Release date: 2020-08-13
This release contains a variety of fixes from 12.3. For information about new features in major release 12, see Section E.23.
A dump/restore is not required for those running 12.X.
However, if you are upgrading from a version earlier than 12.2, see Section E.21.
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 NaN
s
while others found only non-NaN
s, 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.