kyle Samson Kyotaro Horiguchi Lætitia Avrot Lars Kanis Laurenz Albe Lim Myungkyu Liu Huailing Liudmila Mantrova Lloyd Albin Luca Ferrari Luis M. Carril Lukas Eder Lukas Fittl Madelaine Thibaut Madeleine Thompson Magnus Hagander Mahendra Singh Mai Peng Maksim Milyutin Maksym Boguk Malthe Borch Manuel Rigger Marco Atzeri Marco Slot Marina Polyakova Mario De Frutos Dieguez Marius Timmer Mark Chambers Mark Dilger Marko Tiikkaja Markus Winand Martín Marqués Masahiko Sawada Masao Fujii Mateusz Guzik Mathias Brossard Matt Williams Matthias Otterbach Matvey Arye Melanie Plageman Mi Tar Michael Banck Michael Davidson Michael Meskes Michael Paquier Michael Vitale Michel Pelletier Mikalai Keida Mike Palmiotto Mithun Cy Morgan Owens Murat Kabilov Nathan Bossart Nawaz Ahmed Neeraj Kumar Nick Barnes Nico Williams Nikita Glukhov Nikolay Shaplov Ning Yu Nishant Fnu Noah Misch Norbert Benkocs Noriyoshi Shinoda Oleg Bartunov Oleg Samoilov Oleksii Kliukin Ondrej Bouda Oskari Saarenmaa Pan Bian Patrick Francelle Patrick McHardy Paul A. Jungwirth Paul Bonaud Paul Guo Paul Martinez Paul Ramsey Paul Schaap Paul van der Linden Pavan Deolasee Pavel Oskin Pavel Raiskup Pavel Stehule Peifeng Qiu Peter Billen Peter Eisentraut Peter Geoghegan Peter Neave Petr Fedorov Petr Jelínek Petr Slavov Petru-Florin Mihancea Phil Bayer Phil Florent Philip Dubé Pierre Ducroquet Piotr Gabriel Kosinski Piotr Stefaniak Piotr Wlodarczyk Prabhat Sahu Quentin Rameau Rafael Castro Rafia Sabih Rahila Syed Rajkumar Raghuwanshi Rares Salcudean Raúl Marín Rodríguez Regina Obe Renaud Navarro Richard Guo Rick Otten Rikard Falkeborn RK Korlapati Robbie Harwood Robert Haas Robert Treat Robert Vollmert Roger Curley Roman Zharkov Ronan Dunklau Rui Hai Jiang Rushabh Lathia Ryan Lambert Ryo Matsumura Ryohei Nagaura Ryohei Takahashi Samuel Williams Sand Stone Sanyo Capobiango Satoru Koizumi Sean Johnston Serge Latyntsev Sergei Kornilov Sergey Pashkov Sergio Conde Gómez Shawn Debnath Shay Rojansky Sho Kato Shohei Mochizuki Shouyu Luo Simon Riggs Sivasubramanian Ramasubramanian Slawomir Chodnicki Stas Kelvish Stefan Kadow Stepan Yankevych Stephen Amell Stephen Frost Steve Rogerson Steve Singer Steven Winfield Surafel Temesgen Suraj Kharage Suresh Kumar R Takayuki Tsunakawa Takeshi Ideriha Takuma Hoshiai Tasos Maschalidis Tatsuo Ishii Tatsuro Yamada Teodor Sigaev Thom Brown Thomas Munro Thomas Poty Tillmann Schulz Tim Möhlmann Timur Birsh Tobias Bussmann Tom Cassidy Tom Dunstan Tom Gottfried Tom Lane Tomas Vondra Tushar Ahuja Ulf Adams Vaishnavi Prabakaran Victor Petrovykh Victor Wagner Victor Yegorov Vijaykumar Jain Vik Fearing Vlad Sterzhanov Vladimir Baranoff Vladimir Kriukov Wu Fei Yaroslav Schekin Yi Huang Yoshikazu Imai Yugo Nagata Yulian Khodorkovskiy Yuming Wang YunQiang Su Yuri Kurenkov Yusuke Egashira Yuzuko Hosoya Zhou Digoal