In replication, when we shutdown the master, walsender tries to send
all the outstanding WAL records to the standby, and then to exit. This
basically means that all the WAL records are fully synced between
two servers after the clean shutdown of the master. So, after
promoting the standby to new master, we can restart the stopped
master as new standby without the need for a fresh backup from
new master.
But there was one problem so far: though walsender tries to send all
the outstanding WAL records, it doesn't wait for them to be replicated
to the standby. Then, before receiving all the WAL records,
walreceiver can detect the closure of connection and exit. We cannot
guarantee that there is no missing WAL in the standby after clean
shutdown of the master. In this case, backup from new master is
required when restarting the stopped master as new standby.
This patch fixes this problem. It just changes walsender so that it
waits for all the outstanding WAL records to be replicated to the
standby before closing the replication connection.
Per discussion, this is a fix that needs to get backpatched rather than
new feature. So, back-patch to 9.1 where enough infrastructure for
this exists.
Patch by me, reviewed by Andres Freund.
In some cases with higher numbers of subtransactions
it was possible for us to incorrectly initialize
subtrans leading to complaints of missing pages.
Bug report by Sergey Konoplev
Analysis and fix by Andres Freund
In most scenarios a portal without a ResourceOwner is dead and not subject
to any further execution, but a portal for a cursor WITH HOLD remains in
existence with no ResourceOwner after the creating transaction is over.
In this situation, if we attempt to "execute" the portal directly to fetch
data from it, we were setting CurrentResourceOwner to NULL, leading to a
segfault if the datatype output code did anything that required a resource
owner (such as trying to fetch system catalog entries that weren't already
cached). The case appears to be impossible to provoke with stock libpq,
but psqlODBC at least is able to cause it when working with held cursors.
Simplest fix is to just skip the assignment to CurrentResourceOwner, so
that any resources used by the data output operations will be managed by
the transaction-level resource owner instead. For consistency I changed
all the places that install a portal's resowner as current, even though
some of them are probably not reachable with a held cursor's portal.
Per report from Joshua Berry (with thanks to Hiroshi Inoue for developing
a self-contained test case). Back-patch to all supported versions.
We need to increment the refcount on the composite type's cached tuple
descriptor while we do lookups of its column types. Otherwise a cache
flush could occur and release the tuple descriptor before we're done with
it. This fails reliably with -DCLOBBER_CACHE_ALWAYS, but the odds of a
failure in a production build seem rather low (since the pfree'd descriptor
typically wouldn't get scribbled on immediately). That may explain the
lack of any previous reports. Buildfarm issue noted by Christian Ullrich.
Back-patch to 9.1 where the bogus code was added.
getSchemaData() must identify extension member objects and mark them
as not to be dumped. This must happen after reading all objects that can be
direct members of extensions, but before we begin to process table subsidiary
objects. Both rules and event triggers were wrong in this regard.
Backport rules portion of patch to 9.1 -- event triggers do not exist prior to 9.3.
Suggested fix by Tom Lane, initial complaint and patch by me.
When the existing code here was written, it made sense to special-case
RowExprs because that was the only way that we could handle row comparisons
at all. Now that we have record_eq() and arrays of composites, the generic
logic for "scalar" types will in fact work on RowExprs too, so there's no
reason to throw error for combinations of RowExprs and other ways of
forming composite values, nor to ignore the possibility of using a
ScalarArrayOpExpr. But keep using the old logic when comparing two
RowExprs, for consistency with the main transformAExprOp() logic. (This
allows some cases with not-quite-identical rowtypes to succeed, so we might
get push-back if we removed it.) Per bug #8198 from Rafal Rzepecki.
Back-patch to all supported branches, since this works fine as far back as
8.4.
Rafal Rzepecki and Tom Lane
Per discussion, this restriction isn't needed for any real security reason,
and it seems to confuse people more often than it helps them. It could
also result in some database states being unrestorable. So just drop it.
Back-patch to 9.0, where ALTER DEFAULT PRIVILEGES was introduced.
AllocateFile(), AllocateDir(), and some sister routines share a small array
for remembering requests, so that the files can be closed on transaction
failure. Previously that array had a fixed size, MAX_ALLOCATED_DESCS (32).
While historically that had seemed sufficient, Steve Toutant pointed out
that this meant you couldn't scan more than 32 file_fdw foreign tables in
one query, because file_fdw depends on the COPY code which uses
AllocateFile(). There are probably other cases, or will be in the future,
where this nonconfigurable limit impedes users.
We can't completely remove any such limit, at least not without a lot of
work, since each such request requires a kernel file descriptor and most
platforms limit the number we can have. (In principle we could
"virtualize" these descriptors, as fd.c already does for the main VFD pool,
but not without an additional layer of overhead and a lot of notational
impact on the calling code.) But we can at least let the array size be
configurable. Hence, change the code to allow up to max_safe_fds/2
allocated file requests. On modern platforms this should allow several
hundred concurrent file_fdw scans, or more if one increases the value of
max_files_per_process. To go much further than that, we'd need to do some
more work on the data structure, since the current code for closing
requests has potentially O(N^2) runtime; but it should still be all right
for request counts in this range.
Back-patch to 9.1 where contrib/file_fdw was introduced.
Long-standing code has called tolower() on identifier character bytes
with the high bit set. This is clearly an error and produces junk output
when the encoding is multi-byte. This patch therefore restricts this
activity to cases where there is a character with the high bit set AND
the encoding is single-byte.
There have been numerous gripes about this, most recently from Martin
Schäfer.
Backpatch to all live releases.
The planner is aware that it mustn't push down upper-level quals into
subqueries if the quals reference subquery output columns that contain
set-returning functions or volatile functions, or are non-DISTINCT outputs
of a DISTINCT ON subquery. However, it missed making this check when
there were one or more levels of UNION or INTERSECT above the dangerous
expression. This could lead to "set-valued function called in context that
cannot accept a set" errors, as seen in bug #8213 from Eric Soroos, or to
silently wrong answers in the other cases.
To fix, refactor the checks so that we make the column-is-unsafe checks
during subquery_is_pushdown_safe(), which already has to recursively
inspect all arms of a set-operation tree. This makes
qual_is_pushdown_safe() considerably simpler, at the cost that we will
spend some cycles checking output columns that possibly aren't referenced
in any upper qual. But the cases where this code gets executed at all
are already nontrivial queries, so it's unlikely anybody will notice any
slowdown of planning.
This has been broken since commit 05f916e6ad,
which makes the bug over ten years old. A bit surprising nobody noticed it
before now.
In commit 2c92edad48, I broke "EXPLAIN
(ANALYZE)" syntax, because I mistakenly thought that ANALYZE/ANALYSE were
only partially reserved and thus would be included in NonReservedWord;
but actually they're fully reserved so they still need to be called out
here.
A nicer solution would be to demote these words to type_func_name_keyword
status (they can't be less than that because of "VACUUM [ANALYZE] ColId").
While that works fine so far as the core grammar is concerned, it breaks
ECPG's grammar for reasons I don't have time to isolate at the moment.
So do this for the time being.
Per report from Kevin Grittner. Back-patch to 9.0, like the previous
commit.
The new message (and SQLSTATE) matches the corresponding error cases in
namespace.c.
This was thought to be a "can't happen" case when extension.c was written,
so we didn't think hard about how to report it. But it definitely can
happen in 9.2 and later, since we no longer require search_path to contain
any valid schema names. It's probably also possible in 9.1 if search_path
came from a noninteractive source. So, back-patch to all releases
containing this code.
Per report from Sean Chittenden, though this isn't exactly his patch.
The array allocated by GetRunningTransactionLocks() needs to be pfree'd
when we're done with it. Otherwise we leak some memory during each
checkpoint, if wal_level = hot_standby. This manifests as memory bloat
in the checkpointer process, or in bgwriter in versions before we made
the checkpointer separate.
Reported and fixed by Naoya Anzai. Back-patch to 9.0 where the issue
was introduced.
In passing, improve comments for GetRunningTransactionLocks(), and add
an Assert that we didn't overrun the palloc'd array.
"eval q{foo}" used to complain that the error was on line 2 of the eval'd
string, because eval internally tacked on "\n;" so that the end of the
erroneous command was indeed on line 2. But as of Perl 5.18 it more
sanely says that the error is on line 1. To avoid Perl-version-dependent
regression test results, use "eval q{foo;}" instead in the two places
where this matters. Per buildfarm.
Since people might try to use newer Perl versions with older PG releases,
back-patch as far as 9.0 where these test cases were added.
This change makes type_func_name_keywords less reserved than they were
before, by allowing them for role names, language names, EXPLAIN and COPY
options, and SET values for GUCs; which are all places where few if any
actual keywords could appear instead, so no new ambiguities are introduced.
The main driver for this change is to allow "COPY ... (FORMAT BINARY)"
to work without quoting the word "binary". That is an inconsistency that
has been complained of repeatedly over the years (at least by Pavel Golub,
Kurt Lidl, and Simon Riggs); but we hadn't thought of any non-ugly solution
until now.
Back-patch to 9.0 where the COPY (FORMAT BINARY) syntax was introduced.
PathNameOpenFile failed to ensure that the correct value of errno was
returned to its caller after a failure (because it incorrectly supposed
that free() can never change errno). In some cases this would result
in a user-visible failure because an expected ENOENT errno was replaced
with something else. Bogus EINVAL failures have been observed on OS X,
for example.
There were also a couple of places that could mangle an important value
of errno if FDDEBUG was defined. While the usefulness of that debug
support is highly debatable, we might as well make it safe to use,
so add errno save/restore logic to the DO_DB macro.
Per bug #8167 from Nelson Minar, diagnosed by RhodiumToad.
Back-patch to all supported branches.
If OID wraparound should occur while in standalone mode (unlikely but
possible), we want to advance the counter to FirstNormalObjectId not
FirstBootstrapObjectId. Otherwise, user objects might be created with OIDs
in the system-reserved range. That isn't immediately harmful but it poses
a risk of conflicts during future pg_upgrade operations.
Noted by Andres Freund. Back-patch to all supported branches, since all of
them are supported sources for pg_upgrade operations.
This case doesn't normally happen, because the planner usually clamps
all row estimates to at least one row; but I found that it can arise
when dealing with relations excluded by constraints. Without a defense,
estimate_num_groups() can return zero, which leads to divisions by zero
inside the planner as well as assertion failures in the executor.
An alternative fix would be to change set_dummy_rel_pathlist() to make
the size estimate for a dummy relation 1 row instead of 0, but that seemed
pretty ugly; and probably someday we'll want to drop the convention that
the minimum rowcount estimate is 1 row.
Back-patch to 8.4, as the problem can be demonstrated that far back.
WAL segment means a 16 MB physical WAL file; this comment meant a logical
4 GB log file.
Amit Langote. Apply to backbranches only, as the comment is gone in master.
This is a follow-up to the earlier fix, which changed the recycling logic
to recycle WAL segments under the current recovery target timeline. That
turns out to be a bad idea, because installing a recycled segment with
a TLI higher than what we're recovering at the moment means that the recovery
logic will find the recycled WAL segment and try to replay it. It will fail,
but but the mere presence of such a WAL segment will mask any other, real,
file with the same log/seg, but smaller TLI.
Per report from Mitsumasa Kondo. Apply to 9.1 and 9.2, like the previous
fix. Master was already doing this differently; this patch makes 9.1 and
9.2 to do the same thing as master.
Patch b19e4250b4 attempted to
preserve existing behavior regarding statistics generation in the
case that a truncation attempt was canceled due to lock conflicts.
It failed to do this accurately in two regards: (1) autovacuum had
previously generated statistics if the truncate attempt failed to
initially get the lock rather than having started the attempt, and
(2) the VACUUM ANALYZE command had always generated statistics.
Both of these changes were unintended, and are reverted by this
patch. On review, there seems to be consensus that the previous
failure to generate statistics when the truncate was terminated
was more an unfortunate consequence of how that effort was
previously terminated than a feature we want to keep; so this
patch generates statistics even when an autovacuum truncation
attempt terminates early. Another unintended change which is kept
on the basis that it is an improvement is that when a VACUUM
command is truncating, it will the new heuristic for avoiding
blocking other processes, rather than keeping an
AccessExclusiveLock on the table for however long the truncation
takes.
Per multiple reports, with some renaming per patch by Jeff Janes.
Backpatch to 9.0, where problem was created.
There was a high probability of two or more concurrent C.I.C. commands
deadlocking just before completion, because each would wait for the others
to release their reference snapshots. Fix by releasing the snapshot
before waiting for other snapshots to go away.
Per report from Paul Hinze. Back-patch to all active branches.
When creating or manipulating a cached plan for a transaction control
command (particularly ROLLBACK), we must not perform any catalog accesses,
since we might be in an aborted transaction. However, plancache.c busily
saved or examined the search_path for every cached plan. If we were
unlucky enough to do this at a moment where the path's expansion into
schema OIDs wasn't already cached, we'd do some catalog accesses; and with
some more bad luck such as an ill-timed signal arrival, that could lead to
crashes or Assert failures, as exhibited in bug #8095 from Nachiket Vaidya.
Fortunately, there's no real need to consider the search path for such
commands, so we can just skip the relevant steps when the subject statement
is a TransactionStmt. This is somewhat related to bug #5269, though the
failure happens during initial cached-plan creation rather than
revalidation.
This bug has been there since the plan cache was invented, so back-patch
to all supported branches.
The old formula didn't take into account that each WAL sender process needs
a spinlock. We had also already exceeded the fixed number of spinlocks
reserved for misc purposes (10). Bump that to 30.
Backpatch to 9.0, where WAL senders were introduced. If I counted correctly,
9.0 had exactly 10 predefined spinlocks, and 9.1 exceeded that, but bump the
limit in 9.0 too because 10 is uncomfortably close to the edge.
Notice and complain about PQcancel() failures. Also, don't dump core if
an error PGresult doesn't contain severity and message subfields, as it
might not if it was generated by libpq itself. (We have a longstanding
TODO item to improve that, but in the meantime isolationtester had better
cope.)
I tripped across the latter item while investigating a trouble report on
buildfarm member spoonbill. As for the former, there's no evidence that
PQcancel failure is actually involved in spoonbill's problem, but it still
seems like a bad idea to ignore an error return code.
An oversight in commit e710b65c1c allowed
database names beginning with "-" to be treated as though they were secure
command-line switches; and this switch processing occurs before client
authentication, so that even an unprivileged remote attacker could exploit
the bug, needing only connectivity to the postmaster's port. Assorted
exploits for this are possible, some requiring a valid database login,
some not. The worst known problem is that the "-r" switch can be invoked
to redirect the process's stderr output, so that subsequent error messages
will be appended to any file the server can write. This can for example be
used to corrupt the server's configuration files, so that it will fail when
next restarted. Complete destruction of database tables is also possible.
Fix by keeping the database name extracted from a startup packet fully
separate from command-line switches, as had already been done with the
user name field.
The Postgres project thanks Mitsumasa Kondo for discovering this bug,
Kyotaro Horiguchi for drafting the fix, and Noah Misch for recognizing
the full extent of the danger.
Security: CVE-2013-1899
The pg_start_backup() and pg_stop_backup() functions checked the privileges
of the initially-authenticated user rather than the current user, which is
wrong. For example, a user-defined index function could successfully call
these functions when executed by ANALYZE within autovacuum. This could
allow an attacker with valid but low-privilege database access to interfere
with creation of routine backups. Reported and fixed by Noah Misch.
Security: CVE-2013-1901
In commit 0f61d4dd1b, I added code to copy up
column width estimates for each column of a subquery. That code supposed
that the subquery couldn't have any output columns that didn't correspond
to known columns of the current query level --- which is true when a query
is parsed from scratch, but the assumption fails when planning a view that
depends on another view that's been redefined (adding output columns) since
the upper view was made. This results in an assertion failure or even a
crash, as per bug #8025 from lindebg. Remove the Assert and instead skip
the column if its resno is out of the expected range.
Previously, if the postmaster initialized OpenSSL's PRNG (which it will do
when ssl=on in postgresql.conf), the same pseudo-random state would be
inherited by each forked child process. The problem is masked to a
considerable extent if the incoming connection uses SSL encryption, but
when it does not, identical pseudo-random state is made available to
functions like contrib/pgcrypto. The process's PID does get mixed into any
requested random output, but on most systems that still only results in 32K
or so distinct random sequences available across all Postgres sessions.
This might allow an attacker who has database access to guess the results
of "secure" operations happening in another session.
To fix, forcibly reset the PRNG after fork(). Each child process that has
need for random numbers from OpenSSL's generator will thereby be forced to
go through OpenSSL's normal initialization sequence, which should provide
much greater variability of the sequences. There are other ways we might
do this that would be slightly cheaper, but this approach seems the most
future-proof against SSL-related code changes.
This has been assigned CVE-2013-1900, but since the issue and the patch
have already been publicized on pgsql-hackers, there's no point in trying
to hide this commit.
Back-patch to all supported branches.
Marko Kreen
In a heap update, if the old and new tuple were on different pages, and the
new page no longer existed (because it was subsequently truncated away by
vacuum), heap_xlog_update forgot to release the pin on the old buffer. This
bug was introduced by the "Fix multiple problems in WAL replay" patch,
commit 3bbf668de9 (on master branch).
With full_page_writes=off, this triggered an "incorrect local pin count"
error later in replay, if the old page was vacuumed.
This fixes bug #7969, reported by Yunong Xiao. Backpatch to 9.0, like the
commit that introduced this bug.
Dumping invalid indexes can cause problems at restore time, for example
if the reason the index creation failed was because it tried to enforce
a uniqueness condition not satisfied by the table's data. Also, if the
index creation is in fact still in progress, it seems reasonable to
consider it to be an uncommitted DDL change, which pg_dump wouldn't be
expected to dump anyway.
Back-patch to all active versions, and teach them to ignore invalid
indexes in servers back to 8.2, where the concept was introduced.
Michael Paquier
If you have clusters of different versions pointing to the same tablespace
location, we would incorrectly include all the data belonging to the other
versions, too.
Fixes bug #7986, reported by Sergey Burladyan.
These programs don't work against 9.0 or earlier servers, so check that when
the connection is made. That's better than a cryptic error message you got
before.
Also, these programs won't work with a 9.3 server, because the WAL streaming
protocol was changed in a non-backwards-compatible way. As a general rule,
we don't make any guarantee that an old client will work with a new server,
so check that. However, allow a 9.1 client to connect to a 9.2 server, to
avoid breaking environments that currently work; a 9.1 client happens to
work with a 9.2 server, even though we didn't make any great effort to
ensure that.
This patch is for the 9.1 and 9.2 branches, I'll commit a similar patch to
master later. Although this isn't a critical bug fix, it seems safe enough
to back-patch. The error message you got when connecting to a 9.3devel
server without this patch was cryptic enough to warrant backpatching.
Most (all?) of Russia has moved to what's effectively year-round daylight
savings time, so that the "standard" zone names now mean an hour later
than they used to. Update that, notably changing MSK as per recent
complaint from Sergey Konoplev, but also CHOT, GET, IRKT, KGT, KRAT,
MAGT, NOVT, OMST, VLAT, YAKT, YEKT. The corresponding DST abbreviations
are presumably now obsolete, but I left them in place with their old
definitions, just to reduce any possible breakage from this change.
Also add VOLT (Europe/Volgograd), which for some reason we never had
before, as well as MIST (Antarctica/Macquarie), and fix obsolete
definitions of MAWT, TKT, and WST.
When RETURNING is specified, ExecDelete would return a virtual-tuple slot
that could contain pointers into an already-unpinned disk buffer. Another
process could change the buffer contents before we get around to using the
data, resulting in garbage results or even a crash. This seems of fairly
low probability, which may explain why there are no known field reports of
the problem, but it's definitely possible. Fix by forcing the result slot
to be "materialized" before we release pin on the disk buffer.
Back-patch to 9.0; in earlier branches there is no bug because
ExecProcessReturning sent the tuple to the destination immediately. Also,
this is already fixed in HEAD as part of the writable-foreign-tables patch
(where the fix is necessary for DELETE RETURNING to work at all with
postgres_fdw).
The previous coding of this function could get into situations where it
would never terminate, because successive passes would re-add EMPTY arcs
that had been removed by the previous pass. Rewrite the function
completely using a new algorithm that is guaranteed to terminate, and
also seems to be usually faster than the old one. Per Tcl bugs 3604074
and 3606683.
Tom Lane and Don Porter
formatting.c used locale-dependent case folding rules in some code paths
where the result isn't supposed to be locale-dependent, for example
to_char(timestamp, 'DAY'). Since the source data is always just ASCII
in these cases, that usually didn't matter ... but it does matter in
Turkish locales, which have unusual treatment of "i" and "I". To confuse
matters even more, the misbehavior was only visible in UTF8 encoding,
because in single-byte encodings we used pg_toupper/pg_tolower which
don't have locale-specific behavior for ASCII characters. Fix by providing
intentionally ASCII-only case-folding functions and using these where
appropriate. Per bug #7913 from Adnan Dursun. Back-patch to all active
branches, since it's been like this for a long time.
I fixed this code back in commit 841b4a2d5, but didn't think carefully
enough about the behavior near zero, which meant it improperly rejected
1999-12-31 24:00:00. Per report from Magnus Hagander.
Careless use of TopMemoryContext for I/O function data meant that repeated
use of spi_prepare and spi_freeplan would leak memory at the session level,
as per report from Christian Schröder. In addition, spi_prepare
leaked a lot of transient data within the current plperl function's SPI
Proc context, which would be a problem for repeated use of spi_prepare
within a single plperl function call; and it wasn't terribly careful
about releasing permanent allocations in event of an error, either.
In passing, clean up some copy-and-pasteos in query-lookup error messages.
Alex Hunsaker and Tom Lane
parseqatom() failed to check for an error return (NULL result) from its
recursive call to parsebranch(), and in consequence could crash with a
null-pointer dereference after an error return. This bug has been there
since day one, but wasn't noticed before, probably because most error cases
in parsebranch() didn't actually lead to returning NULL. Add the missing
error check, and also tweak parsebranch() to exit in a less indirect
fashion after a call to parseqatom() fails.
Report by Tomasz Karlik, fix by me.
