Upgrading from 9.6.10 to 9.6.21 gives you 2.5 years worth of fixes (400 of them)

List of changes:

• ⇑ Upgrade to 9.6.11 released on 2018-11-08 - docs

  • Fix corner-case failures in has_foo_privilege() family of functions (Tom Lane)

    Return NULL rather than throwing an error when an invalid object OID is provided. Some of these functions got that right already, but not all. has_column_privilege() was additionally capable of crashing on some platforms.

  • Avoid O(N^2) slowdown in regular expression match/split functions on long strings (Andrew Gierth)

  • Fix parsing of standard multi-character operators that are immediately followed by a comment or + or - (Andrew Gierth)

    This oversight could lead to parse errors, or to incorrect assignment of precedence.

  • Avoid O(N^3) slowdown in lexer for long strings of + or - characters (Andrew Gierth)

  • Fix mis-execution of SubPlans when the outer query is being scanned backwards (Andrew Gierth)

  • Fix failure of UPDATE/DELETE ... WHERE CURRENT OF ... after rewinding the referenced cursor (Tom Lane)

    A cursor that scans multiple relations (particularly an inheritance tree) could produce wrong behavior if rewound to an earlier relation.

  • Fix EvalPlanQual to handle conditionally-executed InitPlans properly (Andrew Gierth, Tom Lane)

    This resulted in hard-to-reproduce crashes or wrong answers in concurrent updates, if they contained code such as an uncorrelated sub-SELECT inside a CASE construct.

  • Fix character-class checks to not fail on Windows for Unicode characters above U+FFFF (Tom Lane, Kenji Uno)

    This bug affected full-text-search operations, as well as contrib/ltree and contrib/pg_trgm.

  • Disallow pushing sub-SELECTs containing window functions, LIMIT, or OFFSET to parallel workers (Amit Kapila)

    Such cases could result in inconsistent behavior due to different workers getting different answers, as a result of indeterminacy due to row-ordering variations.

  • Ensure that sequences owned by a foreign table are processed by ALTER OWNER on the table (Peter Eisentraut)

    The ownership change should propagate to such sequences as well, but this was missed for foreign tables.

  • Ensure that the server will process already-received NOTIFY and SIGTERM interrupts before waiting for client input (Jeff Janes, Tom Lane)

  • Fix over-allocation of space for array_out()'s result string (Keiichi Hirobe)

  • Fix memory leak in repeated SP-GiST index scans (Tom Lane)

    This is only known to amount to anything significant in cases where an exclusion constraint using SP-GiST receives many new index entries in a single command.

  • Ensure that ApplyLogicalMappingFile() closes the mapping file when done with it (Tomas Vondra)

    Previously, the file descriptor was leaked, eventually resulting in failures during logical decoding.

  • Fix logical decoding to handle cases where a mapped catalog table is repeatedly rewritten, e.g. by VACUUM FULL (Andres Freund)

  • Prevent starting the server with wal_level set to too low a value to support an existing replication slot (Andres Freund)

  • Avoid crash if a utility command causes infinite recursion (Tom Lane)

  • When initializing a hot standby, cope with duplicate XIDs caused by two-phase transactions on the master (Michael Paquier, Konstantin Knizhnik)

  • Fix event triggers to handle nested ALTER TABLE commands (Michael Paquier, Álvaro Herrera)

  • Propagate parent process's transaction and statement start timestamps to parallel workers (Konstantin Knizhnik)

    This prevents misbehavior of functions such as transaction_timestamp() when executed in a worker.

  • Fix transfer of expanded datums to parallel workers so that alignment is preserved, preventing crashes on alignment-picky platforms (Tom Lane, Amit Kapila)

  • Fix WAL file recycling logic to work correctly on standby servers (Michael Paquier)

    Depending on the setting of archive_mode, a standby might fail to remove some WAL files that could be removed.

  • Fix handling of commit-timestamp tracking during recovery (Masahiko Sawada, Michael Paquier)

    If commit timestamp tracking has been turned on or off, recovery might fail due to trying to fetch the commit timestamp for a transaction that did not record it.

  • Randomize the random() seed in bootstrap and standalone backends, and in initdb (Noah Misch)

    The main practical effect of this change is that it avoids a scenario where initdb might mistakenly conclude that POSIX shared memory is not available, due to name collisions caused by always using the same random seed.

  • Allow DSM allocation to be interrupted (Chris Travers)

  • Avoid failure in a parallel worker when loading an extension that tries to access system caches within its init function (Thomas Munro)

    We don't consider that to be good extension coding practice, but it mostly worked before parallel query, so continue to support it for now.

  • Properly handle turning full_page_writes on dynamically (Kyotaro Horiguchi)

  • Fix possible crash due to double free() during SP-GiST rescan (Andrew Gierth)

  • Avoid possible buffer overrun when replaying GIN page recompression from WAL (Alexander Korotkov, Sivasubramanian Ramasubramanian)

  • Fix missed fsync of a replication slot's directory (Konstantin Knizhnik, Michael Paquier)

  • Fix unexpected timeouts when using wal_sender_timeout on a slow server (Noah Misch)

  • Ensure that hot standby processes use the correct WAL consistency point (Alexander Kukushkin, Michael Paquier)

    This prevents possible misbehavior just after a standby server has reached a consistent database state during WAL replay.

  • Ensure background workers are stopped properly when the postmaster receives a fast-shutdown request before completing database startup (Alexander Kukushkin)

  • Update the free space map during WAL replay of page all-visible/frozen flag changes (Álvaro Herrera)

    Previously we were not careful about this, reasoning that the FSM is not critical data anyway. However, if it's sufficiently out of date, that can result in significant performance degradation after a standby has been promoted to primary. The FSM will eventually be healed by updates, but we'd like it to be good sooner, so work harder at maintaining it during WAL replay.

  • Avoid premature release of parallel-query resources when query end or tuple count limit is reached (Amit Kapila)

    It's only okay to shut down the executor at this point if the caller cannot demand backwards scan afterwards.

  • Don't run atexit callbacks when servicing SIGQUIT (Heikki Linnakangas)

  • Don't record foreign-server user mappings as members of extensions (Tom Lane)

    If CREATE USER MAPPING is executed in an extension script, an extension dependency was created for the user mapping, which is unexpected. Roles can't be extension members, so user mappings shouldn't be either.

  • Make syslogger more robust against failures in opening CSV log files (Tom Lane)

  • Fix psql, as well as documentation examples, to call PQconsumeInput() before each PQnotifies() call (Tom Lane)

    This fixes cases in which psql would not report receipt of a NOTIFY message until after the next command.

  • Fix possible inconsistency in pg_dump's sorting of dissimilar object names (Jacob Champion)

  • Ensure that pg_restore will schema-qualify the table name when emitting DISABLE/ENABLE TRIGGER commands (Tom Lane)

    This avoids failures due to the new policy of running restores with restrictive search path.

  • Fix pg_upgrade to handle event triggers in extensions correctly (Haribabu Kommi)

    pg_upgrade failed to preserve an event trigger's extension-membership status.

  • Fix pg_upgrade's cluster state check to work correctly on a standby server (Bruce Momjian)

  • Enforce type cube's dimension limit in all contrib/cube functions (Andrey Borodin)

    Previously, some cube-related functions could construct values that would be rejected by cube_in(), leading to dump/reload failures.

  • In contrib/postgres_fdw, don't try to ship a variable-free ORDER BY clause to the remote server (Andrew Gierth)

  • Fix contrib/unaccent's unaccent() function to use the unaccent text search dictionary that is in the same schema as the function (Tom Lane)

    Previously it tried to look up the dictionary using the search path, which could fail if the search path has a restrictive value.

  • Fix build problems on macOS 10.14 (Mojave) (Tom Lane)

    Adjust configure to add an -isysroot switch to CPPFLAGS; without this, PL/Perl and PL/Tcl fail to configure or build on macOS 10.14. The specific sysroot used can be overridden at configure time or build time by setting the PG_SYSROOT variable in the arguments of configure or make.

    It is now recommended that Perl-related extensions write $(perl_includespec) rather than -I$(perl_archlibexp)/CORE in their compiler flags. The latter continues to work on most platforms, but not recent macOS.

    Also, it should no longer be necessary to specify --with-tclconfig manually to get PL/Tcl to build on recent macOS releases.

  • Fix MSVC build and regression-test scripts to work on recent Perl versions (Andrew Dunstan)

    Perl no longer includes the current directory in its search path by default; work around that.

  • On Windows, allow the regression tests to be run by an Administrator account (Andrew Dunstan)

    To do this safely, pg_regress now gives up any such privileges at startup.

  • Allow btree comparison functions to return INT_MIN (Tom Lane)

    Up to now, we've forbidden datatype-specific comparison functions from returning INT_MIN, which allows callers to invert the sort order just by negating the comparison result. However, this was never safe for comparison functions that directly return the result of memcmp(), strcmp(), etc, as POSIX doesn't place any such restriction on those functions. At least some recent versions of memcmp() can return INT_MIN, causing incorrect sort ordering. Hence, we've removed this restriction. Callers must now use the INVERT_COMPARE_RESULT() macro if they wish to invert the sort order.

  • Fix recursion hazard in shared-invalidation message processing (Tom Lane)

    This error could, for example, result in failure to access a system catalog or index that had just been processed by VACUUM FULL.

    This change adds a new result code for LockAcquire, which might possibly affect external callers of that function, though only very unusual usage patterns would have an issue with it. The API of LockAcquireExtended is also changed.

  • Save and restore SPI's global variables during SPI_connect() and SPI_finish() (Chapman Flack, Tom Lane)

    This prevents possible interference when one SPI-using function calls another.

  • Avoid using potentially-under-aligned page buffers (Tom Lane)

    Invent new union types PGAlignedBlock and PGAlignedXLogBlock, and use these in place of plain char arrays, ensuring that the compiler can't place the buffer at a misaligned start address. This fixes potential core dumps on alignment-picky platforms, and may improve performance even on platforms that allow misalignment.

  • Make src/port/snprintf.c follow the C99 standard's definition of snprintf()'s result value (Tom Lane)

    On platforms where this code is used (mostly Windows), its pre-C99 behavior could lead to failure to detect buffer overrun, if the calling code assumed C99 semantics.

  • When building on i386 with the clang compiler, require -msse2 to be used (Andres Freund)

    This avoids problems with missed floating point overflow checks.

  • Fix configure's detection of the result type of strerror_r() (Tom Lane)

    The previous coding got the wrong answer when building with icc on Linux (and perhaps in other cases), leading to libpq not returning useful error messages for system-reported errors.

  • Update time zone data files to tzdata release 2018g for DST law changes in Chile, Fiji, Morocco, and Russia (Volgograd), plus historical corrections for China, Hawaii, Japan, Macau, and North Korea.

• ⇑ Upgrade to 9.6.12 released on 2019-02-14 - docs

  • By default, panic instead of retrying after fsync() failure, to avoid possible data corruption (Craig Ringer, Thomas Munro)

    Some popular operating systems discard kernel data buffers when unable to write them out, reporting this as fsync() failure. If we reissue the fsync() request it will succeed, but in fact the data has been lost, so continuing risks database corruption. By raising a panic condition instead, we can replay from WAL, which may contain the only remaining copy of the data in such a situation. While this is surely ugly and inefficient, there are few alternatives, and fortunately the case happens very rarely.

    A new server parameter data_sync_retry has been added to control this; if you are certain that your kernel does not discard dirty data buffers in such scenarios, you can set data_sync_retry to on to restore the old behavior.

  • Include each major release branch's release notes in the documentation for only that branch, rather than that branch and all later ones (Tom Lane)

    The duplication induced by the previous policy was getting out of hand. Our plan is to provide a full archive of release notes on the project's web site, but not duplicate it within each release.

  • Avoid possible deadlock when acquiring multiple buffer locks (Nishant Fnu)

  • Avoid deadlock between hot-standby queries and replay of GIN index page deletion (Alexander Korotkov)

  • Fix possible crashes in logical replication when index expressions or predicates are in use (Peter Eisentraut)

  • Avoid useless and expensive logical decoding of TOAST data during a table rewrite (Tomas Vondra)

  • Fix logic for stopping a subset of WAL senders when synchronous replication is enabled (Paul Guo, Michael Paquier)

  • Avoid possibly writing an incorrect replica identity field in a tuple deletion WAL record (Stas Kelvich)

  • Make the archiver prioritize WAL history files over WAL data files while choosing which file to archive next (David Steele)

  • Fix possible crash in UPDATE with a multiple SET clause using a sub-SELECT as source (Tom Lane)

  • Avoid crash if libxml2 returns a null error message (Sergio Conde Gómez)

  • Fix spurious grouping-related parser errors caused by inconsistent handling of collation assignment (Andrew Gierth)

    In some cases, expressions that should be considered to match were not seen as matching, if they included operations on collatable data types.

  • Check whether the comparison function underlying LEAST() or GREATEST() is leakproof, rather than just assuming it is (Tom Lane)

    Actual information leaks from btree comparison functions are typically hard to provoke, but in principle they could happen.

  • Fix incorrect planning of queries involving nested loops both above and below a Gather plan node (Tom Lane)

    If both levels of nestloop needed to pass the same variable into their right-hand sides, an incorrect plan would be generated.

  • Fix incorrect planning of queries in which a lateral reference must be evaluated at a foreign table scan (Tom Lane)

  • Fix corner-case underestimation of the cost of a merge join (Tom Lane)

    The planner could prefer a merge join when the outer key range is much smaller than the inner key range, even if there are so many duplicate keys on the inner side that this is a poor choice.

  • Avoid O(N^2) planning time growth when a query contains many thousand indexable clauses (Tom Lane)

  • Improve ANALYZE's handling of concurrently-updated rows (Jeff Janes, Tom Lane)

    Previously, rows deleted by an in-progress transaction were omitted from ANALYZE's sample, but this has been found to lead to more inconsistency than including them would do. In effect, the sample now corresponds to an MVCC snapshot as of ANALYZE's start time.

  • Make TRUNCATE ignore inheritance child tables that are temporary tables of other sessions (Amit Langote, Michael Paquier)

    This brings TRUNCATE into line with the behavior of other commands. Previously, such cases usually ended in failure.

  • Fix TRUNCATE to update the statistics counters for the right table (Tom Lane)

    If the truncated table had a TOAST table, that table's counters were reset instead.

  • Process ALTER TABLE ONLY ADD COLUMN IF NOT EXISTS correctly (Greg Stark)

  • Allow UNLISTEN in hot-standby mode (Shay Rojansky)

    This is necessarily a no-op, because LISTEN isn't allowed in hot-standby mode; but allowing the dummy operation simplifies session-state-reset logic in clients.

  • Fix missing role dependencies in some schema and data type permissions lists (Tom Lane)

    In some cases it was possible to drop a role to which permissions had been granted. This caused no immediate problem, but a subsequent dump/reload or upgrade would fail, with symptoms involving attempts to grant privileges to all-numeric role names.

  • Ensure relation caches are updated properly after adding or removing foreign key constraints (Álvaro Herrera)

    This oversight could result in existing sessions failing to enforce a newly-created constraint, or continuing to enforce a dropped one.

  • Ensure relation caches are updated properly after renaming constraints (Amit Langote)

  • Make autovacuum more aggressive about removing leftover temporary tables, and also remove leftover temporary tables during DISCARD TEMP (Álvaro Herrera)

    This helps ensure that remnants from a crashed session are cleaned up more promptly.

  • Fix replay of GiST index micro-vacuum operations so that concurrent hot-standby queries do not see inconsistent state (Alexander Korotkov)

  • Prevent empty GIN index pages from being reclaimed too quickly, causing failures of concurrent searches (Andrey Borodin, Alexander Korotkov)

  • Fix edge-case failures in float-to-integer coercions (Andrew Gierth, Tom Lane)

    Values very slightly above the maximum valid integer value might not be rejected, and then would overflow, producing the minimum valid integer instead. Also, values that should round to the minimum or maximum integer value might be incorrectly rejected.

  • When making a PAM authentication request, don't set the PAM_RHOST variable if the connection is via a Unix socket (Thomas Munro)

    Previously that variable would be set to [local], which is at best unhelpful, since it's supposed to be a host name.

  • Disallow setting client_min_messages higher than ERROR (Jonah Harris, Tom Lane)

    Previously, it was possible to set this variable to FATAL or PANIC, which had the effect of suppressing transmission of ordinary error messages to the client. However, that's contrary to guarantees that are given in the PostgreSQL wire protocol specification, and it caused some clients to become very confused. In released branches, fix this by silently treating such settings as meaning ERROR instead. Version 12 and later will reject those alternatives altogether.

  • Fix ecpglib to use uselocale() or _configthreadlocale() in preference to setlocale() (Michael Meskes, Tom Lane)

    Since setlocale() is not thread-local, and might not even be thread-safe, the previous coding caused problems in multi-threaded ecpg applications.

  • Fix incorrect results for numeric data passed through an ecpg SQLDA (SQL Descriptor Area) (Daisuke Higuchi)

    Values with leading zeroes were not copied correctly.

  • Fix psql's \g target meta-command to work with COPY TO STDOUT (Daniel Vérité)

    Previously, the target option was ignored, so that the copy data always went to the current query output target.

  • Make psql's LaTeX output formats render special characters properly (Tom Lane)

    Backslash and some other ASCII punctuation characters were not rendered correctly, leading to document syntax errors or wrong characters in the output.

  • Fix pg_dump's handling of materialized views with indirect dependencies on primary keys (Tom Lane)

    This led to mis-labeling of such views' dump archive entries, causing harmless warnings about "archive items not in correct section order"; less harmlessly, selective-restore options depending on those labels, such as --section, might misbehave.

  • Avoid null-pointer-dereference crash on some platforms when pg_dump or pg_restore tries to report an error (Tom Lane)

  • Fix contrib/hstore to calculate correct hash values for empty hstore values that were created in version 8.4 or before (Andrew Gierth)

    The previous coding did not give the same result as for an empty hstore value created by a newer version, thus potentially causing wrong results in hash joins or hash aggregation. It is advisable to reindex any hash indexes built on hstore columns, if the table might contain data that was originally stored as far back as 8.4 and was never dumped/reloaded since then.

  • Avoid crashes and excessive runtime with large inputs to contrib/intarray's gist__int_ops index support (Andrew Gierth)

  • Support new Makefile variables PG_CFLAGS, PG_CXXFLAGS, and PG_LDFLAGS in pgxs builds (Christoph Berg)

    This simplifies customization of extension build processes.

  • Fix Perl-coded build scripts to not assume "." is in the search path, since recent Perl versions don't include that (Andrew Dunstan)

  • Fix server command-line option parsing problems on OpenBSD (Tom Lane)

  • Relocate call of set_rel_pathlist_hook so that extensions can use it to supply partial paths for parallel queries (KaiGai Kohei)

    This is not expected to affect existing use-cases.

  • Update time zone data files to tzdata release 2018i for DST law changes in Kazakhstan, Metlakatla, and Sao Tome and Principe. Kazakhstan's Qyzylorda zone is split in two, creating a new zone Asia/Qostanay, as some areas did not change UTC offset. Historical corrections for Hong Kong and numerous Pacific islands.

• ⇑ Upgrade to 9.6.13 released on 2019-05-09 - docs

  • Prevent row-level security policies from being bypassed via selectivity estimators (Dean Rasheed)

    Some of the planner's selectivity estimators apply user-defined operators to values found in pg_statistic (e.g., most-common values). A leaky operator therefore can disclose some of the entries in a data column, even if the calling user lacks permission to read that column. In CVE-2017-7484 we added restrictions to forestall that, but we failed to consider the effects of row-level security. A user who has SQL permission to read a column, but who is forbidden to see certain rows due to RLS policy, might still learn something about those rows' contents via a leaky operator. This patch further tightens the rules, allowing leaky operators to be applied to statistics data only when there is no relevant RLS policy. (CVE-2019-10130)

  • Fix behavior for an UPDATE or DELETE on an inheritance tree or partitioned table in which every table can be excluded (Amit Langote, Tom Lane)

    In such cases, the query did not report the correct set of output columns when a RETURNING clause was present, and if there were any statement-level triggers that should be fired, it didn't fire them.

  • Fix handling of explicit DEFAULT items in an INSERT ... VALUES command with multiple VALUES rows, if the target relation is an updatable view (Amit Langote, Dean Rasheed)

    When the updatable view has no default for the column but its underlying table has one, a single-row INSERT ... VALUES will use the underlying table's default. In the multi-row case, however, NULL was always used. Correct it to act like the single-row case.

  • Fix CREATE VIEW to allow zero-column views (Ashutosh Sharma)

    We should allow this for consistency with allowing zero-column tables. Since a table can be converted to a view, zero-column views could be created even with the restriction in place, leading to dump/reload failures.

  • Add missing support for CREATE TABLE IF NOT EXISTS ... AS EXECUTE ... (Andreas Karlsson)

    The combination of IF NOT EXISTS and EXECUTE should work, but the grammar omitted it.

  • Ensure that sub-SELECTs appearing in row-level-security policy expressions are executed with the correct user's permissions (Dean Rasheed)

    Previously, if the table having the RLS policy was accessed via a view, such checks might be executed as the user calling the view, not as the view owner as they should be.

  • Accept XML documents as valid values of type xml when xmloption is set to content, as required by SQL:2006 and later (Chapman Flack)

    Previously PostgreSQL followed the SQL:2003 definition, which doesn't allow this. But that creates a serious problem for dump/restore: there is no setting of xmloption that will accept all valid XML data. Hence, switch to the 2006 definition.

    pg_dump is also modified to emit SET xmloption = content while restoring data, ensuring that dump/restore works even if the prevailing setting is document.

  • Improve server's startup-time checks for whether a pre-existing shared memory segment is still in use (Noah Misch)

    The postmaster is now more likely to detect that there are still active processes from a previous postmaster incarnation, even if the postmaster.pid file has been removed.

  • Avoid counting parallel workers' transactions as separate transactions (Haribabu Kommi)

  • Fix incompatibility of GIN-index WAL records (Alexander Korotkov)

    A fix applied in February's minor releases was not sufficiently careful about backwards compatibility, leading to problems if a standby server of that vintage reads GIN page-deletion WAL records generated by a primary server of a previous minor release.

  • Tolerate EINVAL and ENOSYS error results, where appropriate, for fsync and sync_file_range calls (Thomas Munro, James Sewell)

    The previous change to panic on file synchronization failures turns out to have been excessively paranoid for certain cases where a failure is predictable and essentially means "operation not supported".

  • Fix "failed to build any N-way joins" planner failures with lateral references leading out of FULL outer joins (Tom Lane)

  • Check the appropriate user's permissions when enforcing rules about letting a leaky operator see pg_statistic data (Dean Rasheed)

    When an underlying table is being accessed via a view, consider the privileges of the view owner while deciding whether leaky operators may be applied to the table's statistics data, rather than the privileges of the user making the query. This makes the planner's rules about what data is visible match up with the executor's, avoiding unnecessarily-poor plans.

  • Speed up planning when there are many equality conditions and many potentially-relevant foreign key constraints (David Rowley)

  • Avoid O(N^2) performance issue when rolling back a transaction that created many tables (Tomas Vondra)

  • Fix race conditions in management of dynamic shared memory (Thomas Munro)

    These could lead to "dsa_area could not attach to segment" or "cannot unpin a segment that is not pinned" errors.

  • Fix race condition in which a hot-standby postmaster could fail to shut down after receiving a smart-shutdown request (Tom Lane)

  • Fix possible crash when pg_identify_object_as_address() is given invalid input (Álvaro Herrera)

  • Tighten validation of encoded SCRAM-SHA-256 and MD5 passwords (Jonathan Katz)

    A password string that had the right initial characters could be mistaken for one that is correctly hashed into SCRAM-SHA-256 or MD5 format. The password would be accepted but would be unusable later.

  • Fix handling of lc_time settings that imply an encoding different from the database's encoding (Juan José Santamaría Flecha, Tom Lane)

    Localized month or day names that include non-ASCII characters previously caused unexpected errors or wrong output in such locales.

  • Fix incorrect operator_precedence_warning checks involving unary minus operators (Rikard Falkeborn)

  • Disallow NaN as a value for floating-point server parameters (Tom Lane)

  • Rearrange REINDEX processing to avoid assertion failures when reindexing individual indexes of pg_class (Andres Freund, Tom Lane)

  • Fix planner assertion failure for parameterized dummy paths (Tom Lane)

  • Insert correct test function in the result of SnapBuildInitialSnapshot() (Antonin Houska)

    No core code cares about this, but some extensions do.

  • Fix intermittent "could not reattach to shared memory" session startup failures on Windows (Noah Misch)

    A previously unrecognized source of these failures is creation of thread stacks for a process's default thread pool. Arrange for such stacks to be allocated in a different memory region.

  • Fix error detection in directory scanning on Windows (Konstantin Knizhnik)

    Errors, such as lack of permissions to read the directory, were not detected or reported correctly; instead the code silently acted as though the directory were empty.

  • Fix grammar problems in ecpg (Tom Lane)

    A missing semicolon led to mistranslation of SET variable = DEFAULT (but not SET variable TO DEFAULT) in ecpg programs, producing syntactically invalid output that the server would reject. Additionally, in a DROP TYPE or DROP DOMAIN command that listed multiple type names, only the first type name was actually processed.

  • Sync ecpg's syntax for CREATE TABLE AS with the server's (Daisuke Higuchi)

  • Fix possible buffer overruns in ecpg's processing of include filenames (Liu Huailing, Fei Wu)

  • Avoid crash in contrib/vacuumlo if an lo_unlink() call failed (Tom Lane)

  • Sync our copy of the timezone library with IANA tzcode release 2019a (Tom Lane)

    This corrects a small bug in zic that caused it to output an incorrect year-2440 transition in the Africa/Casablanca zone, and adds support for zic's new -r option.

  • Update time zone data files to tzdata release 2019a for DST law changes in Palestine and Metlakatla, plus historical corrections for Israel.

    Etc/UCT is now a backward-compatibility link to Etc/UTC, instead of being a separate zone that generates the abbreviation UCT, which nowadays is typically a typo. PostgreSQL will still accept UCT as an input zone abbreviation, but it won't output it.

• ⇑ Upgrade to 9.6.14 released on 2019-06-20 - docs

  • Fix failure of ALTER TABLE ... ALTER COLUMN TYPE when the table has a partial exclusion constraint (Tom Lane)

  • Fix failure of COMMENT command for comments on domain constraints (Daniel Gustafsson, Michael Paquier)

  • Fix faulty generation of merge-append plans (Tom Lane)

    This mistake could lead to "could not find pathkey item to sort" errors.

  • Fix incorrect printing of queries with duplicate join names (Philip Dubé)

    This oversight caused a dump/restore failure for views containing such queries.

  • Fix misoptimization of {1,1} quantifiers in regular expressions (Tom Lane)

    Such quantifiers were treated as no-ops and optimized away; but the documentation specifies that they impose greediness, or non-greediness in the case of the non-greedy variant {1,1}?, on the subexpression they're attached to, and this did not happen. The misbehavior occurred only if the subexpression contained capturing parentheses or a back-reference.

  • Avoid possible failures while initializing a new process's pg_stat_activity data (Tom Lane)

    Certain operations that could fail, such as converting strings extracted from an SSL certificate into the database encoding, were being performed inside a critical section. Failure there would result in database-wide lockup due to violating the access protocol for shared pg_stat_activity data.

  • Fix race condition in check to see whether a pre-existing shared memory segment is still in use by a conflicting postmaster (Tom Lane)

  • Avoid attempting to do database accesses for parameter checking in processes that are not connected to a specific database (Vignesh C, Andres Freund)

    This error could result in failures like "cannot read pg_class without having selected a database".

  • Avoid possible hang in libpq if using SSL and OpenSSL's pending-data buffer contains an exact multiple of 256 bytes (David Binderman)

  • Improve initdb's handling of multiple equivalent names for the system time zone (Tom Lane, Andrew Gierth)

    Make initdb examine the /etc/localtime symbolic link, if that exists, to break ties between equivalent names for the system time zone. This makes initdb more likely to select the time zone name that the user would expect when multiple identical time zones exist. It will not change the behavior if /etc/localtime is not a symlink to a zone data file, nor if the time zone is determined from the TZ environment variable.

    Separately, prefer UTC over other spellings of that time zone, when neither TZ nor /etc/localtime provide a hint. This fixes an annoyance introduced by tzdata 2019a's change to make the UCT and UTC zone names equivalent: initdb was then preferring UCT, which almost nobody wants.

  • Fix ordering of GRANT commands emitted by pg_dump and pg_dumpall for databases and tablespaces (Nathan Bossart, Michael Paquier)

    If cascading grants had been issued, restore might fail due to the GRANT commands being given in an order that didn't respect their interdependencies.

  • Fix misleading error reports from reindexdb (Julien Rouhaud)

  • Ensure that vacuumdb returns correct status if an error occurs while using parallel jobs (Julien Rouhaud)

  • Fix contrib/auto_explain to not cause problems in parallel queries (Tom Lane)

    Previously, a parallel worker might try to log its query even if the parent query were not being logged by auto_explain. This would work sometimes, but it's confusing, and in some cases it resulted in failures like "could not find key N in shm TOC".

    Also, fix an off-by-one error that resulted in not necessarily logging every query even when the sampling rate is set to 1.0.

  • In contrib/postgres_fdw, account for possible data modifications by local BEFORE ROW UPDATE triggers (Shohei Mochizuki)

    If a trigger modified a column that was otherwise not changed by the UPDATE, the new value was not transmitted to the remote server.

  • On Windows, avoid failure when the database encoding is set to SQL_ASCII and we attempt to log a non-ASCII string (Noah Misch)

    The code had been assuming that such strings must be in UTF-8, and would throw an error if they didn't appear to be validly encoded. Now, just transmit the untranslated bytes to the log.

  • Make PL/pgSQL's header files C++-safe (George Tarasov)

• ⇑ Upgrade to 9.6.15 released on 2019-08-08 - docs

  • Require schema qualification to cast to a temporary type when using functional cast syntax (Noah Misch)

    We have long required invocations of temporary functions to explicitly specify the temporary schema, that is pg_temp.func_name(args). Require this as well for casting to temporary types using functional notation, for example pg_temp.type_name(arg). Otherwise it's possible to capture a function call using a temporary object, allowing privilege escalation in much the same ways that we blocked in CVE-2007-2138. (CVE-2019-10208)

  • Fix failure of ALTER TABLE ... ALTER COLUMN TYPE when altering multiple columns' types in one command (Tom Lane)

    This fixes a regression introduced in the most recent minor releases: indexes using the altered columns were not processed correctly, leading to strange failures during ALTER TABLE.

  • Don't optimize away GROUP BY columns when the table involved is an inheritance parent (David Rowley)

    Normally, if a table's primary key column(s) are included in GROUP BY, it's safe to drop any other grouping columns, since the primary key columns are enough to make the groups unique. This rule does not work if the query is also reading inheritance child tables, though; the parent's uniqueness does not extend to the children.

  • Avoid using unnecessary sort steps for some queries with GROUPING SETS (Andrew Gierth, Richard Guo)

  • Fix mishandling of multi-column foreign keys when rebuilding a foreign key constraint (Tom Lane)

    ALTER TABLE could make an incorrect decision about whether revalidation of a foreign key is necessary, if not all columns of the key are of the same type. It seems likely that the error would always have been in the conservative direction, that is revalidating unnecessarily.

  • Avoid spurious deadlock errors when upgrading a tuple lock (Oleksii Kliukin)

    When two or more transactions are waiting for a transaction T1 to release a tuple-level lock, and T1 upgrades its lock to a higher level, a spurious deadlock among the waiting transactions could be reported when T1 finishes.

  • Fix failure to resolve deadlocks involving multiple parallel worker processes (Rui Hai Jiang)

    It is not clear whether this bug is reachable with non-artificial queries, but if it did happen, the queries involved in an otherwise-resolvable deadlock would block until canceled.

  • Prevent incorrect canonicalization of date ranges with infinity endpoints (Laurenz Albe)

    It's incorrect to try to convert an open range to a closed one or vice versa by incrementing or decrementing the endpoint value, if the endpoint is infinite; so leave the range alone in such cases.

  • Fix loss of fractional digits when converting very large money values to numeric (Tom Lane)

  • Fix spinlock assembly code for MIPS CPUs so that it works on MIPS r6 (YunQiang Su)

  • Make libpq ignore carriage return (\r) in connection service files (Tom Lane, Michael Paquier)

    In some corner cases, service files containing Windows-style newlines could be mis-parsed, resulting in connection failures.

  • In psql, avoid offering incorrect tab completion options after SET variable = (Tom Lane)

  • Fix pg_dump to ensure that custom operator classes are dumped in the right order (Tom Lane)

    If a user-defined opclass is the subtype opclass of a user-defined range type, related objects were dumped in the wrong order, producing an unrestorable dump. (The underlying failure to handle opclass dependencies might manifest in other cases too, but this is the only known case.)

  • Fix contrib/passwordcheck to coexist with other users of check_password_hook (Michael Paquier)

  • Fix contrib/sepgsql tests to work under recent SELinux releases (Mike Palmiotto)

  • Improve stability of src/test/recovery regression tests (Michael Paquier)

  • Reduce stderr output from pg_upgrade's test script (Tom Lane)

  • Fix TAP tests to work with msys Perl, in cases where the build directory is on a non-root msys mount point (Noah Misch)

  • Support building Postgres with Microsoft Visual Studio 2019 (Haribabu Kommi)

  • In Visual Studio builds, honor WindowsSDKVersion environment variable, if that's set (Peifeng Qiu)

    This fixes build failures in some configurations.

  • Support OpenSSL 1.1.0 and newer in Visual Studio builds (Juan José Santamaría Flecha, Michael Paquier)

  • Allow make options to be passed down to gmake when non-GNU make is invoked at the top level (Thomas Munro)

  • Avoid choosing localtime or posixrules as TimeZone during initdb (Tom Lane)

    In some cases initdb would choose one of these artificial zone names over the "real" zone name. Prefer any other match to the C library's timezone behavior over these two.

  • Adjust pg_timezone_names view to show the Factory time zone if and only if it has a short abbreviation (Tom Lane)

    Historically, IANA set up this artificial zone with an "abbreviation" like Local time zone must be set--see zic manual page. Modern versions of the tzdb database show -00 instead, but some platforms alter the data to show one or another of the historical phrases. Show this zone only if it uses the modern abbreviation.

  • Sync our copy of the timezone library with IANA tzcode release 2019b (Tom Lane)

    This adds support for zic's new -b slim option to reduce the size of the installed zone files. We are not currently using that, but may enable it in future.

  • Update time zone data files to tzdata release 2019b for DST law changes in Brazil, plus historical corrections for Hong Kong, Italy, and Palestine.

• ⇑ Upgrade to 9.6.16 released on 2019-11-14 - docs

  • Fix failure of ALTER TABLE SET with a custom relation option (Michael Paquier)

  • Disallow changing a multiply-inherited column's type if not all parent tables were changed (Tom Lane)

    Previously, this was allowed, whereupon queries on the now-out-of-sync parent would fail.

  • 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.

  • 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.

  • Fix handling of whole-row variables in WITH CHECK OPTION expressions and row-level-security policy expressions (Andres Freund)

    Previously, such usage might result in bogus errors about row type mismatches.

  • Avoid postmaster failure if a parallel query requests a background worker when no postmaster child process array slots remain free (Tom Lane)

  • Prevent possible double-free if a BEFORE UPDATE trigger returns the old tuple as-is, and it is not the last such trigger (Thomas Munro)

  • Provide a relevant error context line when an error occurs while setting GUC parameters during parallel worker startup (Thomas Munro)

  • In serializable mode, ensure that row-level predicate locks are acquired on the correct version of the row (Thomas Munro, Heikki Linnakangas)

    If the visible version of the row is HOT-updated, the lock might be taken on its now-dead predecessor, resulting in subtle failures to guarantee serialization.

  • 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.

  • Avoid unwanted delay during shutdown of a logical replication walsender (Craig Ringer, Álvaro Herrera)

  • 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.

  • In logical decoding, ensure that sub-transactions are correctly accounted for when reconstructing a snapshot (Masahiko Sawada)

    This error leads to assertion failures; it's unclear whether any bad effects exist in production builds.

  • Fix race condition during backend exit, when the backend process has previously waited for synchronous replication to occur (Dongming Liu)

  • Fix ALTER SYSTEM to cope with duplicate entries in postgresql.auto.conf (Ian Barwick)

    ALTER SYSTEM itself will not generate such a state, but external tools that modify postgresql.auto.conf could do so. Duplicate entries for the target variable will now be removed, and then the new setting (if any) will be appended at the end.

  • Reject include directives with empty file names in configuration files, and report include-file recursion more clearly (Ian Barwick, Tom Lane)

  • 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 some cases where an incomplete date specification is not detected in time with time zone input (Alexander Lakhin)

    If a time zone with a time-varying UTC offset is specified, then a date must be as well, so that the offset can be resolved. Depending on the syntax used, this check was not enforced in some cases, allowing bogus output to be produced.

  • 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 detection of edge-case integer overflow in interval multiplication (Yuya Watari)

  • Avoid crashes if ispell text search dictionaries contain wrong affix data (Arthur Zakirov)

  • Fix incorrect compression logic for GIN posting lists (Heikki Linnakangas)

    A GIN posting list item can require 7 bytes if the distance between adjacent indexed TIDs exceeds 16TB. One step in the logic was out of sync with that, and might try to write the value into a 6-byte buffer. In principle this could cause a stack overrun, but on most architectures it's likely that the next byte would be unused alignment padding, making the bug harmless. In any case the bug would be very difficult to hit.

  • Fix handling of infinity, NaN, and NULL values in KNN-GiST (Alexander Korotkov)

    The query's output order could be wrong (different from a plain sort's result) if some distances computed for non-null column values are infinity or NaN.

  • Fix handling of searches for NULL in KNN-SP-GiST (Nikita Glukhov)

  • On Windows, recognize additional spellings of the "Norwegian (Bokmål)" locale name (Tom Lane)

  • 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.

  • In psql, resynchronize internal state about the server after an unexpected connection loss and successful reconnection (Peter Billen, Tom Lane)

    Ordinarily this is unnecessary since the state would be the same anyway. But it can matter in corner cases, such as where the connection might lead to one of several servers. This change causes psql to re-issue any interactive messages that it would have issued at startup, for example about whether SSL is in use.

  • Avoid platform-specific null pointer dereference in psql (Quentin Rameau)

  • Fix pg_dump's handling of circular dependencies in views (Tom Lane)

    In some cases a view may depend on an object that pg_dump needs to dump later than the view; the most common example is that a query using GROUP BY on a primary-key column may be semantically invalid without the primary key. This is now handled by emitting a dummy CREATE VIEW command that just establishes the view's column names and types, and then later emitting CREATE OR REPLACE VIEW with the full view definition. Previously, the dummy definition was actually a CREATE TABLE command, and this was automagically converted to a view by a later CREATE RULE command. The new approach has been used successfully in PostgreSQL version 10 and later. We are back-patching it into older releases now because of reports that the previous method causes bogus error messages about the view's replica identity status. This change also avoids problems when trying to use the --clean option during a restore involving such a view.

  • 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.

  • Fix pg_dump to work again with pre-8.3 source servers (Tom Lane)

    A previous fix caused pg_dump to always try to query pg_opfamily, but that catalog doesn't exist before version 8.3.

  • In pg_restore, treat -f - as meaning "output to stdout" (Álvaro Herrera)

    This synchronizes pg_restore's behavior with some other applications, and in particular makes pre-v12 branches act similarly to version 12's pg_restore, simplifying creation of dump/restore scripts that work across multiple PostgreSQL versions. Before this change, pg_restore interpreted such a switch as meaning "output to a file named -", but few people would want that.

  • 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.

  • Detect file read errors during pg_basebackup (Jeevan Chalke)

  • In pg_rewind with an online source cluster, disable timeouts, much as pg_dump does (Alexander Kukushkin)

  • 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, include the newitemoff field in btree page split records (Peter Geoghegan)

  • 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)

  • Fix vacuumdb with a high --jobs option to handle running out of file descriptors better (Michael Paquier)

  • Fix contrib/intarray's GiST opclasses to not fail for empty arrays with <@ (Tom Lane)

    A clause like array_column <@ constant_array is considered indexable, but the index search may not find empty array values; of course, such entries should trivially match the search.

    The only practical back-patchable fix for this requires making <@ index searches scan the whole index, which is what this patch does. This is unfortunate: it means that the query performance is likely worse than a plain sequential scan would be.

    Applications whose performance is adversely impacted by this change have a couple of options. They could switch to a GIN index, which doesn't have this bug, or they could replace array_column <@ constant_array with array_column <@ constant_array AND array_column && constant_array. That will provide about the same performance as before, and it will find all non-empty subsets of the given constant array, which is all that could reliably be expected of the query before.

  • Allow configure --with-python to succeed when only python3 or only python2 can be found (Peter Eisentraut, Tom Lane)

    Search for python, then python3, then python2, so that configure can succeed in the increasingly-more-common situation where there is no executable named simply python. It's still possible to override this choice by setting the PYTHON environment variable.

  • 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 PowerPC, avoid depending on the xlc compiler's __fetch_and_add() function (Noah Misch)

    xlc 13 and newer interpret this function in a way incompatible with our usage, resulting in an unusable build of PostgreSQL. Fix by using custom assembly code instead.

  • 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)

  • Update time zone data files to tzdata release 2019c for DST law changes in Fiji and Norfolk Island, plus historical corrections for Alberta, Austria, Belgium, British Columbia, Cambodia, Hong Kong, Indiana (Perry County), Kaliningrad, Kentucky, Michigan, Norfolk Island, South Korea, and Turkey.

• ⇑ Upgrade to 9.6.17 released on 2020-02-13 - docs

  • 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)

  • Avoid failure in logical decoding when a large transaction must be spilled into many separate temporary files (Amit Khandekar)

  • Fix failure in logical replication publisher after a database crash and restart (Vignesh C)

  • 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.

  • 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 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 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)

  • 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.

  • Improve performance of hash joins with very large inner relations (Thomas Munro)

  • Fix edge-case crashes and misestimations in selectivity calculations for the <@ and @> range operators (Michael Paquier, Andrey Borodin, Tom Lane)

  • 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)

  • 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)

  • 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.

  • 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.

  • 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)

  • 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.

  • 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.

  • 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.

  • 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.

• ⇑ Upgrade to 9.6.18 released on 2020-05-14 - docs

  • 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)

  • 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.

  • 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.

  • 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)

  • 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)

  • Avoid possibly showing "waiting" twice in a process's PS status (Masahiko Sawada)

  • 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.

  • 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.

  • 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.

  • Ensure nextXid can't go backwards on a standby server (Eka Palamadai)

    This race condition could allow incorrect hot standby feedback messages to be sent back to the primary server, potentially allowing VACUUM to run too soon on the primary.

  • 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)

  • 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.

  • 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)

  • Fix cache reference leak in contrib/sepgsql (Michael Luo)

  • Avoid failures when dealing with Unix-style locale names on Windows (Juan José Santamaría Flecha)

  • 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.

• ⇑ Upgrade to 9.6.19 released on 2020-08-13 - docs

  • 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)

  • 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 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 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).

  • Undo double-quoting of index names in EXPLAIN's non-text output formats (Tom Lane, Euler Taveira)

  • 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".

  • 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.

  • 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.

  • 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 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.

  • 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".

  • 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 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.

  • Use POSIX-standard strsignal() in place of the BSD-ish sys_siglist[] (Tom Lane)

    This avoids build failures with very recent versions of glibc.

  • 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.

• ⇑ Upgrade to 9.6.20 released on 2020-11-12 - docs

  • Block DECLARE CURSOR ... WITH HOLD and firing of deferred triggers within index expressions and materialized view queries (Noah Misch)

    This is essentially a leak in the "security restricted operation" sandbox mechanism. An attacker having permission to create non-temporary SQL objects could parlay this leak to execute arbitrary SQL code as a superuser.

    The PostgreSQL Project thanks Etienne Stalmans for reporting this problem. (CVE-2020-25695)

  • Fix usage of complex connection-string parameters in pg_dump, pg_restore, clusterdb, reindexdb, and vacuumdb (Tom Lane)

    The -d parameter of pg_dump and pg_restore, or the --maintenance-db parameter of the other programs mentioned, can be a "connection string" containing multiple connection parameters rather than just a database name. In cases where these programs need to initiate additional connections, such as parallel processing or processing of multiple databases, the connection string was forgotten and just the basic connection parameters (database name, host, port, and username) were used for the additional connections. This could lead to connection failures if the connection string included any other essential information, such as non-default SSL or GSS parameters. Worse, the connection might succeed but not be encrypted as intended, or be vulnerable to man-in-the-middle attacks that the intended connection parameters would have prevented. (CVE-2020-25694)

  • When psql's \connect command re-uses connection parameters, ensure that all non-overridden parameters from a previous connection string are re-used (Tom Lane)

    This avoids cases where reconnection might fail due to omission of relevant parameters, such as non-default SSL or GSS options. Worse, the reconnection might succeed but not be encrypted as intended, or be vulnerable to man-in-the-middle attacks that the intended connection parameters would have prevented. This is largely the same problem as just cited for pg_dump et al, although psql's behavior is more complex since the user may intentionally override some connection parameters. (CVE-2020-25694)

  • Prevent psql's \gset command from modifying specially-treated variables (Noah Misch)

    \gset without a prefix would overwrite whatever variables the server told it to. Thus, a compromised server could set specially-treated variables such as PROMPT1, giving the ability to execute arbitrary shell code in the user's session.

    The PostgreSQL Project thanks Nick Cleaton for reporting this problem. (CVE-2020-25696)

  • Prevent possible data loss from concurrent truncations of SLRU logs (Noah Misch)

    This rare problem would manifest in later "apparent wraparound" or "could not access status of transaction" errors.

  • Ensure that SLRU directories are properly fsync'd during checkpoints (Thomas Munro)

    This prevents possible data loss in a subsequent operating system crash.

  • Fix ALTER ROLE for users with the BYPASSRLS attribute (Tom Lane, Stephen Frost)

    The BYPASSRLS attribute is only allowed to be changed by superusers, but other ALTER ROLE operations, such as password changes, should be allowed with only ordinary permission checks. The previous coding erroneously restricted all changes on such a role to superusers.

  • Fix handling of expressions in CREATE TABLE LIKE with inheritance (Tom Lane)

    If a CREATE TABLE command uses both LIKE and traditional inheritance, column references in CHECK constraints and expression indexes that came from a LIKE parent table tended to get mis-numbered, resulting in wrong answers and/or bizarre error messages. The same could happen in GENERATED expressions, in branches that have that feature.

  • Fix off-by-one conversion of negative years to BC dates in to_date() and to_timestamp() (Dar Alathar-Yemen, Tom Lane)

    Also, arrange for the combination of a negative year and an explicit "BC" marker to cancel out and produce AD.

  • Ensure that standby servers will archive WAL timeline history files when archive_mode is set to always (Grigory Smolkin, Fujii Masao)

    This oversight could lead to failure of subsequent PITR recovery attempts.

  • During "smart" shutdown, don't terminate background processes until all client (foreground) sessions are done (Tom Lane)

    The previous behavior broke parallel query processing, since the postmaster would terminate parallel workers and refuse to launch any new ones. It also caused autovacuum to cease functioning, which could have dire long-term effects if the surviving client sessions make a lot of data changes.

  • Avoid recursive consumption of stack space while processing signals in the postmaster (Tom Lane)

    Heavy use of parallel processing has been observed to cause postmaster crashes due to too many concurrent signals requesting creation of a parallel worker process.

  • Avoid running atexit handlers when exiting due to SIGQUIT (Kyotaro Horiguchi, Tom Lane)

    Most server processes followed this practice already, but the archiver process was overlooked. Backends that were still waiting for a client startup packet got it wrong, too.

  • Avoid misoptimization of subquery qualifications that reference apparently-constant grouping columns (Tom Lane)

    A "constant" subquery output column isn't really constant if it is a grouping column that appears in only some of the grouping sets.

  • Avoid failure when SQL function inlining changes the shape of a potentially-hashable subplan comparison expression (Tom Lane)

  • While building or re-building an index, tolerate the appearance of new HOT chains due to concurrent updates (Anastasia Lubennikova, Álvaro Herrera)

    This oversight could lead to "failed to find parent tuple for heap-only tuple" errors.

  • Ensure that data is detoasted before being inserted into a BRIN index (Tomas Vondra)

    Index entries are not supposed to contain out-of-line TOAST pointers, but BRIN didn't get that memo. This could lead to errors like "missing chunk number 0 for toast value NNN". (If you are faced with such an error from an existing index, REINDEX should be enough to fix it.)

  • Handle concurrent desummarization correctly during BRIN index scans (Alexander Lakhin, Álvaro Herrera)

    Previously, if a page range was desummarized at just the wrong time, an index scan might falsely raise an error indicating index corruption.

  • Fix rare "lost saved point in index" errors in scans of multicolumn GIN indexes (Tom Lane)

  • Fix use-after-free hazard when an event trigger monitors an ALTER TABLE operation (Jehan-Guillaume de Rorthais)

  • Fix incorrect error message about inconsistent moving-aggregate data types (Jeff Janes)

  • Avoid lockup when a parallel worker reports a very long error message (Vignesh C)

  • Avoid unnecessary failure when transferring very large payloads through shared memory queues (Markus Wanner)

  • Fix relation cache memory leaks with RLS policies (Tom Lane)

  • Fix small memory leak when SIGHUP processing decides that a new GUC variable value cannot be applied without a restart (Tom Lane)

  • Make libpq support arbitrary-length lines in .pgpass files (Tom Lane)

    This is mostly useful to allow using very long security tokens as passwords.

  • In libpq for Windows, call WSAStartup() once per process and WSACleanup() not at all (Tom Lane, Alexander Lakhin)

    Previously, libpq invoked WSAStartup() at connection start and WSACleanup() at connection cleanup. However, it appears that calling WSACleanup() can interfere with other program operations; notably, we have observed rare failures to emit expected output to stdout. There appear to be no ill effects from omitting the call, so do that. (This also eliminates a performance issue from repeated DLL loads and unloads when a program performs a series of database connections.)

  • Fix ecpg library's per-thread initialization logic for Windows (Tom Lane, Alexander Lakhin)

    Multi-threaded ecpg applications could suffer rare misbehavior due to incorrect locking.

  • On Windows, make psql read the output of a backtick command in text mode, not binary mode (Tom Lane)

    This ensures proper handling of newlines.

  • Ensure that pg_dump collects per-column information about extension configuration tables (Fabrízio de Royes Mello, Tom Lane)

    Failure to do this led to crashes when specifying --inserts, or underspecified (though usually correct) COPY commands when using COPY to reload the tables' data.

  • Make pg_upgrade check for pre-existence of tablespace directories in the target cluster (Bruce Momjian)

  • Fix potential memory leak in contrib/pgcrypto (Michael Paquier)

  • Add check for an unlikely failure case in contrib/pgcrypto (Daniel Gustafsson)

  • Use return not exit() in configure's test programs (Peter Eisentraut)

    This avoids failures with pickier compilers.

  • Update time zone data files to tzdata release 2020d for DST law changes in Fiji, Morocco, Palestine, the Canadian Yukon, Macquarie Island, and Casey Station (Antarctica); plus historical corrections for France, Hungary, Monaco, and Palestine.

  • Sync our copy of the timezone library with IANA tzcode release 2020d (Tom Lane)

    This absorbs upstream's change of zic's default output option from "fat" to "slim". That's just cosmetic for our purposes, as we continue to select the "fat" mode in pre-v13 branches. This change also ensures that strftime() does not change errno unless it fails.

• ⇑ Upgrade to 9.6.21 released on 2021-02-11 - docs

  • Fix CREATE INDEX CONCURRENTLY to wait for concurrent prepared transactions (Andrey Borodin)

    At the point where CREATE INDEX CONCURRENTLY waits for all concurrent transactions to complete so that it can see rows they inserted, it must also wait for all prepared transactions to complete, for the same reason. Its failure to do so meant that rows inserted by prepared transactions might be omitted from the new index, causing queries relying on the index to miss such rows. In installations that have enabled prepared transactions (max_prepared_transactions > 0), it's recommended to reindex any concurrently-built indexes in case this problem occurred when they were built.

  • Avoid incorrect results when WHERE CURRENT OF is applied to a cursor whose plan contains a MergeAppend node (Tom Lane)

    This case is unsupported (in general, a cursor using ORDER BY is not guaranteed to be simply updatable); but the code previously did not reject it, and could silently give false matches.

  • Fix crash when WHERE CURRENT OF is applied to a cursor whose plan contains a custom scan node (David Geier)

  • Fix planner's handling of a placeholder that is computed at some join level and used only at that same level (Tom Lane)

    This oversight could lead to "failed to build any N-way joins" planner errors.

  • Be more careful about whether index AMs support mark/restore (Andrew Gierth)

    This prevents errors about missing support functions in rare edge cases.

  • Fix ALTER DEFAULT PRIVILEGES to handle duplicated arguments safely (Michael Paquier)

    Duplicate role or schema names within the same command could lead to "tuple already updated by self" errors or unique-constraint violations.

  • Flush ACL-related caches when pg_authid changes (Noah Misch)

    This change ensures that permissions-related decisions will promptly reflect the results of ALTER ROLE ... [NO] INHERIT.

  • Prevent misprocessing of ambiguous CREATE TABLE LIKE clauses (Tom Lane)

    A LIKE clause is re-examined after initial creation of the new table, to handle importation of indexes and such. It was possible for this re-examination to find a different table of the same name, causing unexpected behavior; one example is where the new table is a temporary table of the same name as the LIKE target.

  • Rearrange order of operations in CREATE TABLE LIKE so that indexes are cloned before building foreign key constraints (Tom Lane)

    This fixes the case where a self-referential foreign key constraint declared in the outer CREATE TABLE depends on an index that's coming from the LIKE clause.

  • Disallow converting an inheritance child table to a view (Tom Lane)

  • Ensure that disk space allocated for a dropped relation is released promptly at commit (Thomas Munro)

    Previously, if the dropped relation spanned multiple 1GB segments, only the first segment was truncated immediately. Other segments were simply unlinked, which doesn't authorize the kernel to release the storage so long as any other backends still have the files open.

  • Fix handling of backslash-escaped multibyte characters in COPY FROM (Heikki Linnakangas)

    A backslash followed by a multibyte character was not handled correctly. In some client character encodings, this could lead to misinterpreting part of a multibyte character as a field separator or end-of-copy-data marker.

  • Avoid preallocating executor hash tables in EXPLAIN without ANALYZE (Alexey Bashtanov)

  • Fix recently-introduced race conditions in LISTEN/NOTIFY queue handling (Tom Lane)

    A newly-listening backend could attempt to read SLRU pages that were in process of being truncated, possibly causing an error.

    The queue tail pointer could become set to a value that's not equal to the queue position of any backend, resulting in effective disabling of the queue truncation logic. Continued use of NOTIFY then led to queue-fill warnings, and eventually to inability to send any more notifies until the server is restarted.

  • Allow the jsonb concatenation operator to handle all combinations of JSON data types (Tom Lane)

    We can concatenate two JSON objects or two JSON arrays. Handle other cases by wrapping non-array inputs in one-element arrays, then performing an array concatenation. Previously, some combinations of inputs followed this rule but others arbitrarily threw an error.

  • Fix use of uninitialized value while parsing a * quantifier in a BRE-mode regular expression (Tom Lane)

    This error could cause the quantifier to act non-greedy, that is behave like a *? quantifier would do in full regular expressions.

  • Fix numeric power() for the case where the exponent is exactly INT_MIN (-2147483648) (Dean Rasheed)

    Previously, a result with no significant digits was produced.

  • Prevent possible data loss from incorrect detection of the wraparound point of an SLRU log (Noah Misch)

    The wraparound point typically falls in the middle of a page, which must be rounded off to a page boundary, and that was not done correctly. No issue could arise unless an installation had gotten to within one page of SLRU overflow, which is unlikely in a properly-functioning system. If this did happen, it would manifest in later "apparent wraparound" or "could not access status of transaction" errors.

  • Fix memory leak in walsender processes while sending new snapshots for logical decoding (Amit Kapila)

  • Fix walsender to accept additional commands after terminating replication (Jeff Davis)

  • Ensure detection of deadlocks between hot standby backends and the startup (WAL-application) process (Fujii Masao)

    The startup process did not run the deadlock detection code, so that in situations where the startup process is last to join a circular wait situation, the deadlock might never be recognized.

  • Fix portability problem in parsing of recovery_target_xid values (Michael Paquier)

    The target XID is potentially 64 bits wide, but it was parsed with strtoul(), causing misbehavior on platforms where long is 32 bits (such as Windows).

  • Avoid assertion failure in pg_get_functiondef() when examining a function with a TRANSFORM option (Tom Lane)

  • In psql, re-allow including a password in a connection_string argument of a \connect command (Tom Lane)

    This used to work, but a recent bug fix caused the password to be ignored (resulting in prompting for a password).

  • Fix assorted bugs in psql's \help command (Kyotaro Horiguchi, Tom Lane)

    \help with two argument words failed to find a command description using only the first word, for example \help reset all should show the help for RESET but did not. Also, \help often failed to invoke the pager when it should. It also leaked memory.

  • Fix pg_dump to handle WITH GRANT OPTION in an extension's initial privileges (Noah Misch)

    If an extension's script creates an object and grants privileges on it with grant option, then later the user revokes such privileges, pg_dump would generate incorrect SQL for reproducing the situation. (Few if any extensions do this today.)

  • In pg_rewind, ensure that all WAL is accounted for when rewinding a standby server (Ian Barwick, Heikki Linnakangas)

  • Report the correct database name in connection failure error messages from some client programs (Álvaro Herrera)

    If the database name was defaulted rather than given on the command line, pg_dumpall, pgbench, oid2name, and vacuumlo would produce misleading error messages after a connection failure.

  • Fix memory leak in contrib/auto_explain (Japin Li)

    Memory consumed while producing the EXPLAIN output was not freed until the end of the current transaction (for a top-level statement) or the end of the surrounding statement (for a nested statement). This was particularly a problem with log_nested_statements enabled.

  • In contrib/postgres_fdw, avoid leaking open connections to remote servers when a user mapping or foreign server object is dropped (Bharath Rupireddy)

    Open connections that depend on a dropped user mapping or foreign server can no longer be referenced, but formerly they were kept around anyway for the duration of the local session.

  • In contrib/pgcrypto, check for error returns from OpenSSL's EVP functions (Michael Paquier)

    We do not really expect errors here, but this change silences warnings from static analysis tools.

  • In contrib/pg_trgm's GiST index support, avoid crash in the rare case that picksplit is called on exactly two index items (Andrew Gierth, Alexander Korotkov)

  • Fix miscalculation of timeouts in contrib/pg_prewarm and contrib/postgres_fdw (Alexey Kondratov, Tom Lane)

    The main loop in contrib/pg_prewarm's autoprewarm parent process underestimated its desired sleep time by a factor of 1000, causing it to consume much more CPU than intended. When waiting for a result from a remote server, contrib/postgres_fdw overestimated the desired timeout by a factor of 1000 (though this error had been mitigated by imposing a clamp to 60 seconds).

    Both of these errors stemmed from incorrectly converting seconds-and-microseconds to milliseconds. Introduce a new API TimestampDifferenceMilliseconds() to make it easier to get this right in the future.

  • Improve configure's heuristics for selecting PG_SYSROOT on macOS (Tom Lane)

    The new method is more likely to produce desirable results when Xcode is newer than the underlying operating system. Choosing a sysroot that does not match the OS version may result in nonfunctional executables.

  • While building on macOS, specify -isysroot in link steps as well as compile steps (James Hilliard)

    This likewise improves the results when Xcode is out of sync with the operating system.

  • Update time zone data files to tzdata release 2021a for DST law changes in Russia (Volgograd zone) and South Sudan, plus historical corrections for Australia, Bahamas, Belize, Bermuda, Ghana, Israel, Kenya, Nigeria, Palestine, Seychelles, and Vanuatu.

    Notably, the Australia/Currie zone has been corrected to the point where it is identical to Australia/Hobart.

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