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Although we were careful to lock the object being added or dropped,
we failed to get any sort of lock on the extension itself. This
allowed the ALTER to proceed in parallel with a DROP EXTENSION,
which is problematic for a couple of reasons. If both commands
succeeded we'd be left with a dangling link in pg_depend, which
would cause problems later. Also, if the ALTER failed for some
reason, it might try to print the extension's name, and that could
result in a crash or (in older branches) a silly error message
complaining about extension "(null)".
Per bug #17098 from Alexander Lakhin. Back-patch to all
supported branches.
Discussion: https://postgr.es/m/17098-b960f3616c861f83@postgresql.org
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It's not really necessary for this function to open or lock the
relation associated with the pg_policy entry it's modifying. The
error checks it's making on the rel are if anything counterproductive
(e.g., if we don't want to allow installation of policies on system
catalogs, here is not the place to prevent that). In particular, it
seems just wrong to insist on an ownership check. That has the net
effect of forcing people to use superuser for DROP OWNED BY, which
surely is not an effect we want. Also there is no point in rebuilding
the dependencies of the policy expressions, which aren't being
changed. Lastly, locking the table also seems counterproductive; it's
not helping to prevent race conditions, since we failed to re-read the
pg_policy row after acquiring the lock. That means that concurrent
DDL would likely result in "tuple concurrently updated/deleted"
errors; which is the same behavior this code will produce, with less
overhead.
Per discussion of bug #17062. Back-patch to all supported versions,
as the failure cases this eliminates seem just as undesirable in 9.6
as in HEAD.
Discussion: https://postgr.es/m/1573181.1624220108@sss.pgh.pa.us
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Ordinarily, a pg_policy.polroles array wouldn't list the same role
more than once; but CREATE POLICY does not prevent that. If we
perform DROP OWNED BY on a role that is listed more than once,
RemoveRoleFromObjectPolicy either suffered an assertion failure
or encountered a tuple-updated-by-self error. Rewrite it to cope
correctly with duplicate entries, and add a CommandCounterIncrement
call to prevent the other problem.
Per discussion, there's other cleanup that ought to happen here,
but this seems like the minimum essential fix.
Per bug #17062 from Alexander Lakhin. It's been broken all along,
so back-patch to all supported branches.
Discussion: https://postgr.es/m/17062-11f471ae3199ca23@postgresql.org
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This works fine in the "simple Query" code path; but if the
statement is in the plan cache then it's corrupted for future
re-execution. Apply copyObject() to protect the original
tree from modification, as we've done elsewhere.
This narrow fix is applied only to the back branches. In HEAD,
the problem was fixed more generally by commit 7c337b6b5; but
that changed ProcessUtility's API, so it's infeasible to
back-patch.
Per bug #17053 from Charles Samborski.
Discussion: https://postgr.es/m/931771.1623893989@sss.pgh.pa.us
Discussion: https://postgr.es/m/17053-3ca3f501bbc212b4@postgresql.org
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When stuffing a plan from the plancache into a Portal, one is
not supposed to risk throwing an error between GetCachedPlan and
PortalDefineQuery; if that happens, the plan refcount incremented
by GetCachedPlan will be leaked. I managed to break this rule
while refactoring code in 9dbf2b7d7. There is no visible
consequence other than some memory leakage, and since nobody is
very likely to trigger the relevant error conditions many times
in a row, it's not surprising we haven't noticed. Nonetheless,
it's a bug, so rearrange the order of operations to remove the
hazard.
Noted on the way to looking for a better fix for bug #17053.
This mistake is pretty old, so back-patch to all supported
branches.
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The internal SQL queries used by REFRESH MATERIALIZED VIEW CONCURRENTLY
include some aliases for its diff and temporary relations with
rather-generic names: diff, newdata, newdata2 and mv. Depending on the
queries used for the materialized view, using CONCURRENTLY could lead to
some internal failures if the query and those internal aliases conflict.
Those names have been chosen in 841c29c8. This commit switches instead
to a naming pattern which is less likely going to cause conflicts, based
on an idea from Thomas Munro, by appending _$ to those aliases. This is
not perfect as those new names could still conflict, but at least it has
the advantage to keep the code readable and simple while reducing the
likelihood of conflicts to be close to zero.
Reported-by: Mathis Rudolf
Author: Bharath Rupireddy
Reviewed-by: Bernd Helmle, Thomas Munro, Michael Paquier
Discussion: https://postgr.es/m/109c267a-10d2-3c53-b60e-720fcf44d9e8@credativ.de
Backpatch-through: 9.6
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Most GUC check hooks that inspect database state have special checks
that prevent them from throwing hard errors for state-dependent issues
when source == PGC_S_TEST. This allows, for example,
"ALTER DATABASE d SET default_text_search_config = foo" when the "foo"
configuration hasn't been created yet. Without this, we have problems
during dump/reload or pg_upgrade, because pg_dump has no idea about
possible dependencies of GUC values and can't ensure a safe restore
ordering.
However, check_role() and check_session_authorization() hadn't gotten
the memo about that, and would throw hard errors anyway. It's not
entirely clear what is the use-case for "ALTER ROLE x SET role = y",
but we've now heard two independent complaints about that bollixing
an upgrade, so apparently some people are doing it.
Hence, fix these two functions to act more like other check hooks
with similar needs. (But I did not change their insistence on
being inside a transaction, as it's still not apparent that setting
either GUC from the configuration file would be wise.)
Also fix check_temp_buffers, which had a different form of the disease
of making state-dependent checks without any exception for PGC_S_TEST.
A cursory survey of other GUC check hooks did not find any more issues
of this ilk. (There are a lot of interdependencies among
PGC_POSTMASTER and PGC_SIGHUP GUCs, which may be a bad idea, but
they're not relevant to the immediate concern because they can't be
set via ALTER ROLE/DATABASE.)
Per reports from Charlie Hornsby and Nathan Bossart. Back-patch
to all supported branches.
Discussion: https://postgr.es/m/HE1P189MB0523B31598B0C772C908088DB7709@HE1P189MB0523.EURP189.PROD.OUTLOOK.COM
Discussion: https://postgr.es/m/20160711223641.1426.86096@wrigleys.postgresql.org
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If a multi-byte character is escaped with a backslash in TEXT mode input,
and the encoding is one of the client-only encodings where the bytes after
the first one can have an ASCII byte "embedded" in the char, we didn't
skip the character correctly. After a backslash, we only skipped the first
byte of the next character, so if it was a multi-byte character, we would
try to process its second byte as if it was a separate character. If it
was one of the characters with special meaning, like '\n', '\r', or
another '\\', that would cause trouble.
One such exmple is the byte sequence '\x5ca45c2e666f6f' in Big5 encoding.
That's supposed to be [backslash][two-byte character][.][f][o][o], but
because the second byte of the two-byte character is 0x5c, we incorrectly
treat it as another backslash. And because the next character is a dot, we
parse it as end-of-copy marker, and throw an "end-of-copy marker corrupt"
error.
Backpatch to all supported versions.
Reviewed-by: John Naylor, Kyotaro Horiguchi
Discussion: https://www.postgresql.org/message-id/a897f84f-8dca-8798-3139-07da5bb38728%40iki.fi
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Every core SLRU wraps around. With the exception of pg_notify, the wrap
point can fall in the middle of a page. Account for this in the
PagePrecedes callback specification and in SimpleLruTruncate()'s use of
said callback. Update each callback implementation to fit the new
specification. This changes SerialPagePrecedesLogically() from the
style of asyncQueuePagePrecedes() to the style of CLOGPagePrecedes().
(Whereas pg_clog and pg_serial share a key space, pg_serial is nothing
like pg_notify.) The bug fixed here has the same symptoms and user
followup steps as 592a589a04bd456410b853d86bd05faa9432cbbb. Back-patch
to 9.5 (all supported versions).
Reviewed by Andrey Borodin and (in earlier versions) by Tom Lane.
Discussion: https://postgr.es/m/20190202083822.GC32531@gust.leadboat.com
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Commit 566372b3d fixed some race conditions involving concurrent
SimpleLruTruncate calls, but it introduced new ones in async.c.
A newly-listening backend could attempt to read Notify SLRU pages that
were in process of being truncated, possibly causing an error. Also,
the QUEUE_TAIL pointer could become set to a value that's not equal to
the queue position of any backend. While that's fairly harmless in
v13 and up (thanks to commit 51004c717), in older branches it resulted
in near-permanent disabling of the queue truncation logic, so that
continued use of NOTIFY led to queue-fill warnings and eventual
inability to send any more notifies. (A server restart is enough to
make that go away, but it's still pretty unpleasant.)
The core of the problem is confusion about whether QUEUE_TAIL
represents the "logical" tail of the queue (i.e., the oldest
still-interesting data) or the "physical" tail (the oldest data we've
not yet truncated away). To fix, split that into two variables.
QUEUE_TAIL regains its definition as the logical tail, and we
introduce a new variable to track the oldest un-truncated page.
Per report from Mikael Gustavsson. Like the previous patch,
back-patch to all supported branches.
Discussion: https://postgr.es/m/1b8561412e8a4f038d7a491c8b922788@smhi.se
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Specifically, this blocks DECLARE ... WITH HOLD and firing of deferred
triggers within index expressions and materialized view queries. An
attacker having permission to create non-temp objects in at least one
schema could execute arbitrary SQL functions under the identity of the
bootstrap superuser. One can work around the vulnerability by disabling
autovacuum and not manually running ANALYZE, CLUSTER, REINDEX, CREATE
INDEX, VACUUM FULL, or REFRESH MATERIALIZED VIEW. (Don't restore from
pg_dump, since it runs some of those commands.) Plain VACUUM (without
FULL) is safe, and all commands are fine when a trusted user owns the
target object. Performance may degrade quickly under this workaround,
however. Back-patch to 9.5 (all supported versions).
Reviewed by Robert Haas. Reported by Etienne Stalmans.
Security: CVE-2020-25695
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Revert 59ab4ac32, as well as the followup fix 33862cb9c, in all
branches. We need to think a bit harder about what the behavior
of LOCK TABLE on views should be, and there's no time for that
before next week's releases. We'll take another crack at this
later.
Discussion: https://postgr.es/m/16703-e348f58aab3cf6cc@postgresql.org
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The intention in commit 491c029db was to require superuserness to
change the BYPASSRLS property, but the actual effect of the coding
in AlterRole() was to require superuserness to change anything at all
about a BYPASSRLS role. Other properties of a BYPASSRLS role should
be changeable under the same rules as for a normal role, though.
Fix that, and also take care of some documentation omissions related
to BYPASSRLS and REPLICATION role properties.
Tom Lane and Stephen Frost, per bug report from Wolfgang Walther.
Back-patch to all supported branches.
Discussion: https://postgr.es/m/a5548a9f-89ee-3167-129d-162b5985fcf8@technowledgy.de
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EventTriggerAlterTableEnd neglected to make sure that it built its
output list in the right context. In simple cases this was masked
because the function is called in PortalContext which will be
sufficiently long-lived anyway; but that doesn't make it not a bug.
Commit ced138e8c fixed this in HEAD and v13, but mistakenly chose
not to back-patch further. Back-patch the same code change all
the way (I didn't bother with the test case though, as it would
prove nothing in pre-v13 branches).
Per report from Arseny Sher.
Original fix by Jehan-Guillaume de Rorthais.
Discussion: https://postgr.es/m/877drcyprb.fsf@ars-thinkpad
Discussion: https://postgr.es/m/20200902193715.6e0269d4@firost
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The restriction that only tables and views can be locked by LOCK TABLE
is quite arbitrary, since the underlying mechanism can lock any relation
type. Drop the restriction so that programs such as pg_dump can lock
all relations they're interested in, preventing schema changes that
could cause a dump to fail after expending much effort.
Backpatch to 9.5.
Author: Álvaro Herrera <alvherre@alvh.no-ip.org>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reported-by: Wells Oliver <wells.oliver@gmail.com>
Discussion: https://postgr.es/m/20201021200659.GA32358@alvherre.pgsql
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This function leaked some memory while loading qual clauses for
an RLS policy. While ordinarily negligible, that could build up
in some repeated-reload cases, as reported by Konstantin Knizhnik.
We can improve matters by borrowing the coding long used in
RelationBuildRuleLock: build stringToNode's result directly in
the target context, and remember to explicitly pfree the
input string.
This patch by no means completely guarantees zero leaks within
this function, since we have no real guarantee that the catalog-
reading subroutines it calls don't leak anything. However,
practical tests suggest that this is enough to resolve the issue.
In any case, any remaining leaks are similar to those risked by
RelationBuildRuleLock and other relcache-loading subroutines.
If we need to fix them, we should adopt a more global approach
such as that used by the RECOVER_RELATION_BUILD_MEMORY hack.
While here, let's remove the need for an expensive PG_TRY block by
using MemoryContextSetParent to reparent an initially-short-lived
context for the RLS data.
Back-patch to all supported branches.
Discussion: https://postgr.es/m/21356c12-8917-8249-b35f-1c447231922b@postgrespro.ru
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The SimpleLruTruncate() header comment states the new coding rule. To
achieve this, add locktype "frozenid" and two LWLocks. This closes a
rare opportunity for data loss, which manifested as "apparent
wraparound" or "could not access status of transaction" errors. Data
loss is more likely in pg_multixact, due to released branches' thin
margin between multiStopLimit and multiWrapLimit. If a user's physical
replication primary logged ": apparent wraparound" messages, the user
should rebuild standbys of that primary regardless of symptoms. At less
risk is a cluster having emitted "not accepting commands" errors or
"must be vacuumed" warnings at some point. One can test a cluster for
this data loss by running VACUUM FREEZE in every database. Back-patch
to 9.5 (all supported versions).
Discussion: https://postgr.es/m/20190218073103.GA1434723@rfd.leadboat.com
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Hostile objects located within the installation-time search_path could
capture references in an extension's installation or upgrade script.
If the extension is being installed with superuser privileges, this
opens the door to privilege escalation. While such hazards have existed
all along, their urgency increases with the v13 "trusted extensions"
feature, because that lets a non-superuser control the installation path
for a superuser-privileged script. Therefore, make a number of changes
to make such situations more secure:
* Tweak the construction of the installation-time search_path to ensure
that references to objects in pg_catalog can't be subverted; and
explicitly add pg_temp to the end of the path to prevent attacks using
temporary objects.
* Disable check_function_bodies within installation/upgrade scripts,
so that any security gaps in SQL-language or PL-language function bodies
cannot create a risk of unwanted installation-time code execution.
* Adjust lookup of type input/receive functions and join estimator
functions to complain if there are multiple candidate functions. This
prevents capture of references to functions whose signature is not the
first one checked; and it's arguably more user-friendly anyway.
* Modify various contrib upgrade scripts to ensure that catalog
modification queries are executed with secure search paths. (These
are in-place modifications with no extension version changes, since
it is the update process itself that is at issue, not the end result.)
Extensions that depend on other extensions cannot be made fully secure
by these methods alone; therefore, revert the "trusted" marking that
commit eb67623c9 applied to earthdistance and hstore_plperl, pending
some better solution to that set of issues.
Also add documentation around these issues, to help extension authors
write secure installation scripts.
Patch by me, following an observation by Andres Freund; thanks
to Noah Misch for review.
Security: CVE-2020-14350
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An ALTER TABLE to validate a foreign key in which another subcommand
already caused a pending table rewrite could fail due to ALTER TABLE
attempting to validate the foreign key before the actual table rewrite
takes place. This situation could result in an error such as:
ERROR: could not read block 0 in file "base/nnnnn/nnnnn": read only 0 of 8192 bytes
The failure here was due to the SPI call which validates the foreign key
trying to access an index which is yet to be rebuilt.
Similarly, we also incorrectly tried to validate CHECK constraints before
the heap had been rewritten.
The fix for both is to delay constraint validation until phase 3, after
the table has been rewritten. For CHECK constraints this means a slight
behavioral change. Previously ALTER TABLE VALIDATE CONSTRAINT on
inheritance tables would be validated from the bottom up. This was
different from the order of evaluation when a new CHECK constraint was
added. The changes made here aligns the VALIDATE CONSTRAINT evaluation
order for inheritance tables to be the same as ADD CONSTRAINT, which is
generally top-down.
Reported-by: Nazli Ugur Koyluoglu, using SQLancer
Discussion: https://postgr.es/m/CAApHDvp%3DZXv8wiRyk_0rWr00skhGkt8vXDrHJYXRMft3TjkxCA%40mail.gmail.com
Backpatch-through: 9.5 (all supported versions)
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Commit ecd9e9f0b fixed the problem in the wrong place, causing unwanted
side-effects on the behavior of GetNextTempTableSpace(). Instead,
let's make SharedFileSetInit() responsible for subbing in the value
of MyDatabaseTableSpace when the default tablespace is called for.
The convention about what is in the tempTableSpaces[] array is
evidently insufficiently documented, so try to improve that.
It also looks like SharedFileSetInit() is doing the wrong thing in the
case where temp_tablespaces is empty. It was hard-wiring use of the
pg_default tablespace, but it seems like using MyDatabaseTableSpace
is more consistent with what happens for other temp files.
Back-patch the reversion of PrepareTempTablespaces()'s behavior to
9.5, as ecd9e9f0b was. The changes in SharedFileSetInit() go back
to v11 where that was introduced. (Note there is net zero code change
before v11 from these two patch sets, so nothing to release-note.)
Magnus Hagander and Tom Lane
Discussion: https://postgr.es/m/CABUevExg5YEsOvqMxrjoNvb3ApVyH+9jggWGKwTDFyFCVWczGQ@mail.gmail.com
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A likely copy/paste error in 98e8b480532 from back in 2004 would
cause temp tablespace to be reset to InvalidOid if temp_tablespaces
was set to the same value as the primary tablespace in the database.
This would cause shared filesets (such as for parallel hash joins)
to ignore them, putting the temporary files in the default tablespace
instead of the configured one. The bug is in the old code, but it
appears to have been exposed only once we had shared filesets.
Reviewed-By: Daniel Gustafsson
Discussion: https://postgr.es/m/CABUevExg5YEsOvqMxrjoNvb3ApVyH+9jggWGKwTDFyFCVWczGQ@mail.gmail.com
Backpatch-through: 9.5
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explain_get_index_name() applied quote_identifier() to the index name.
This is fine for text output, but the non-text output formats all have
their own quoting conventions and would much rather start from the
actual index name. For example in JSON you'd get something like
"Index Name": "\"My Index\"",
which is surely not desirable, especially when the same does not
happen for table names. Hence, move the responsibility for applying
quoting out to the callers, where it can go into already-existing
special code paths for text format.
This changes the API spec for users of explain_get_index_name_hook:
before, they were supposed to apply quote_identifier() if necessary,
now they should not. Research suggests that the only publicly
available user of the hook is hypopg, and it actually forgot to
apply quoting anyway, so it's fine. (In any case, there's no
behavioral change for the output of a hook as seen in non-text
EXPLAIN formats, so this won't break any case that programs should
be relying on.)
Digging in the commit logs, it appears that quoting was included in
explain_get_index_name's duties when commit 604ffd280 invented it;
and that was fine at the time because we only had text output format.
This should have been rethought when non-text formats were invented,
but it wasn't.
This is a fairly clear bug for users of non-text EXPLAIN formats,
so back-patch to all supported branches.
Per bug #16502 from Maciek Sakrejda. Patch by me (based on
investigation by Euler Taveira); thanks to Julien Rouhaud for review.
Discussion: https://postgr.es/m/16502-57bd1c9f913ed1d1@postgresql.org
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CreateRole() was passing a Value node, not a RoleSpec node, for the
newly-created role name when adding the role as a member of existing
roles for the IN ROLE syntax.
This mistake went unnoticed because the node in question is used only
for error messages and is not accessed on non-error paths.
In older pg versions (such as 9.5 where this was found), this results
in an "unexpected node type" error in place of the real error. That
node type check was removed at some point, after which the code would
accidentally fail to fail on 64-bit platforms (on which accessing the
Value node as if it were a RoleSpec would be mostly harmless) or give
an "unexpected role type" error on 32-bit platforms.
Fix the code to pass the correct node type, and add an lfirst_node
assertion just in case.
Per report on irc from user m1chelangelo.
Backpatch all the way, because this error has been around for a long
time.
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A table rewritten by ALTER TABLE would lose tracking of an index usable
for CLUSTER. This setting is tracked by pg_index.indisclustered and is
controlled by ALTER TABLE, so some extra work was needed to restore it
properly. Note that ALTER TABLE only marks the index that can be used
for clustering, and does not do the actual operation.
Author: Amit Langote, Justin Pryzby
Reviewed-by: Ibrar Ahmed, Michael Paquier
Discussion: https://postgr.es/m/20200202161718.GI13621@telsasoft.com
Backpatch-through: 9.5
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This reverts commit cb2fd7eac285b1b0a24eeb2b8ed4456b66c5a09f. Per
numerous buildfarm members, it was incompatible with parallel query, and
a test case assumed LP64. Back-patch to 9.5 (all supported versions).
Discussion: https://postgr.es/m/20200321224920.GB1763544@rfd.leadboat.com
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Until now, only selected bulk operations (e.g. COPY) did this. If a
given relfilenode received both a WAL-skipping COPY and a WAL-logged
operation (e.g. INSERT), recovery could lose tuples from the COPY. See
src/backend/access/transam/README section "Skipping WAL for New
RelFileNode" for the new coding rules. Maintainers of table access
methods should examine that section.
To maintain data durability, just before commit, we choose between an
fsync of the relfilenode and copying its contents to WAL. A new GUC,
wal_skip_threshold, guides that choice. If this change slows a workload
that creates small, permanent relfilenodes under wal_level=minimal, try
adjusting wal_skip_threshold. Users setting a timeout on COMMIT may
need to adjust that timeout, and log_min_duration_statement analysis
will reflect time consumption moving to COMMIT from commands like COPY.
Internally, this requires a reliable determination of whether
RollbackAndReleaseCurrentSubTransaction() would unlink a relation's
current relfilenode. Introduce rd_firstRelfilenodeSubid. Amend the
specification of rd_createSubid such that the field is zero when a new
rel has an old rd_node. Make relcache.c retain entries for certain
dropped relations until end of transaction.
Back-patch to 9.5 (all supported versions). This introduces a new WAL
record type, XLOG_GIST_ASSIGN_LSN, without bumping XLOG_PAGE_MAGIC. As
always, update standby systems before master systems. This changes
sizeof(RelationData) and sizeof(IndexStmt), breaking binary
compatibility for affected extensions. (The most recent commit to
affect the same class of extensions was
089e4d405d0f3b94c74a2c6a54357a84a681754b.)
Kyotaro Horiguchi, reviewed (in earlier, similar versions) by Robert
Haas. Heikki Linnakangas and Michael Paquier implemented earlier
designs that materially clarified the problem. Reviewed, in earlier
designs, by Andrew Dunstan, Andres Freund, Alvaro Herrera, Tom Lane,
Fujii Masao, and Simon Riggs. Reported by Martijn van Oosterhout.
Discussion: https://postgr.es/m/20150702220524.GA9392@svana.org
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swap_relation_files() calls toast_get_valid_index() to find and lock
this index, just before swapping with the rebuilt TOAST index. The
latter function releases the lock before returning. Potential for
mischief is low; a concurrent session can issue ALTER INDEX ... SET
(fillfactor = ...), which is not alarming. Nonetheless, changing
pg_class.relfilenode without a lock is unconventional. Back-patch to
9.5 (all supported versions), because another fix needs this.
Discussion: https://postgr.es/m/20191226001521.GA1772687@rfd.leadboat.com
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If an index was explicitly set as replica identity index, this setting
was lost when a table was rewritten by ALTER TABLE. Because this
setting is part of pg_index but actually controlled by ALTER
TABLE (not part of CREATE INDEX, say), we have to do some extra work
to restore it.
Based-on-patch-by: Quan Zongliang <quanzongliang@gmail.com>
Reviewed-by: Euler Taveira <euler.taveira@2ndquadrant.com>
Discussion: https://www.postgresql.org/message-id/flat/c70fcab2-4866-0d9f-1d01-e75e189db342@gmail.com
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If the command is attempted for an extension that the object already
depends on, silently do nothing.
In particular, this means that if a database containing multiple such
entries is dumped, the restore will silently do the right thing and
record just the first one. (At least, in a world where pg_dump does
dump such entries -- which it doesn't currently, but it will.)
Backpatch to 9.6, where this kind of dependency was introduced.
Reviewed-by: Ibrar Ahmed, Tom Lane (offlist)
Discussion: https://postgr.es/m/20200217225333.GA30974@alvherre.pgsql
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VACUUM may truncate heap in several batches. The activity report
is logged for each batch, and contains the number of pages in the table
before and after the truncation, and also the elapsed time during
the truncation. Previously the elapsed time reported in each batch was
the total elapsed time since starting the truncation until finishing
each batch. For example, if the truncation was processed dividing into
three batches, the second batch reported the accumulated time elapsed
during both first and second batches. This is strange and confusing
because the number of pages in the table reported together is not
total. Instead, each batch should report the time elapsed during
only that batch.
The cause of this issue was that the resource usage snapshot was
initialized only at the beginning of the truncation and was never
reset later. This commit fixes the issue by changing VACUUM so that
the resource usage snapshot is reset at each batch.
Back-patch to all supported branches.
Reported-by: Tatsuhito Kasahara
Author: Tatsuhito Kasahara
Reviewed-by: Masahiko Sawada, Fujii Masao
Discussion: https://postgr.es/m/CAP0=ZVJsf=NvQuy+QXQZ7B=ZVLoDV_JzsVC1FRsF1G18i3zMGg@mail.gmail.com
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Marking an object as dependant on an extension did not have any
privilege check whatsoever; this allowed any user to mark objects as
droppable by anyone able to DROP EXTENSION, which could be used to cause
system-wide havoc. Disallow by checking that the calling user owns the
mentioned object.
(No constraints are placed on the extension.)
Security: CVE-2020-1720
Reported-by: Tom Lane
Discussion: 31605.1566429043@sss.pgh.pa.us
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This commit reverts the fix "Make inherited TRUNCATE perform access
permission checks on parent table only" only in the back branches.
It's not hard to imagine that there are some applications expecting
the old behavior and the fix breaks their security. To avoid this
compatibility problem, we decided to apply the fix only in HEAD and
revert it in all supported back branches.
Discussion: https://postgr.es/m/21015.1580400165@sss.pgh.pa.us
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Previously, TRUNCATE command through a parent table checked the
permissions on not only the parent table but also the children tables
inherited from it. This was a bug and inherited queries should perform
access permission checks on the parent table only. This commit fixes
that bug.
Back-patch to all supported branches.
Author: Amit Langote
Reviewed-by: Fujii Masao
Discussion: https://postgr.es/m/CAHGQGwFHdSvifhJE+-GSNqUHSfbiKxaeQQ7HGcYz6SC2n_oDcg@mail.gmail.com
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Attempting to use CREATE INDEX, DROP INDEX or REINDEX with CONCURRENTLY
on a temporary relation with ON COMMIT actions triggered unexpected
errors because those operations use multiple transactions internally to
complete their work. Here is for example one confusing error when using
ON COMMIT DELETE ROWS:
ERROR: index "foo" already contains data
Issues related to temporary relations and concurrent indexing are fixed
in this commit by enforcing the non-concurrent path to be taken for
temporary relations even if using CONCURRENTLY, transparently to the
user. Using a non-concurrent path does not matter in practice as locks
cannot be taken on a temporary relation by a session different than the
one owning the relation, and the non-concurrent operation is more
effective.
The problem exists with REINDEX since v12 with the introduction of
CONCURRENTLY, and with CREATE/DROP INDEX since CONCURRENTLY exists for
those commands. In all supported versions, this caused only confusing
error messages to be generated. Note that with REINDEX, it was also
possible to issue a REINDEX CONCURRENTLY for a temporary relation owned
by a different session, leading to a server crash.
The idea to enforce transparently the non-concurrent code path for
temporary relations comes originally from Andres Freund.
Reported-by: Manuel Rigger
Author: Michael Paquier, Heikki Linnakangas
Reviewed-by: Andres Freund, Álvaro Herrera, Heikki Linnakangas
Discussion: https://postgr.es/m/CA+u7OA6gP7YAeCguyseusYcc=uR8+ypjCcgDDCTzjQ+k6S9ksQ@mail.gmail.com
Backpatch-through: 9.4
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This reverts commit a052f6c, following complains from Robert Haas and
Tom Lane. Backpatch down to 9.4, like the previous commit.
Discussion: https://postgr.es/m/CA+TgmobL4npEX5=E5h=5Jm_9mZun3MT39Kq2suJFVeamc9skSQ@mail.gmail.com
Backpatch-through: 9.4
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This operation was possible for the owner of the schema or a superuser.
Down to 9.4, doing this operation would cause inconsistencies in a
session whose temporary schema was dropped, particularly if trying to
create new temporary objects after the drop. A more annoying
consequence is a crash of autovacuum on an assertion failure when
logging information about an orphaned temp table dropped. Note that
because of 246a6c8 (present in v11~), which has made the removal of
orphaned temporary tables more aggressive, the failure could be
triggered more easily, but it is possible to reproduce down to 9.4.
Reported-by: Mahendra Singh, Prabhat Sahu
Author: Michael Paquier
Reviewed-by: Kyotaro Horiguchi, Mahendra Singh
Discussion: https://postgr.es/m/CAKYtNAr9Zq=1-ww4etHo-VCC-k120YxZy5OS01VkaLPaDbv2tg@mail.gmail.com
Backpatch-through: 9.4
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This patch ensures that, if any notify messages were received during
a just-finished transaction, they get sent to the frontend just before
not just after the ReadyForQuery message. With libpq and other client
libraries that act similarly, this guarantees that the client will see
the notify messages as available as soon as it thinks the transaction
is done.
This probably makes no difference in practice, since in realistic
use-cases the application would have to cope with asynchronous
arrival of notify events anyhow. However, it makes it a lot easier
to build cross-session-notify test cases with stable behavior.
I'm a bit surprised now that we've not seen any buildfarm instability
with the test cases added by commit b10f40bf0. Tests that I intend
to add in an upcoming bug fix are definitely unstable without this.
Back-patch to 9.6, which is as far back as we can do NOTIFY testing
with the isolationtester infrastructure.
Discussion: https://postgr.es/m/13881.1574557302@sss.pgh.pa.us
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Commits 801c2dc7 and 801c2dc7 made it possible for vacuum to
try to freeze a multixact that is still running. That was
prevented by a check, but raised an error. Repair.
Back-patch all the way.
Author: Nathan Bossart, Jeremy Schneider
Reported-by: Jeremy Schneider
Reviewed-by: Jim Nasby, Thomas Munro
Discussion: https://postgr.es/m/DAFB8AFF-2F05-4E33-AD7F-FF8B0F760C17%40amazon.com
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If a table inherits from multiple unrelated parents, we must disallow
changing the type of a column inherited from multiple such parents, else
it would be out of step with the other parents. However, it's possible
for the column to ultimately be inherited from just one common ancestor,
in which case a change starting from that ancestor should still be
allowed. (I would not be excited about preserving that option, were
it not that we have regression test cases exercising it already ...)
It's slightly annoying that this patch looks different from the logic
with the same end goal in renameatt(), and more annoying that it
requires an extra syscache lookup to make the test. However, the
recursion logic is quite different in the two functions, and a
back-patched bug fix is no place to be trying to unify them.
Per report from Manuel Rigger. Back-patch to 9.5. The bug exists in
9.4 too (and doubtless much further back); but the way the recursion
is done in 9.4 is a good bit different, so that substantial refactoring
would be needed to fix it in 9.4. I'm disinclined to do that, or risk
introducing new bugs, for a bug that has escaped notice for this long.
Discussion: https://postgr.es/m/CA+u7OA4qogDv9rz1HAb-ADxttXYPqQdUdPY_yd4kCzywNxRQXA@mail.gmail.com
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This is a variant of the problem fixed in commit 25b692568, which
unfortunately we failed to detect at the time. If an update trigger
returns the "old" tuple, as it's entitled to do, then a subsequent
iteration of the loop in ExecBRUpdateTriggers would have "oldtuple"
equal to "trigtuple" and would fail to notice that it shouldn't
free that.
In addition to fixing the code, extend the test case added by
25b692568 so that it covers multiple-trigger-iterations cases.
This problem does not manifest in v12/HEAD, as a result of the
relevant code having been largely rewritten for slotification.
However, include the test case into v12/HEAD anyway, since this
is clearly an area that someone could break again in future.
Per report from Piotr Gabriel Kosinski. Back-patch into all
supported branches, since the bug seems quite old.
Diagnosis and code fix by Thomas Munro, test case by me.
Discussion: https://postgr.es/m/CAFMLSdP0rd7LqC3j-H6Fh51FYSt5A10DDh-3=W4PPc4LLUQ8YQ@mail.gmail.com
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This should lappend the OIDs, not lcons them; the existing code produced
a list in reversed order. This is harmless for single-key FKs or FKs
where all the key columns are of the same type, which probably explains
how it went unnoticed. But if those conditions are not met,
ATAddForeignKeyConstraint would make the wrong decision about whether an
existing FK needs to be revalidated. I think it would almost always err
in the safe direction by revalidating a constraint that didn't need it.
You could imagine scenarios where the pfeqop check was fooled by
swapping the types of two FK columns in one ALTER TABLE, but that case
would probably be rejected by other tests, so it might be impossible to
get to the worst-case scenario where an FK should be revalidated and
isn't. (And even then, it's likely to be fine, unless there are weird
inconsistencies in the equality behavior of the replacement types.)
However, this is a performance bug at least.
Noted while poking around to see whether lcons calls could be converted
to lappend.
This bug is old, dating to commit cb3a7c2b9, so back-patch to all
supported branches.
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Commit 83e176ec1 moved row sampling functions from analyze.c to
utils/misc/sampling.c, but failed to update comment referring to
the sampling algorithm from Jeff Vitter's paper. Correct the
comment by pointing to utils/misc/sampling.c.
Author: Etsuro Fujita
Discussion: https://postgr.es/m/CAPmGK154gp%2BQd%3DcorQOv%2BPmbyVyZBjp_%2Bhb766UJeD1e_ie6XQ%40mail.gmail.com
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This patch reverts all the code changes of commit e76de8861, which turns
out to have been seriously misguided. We can't wait till later to compute
the definition string for an index; we must capture that before applying
the data type change for any column it depends on, else ruleutils.c will
deliverr wrong/misleading results. (This fine point was documented
nowhere, of course.)
I'd also managed to forget that ATExecAlterColumnType executes once per
ALTER COLUMN TYPE clause, not once per statement; which resulted in the
code being basically completely broken for any case in which multiple ALTER
COLUMN TYPE clauses are applied to a table having non-constraint indexes
that must be rebuilt. Through very bad luck, none of the existing test
cases nor the ones added by e76de8861 caught that, but of course it was
soon found in the field.
The previous patch also had an implicit assumption that if a constraint's
index had a dependency on a table column, so would the constraint --- but
that isn't actually true, so it didn't fix such cases.
Instead of trying to delete unneeded index dependencies later, do the
is-there-a-constraint lookup immediately on seeing an index dependency,
and switch to remembering the constraint if so. In the unusual case of
multiple column dependencies for a constraint index, this will result in
duplicate constraint lookups, but that's not that horrible compared to all
the other work that happens here. Besides, such cases did not work at all
before, so it's hard to argue that they're performance-critical for anyone.
Per bug #15865 from Keith Fiske. As before, back-patch to all supported
branches.
Discussion: https://postgr.es/m/15865-17940eacc8f8b081@postgresql.org
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ATExecAlterColumnType failed to consider the possibility that an index
that needs to be rebuilt might be a child of a constraint that needs to be
rebuilt. We missed this so far because usually a constraint index doesn't
have a direct dependency on its table, just on the constraint object.
But if there's a WHERE clause, then dependency analysis of the WHERE
clause results in direct dependencies on the column(s) mentioned in WHERE.
This led to trying to drop and rebuild both the constraint and its
underlying index.
In v11/HEAD, we successfully drop both the index and the constraint,
and then try to rebuild both, and of course the second rebuild hits a
duplicate-index-name problem. Before v11, it fails with obscure messages
about a missing relation OID, due to trying to drop the index twice.
This is essentially the same kind of problem noted in commit
20bef2c31: the possible dependency linkages are broader than what
ATExecAlterColumnType was designed for. It was probably OK when
written, but it's certainly been broken since the introduction of
partial exclusion constraints. Fix by adding an explicit check
for whether any of the indexes-to-be-rebuilt belong to any of the
constraints-to-be-rebuilt, and ignoring any that do.
In passing, fix a latent bug introduced by commit 8b08f7d48: in
get_constraint_index() we must "continue" not "break" when rejecting
a relation of a wrong relkind. This is harmless today because we don't
expect that code path to be taken anyway; but if there ever were any
relations to be ignored, the existing coding would have an extremely
undesirable dependency on the order of pg_depend entries.
Also adjust a couple of obsolete comments.
Per bug #15835 from Yaroslav Schekin. Back-patch to all supported
branches.
Discussion: https://postgr.es/m/15835-32d9b7a76c06a7a9@postgresql.org
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Vignesh found this bug in the check function for
default_table_access_method's check hook, but that was just copied
from older GUCs. Investigation by Michael and me then found the bug in
further places.
When not connected to a database (e.g. in a walsender connection), we
cannot perform (most) GUC checks that need database access. Even when
only shared tables are needed, unless they're
nailed (c.f. RelationCacheInitializePhase2()), they cannot be accessed
without pg_class etc. being present.
Fix by extending the existing IsTransactionState() checks to also
check for MyDatabaseOid.
Reported-By: Vignesh C, Michael Paquier, Andres Freund
Author: Vignesh C, Andres Freund
Discussion: https://postgr.es/m/CALDaNm1KXK9gbZfY-p_peRFm_XrBh1OwQO1Kk6Gig0c0fVZ2uw%40mail.gmail.com
Backpatch: 9.4-
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We should logically have allowed this case when we allowed zero-column
tables, but it was overlooked.
Although this might be thought a feature addition, it's really a bug
fix, because it was possible to create a zero-column view via
the convert-table-to-view code path, and then you'd have a situation
where dump/reload would fail. Hence, back-patch to all supported
branches.
Arrange the added test cases to provide coverage of the related
pg_dump code paths (since these views will be dumped and reloaded
during the pg_upgrade regression test). I also made them test
the case where pg_dump has to postpone the view rule into post-data,
which disturbingly had no regression coverage before.
Report and patch by Ashutosh Sharma (test case by me)
Discussion: https://postgr.es/m/CAE9k0PkmHdeSaeZt2ujnb_cKucmK3sDDceDzw7+d5UZoNJPYOg@mail.gmail.com
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This patch changes the rule for whether or not a tuple seen by ANALYZE
should be included in its sample.
When we last touched this logic, in commit 51e1445f1, we weren't
thinking very hard about tuples being UPDATEd by a long-running
concurrent transaction. In such a case, we might see the pre-image as
either LIVE or DELETE_IN_PROGRESS depending on timing; and we might see
the post-image not at all, or as INSERT_IN_PROGRESS. Since the existing
code will not sample either DELETE_IN_PROGRESS or INSERT_IN_PROGRESS
tuples, this leads to concurrently-updated rows being omitted from the
sample entirely. That's not very helpful, and it's especially the wrong
thing if the concurrent transaction ends up rolling back.
The right thing seems to be to sample DELETE_IN_PROGRESS rows just as if
they were live. This makes the "sample it" and "count it" decisions the
same, which seems good for consistency. It's clearly the right thing
if the concurrent transaction ends up rolling back; in effect, we are
sampling as though IN_PROGRESS transactions haven't happened yet.
Also, this combination of choices ensures maximum robustness against
the different combinations of whether and in which state we might see the
pre- and post-images of an update.
It's slightly annoying that we end up recording immediately-out-of-date
stats in the case where the transaction does commit, but on the other
hand the stats are fine for columns that didn't change in the update.
And the alternative of sampling INSERT_IN_PROGRESS rows instead seems
like a bad idea, because then the sampling would be inconsistent with
the way rows are counted for the stats report.
Per report from Mark Chambers; thanks to Jeff Janes for diagnosing
what was happening. Back-patch to all supported versions.
Discussion: https://postgr.es/m/CAFh58O_Myr6G3tcH3gcGrF-=OExB08PJdWZcSBcEcovaiPsrHA@mail.gmail.com
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Inheritance trees can include temporary tables if the parent is
permanent, which makes possible the presence of multiple temporary
children from different sessions. Trying to issue a TRUNCATE on the
parent in this scenario causes a failure, so similarly to any other
queries just ignore such cases, which makes TRUNCATE work
transparently.
This makes truncation behave similarly to any other DML query working on
the parent table with queries which need to be issues on children. A
set of isolation tests is added to cover basic cases.
Reported-by: Zhou Digoal
Author: Amit Langote, Michael Paquier
Discussion: https://postgr.es/m/15565-ce67a48d0244436a@postgresql.org
Backpatch-through: 9.4
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The flag for IF NOT EXISTS was only being passed down in the normal
recursing case. It's been this way since originally added in 9.6 in
commit 2cd40adb85 so backpatch back to 9.6.
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This is an oversight from recent commit b13fd344. While on it, tweak
the previous test with a better name for the renamed primary key.
Detected by buildfarm member prion which forces relation cache release
with -DRELCACHE_FORCE_RELEASE. Back-patch down to 9.4 as the previous
commit.
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