Dead or half-dead index leaf pages were incorrectly reported as live, as a
consequence of a code rearrangement I made (during a moment of severe brain
fade, evidently) in commit d287818eb5.
The index metapage was not counted in index_size, causing that result to
not agree with the actual index size on-disk.
Index root pages were not counted in internal_pages, which is inconsistent
compared to the case of a root that's also a leaf (one-page index), where
the root would be counted in leaf_pages. Aside from that inconsistency,
this could lead to additional transient discrepancies between the reported
page counts and index_size, since it's possible for pgstatindex's scan to
see zero or multiple pages marked as BTP_ROOT, if the root moves due to
a split during the scan. With these fixes, index_size will always be
exactly one page more than the sum of the displayed page counts.
Also, the index_size result was incorrectly documented as being measured in
pages; it's always been measured in bytes. (While fixing that, I couldn't
resist doing some small additional wordsmithing on the pgstattuple docs.)
Including the metapage causes the reported index_size to not be zero for
an empty index. To preserve the desired property that the pgstattuple
regression test results are platform-independent (ie, BLCKSZ configuration
independent), scale the index_size result in the regression tests.
The documentation issue was reported by Otsuka Kenji, and the inconsistent
root page counting by Peter Geoghegan; the other problems noted by me.
Back-patch to all supported branches, because this has been broken for
a long time.
Clarify the description of which transactions will block a CREATE INDEX
CONCURRENTLY command from proceeding, and mention that the index might
still not be usable after CREATE INDEX completes. (This happens if the
index build detected broken HOT chains, so that pg_index.indcheckxmin gets
set, and there are open old transactions preventing the xmin horizon from
advancing past the index's initial creation. I didn't want to explain what
broken HOT chains are, though, so I omitted an explanation of exactly when
old transactions prevent the index from being used.)
Per discussion with Chris Travers. Back-patch to all supported branches,
since the same text appears in all of them.
Many automated test suites call pg_ctl. Buildfarm members axolotl,
hornet, mandrill, shearwater, sungazer and tern have failed when server
shutdown took longer than the pg_ctl default 60s timeout. This addition
permits slow hosts to easily raise the timeout without us editing a
--timeout argument into every test suite pg_ctl call. Back-patch to 9.1
(all supported versions) for the sake of automated testing.
Reviewed by Tom Lane.
Get rid of the false implication that PRIMARY KEY is exactly equivalent to
UNIQUE + NOT NULL. That was more-or-less true at one time in our
implementation, but the standard doesn't say that, and we've grown various
features (many of them required by spec) that treat a pkey differently from
less-formal constraints. Per recent discussion on pgsql-general.
I failed to resist the temptation to do some other wordsmithing in the
same area.
As pointed out by Michael Paquier, recovery_min_apply_delay didn't exist
in 9.0-9.3, making the release note text not very useful. Instead make it
talk about recovery_target_xid, which did exist then.
9.0 is already out of support, but we can fix the text in the newer
branches' copies of its release notes.
Common mathematical convention is that exponentiation associates right to
left. We aren't going to change the parser for this, but we could note
it in the operator's description. (It's already noted in the operator
precedence/associativity table, but users might not look there.)
Per bug #13829 from Henrik Pauli.
This has worked that way for a long time, maybe always, but you would
not have known it from the documentation. Also back-patch the notes
I added to HEAD earlier today about behavior of the "-f -" switch,
which likewise have been valid for many releases.
In commit 1ea0c73c2 I added a section to user-manag.sgml about how to drop
roles that own objects; but as pointed out by Stephen Frost, I neglected
that shared objects (databases or tablespaces) may need special treatment.
Fix that. Back-patch to supported versions, like the previous patch.
The POSIX standard for tar headers requires archive member sizes to be
printed in octal with at most 11 digits, limiting the representable file
size to 8GB. However, GNU tar and apparently most other modern tars
support a convention in which oversized values can be stored in base-256,
allowing any practical file to be a tar member. Adopt this convention
to remove two limitations:
* pg_dump with -Ft output format failed if the contents of any one table
exceeded 8GB.
* pg_basebackup failed if the data directory contained any file exceeding
8GB. (This would be a fatal problem for installations configured with a
table segment size of 8GB or more, and it has also been seen to fail when
large core dump files exist in the data directory.)
File sizes under 8GB are still printed in octal, so that no compatibility
issues are created except in cases that would have failed entirely before.
In addition, this patch fixes several bugs in the same area:
* In 9.3 and later, we'd defined tarCreateHeader's file-size argument as
size_t, which meant that on 32-bit machines it would write a corrupt tar
header for file sizes between 4GB and 8GB, even though no error was raised.
This broke both "pg_dump -Ft" and pg_basebackup for such cases.
* pg_restore from a tar archive would fail on tables of size between 4GB
and 8GB, on machines where either "size_t" or "unsigned long" is 32 bits.
This happened even with an archive file not affected by the previous bug.
* pg_basebackup would fail if there were files of size between 4GB and 8GB,
even on 64-bit machines.
* In 9.3 and later, "pg_basebackup -Ft" failed entirely, for any file size,
on 64-bit big-endian machines.
In view of these potential data-loss bugs, back-patch to all supported
branches, even though removal of the documented 8GB limit might otherwise
be considered a new feature rather than a bug fix.
In commit a5ec86a7c7 I wrote a quick hack
that reduced the number of TeX string pool entries created while converting
our documentation to PDF form. That held the fort for awhile, but as of
HEAD we're back up against the same limitation. It turns out that the
original coding of \FlowObjectSetup actually results in *three* string pool
entries being generated for every "flow object" (that is, potential
cross-reference target) in the documentation, and my previous hack only got
rid of one of them. With a little more care, we can reduce the string
count to one per flow object plus one per actually-cross-referenced flow
object (about 115000 + 5000 as of current HEAD); that should work until
the documentation volume roughly doubles from where it is today.
As a not-incidental side benefit, this change also causes pdfjadetex to
stop emitting unreferenced hyperlink anchors (bookmarks) into the PDF file.
It had been making one willy-nilly for every flow object; now it's just one
per actually-cross-referenced object. This results in close to a 2X
savings in PDF file size. We will still want to run the output through
"jpdftweak" to get it to be compressed; but we no longer need removal of
unreferenced bookmarks, so we might be able to find a quicker tool for
that step.
Although the failure only affects HEAD and US-format output at the moment,
9.5 cannot be more than a few pages short of failing likewise, so it
will inevitably fail after a few rounds of minor-version release notes.
I don't have a lot of faith that we'll never hit the limit in the older
branches; and anyway it would be nice to get rid of jpdftweak across the
board. Therefore, back-patch to all supported branches.
In general one may have to run both REASSIGN OWNED and DROP OWNED to get
rid of all the dependencies of a role to be dropped. This was alluded to
in the REASSIGN OWNED man page, but not really spelled out in full; and in
any case the procedure ought to be documented in a more prominent place
than that. Add a section to the "Database Roles" chapter explaining this,
and do a bit of wordsmithing in the relevant commands' man pages.
The documentation for the autovacuum_multixact_freeze_max_age and
autovacuum_freeze_max_age relation level parameters contained:
"Note that while you can set autovacuum_multixact_freeze_max_age very
small, or even zero, this is usually unwise since it will force frequent
vacuuming."
which hasn't been true since these options were made relation options,
instead of residing in the pg_autovacuum table (834a6da4f7).
Remove the outdated sentence. Even the lowered limits from 2596d70 are
high enough that this doesn't warrant calling out the risk in the CREATE
TABLE docs.
Per discussion with Tom Lane and Alvaro Herrera
Discussion: 26377.1443105453@sss.pgh.pa.us
Backpatch: 9.0- (in parts)
It's not terribly hard to devise regular expressions that take large
amounts of time and/or memory to process. Recent testing by Greg Stark has
also shown that machines with small stack limits can be driven to stack
overflow by suitably crafted regexps. While we intend to fix these things
as much as possible, it's probably impossible to eliminate slow-execution
cases altogether. In any case we don't want to treat such things as
security issues. The history of that code should already discourage
prudent DBAs from allowing execution of regexp patterns coming from
possibly-hostile sources, but it seems like a good idea to warn about the
hazard explicitly.
Currently, similar_escape() allows access to enough of the underlying
regexp behavior that the warning has to apply to SIMILAR TO as well.
We might be able to make it safer if we tightened things up to allow only
SQL-mandated capabilities in SIMILAR TO; but that would be a subtly
non-backwards-compatible change, so it requires discussion and probably
could not be back-patched.
Per discussion among pgsql-security list.
The docs claimed that \uhhhh would be interpreted as a Unicode value
regardless of the database encoding, but it's never been implemented
that way: \uhhhh and \xhhhh actually mean exactly the same thing, namely
the character that pg_mb2wchar translates to 0xhhhh. Moreover we were
falsely dismissive of the usefulness of Unicode code points above FFFF.
Fix that.
It's been like this for ages, so back-patch to all supported branches.
The default argument, if given, has to be of exactly the same datatype
as the first argument; but this was not stated in so many words, and
the error message you get about it might not lead your thought in the
right direction. Per bug #13587 from Robert McGehee.
A quick scan says that these are the only two built-in functions with two
anyelement arguments and no other polymorphic arguments. There are plenty
of cases of, eg, anyarray and anyelement, but those seem less likely to
confuse. For instance this doesn't seem terribly hard to figure out:
"function array_remove(integer[], numeric) does not exist". So I've
contented myself with fixing these two cases.
The table-rewriting forms of ALTER TABLE are MVCC-unsafe, in much the same
way as TRUNCATE, because they replace all rows of the table with newly-made
rows with a new xmin. (Ideally, concurrent transactions with old snapshots
would continue to see the old table contents, but the data is not there
anymore --- and if it were there, it would be inconsistent with the table's
updated rowtype, so there would be serious implementation problems to fix.)
This was nowhere documented though, and the problem was only documented for
TRUNCATE in a note in the TRUNCATE reference page. Create a new "Caveats"
section in the MVCC chapter that can be home to this and other limitations
on serializable consistency.
In passing, fix a mistaken statement that VACUUM and CLUSTER would reclaim
space occupied by a dropped column. They don't reconstruct existing tuples
so they couldn't do that.
Back-patch to all supported branches.
Although initdb has long discouraged use of a filesystem mount-point
directory as a PG data directory, this point was covered nowhere in the
user-facing documentation. Also, with the popularity of pg_upgrade,
we really need to recommend that the PG user own not only the data
directory but its parent directory too. (Without a writable parent
directory, operations such as "mv data data.old" fail immediately.
pg_upgrade itself doesn't do that, but wrapper scripts for it often do.)
Hence, adjust the "Creating a Database Cluster" section to address
these points. I also took the liberty of wordsmithing the discussion
of NFS a bit.
These considerations aren't by any means new, so back-patch to all
supported branches.
While postgres' use of SSL renegotiation is a good idea in theory, it
turned out to not work well in practice. The specification and openssl's
implementation of it have lead to several security issues. Postgres' use
of renegotiation also had its share of bugs.
Additionally OpenSSL has a bunch of bugs around renegotiation, reported
and open for years, that regularly lead to connections breaking with
obscure error messages. We tried increasingly complex workarounds to get
around these bugs, but we didn't find anything complete.
Since these connection breakages often lead to hard to debug problems,
e.g. spuriously failing base backups and significant latency spikes when
synchronous replication is used, we have decided to change the default
setting for ssl renegotiation to 0 (disabled) in the released
backbranches and remove it entirely in 9.5 and master..
Author: Michael Paquier, with changes by me
Discussion: 20150624144148.GQ4797@alap3.anarazel.de
Backpatch: 9.0-9.4; 9.5 and master get a different patch
Tom fixed another one of these in commit 7f32dbcd, but there was another
almost identical one in libpq docs. Per his comment:
HP's web server has apparently become case-sensitive sometime recently.
Per bug #13479 from Daniel Abraham. Corrected link identified by Alvaro.
Also sneak entries for commits 97ff2a564 et al into the sections for
the previous releases in the relevant branches. Those fixes did go out
in the previous releases, but missed getting documented.
This has been the predominant outcome. When the output of decrypting
with a wrong key coincidentally resembled an OpenPGP packet header,
pgcrypto could instead report "Corrupt data", "Not text data" or
"Unsupported compression algorithm". The distinct "Corrupt data"
message added no value. The latter two error messages misled when the
decrypted payload also exhibited fundamental integrity problems. Worse,
error message variance in other systems has enabled cryptologic attacks;
see RFC 4880 section "14. Security Considerations". Whether these
pgcrypto behaviors are likewise exploitable is unknown.
In passing, document that pgcrypto does not resist side-channel attacks.
Back-patch to 9.0 (all supported versions).
Security: CVE-2015-3167
