The target cluster that was rewound needs to perform recovery from
the checkpoint created at failover, which leads it to remove or recreate
some files and directories that may have been copied from the source
cluster. So pg_rewind can skip synchronizing such files and directories,
and which reduces the amount of data transferred during a rewind
without changing the usefulness of the operation.
Author: Michael Paquier
Reviewed-by: Anastasia Lubennikova, Stephen Frost and me
Discussion: https://postgr.es/m/20180205071022.GA17337@paquier.xyz
After processing the filemap to build the list of chunks that will be
fetched from the source to rewing the target server, it is possible that
a file which was previously processed is removed from the source. A
simple example of such an occurence is a WAL segment which gets recycled
on the target in-between. When the filemap is processed, files not
categorized as relation files are first truncated to prepare for its
full copy of which is going to be taken from the source, divided into a
set of junks. However, for a recycled WAL segment, this would result in
a segment which has a zero-byte size. With such an empty file,
post-rewind recovery thinks that records are saved but they are actually
not because of the truncation which happened when processing the
filemap, resulting in data loss.
In order to fix the problem, make sure that files which are found as
removed on the source when receiving chunks of them are as well deleted
on the target server for consistency.
Back-patch to 9.5 where pg_rewind was added.
Author: Tsunakawa Takayuki
Reviewed-by: Michael Paquier
Reported-by: Tsunakawa Takayuki
Discussion: https://postgr.es/m/0A3221C70F24FB45833433255569204D1F8DAAA2%40G01JPEXMBYT05
If the value of an index expression is unchanged after UPDATE,
allow HOT updates where previously we disallowed them, giving
a significant performance boost in those cases.
Particularly useful for indexes such as JSON->>field where the
JSON value changes but the indexed value does not.
Submitted as "surjective indexes" patch, now enabled by use
of new "recheck_on_update" parameter.
Author: Konstantin Knizhnik
Reviewer: Simon Riggs, with much wordsmithing and some cleanup
Setting random could increase reproducibility of test in some cases. Patch
suggests three providers for seed: time (default), strong random
generator (if available) and unsigned constant. Seed could be set from
command line or enviroment variable.
Author: Fabien Coelho
Reviewed by: Chapman Flack
Discussion: https://www.postgresql.org/message-id/flat/20160407082711.q7iq3ykffqxcszkv@alap3.anarazel.de
This adds a new option --wal-segsize (analogous to initdb) that changes
the WAL segment size in pg_control.
Author: Nathan Bossart <bossartn@amazon.com>
We were running out of good single-letter options for some upcoming
pg_resetwal functionality, so add long options to create more
possibilities. Add to pg_controldata as well for symmetry.
based on patch by Bossart, Nathan <bossartn@amazon.com>
For years, our makefiles have correctly observed that "there is no correct
way to write a rule that generates two files". However, what we did is to
provide empty rules that "generate" the secondary output files from the
primary one, and that's not right either. Depending on the details of
the creating process, the primary file might end up timestamped later than
one or more secondary files, causing subsequent make runs to consider the
secondary file(s) out of date. That's harmless in a plain build, since
make will just re-execute the empty rule and nothing happens. But it's
fatal in a VPATH build, since make will expect the secondary file to be
rebuilt in the build directory. This would manifest as "file not found"
failures during VPATH builds from tarballs, if we were ever unlucky enough
to ship a tarball with apparently out-of-date secondary files. (It's not
clear whether that has ever actually happened, but it definitely could.)
To ensure that secondary output files have timestamps >= their primary's,
change our makefile convention to be that we provide a "touch $@" action
not an empty rule. Also, make sure that this rule actually gets invoked
during a distprep run, else the hazard remains.
It's been like this a long time, so back-patch to all supported branches.
In HEAD, I skipped the changes in src/backend/catalog/Makefile, because
those rules are due to get replaced soon in the bootstrap data format
patch, and there seems no need to create a merge issue for that patch.
If for some reason we fail to land that patch in v11, we'll need to
back-fill the changes in that one makefile from v10.
Discussion: https://postgr.es/m/18556.1521668179@sss.pgh.pa.us
Code that prints out the contents of setconfig or proconfig arrays in
SQL format needs to handle GUC_LIST_QUOTE variables differently from
other ones, because for those variables, flatten_set_variable_args()
already applied a layer of quoting. The value can therefore safely
be printed as-is, and indeed must be, or flatten_set_variable_args()
will muck it up completely on reload. For all other GUC variables,
it's necessary and sufficient to quote the value as a SQL literal.
We'd recognized the need for this long ago, but mis-analyzed the
need slightly, thinking that all GUC_LIST_INPUT variables needed
the special treatment. That's actually wrong, since a valid value
of a LIST variable might include characters that need quoting,
although no existing variables accept such values.
More to the point, we hadn't made any particular effort to keep the
various places that deal with this up-to-date with the set of variables
that actually need special treatment, meaning that we'd do the wrong
thing with, for example, temp_tablespaces values. This affects dumping
of SET clauses attached to functions, as well as ALTER DATABASE/ROLE SET
commands.
In ruleutils.c we can fix it reasonably honestly by exporting a guc.c
function that allows discovering the flags for a given GUC variable.
But pg_dump doesn't have easy access to that, so continue the old method
of having a hard-wired list of affected variable names. At least we can
fix it to have just one list not two, and update the list to match
current reality.
A remaining problem with this is that it only works for built-in
GUC variables. pg_dump's list obvious knows nothing of third-party
extensions, and even the "ask guc.c" method isn't bulletproof since
the relevant extension might not be loaded. There's no obvious
solution to that, so for now, we'll just have to discourage extension
authors from inventing custom GUCs that need GUC_LIST_QUOTE.
This has been busted for a long time, so back-patch to all supported
branches.
Michael Paquier and Tom Lane, reviewed by Kyotaro Horiguchi and
Pavel Stehule
Discussion: https://postgr.es/m/20180111064900.GA51030@paquier.xyz
If the control file is corrupted and specifies the WAL segment size
to be 0 bytes, calculating the latest checkpoint's REDO WAL file
will fail with a division-by-zero error. Show it as "???" instead.
Also reword the warning message a bit and send it to stdout, like the
other pre-existing warning messages.
Add some tests for dealing with a corrupted pg_control file.
Author: Nathan Bossart <bossartn@amazon.com>, tests by me
In e170b8c8, protection against modified search_path was added. However,
PostgreSQL versions prior to 10 does not accept SQL commands over a
replication connection, so the protection would generate a syntax error.
Since we cannot run SQL commands on it, we are also not vulnerable to
the issue that e170b8c8 fixes, so we can just skip this command for
older versions.
Author: Michael Paquier <michael@paquier.xyz>
We call this thing a "transaction block" everywhere except in a few
functions, where it is mysteriously called a "transaction chain". In
the SQL standard, a transaction chain is something different. So rename
these functions to match the common terminology.
Reviewed-by: Alvaro Herrera <alvherre@alvh.no-ip.org>
Fix the warnings created by the compiler warning options
-Wformat-overflow=2 -Wformat-truncation=2, supported since GCC 7. This
is a more aggressive variant of the fixes in
6275f5d28a, which GCC 7 warned about by
default.
The issues are all harmless, but some dubious coding patterns are
cleaned up.
One issue that is of external interest is that BGW_MAXLEN is increased
from 64 to 96. Apparently, the old value would cause the bgw_name of
logical replication workers to be truncated in some circumstances.
But this doesn't actually add those warning options. It appears that
the warnings depend a bit on compilation and optimization options, so it
would be annoying to have to keep up with that. This is more of a
once-in-a-while cleanup.
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Historically, tab completion for functions has offered the names of
aggregates as well. This is essential in at least one context, namely
GRANT/REVOKE, because there is no GRANT ON AGGREGATE syntax. There
are other cases where a command that nominally is for functions will
allow aggregates as well, though not all do.
Commit fd1a421fe changed this query to disallow aggregates, but that
doesn't seem to have been thought through very carefully. Change it
to allow aggregates (but still ignore procedures).
We might at some point tighten this up, but it'd require sorting through
all the uses of this query to see which ones should offer aggregate
names and which shouldn't. Given the lack of field complaints about
the historical laxity here, that's work I'm not eager to do right now.
Discussion: https://postgr.es/m/14268.1520283126@sss.pgh.pa.us
The server won't actually start with that setting anymore, not since
we raised the default max_wal_senders to 10. Per discussion, we don't
wish to back down on that default, so instead raise the effective floor
for max_connections (to 20). It's still possible to configure a smaller
setting manually, but initdb won't set it that way.
Since that change happened in v10, back-patch to v10.
Kyotaro Horiguchi
Discussion: https://postgr.es/m/20180209.170823.42008365.horiguchi.kyotaro@lab.ntt.co.jp
Up to now we've not worried about whether psql's tab completion queries
would work against prior server versions. But since we support older
server versions in describe.c, we really ought to do so here as well.
Failing to take care of this not only leads to loss of tab-completion
service when using an older server, but risks aborting a user's open
transaction when we send an incompatible query to the server.
The recent changes in pg_proc.prokind are one reason to take this more
seriously now than before, and the proposed patch for completion after
SELECT needs some such capability as well.
Hence, create some infrastructure to allow selection of one of several
versions of a query depending on server version. For cases where we
just need to select one of several query strings, introduce VersionedQuery
and COMPLETE_WITH_VERSIONED_QUERY(). Likewise extend the SchemaQuery
infrastructure to allow versioning of those.
I went ahead and fixed the prokind issues, to serve as an illustration
of how to use versioned SchemaQuery. To have some illustration of
VersionedQuery, change the support for completion of publication and
subscription names so that psql will not send sure-to-fail queries to
pre-v10 servers. There is much more that should be done to make tab
completion more friendly to older servers, but this commit is mainly
meant to get the infrastructure in place, so I stopped here.
Discussion: https://postgr.es/m/24314.1520190408@sss.pgh.pa.us
pg_rewind checks whether each file is a relation data file, from its path.
Previously this check logic had the bug which made pg_rewind fail to
recognize any relation data files in tablespaces. Which also caused
an assertion failure in pg_rewind.
Back-patch to 9.5 where pg_rewind was added.
Author: Takayuki Tsunakawa
Reviewed-by: Michael Paquier
Discussion: https://postgr.es/m/0A3221C70F24FB45833433255569204D1F8D6C7A@G01JPEXMBYT05
Previously, it'd try to create log files under the source directory
not the build directory. This fell over if the source isn't writable
by the building user.
Fabien Coelho
Discussion: https://postgr.es/m/alpine.DEB.2.20.1801101038340.2283@lancre
The new column distinguishes normal functions, procedures, aggregates,
and window functions. This replaces the existing columns proisagg and
proiswindow, and replaces the convention that procedures are indicated
by prorettype == 0. Also change prorettype to be VOIDOID for procedures.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
This makes the client programs behave as documented regardless of the
connect-time search_path and regardless of user-created objects. Today,
a malicious user with CREATE permission on a search_path schema can take
control of certain of these clients' queries and invoke arbitrary SQL
functions under the client identity, often a superuser. This is
exploitable in the default configuration, where all users have CREATE
privilege on schema "public".
This changes behavior of user-defined code stored in the database, like
pg_index.indexprs and pg_extension_config_dump(). If they reach code
bearing unqualified names, "does not exist" or "no schema has been
selected to create in" errors might appear. Users may fix such errors
by schema-qualifying affected names. After upgrading, consider watching
server logs for these errors.
The --table arguments of src/bin/scripts clients have been lax; for
example, "vacuumdb -Zt pg_am\;CHECKPOINT" performed a checkpoint. That
now fails, but for now, "vacuumdb -Zt 'pg_am(amname);CHECKPOINT'" still
performs a checkpoint.
Back-patch to 9.3 (all supported versions).
Reviewed by Tom Lane, though this fix strategy was not his first choice.
Reported by Arseniy Sharoglazov.
Security: CVE-2018-1058
Historically, pg_dump has "set search_path = foo, pg_catalog" when
dumping an object in schema "foo", and has also caused that setting
to be used while restoring the object. This is problematic because
functions and operators in schema "foo" could capture references meant
to refer to pg_catalog entries, both in the queries issued by pg_dump
and those issued during the subsequent restore run. That could
result in dump/restore misbehavior, or in privilege escalation if a
nefarious user installs trojan-horse functions or operators.
This patch changes pg_dump so that it does not change the search_path
dynamically. The emitted restore script sets the search_path to what
was used at dump time, and then leaves it alone thereafter. Created
objects are placed in the correct schema, regardless of the active
search_path, by dint of schema-qualifying their names in the CREATE
commands, as well as in subsequent ALTER and ALTER-like commands.
Since this change requires a change in the behavior of pg_restore
when processing an archive file made according to this new convention,
bump the archive file version number; old versions of pg_restore will
therefore refuse to process files made with new versions of pg_dump.
Security: CVE-2018-1058
Commit b3f840120 changed pg_upgrade so that it'd actually drop and
re-create the template1 and postgres databases in the new cluster.
That works fine, serially. With the -j option it's not so fine, because
other per-database jobs might be launched while the template1 database is
dropped. Since they attempt to connect there to start up, kaboom.
This is the cause of the intermittent failures buildfarm member jacana
has been showing for the last month; evidently it is the only BF member
configured to run the pg_upgrade test with parallelism enabled.
Fix by processing template1 separately before we get into the parallel
sub-job launch loop. (We could alternatively have made the postgres DB
be the special case, but it seems likely that template1 will contain
less stuff and so we lose less parallelism with this choice.)
This oversight led to data corruption in matviews, manifesting as
"could not access status of transaction" before our most recent releases,
and "found xmin from before relfrozenxid" errors since then.
The proximate cause of the problem seems to have been confusion between
the task of preserving dropped-column status and the task of preserving
frozenxid status. Those are required for distinct sets of relkinds,
and the reasoning was entirely undocumented in the source code. In hopes
of forestalling future errors of the same kind, try to improve the
commentary in this area.
In passing, also improve the remarkably unhelpful comments around
pg_upgrade's set_frozenxids(). That's not actually buggy AFAICS,
but good luck figuring out what it does from the old comments.
Per report from Claudio Freire. It appears that bug #14852 from Alexey
Ermakov is an earlier report of the same issue, and there may be other
cases that we failed to identify at the time.
Patch by me based on analysis by Andres Freund. The bug dates back
to the introduction of matviews, so back-patch to all supported branches.
Discussion: https://postgr.es/m/CAGTBQpbrY9CdRGGhyBZ9yqY4jWaGC85rUF4X+R7d-aim=mBNsw@mail.gmail.com
Discussion: https://postgr.es/m/20171013115320.28049.86457@wrigleys.postgresql.org
The previous coding here applied atoi() to strings that could represent
values too large to fit in an int. If the overflowed value happened to
match one of the cases it was looking for, it would drop that limit
value from the output, leading to incorrect restoration of the sequence.
Avoid the unsafe behavior, and also make the logic cleaner by explicitly
calculating the default min/max values for the appropriate kind of
sequence.
Reported and patched by Alexey Bashtanov, though I whacked his patch
around a bit. Back-patch to v10 where the faulty logic was added.
Discussion: https://postgr.es/m/cb85a9a5-946b-c7c4-9cf2-6cd6e25d7a33@imap.cc
If we restrict unique constraints on partitioned tables so that they
must always include the partition key, then our standard approach to
unique indexes already works --- each unique key is forced to exist
within a single partition, so enforcing the unique restriction in each
index individually is enough to have it enforced globally. Therefore we
can implement unique indexes on partitions by simply removing a few
restrictions (and adding others.)
Discussion: https://postgr.es/m/20171222212921.hi6hg6pem2w2t36z@alvherre.pgsql
Discussion: https://postgr.es/m/20171229230607.3iib6b62fn3uaf47@alvherre.pgsql
Reviewed-by: Simon Riggs, Jesper Pedersen, Peter Eisentraut, Jaime
Casanova, Amit Langote
All of these are false positives, but in each case a fair amount of
analysis is needed to see that, and it's not too surprising that not all
compilers are smart enough. (In particular, in the logtape.c case, a
compiler lacking the knowledge provided by the Assert would almost surely
complain, so that this warning will be seen in any non-assert build.)
Some of these are of long standing while others are pretty recent,
but it only seems worth fixing them in HEAD.
Jaime Casanova, tweaked a bit by me
Discussion: https://postgr.es/m/CAJGNTeMcYAMJdPAom52dppLMtF-UnEZi0dooj==75OEv1EoBZA@mail.gmail.com
pg_dump supposed that a stats object necessarily shares the same schema
as its underlying table, and that it doesn't have a separate owner.
These things may have been true during early development of the feature,
but they are not true as of v10 release.
Failure to track the object's schema separately turns out to have only
limited consequences, because pg_get_statisticsobjdef() always schema-
qualifies the target object name in the generated CREATE STATISTICS command
(a decision out of step with the rest of ruleutils.c, but I digress).
Therefore the restored object would be in the right schema, so that the
only problem is that the TOC entry would be mislabeled as to schema. That
could lead to wrong decisions for schema-selective restores, for example.
The ownership issue is a bit more serious: not only was the TOC entry
potentially mislabeled as to owner, but pg_dump didn't bother to issue an
ALTER OWNER command at all, so that after restore the stats object would
continue to be owned by the restoring superuser.
A final point is that decisions as to whether to dump a stats object or
not were driven by whether the underlying table was dumped or not. While
that's not wrong on its face, it won't scale nicely to the planned future
extension to cross-table statistics. Moreover, that design decision comes
out of the view of stats objects as being auxiliary to a particular table,
like a rule or trigger, which is exactly where the above problems came
from. Since we're now treating stats objects more like independent objects
in their own right, they ought to behave like standalone objects for this
purpose too. So change to using the generic selectDumpableObject() logic
for them (which presently amounts to "dump if containing schema is to be
dumped").
Along the way to fixing this, restructure so that getExtendedStatistics
collects the identity info (only) for all extended stats objects in one
query, and then for each object actually being dumped, we retrieve the
definition in dumpStatisticsExt. This is necessary to ensure that
schema-qualification in the generated CREATE STATISTICS command happens
with respect to the search path that pg_dump will now be using at restore
time (ie, the schema the stats object is in, not that of the underlying
table). It's probably also significantly faster in the typical scenario
where only a minority of tables have extended stats.
Back-patch to v10 where extended stats were introduced.
Discussion: https://postgr.es/m/18272.1518328606@sss.pgh.pa.us
pg_upgrade has always attempted to ensure that the transient dump files
it creates are inaccessible except to the owner. However, refactoring
in commit 76a7650c4 broke that for the file containing "pg_dumpall -g"
output; since then, that file was protected according to the process's
default umask. Since that file may contain role passwords (hopefully
encrypted, but passwords nonetheless), this is a particularly unfortunate
oversight. Prudent users of pg_upgrade on multiuser systems would
probably run it under a umask tight enough that the issue is moot, but
perhaps some users are depending only on pg_upgrade's umask changes to
protect their data.
To fix this in a future-proof way, let's just tighten the umask at
process start. There are no files pg_upgrade needs to write at a
weaker security level; and if there were, transiently relaxing the
umask around where they're created would be a safer approach.
Report and patch by Tom Lane; the idea for the fix is due to Noah Misch.
Back-patch to all supported branches.
Security: CVE-2018-1053
Issuing 'quit'/'exit' in an empty psql buffer exits psql. Issuing
'quit'/'exit' in a non-empty psql buffer alone on a line with no prefix
whitespace issues a hint on how to exit.
Also add similar 'help' hints for 'help' in a non-empty psql buffer.
Reported-by: Everaldo Canuto
Discussion: https://postgr.es/m/flat/CALVFHFb-C_5_94hueWg6Dd0zu7TfbpT7hzsh9Zf0DEDOSaAnfA%40mail.gmail.com
Author: original author Robert Haas, modified by me
When a password is needed, cases such as
psql -d "postgresql://alice@localhost/testdb" -U bob
would incorrectly prompt for "Password for user bob: ", when actually the
connection will be attempted with username alice. The priority order of
which name to use isn't that important here, but the misleading prompt is.
When we are prompting for a password after initial connection failure,
we can fix this reliably by looking at PQuser(conn) to see how libpq
interpreted the connection arguments. But when we're doing a forced
password prompt because of a -W switch, we can't use that solution.
Fortunately, because the main use of -W is for noninteractive situations,
it's less critical to produce a helpful prompt in such cases. I made
the startup prompt for -W just say "Password: " all the time, rather
than expending extra code on trying to identify which username to use.
In the case of a \c command (after -W has been given), there's already
logic in do_connect that determines whether the "dbname" is a connstring
or URI, so we can avoid lobotomizing the prompt except in cases that
are actually dubious. (We could do similarly in startup.c if anyone
complains, but for now it seems not worthwhile, especially since that
would still be only a partial solution.)
Per bug #15025 from Akos Vandra. Although this is arguably a bug fix,
it doesn't seem worth back-patching. The case where it matters seems
like a very corner-case usage, and someone might complain that we'd
changed the behavior of -W in a minor release.
Discussion: https://postgr.es/m/20180123130013.7407.24749@wrigleys.postgresql.org
We have switches already to suppress other subsidiary object properties,
such as ACLs, security labels, ownership, and tablespaces, so just on
the grounds of symmetry we should allow suppressing comments as well.
Also, commit 0d4e6ed30 added a positive reason to have this feature,
i.e. to allow obtaining the old behavior of selective pg_restore should
anyone desire that.
Recent commits have removed the cases where pg_dump emitted comments on
built-in objects that the restoring user might not have privileges to
comment on, so the original primary motivation for this feature is gone,
but it still seems at least somewhat useful in its own right.
Robins Tharakan, reviewed by Fabrízio Mello
Discussion: https://postgr.es/m/CAEP4nAx22Z4ch74oJGzr5RyyjcyUSbpiFLyeYXX8pehfou92ug@mail.gmail.com
Bruce Momjian
Magnus Hagander
Fujii Masao
Simon Riggs
Teodor Sigaev
Peter Eisentraut
Tom Lane
Andres Freund
Noah Misch
Alvaro Herrera