Upgrading from 12.3 to 12.6 gives you 9.1 months worth of fixes (177 of them)

List of changes:

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

  • Set a secure search_path in logical replication walsenders and apply workers (Noah Misch)

    A malicious user of either the publisher or subscriber database could potentially cause execution of arbitrary SQL code by the role running replication, which is often a superuser. Some of the risks here are equivalent to those described in CVE-2018-1058, and are mitigated in this patch by ensuring that the replication sender and receiver execute with empty search_path settings. (As with CVE-2018-1058, that change might cause problems for under-qualified names used in replicated tables' DDL.) Other risks are inherent in replicating objects that belong to untrusted roles; the most we can do is document that there is a hazard to consider. (CVE-2020-14349)

  • Make contrib modules' installation scripts more secure (Tom Lane)

    Attacks similar to those described in CVE-2018-1058 could be carried out against an extension installation script, if the attacker can create objects in either the extension's target schema or the schema of some prerequisite extension. Since extensions often require superuser privilege to install, this can open a path to obtaining superuser privilege. To mitigate this risk, be more careful about the search_path used to run an installation script; disable check_function_bodies within the script; and fix catalog-adjustment queries used in some contrib modules to ensure they are secure. Also provide documentation to help third-party extension authors make their installation scripts secure. This is not a complete solution; extensions that depend on other extensions can still be at risk if installed carelessly. (CVE-2020-14350)

  • Fix edge cases in partition pruning (Etsuro Fujita, Dmitry Dolgov)

    When there are multiple partition key columns, generation of pruning tests could misbehave if some columns had no constraining WHERE clauses or multiple constraining clauses. This could lead to server crashes, incorrect query results, or assertion failures.

  • Fix construction of parameterized BitmapAnd and BitmapOr index scans on the inside of partition-wise nestloop joins (Tom Lane)

    A plan in which such a scan needed to use a value from the outside of the join would usually crash at execution.

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

  • In logical replication walsender, fix failure to send feedback messages after sending a keepalive message (Álvaro Herrera)

    This is a relatively minor problem when using built-in logical replication, because the built-in walreceiver will send a feedback reply (which clears the incorrect state) fairly frequently anyway. But with some other replication systems, such as pglogical, it causes significant performance issues.

  • Fix firing of column-specific UPDATE triggers in logical replication subscribers (Tom Lane)

    The code neglected to account for the possibility of column numbers being different between the publisher and subscriber tables, so that if those were indeed different, wrong decisions might be made about which triggers to fire.

  • Update oldest xmin and LSN values during pg_replication_slot_advance() (Michael Paquier)

    This function previously failed to do that, possibly preventing resource cleanup (such as removal of no-longer-needed WAL segments) after manual advancement of a replication slot.

  • Fix slow execution of ts_headline() (Tom Lane)

    The phrase-search fix added in our previous set of minor releases could cause ts_headline() to take unreasonable amounts of time for long documents; to make matters worse, the query was not cancellable within the troublesome loop.

  • Ensure the repeat() function can be interrupted by query cancel (Joe Conway)

  • Fix pg_current_logfile() to not include a carriage return (\r) in its result on Windows (Tom Lane)

  • Ensure that pg_read_file() and related functions read until EOF is reached (Joe Conway)

    Previously, if not given a specific data length to read, these functions would stop at whatever file length was reported by stat(). That's unhelpful for pipes and other sorts of virtual files.

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

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

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

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

  • Fix mis-handling of NaN inputs during parallel aggregation on numeric-type columns (Tom Lane)

    If some partial aggregation workers found only NaNs while others found only non-NaNs, the results were combined incorrectly, possibly leading to the wrong overall result (i.e., not NaN when it should be).

  • Reject time-of-day values greater than 24 hours (Tom Lane)

    The intention of the datetime input code is to allow “24:00:00” or equivalently “23:59:60”, but no larger value. However, the range check was miscoded so that it would accept “23:59:60.nnn” with nonzero fractional-second nnn. In timestamp values this would result in wrapping into the first second of the next day. In time and timetz values, the stored value would actually be more than 24 hours, causing dump/reload failures and possibly other misbehavior.

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

  • Fix EXPLAIN's accounting for resource usage, particularly buffer accesses, in parallel workers in a plan using Gather Merge nodes (Jehan-Guillaume de Rorthais)

  • Fix timing of constraint revalidation in ALTER TABLE (David Rowley)

    If ALTER TABLE needs to fully rewrite the table's contents (for example, due to change of a column's data type) and also needs to scan the table to re-validate foreign keys or CHECK constraints, it sometimes did things in the wrong order, leading to odd errors such as “could not read block 0 in file "base/nnnnn/nnnnn": read only 0 of 8192 bytes”.

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

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

  • Work around incorrect not-null markings for pg_subscription.subslotname and pg_subscription_rel.srsublsn (Tom Lane)

    The bootstrap catalog data incorrectly marks these two catalog columns as always non-null. There's no easy way to correct that mistake in existing installations (though v13 and later will have the correct markings). The main place that depends on that marking being correct is JIT-enabled tuple deconstruction, so teach it to explicitly ignore the marking for these two columns. Also adjust some C code that accessed srsublsn without checking to see if it's null; a crash from that is improbable but perhaps not impossible.

  • Cope with LATERAL references in restriction clauses attached to an un-flattened sub-SELECT in the FROM clause (Tom Lane)

    This oversight could result in assertion failures or crashes at query execution.

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

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

  • Avoid believing that a never-analyzed foreign table has zero tuples (Tom Lane)

    This primarily affected the planner's estimate of the number of groups that would be obtained by GROUP BY.

  • Remove bogus warning about “leftover placeholder tuple” in BRIN index de-summarization (Álvaro Herrera)

    The case can occur legitimately after a cancelled vacuum, so warning about it is overly noisy.

  • Fix selection of tablespaces for “shared fileset” temporary files (Magnus Hagander, Tom Lane)

    If temp_tablespaces is empty or explicitly names the database's primary tablespace, such files got placed into the pg_default tablespace rather than the database's primary tablespace as expected.

  • Fix corner-case error in masking of SP-GiST index pages during WAL consistency checking (Alexander Korotkov)

    This could cause false failure reports when wal_consistency_checking is enabled.

  • Improve error handling in the server's buffile module (Thomas Munro)

    Fix some cases where I/O errors were indistinguishable from reaching EOF, or were not reported at all. Also add details such as block numbers and byte counts where appropriate.

  • Fix conflict-checking anomalies in SERIALIZABLE isolation mode (Peter Geoghegan)

    If a concurrently-inserted tuple was updated by a different concurrent transaction, and neither tuple version was visible to the current transaction's snapshot, serialization conflict checking could draw the wrong conclusions about whether the tuple was relevant to the results of the current transaction. This could allow a serializable transaction to commit when it should have failed with a serialization error.

  • Avoid repeated marking of dead btree index entries as dead (Masahiko Sawada)

    While functionally harmless, this led to useless WAL traffic when checksums are enabled or wal_log_hints is on.

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

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

  • Avoid trouble during cleanup of a non-exclusive backup when JIT compilation has been activated during the backup (Robert Haas)

  • Fix failure of some code paths to acquire the correct lock before modifying pg_control (Nathan Bossart, Fujii Masao)

    This oversight could allow pg_control to be written out with an inconsistent checksum, possibly causing trouble later, including inability to restart the database if it crashed before the next pg_control update.

  • Fix errors in currtid() and currtid2() (Michael Paquier)

    These functions (which are undocumented and used only by ancient versions of the ODBC driver) contained coding errors that could result in crashes, or in confusing error messages such as “could not open file” when applied to a relation having no storage.

  • Avoid calling elog() or palloc() while holding a spinlock (Michael Paquier, Tom Lane)

    Logic associated with replication slots had several violations of this coding rule. While the odds of trouble are quite low, an error in the called function would lead to a stuck spinlock.

  • Fix assertion in logical replication subscriber to allow use of REPLICA IDENTITY FULL (Euler Taveira)

    This was just an incorrect assertion, so it has no impact on standard production builds.

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

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

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

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

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

  • Report out-of-disk-space errors properly in pg_dump and pg_basebackup (Justin Pryzby, Tom Lane, Álvaro Herrera)

    Some code paths could produce silly reports like “could not write file: Success”.

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

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

  • Fix parallel restore of tables having both table-level privileges and per-column privileges (Tom Lane)

    The table-level privilege grants have to be applied first, but a parallel restore did not reliably order them that way; this could lead to “tuple concurrently updated” errors, or to disappearance of some per-column privilege grants. The fix for this is to include dependency links between such entries in the archive file, meaning that a new dump has to be taken with a corrected pg_dump to ensure that the problem will not recur.

  • Ensure that pg_upgrade runs with vacuum_defer_cleanup_age set to zero in the target cluster (Bruce Momjian)

    If the target cluster's configuration has been modified to set vacuum_defer_cleanup_age to a nonzero value, that prevented freezing of the system catalogs from working properly, which caused the upgrade to fail in confusing ways. Ensure that any such setting is overridden for the duration of the upgrade.

  • Fix pg_recvlogical to drain pending messages before exiting (Noah Misch)

    Without this, the replication sender might detect a send failure and exit without making the expected final update to the replication slot's LSN position. That led to re-transmitting data after the next connection. It was also possible to miss error messages sent after the last data that pg_recvlogical wants to consume.

  • Fix pg_rewind's handling of just-deleted files in the source data directory (Justin Pryzby, Michael Paquier)

    When working with an on-line source database, concurrent file deletions are possible, but pg_rewind would get confused if deletion happened between seeing a file's directory entry and examining it with stat().

  • Make pg_test_fsync use binary I/O mode on Windows (Michael Paquier)

    Previously it wrote the test file in text mode, which is not an accurate reflection of PostgreSQL's actual usage.

  • Fix contrib/amcheck to not complain about deleted index pages that are empty (Alexander Korotkov)

    This state of affairs is normal during WAL replay.

  • Fix failure to initialize local state correctly in contrib/dblink (Joe Conway)

    With the right combination of circumstances, this could lead to dblink_close() issuing an unexpected remote COMMIT.

  • Fix contrib/pgcrypto's misuse of deflate() (Tom Lane)

    The pgp_sym_encrypt functions could produce incorrect compressed data due to mishandling of zlib's API requirements. We have no reports of this error manifesting with stock zlib, but it can be seen when using IBM's zlibNX implementation.

  • Fix corner case in decompression logic in contrib/pgcrypto's pgp_sym_decrypt functions (Kyotaro Horiguchi, Michael Paquier)

    A compressed stream can validly end with an empty packet, but the decompressor failed to handle this and would complain about corrupt data.

  • Support building our NLS code with Microsoft Visual Studio 2015 or later (Juan José Santamaría Flecha, Davinder Singh, Amit Kapila)

  • Avoid possible failure of our MSVC install script when there is a file named configure several levels above the source code tree (Arnold Müller)

    This could confuse some logic that looked for configure to identify the top level of the source tree.

• ⇑ Upgrade to 12.5 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.

  • Ensure that ALTER TABLE ONLY ... ENABLE/DISABLE TRIGGER does not recurse to child tables (Álvaro Herrera)

    Previously the ONLY flag was ignored.

  • Avoid unnecessary recursion to partitions in ALTER TABLE SET NOT NULL, when the target column is already marked NOT NULL (Tom Lane)

    This avoids a potential deadlock in parallel pg_restore.

  • 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.

  • Disallow DROP INDEX CONCURRENTLY on a partitioned table (Álvaro Herrera, Michael Paquier)

    This case failed anyway, but with a confusing error message.

  • Allow LOCK TABLE to succeed on a self-referential view (Tom Lane)

    It previously threw an error complaining about infinite recursion, but there seems no need to disallow the case.

  • Retain statistics about an index across REINDEX CONCURRENTLY (Michael Paquier, Fabrízio de Royes Mello)

    Non-concurrent reindexing has always preserved such statistics.

  • Fix incorrect progress reporting from REINDEX CONCURRENTLY (Matthias van de Meent, Michael Paquier)

  • Ensure that GENERATED columns are updated when the column(s) they depend on are updated via a rule or an updatable view (Tom Lane)

    This fix also takes care of possible failure to fire a column-specific trigger in such cases.

  • Recheck default partition constraints while routing an inserted or updated tuple to the correct partition (Amit Langote, Álvaro Herrera)

    This fixes race conditions when partitions are added concurrently with the insertion.

  • Fix failures with collation-dependent partition bound expressions (Tom Lane)

  • Support hashing of text arrays (Peter Eisentraut)

    Array hashing failed if the array element type is collatable. Notably, this prevented using hash partitioning with a text array column as partition key.

  • 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.

  • Fix “cache lookup failed for relation 0” failures in logical replication workers (Tom Lane)

    The real-world impact is small, since the failure is unlikely, and if it does happen the worker would just exit and be restarted.

  • Prevent logical replication workers from sending redundant ping requests (Tom Lane)

  • 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.

  • Fix possible crash when considering partition-wise joins during GEQO planning (Tom Lane)

  • 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.

  • Fix failure of parallel B-tree index scans when the index condition is unsatisfiable (James Hunter)

  • 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 buffered GiST index builds to work when the index has included columns (Pavel Borisov)

  • Fix unportable use of getnameinfo() in pg_hba_file_rules view (Tom Lane)

    On FreeBSD 11, and possibly other platforms, the view's address and netmask columns were always null due to this error.

  • Avoid crash if debug_query_string is NULL when starting a parallel worker (Noah Misch)

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

  • Avoid failures when a BEFORE ROW UPDATE trigger returns the “old” row of a table having dropped or “missing” columns (Amit Langote, Tom Lane)

    This method of suppressing an update could result in crashes, unexpected CHECK constraint failures, or incorrect RETURNING output, because “missing” columns would read as NULLs for those purposes. (A column is “missing” for this purpose if it was added by ALTER TABLE ADD COLUMN with a non-NULL, but constant, default value.) Dropped columns could cause trouble as well.

  • 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 incorrect handling of template function attributes in JIT code generation (Andres Freund)

    This has been shown to cause crashes on s390x, and very possibly there are other cases on other platforms.

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

  • Fix edge-case memory leak in index_get_partition() (Justin Pryzby)

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

  • Fix memory leaks in PL/pgsql's CALL processing (Pavel Stehule, 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.

  • Ensure that parallel pg_restore processes foreign keys referencing partitioned tables in the correct order (Álvaro Herrera)

    Previously, it might try to restore a foreign key constraint before the required indexes were all in place, leading to an error.

  • 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)

  • Fix recently-added timetz test case so it works when the USA is not observing daylight savings time (Tom Lane)

  • 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 12.6 released on 2021-02-11 - docs

  • Fix information leakage in constraint-violation error messages (Heikki Linnakangas)

    If an UPDATE command attempts to move a row to a different partition but finds that it violates some constraint on the new partition, and the columns in that partition are in different physical positions than in the parent table, the error message could reveal the contents of columns that the user does not have SELECT privilege on. (CVE-2021-3393)

  • Fix incorrect detection of concurrent page splits while inserting into a GiST index (Heikki Linnakangas)

    Concurrent insertions could lead to a corrupt index with entries placed in the wrong pages. It's recommended to reindex any GiST index that's been subject to concurrent insertions.

  • 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 crash when a CALL or DO statement that performs a transaction rollback is executed via extended query protocol (Thomas Munro, Tom Lane)

    In PostgreSQL 13, this case reliably caused a null-pointer dereference. In earlier versions the bug seems to have no visible symptoms, but it's not quite clear that it could never cause a problem.

  • Fix partition pruning logic to handle asymmetric hash partition sets (Tom Lane)

    If a hash-partitioned table has unequally-sized partitions (that is, varying modulus values), or it lacks partitions for some remainder values, then the planner's pruning logic could mistakenly conclude that some partitions don't need to be scanned, leading to failure to find rows that the query should find.

  • 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 mishandling of placeholders whose evaluation should be delayed by an outer join (Tom Lane)

    This occurs in particular with trivial subqueries containing lateral references to outer-join outputs. The mistake could result in a malformed plan. The known cases trigger a “failed to assign all NestLoopParams to plan nodes” error, but other symptoms may be possible.

  • Fix planner's handling of placeholders during removal of useless RESULT RTEs (Tom Lane)

    This oversight could lead to “no relation entry for relid N” planner errors.

  • 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.

  • Adjust settings to make it more difficult to run out of DSM slots during heavy usage of parallel queries (Thomas Munro)

  • Fix overestimate of the amount of shared memory needed for parallel queries (Takayuki Tsunakawa)

  • 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 CREATE STATISTICS on system catalogs (Tomas Vondra)

  • 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.

  • Prevent dropping a tablespace that is referenced by a partitioned relation, but is not used for any actual storage (Álvaro Herrera)

    Previously this was allowed, but subsequent operations on the partitioned relation would fail.

  • Fix progress reporting for CLUSTER (Matthias van de Meent)

  • 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.

  • Fix integer-overflow cases in substring() functions (Tom Lane, Pavel Stehule)

    If the specified starting index and length overflow an integer when added together, substring() misbehaved, either throwing a bogus “negative substring length” error for a case that should succeed, or failing to complain that a negative length is negative (and instead returning the whole string, in most cases).

  • 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 possible failure to detect recovery conflicts while deleting an index entry that references a HOT chain (Peter Geoghegan)

    The code failed to traverse the HOT chain and might thus compute a too-old XID horizon, which could lead to incorrect conflict processing in hot standby. The practical impact of this bug is limited; in most cases the correct XID horizon would be found anyway from nearby operations.

  • Ensure that a nonempty value of krb_server_keyfile always overrides any setting of KRB5_KTNAME in the server's environment (Tom Lane)

    Previously, which setting took precedence depended on whether the client requests GSS encryption.

  • In server log messages about failing to match connections to pg_hba.conf entries, include details about whether GSS encryption has been activated (Kyotaro Horiguchi, Tom Lane)

    This is relevant data if hostgssenc or hostnogssenc entries exist.

  • Fix assorted issues in server's support for GSS encryption (Tom Lane)

    Remove pointless restriction that only GSS authentication can be used on a GSS-encrypted connection. Add GSS encryption information to connection-authorized log messages. Include GSS-related space when computing the required size of shared memory (this omission could have caused problems with very high max_connections settings). Avoid possible infinite recursion when reporting an unrecoverable GSS encryption error.

  • Ensure that unserviced requests for background workers are cleaned up when the postmaster begins a “smart” or “fast” shutdown sequence (Tom Lane)

    Previously, there was a race condition whereby a child process that had requested a background worker just before shutdown could wait indefinitely, preventing shutdown from completing.

  • 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 trying to use parallel index build in a standalone backend (Yulin Pei)

  • Allow index AMs to support included columns without necessarily supporting multiple key columns (Tom Lane)

  • Avoid assertion failure during parallel aggregation of an aggregate with a non-strict deserialization function (Andrew Gierth)

    No such aggregate functions exist in core PostgreSQL, but some extensions such as PostGIS provide some. The mistake is harmless anyway in a non-assert build.

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

  • Fix data structure misallocation in PL/pgSQL's CALL statement (Tom Lane)

    A CALL in a PL/pgSQL procedure, to another procedure that has OUT parameters, would fail if the called procedure did a COMMIT or ROLLBACK.

  • In libpq, do not skip trying SSL after GSS encryption (Tom Lane)

    If we successfully made a GSS-encrypted connection, but then failed during authentication, we would fall back to an unencrypted connection rather than next trying an SSL-encrypted connection. This could lead to unexpected connection failure, or to silently getting an unencrypted connection where an encrypted one is expected. Fortunately, GSS encryption could only succeed if both client and server hold valid tickets in the same Kerberos infrastructure. It seems unlikely for that to be true in an environment that requires SSL encryption instead.

  • 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).

  • In psql's \d commands, don't truncate the display of column default values (Tom Lane)

    Formerly, they were arbitrarily truncated at 128 characters.

  • 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's dumping of inherited generated columns (Peter Eisentraut)

    The previous behavior resulted in (harmless) errors during restore.

  • In pg_dump, ensure that the restore script runs ALTER PUBLICATION ADD TABLE commands as the owner of the publication, and similarly runs ALTER INDEX ATTACH PARTITION commands as the owner of the partitioned index (Tom Lane)

    Previously, these commands would be run by the role that started the restore script; which will usually work, but in corner cases that role might not have adequate permissions.

  • 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)

  • In pgbench, disallow a digit as the first character of a variable name (Fabien Coelho)

    This prevents trying to substitute variables into timestamp literal values, which may contain strings like 12:34.

  • 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.

  • Make contrib/pg_prewarm more robust when the cluster is shut down before prewarming is complete (Tom Lane)

    Previously, autoprewarm would rewrite its status file with only the block numbers that it had managed to load so far, thus perhaps largely disabling the prewarm functionality in the next startup. Instead, suppress status file updates until the initial loading pass is complete.

  • 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.

  • Fix JIT compilation to be compatible with LLVM 11 and LLVM 12 (Andres Freund)

  • Fix potential mishandling of references to boolean variables in JIT expression compilation (Andres Freund)

    No field reports attributable to this have been seen, but it seems likely that it could cause problems on some architectures.

  • Fix compile failure with ICU 68 and later (Tom Lane)

  • Avoid memcpy() with a NULL source pointer and zero count during partitioned index creation (Álvaro Herrera)

    While such a call is not known to cause problems in itself, some compilers assume that the arguments of memcpy() are never NULL, which could result in incorrect optimization of nearby code.

  • 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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