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13127 Commits

Author SHA1 Message Date
Tom Lane
c83aed34be Avoid wholesale autovacuuming when autovacuum is nominally off.
When autovacuum is nominally off, we will still launch autovac workers
to vacuum tables that are at risk of XID wraparound.  But after we'd done
that, an autovac worker would proceed to autovacuum every table in the
targeted database, if they meet the usual thresholds for autovacuuming.
This is at best pretty unexpected; at worst it delays response to the
wraparound threat.  Fix it so that if autovacuum is nominally off, we
*only* do forced vacuums and not any other work.

Per gripe from Andrey Zhidenkov.  This has been like this all along,
so back-patch to all supported branches.
2014-07-30 14:41:53 -04:00
Heikki Linnakangas
1578d13dc7 Treat 2PC commit/abort the same as regular xacts in recovery.
There were several oversights in recovery code where COMMIT/ABORT PREPARED
records were ignored:

* pg_last_xact_replay_timestamp() (wasn't updated for 2PC commits)
* recovery_min_apply_delay (2PC commits were applied immediately)
* recovery_target_xid (recovery would not stop if the XID used 2PC)

The first of those was reported by Sergiy Zuban in bug #11032, analyzed by
Tom Lane and Andres Freund. The bug was always there, but was masked before
commit d19bd29f07aef9e508ff047d128a4046cc8bc1e2, because COMMIT PREPARED
always created an extra regular transaction that was WAL-logged.

Backpatch to all supported versions (older versions didn't have all the
features and therefore didn't have all of the above bugs).
2014-07-29 11:58:01 +03:00
Robert Haas
18470e5f2f Avoid access to already-released lock in LockRefindAndRelease.
Spotted by Tom Lane.
2014-07-24 08:39:46 -04:00
Tom Lane
810f0d2a2d Check block number against the correct fork in get_raw_page().
get_raw_page tried to validate the supplied block number against
RelationGetNumberOfBlocks(), which of course is only right when
accessing the main fork.  In most cases, the main fork is longer
than the others, so that the check was too weak (allowing a
lower-level error to be reported, but no real harm to be done).
However, very small tables could have an FSM larger than their heap,
in which case the mistake prevented access to some FSM pages.
Per report from Torsten Foertsch.

In passing, make the bad-block-number error into an ereport not elog
(since it's certainly not an internal error); and fix sloppily
maintained comment for RelationGetNumberOfBlocksInFork.

This has been wrong since we invented relation forks, so back-patch
to all supported branches.
2014-07-22 11:45:57 -04:00
Tom Lane
f54d97c5ef Reject out-of-range numeric timezone specifications.
In commit 631dc390f49909a5c8ebd6002cfb2bcee5415a9d, we started to handle
simple numeric timezone offsets via the zic library instead of the old
CTimeZone/HasCTZSet kluge.  However, we overlooked the fact that the zic
code will reject UTC offsets exceeding a week (which seems a bit arbitrary,
but not because it's too tight ...).  This led to possibly setting
session_timezone to NULL, which results in crashes in most timezone-related
operations as of 9.4, and crashes in a small number of places even before
that.  So check for NULL return from pg_tzset_offset() and report an
appropriate error message.  Per bug #11014 from Duncan Gillis.

Back-patch to all supported branches, like the previous patch.
(Unfortunately, as of today that no longer includes 8.4.)
2014-07-21 22:41:30 -04:00
Peter Eisentraut
44c4013431 Translation updates 2014-07-21 01:02:07 -04:00
Tom Lane
a223b9e361 Fix two low-probability memory leaks in regular expression parsing.
If pg_regcomp failed after having invoked markst/cleanst, it would leak any
"struct subre" nodes it had created.  (We've already detected all regex
syntax errors at that point, so the only likely causes of later failure
would be query cancel or out-of-memory.)  To fix, make sure freesrnode
knows the difference between the pre-cleanst and post-cleanst cleanup
procedures.  Add some documentation of this less-than-obvious point.

Also, newlacon did the wrong thing with an out-of-memory failure from
realloc(), so that the previously allocated array would be leaked.

Both of these are pretty low-probability scenarios, but a bug is a bug,
so patch all the way back.

Per bug #10976 from Arthur O'Dwyer.
2014-07-18 13:00:48 -04:00
Alvaro Herrera
b42f09fc80 Fix REASSIGN OWNED for text search objects
Trying to reassign objects owned by a user that had text search
dictionaries or configurations used to fail with:
ERROR:  unexpected classid 3600
or
ERROR:  unexpected classid 3602

Fix by adding cases for those object types in a switch in pg_shdepend.c.

Both REASSIGN OWNED and text search objects go back all the way to 8.1,
so backpatch to all supported branches.  In 9.3 the alter-owner code was
made generic, so the required change in recent branches is pretty
simple; however, for 9.2 and older ones we need some additional
reshuffling to enable specifying objects by OID rather than name.

Text search templates and parsers are not owned objects, so there's no
change required for them.

Per bug #9749 reported by Michal Novotný
2014-07-15 13:24:07 -04:00
Simon Riggs
2dde11a632 Reset master xmin when hot_standby_feedback disabled.
If walsender has xmin of standby then ensure we
reset the value to 0 when we change from hot_standby_feedback=on
to hot_standby_feedback=off.
2014-07-15 14:40:23 +01:00
Tom Lane
261f954e7a Fix bug with whole-row references to append subplans.
ExecEvalWholeRowVar incorrectly supposed that it could "bless" the source
TupleTableSlot just once per query.  But if the input is coming from an
Append (or, perhaps, other cases?) more than one slot might be returned
over the query run.  This led to "record type has not been registered"
errors when a composite datum was extracted from a non-blessed slot.

This bug has been there a long time; I guess it escaped notice because when
dealing with subqueries the planner tends to expand whole-row Vars into
RowExprs, which don't have the same problem.  It is possible to trigger
the problem in all active branches, though, as illustrated by the added
regression test.
2014-07-11 19:12:45 -04:00
Tom Lane
189bd09cbd Don't assume a subquery's output is unique if there's a SRF in its tlist.
While the x output of "select x from t group by x" can be presumed unique,
this does not hold for "select x, generate_series(1,10) from t group by x",
because we may expand the set-returning function after the grouping step.
(Perhaps that should be re-thought; but considering all the other oddities
involved with SRFs in targetlists, it seems unlikely we'll change it.)
Put a check in query_is_distinct_for() so it's not fooled by such cases.

Back-patch to all supported branches.

David Rowley
2014-07-08 14:03:23 -04:00
Tom Lane
981518ea19 Add some errdetail to checkRuleResultList().
This function wasn't originally thought to be really user-facing,
because converting a table to a view isn't something we expect people
to do manually.  So not all that much effort was spent on the error
messages; in particular, while the code will complain that you got
the column types wrong it won't say exactly what they are.  But since
we repurposed the code to also check compatibility of rule RETURNING
lists, it's definitely user-facing.  It now seems worthwhile to add
errdetail messages showing exactly what the conflict is when there's
a mismatch of column names or types.  This is prompted by bug #10836
from Matthias Raffelsieper, which might have been forestalled if the
error message had reported the wrong column type as being "record".

Per Alvaro's advice, back-patch to branches before 9.4, but resist
the temptation to rephrase any existing strings there.  Adding new
strings is not really a translation degradation; anyway having the
info presented in English is better than not having it at all.
2014-07-02 14:20:40 -04:00
Tom Lane
0cf16686bc Back-patch "Fix EquivalenceClass processing for nested append relations".
When we committed a87c729153e372f3731689a7be007bc2b53f1410, we somehow
failed to notice that it didn't merely improve plan quality for expression
indexes; there were very closely related cases that failed outright with
"could not find pathkey item to sort".  The failing cases seem to be those
where the planner was already capable of selecting a MergeAppend plan,
and there was inheritance involved: the lack of appropriate eclass child
members would prevent prepare_sort_from_pathkeys() from succeeding on the
MergeAppend's child plan nodes for inheritance child tables.

Accordingly, back-patch into 9.1 through 9.3, along with an extra
regression test case covering the problem.

Per trouble report from Michael Glaesemann.
2014-06-26 10:42:03 -07:00
Heikki Linnakangas
1c9f9e888f Don't allow foreign tables with OIDs.
The syntax doesn't let you specify "WITH OIDS" for foreign tables, but it
was still possible with default_with_oids=true. But the rest of the system,
including pg_dump, isn't prepared to handle foreign tables with OIDs
properly.

Backpatch down to 9.1, where foreign tables were introduced. It's possible
that there are databases out there that already have foreign tables with
OIDs. There isn't much we can do about that, but at least we can prevent
them from being created in the future.

Patch by Etsuro Fujita, reviewed by Hadi Moshayedi.
2014-06-24 13:30:54 +03:00
Tom Lane
b568d38361 Avoid leaking memory while evaluating arguments for a table function.
ExecMakeTableFunctionResult evaluated the arguments for a function-in-FROM
in the query-lifespan memory context.  This is insignificant in simple
cases where the function relation is scanned only once; but if the function
is in a sub-SELECT or is on the inside of a nested loop, any memory
consumed during argument evaluation can add up quickly.  (The potential for
trouble here had been foreseen long ago, per existing comments; but we'd
not previously seen a complaint from the field about it.)  To fix, create
an additional temporary context just for this purpose.

Per an example from MauMau.  Back-patch to all active branches.
2014-06-19 22:13:51 -04:00
Tom Lane
8023235357 Fix ancient encoding error in hungarian.stop.
When we grabbed this file off the Snowball project's website, we mistakenly
supposed that it was in LATIN1 encoding, but evidently it was actually in
LATIN2.  This resulted in ő (o-double-acute, U+0151, which is code 0xF5 in
LATIN2) being misconverted into õ (o-tilde, U+00F5), as complained of in
bug #10589 from Zoltán Sörös.  We'd have messed up u-double-acute too,
but there aren't any of those in the file.  Other characters used in the
file have the same codes in LATIN1 and LATIN2, which no doubt helped hide
the problem for so long.

The error is not only ours: the Snowball project also was confused about
which encoding is required for Hungarian.  But dealing with that will
require source-code changes that I'm not at all sure we'll wish to
back-patch.  Fixing the stopword file seems reasonably safe to back-patch
however.
2014-06-10 22:48:45 -04:00
Tom Lane
187ae17300 Fix planner bug with nested PlaceHolderVars in 9.2 (only).
Commit 9e7e29c75ad441450f9b8287bd51c13521641e3b fixed some problems with
LATERAL references in PlaceHolderVars, one of which was that "createplan.c
wasn't handling nested PlaceHolderVars properly".  I failed to see that
this problem might occur in older versions as well; but it can, as
demonstrated in bug #10587 from Geoff Speicher.  In this case the nesting
occurs due to push-down of PlaceHolderVar expressions into a parameterized
path.  So, back-patch the relevant changes from 9e7e29c75ad4 into 9.2 where
parameterized paths were introduced.  (Perhaps I'm still being too myopic,
but I'm hesitant to change older branches without some evidence that the
case can occur there.)
2014-06-09 21:28:56 -04:00
Tom Lane
93328b2dfb Fix infinite loop when splitting inner tuples in SPGiST text indexes.
Previously, the code used a node label of zero both for strings that
contain no bytes beyond the inner tuple's prefix, and for cases where an
"allTheSame" inner tuple has to be split to allow a string with a different
next byte to be inserted into it.  Failing to distinguish these cases meant
that if a string ending with the current prefix needed to be inserted into
an allTheSame tuple, we got into an infinite loop, because after splitting
the tuple we'd descend into the child allTheSame tuple and then find we
need to split again.

To fix, instead use -1 and -2 as the node labels for these two cases.
This requires widening the node label type from "char" to int2, but
fortunately SPGiST stores all pass-by-value node label types in their
Datum representation, which means that this change is transparently upward
compatible so far as the on-disk representation goes.  We continue to
recognize zero as a dummy node label for reading purposes, but will not
attempt to push new index entries down into such a label, so that the loop
won't occur even when dealing with an existing index.

Per report from Teodor Sigaev.  Back-patch to 9.2 where the faulty
code was introduced.
2014-06-09 16:30:46 -04:00
Tom Lane
4fb6478275 Add defenses against running with a wrong selection of LOBLKSIZE.
It's critical that the backend's idea of LOBLKSIZE match the way data has
actually been divided up in pg_largeobject.  While we don't provide any
direct way to adjust that value, doing so is a one-line source code change
and various people have expressed interest recently in changing it.  So,
just as with TOAST_MAX_CHUNK_SIZE, it seems prudent to record the value in
pg_control and cross-check that the backend's compiled-in setting matches
the on-disk data.

Also tweak the code in inv_api.c so that fetches from pg_largeobject
explicitly verify that the length of the data field is not more than
LOBLKSIZE.  Formerly we just had Asserts() for that, which is no protection
at all in production builds.  In some of the call sites an overlength data
value would translate directly to a security-relevant stack clobber, so it
seems worth one extra runtime comparison to be sure.

In the back branches, we can't change the contents of pg_control; but we
can still make the extra checks in inv_api.c, which will offer some amount
of protection against running with the wrong value of LOBLKSIZE.
2014-06-05 11:31:12 -04:00
Andres Freund
315442c011 Fix longstanding bug in HeapTupleSatisfiesVacuum().
HeapTupleSatisfiesVacuum() didn't properly discern between
DELETE_IN_PROGRESS and INSERT_IN_PROGRESS for rows that have been
inserted in the current transaction and deleted in a aborted
subtransaction of the current backend. At the very least that caused
problems for CLUSTER and CREATE INDEX in transactions that had
aborting subtransactions producing rows, leading to warnings like:
WARNING:  concurrent delete in progress within table "..."
possibly in an endless, uninterruptible, loop.

Instead of treating *InProgress xmins the same as *IsCurrent ones,
treat them as being distinct like the other visibility routines. As
implemented this separatation can cause a behaviour change for rows
that have been inserted and deleted in another, still running,
transaction. HTSV will now return INSERT_IN_PROGRESS instead of
DELETE_IN_PROGRESS for those. That's both, more in line with the other
visibility routines and arguably more correct. The latter because a
INSERT_IN_PROGRESS will make callers look at/wait for xmin, instead of
xmax.
The only current caller where that's possibly worse than the old
behaviour is heap_prune_chain() which now won't mark the page as
prunable if a row has concurrently been inserted and deleted. That's
harmless enough.

As a cautionary measure also insert a interrupt check before the gotos
in IndexBuildHeapScan() that lead to the uninterruptible loop. There
are other possible causes, like a row that several sessions try to
update and all fail, for repeated loops and the cost of doing so in
the retry case is low.

As this bug goes back all the way to the introduction of
subtransactions in 573a71a5da backpatch to all supported releases.

Reported-By: Sandro Santilli
2014-06-04 23:25:52 +02:00
Andres Freund
f998e99400 Set the process latch when processing recovery conflict interrupts.
Because RecoveryConflictInterrupt() didn't set the process latch
anything using the latter to wait for events didn't get notified about
recovery conflicts. Most latch users are never the target of recovery
conflicts, which explains the lack of reports about this until
now.
Since 9.3 two possible affected users exist though: The sql callable
pg_sleep() now uses latches to wait and background workers are
expected to use latches in their main loop. Both would currently wait
until the end of WaitLatch's timeout.

Fix by adding a SetLatch() to RecoveryConflictInterrupt(). It'd also
be possible to fix the issue by having each latch user set
set_latch_on_sigusr1. That seems failure prone and though, as most of
these callsites won't often receive recovery conflicts and thus will
likely only be tested against normal query cancels et al. It'd also be
unnecessarily verbose.

Backpatch to 9.1 where latches were introduced. Arguably 9.3 would be
sufficient, because that's where pg_sleep() was converted to waiting
on the latch and background workers got introduced; but there could be
user level code making use of the latch pre 9.3.
2014-06-03 14:18:04 +02:00
Tom Lane
952b036054 Revert "Fix bogus %name-prefix option syntax in all our Bison files."
This reverts commit 867363cbcbc3d0ccac813a74fbc8236d8873c266.

It turns out that the %name-prefix syntax without "=" does not work
at all in pre-2.4 Bison.  We are not prepared to make such a large
jump in minimum required Bison version just to suppress a warning
message in a version hardly any developers are using yet.
When 3.0 gets more popular, we'll figure out a way to deal with this.
In the meantime, BISONFLAGS=-Wno-deprecated is recommendable for
anyone using 3.0 who doesn't want to see the warning.
2014-05-28 19:29:05 -04:00
Tom Lane
867363cbcb Fix bogus %name-prefix option syntax in all our Bison files.
%name-prefix doesn't use an "=" sign according to the Bison docs, but it
silently accepted one anyway, until Bison 3.0.  This was originally a
typo of mine in commit 012abebab1bc72043f3f670bf32e91ae4ee04bd2, and we
seem to have slavishly copied the error into all the other grammar files.

Per report from Vik Fearing; analysis by Peter Eisentraut.

Back-patch to all active branches, since somebody might try to build
a back branch with up-to-date tools.
2014-05-28 15:41:58 -04:00
Magnus Hagander
dbcde0f4d6 Ensure cleanup in case of early errors in streaming base backups
Move the code that sends the initial status information as well as the
calculation of paths inside the ENSURE_ERROR_CLEANUP block. If this code
failed, we would "leak" a counter of number of concurrent backups, thereby
making the system always believe it was in backup mode. This could happen
if the sending failed (which it probably never did given that the small
amount of data to send would never cause a flush). It is very low risk, but
all operations after do_pg_start_backup should be protected.
2014-05-28 13:03:21 +02:00
Tom Lane
31f579f09c Prevent auto_explain from changing the output of a user's EXPLAIN.
Commit af7914c6627bcf0b0ca614e9ce95d3f8056602bf, which introduced the
EXPLAIN (TIMING) option, for some reason coded explain.c to look at
planstate->instrument->need_timer rather than es->timing to decide
whether to print timing info.  However, the former flag might get set
as a result of contrib/auto_explain wanting timing information.  We
certainly don't want activation of auto_explain to change user-visible
statement behavior, so fix that.

Also fix an independent bug introduced in the same patch: in the code
path for a never-executed node with a machine-friendly output format,
if timing was selected, it would fail to print the Actual Rows and Actual
Loops items.

Per bug #10404 from Tomonari Katsumata.  Back-patch to 9.2 where the
faulty code was introduced.
2014-05-20 12:20:57 -04:00
Heikki Linnakangas
0128a7712d Use 0-based numbering in comments about backup blocks.
The macros and functions that work with backup blocks in the redo function
use 0-based numbering, so let's use that consistently in the function that
generates the records too. Makes it so much easier to compare the
generation and replay functions.

Backpatch to 9.0, where we switched from 1-based to 0-based numbering.
2014-05-19 13:27:21 +03:00
Heikki Linnakangas
0d4c75f4de Initialize tsId and dbId fields in WAL record of COMMIT PREPARED.
Commit dd428c79 added dbId and tsId to the xl_xact_commit struct but missed
that prepared transaction commits reuse that struct. Fix that.

Because those fields were left unitialized, replaying a commit prepared WAL
record in a hot standby node would fail to remove the relcache init file.
That can lead to "could not open file" errors on the standby. Relcache init
file only needs to be removed when a system table/index is rewritten in the
transaction using two phase commit, so that should be rare in practice. In
HEAD, the incorrect dbId/tsId values are also used for filtering in logical
replication code, causing the transaction to always be filtered out.

Analysis and fix by Andres Freund. Backpatch to 9.0 where hot standby was
introduced.
2014-05-16 10:05:57 +03:00
Tom Lane
9601cb7bcc Fix unportable setvbuf() usage in initdb.
In yesterday's commit 2dc4f011fd61501cce507be78c39a2677690d44b, I tried
to force buffering of stdout/stderr in initdb to be what it is by
default when the program is run interactively on Unix (since that's how
most manual testing is done).  This tripped over the fact that Windows
doesn't support _IOLBF mode.  We dealt with that a long time ago in
syslogger.c by falling back to unbuffered mode on Windows.  Export that
solution in port.h and use it in initdb.

Back-patch to 8.4, like the previous commit.
2014-05-15 15:58:01 -04:00
Heikki Linnakangas
479a36f234 Handle duplicate XIDs in txid_snapshot.
The proc array can contain duplicate XIDs, when a transaction is just being
prepared for two-phase commit. To cope, remove any duplicates in
txid_current_snapshot(). Also ignore duplicates in the input functions, so
that if e.g. you have an old pg_dump file that already contains duplicates,
it will be accepted.

Report and fix by Jan Wieck. Backpatch to all supported versions.
2014-05-15 18:31:00 +03:00
Heikki Linnakangas
d8dbeb0482 Fix race condition in preparing a transaction for two-phase commit.
To lock a prepared transaction's shared memory entry, we used to mark it
with the XID of the backend. When the XID was no longer active according
to the proc array, the entry was implicitly considered as not locked
anymore. However, when preparing a transaction, the backend's proc array
entry was cleared before transfering the locks (and some other state) to
the prepared transaction's dummy PGPROC entry, so there was a window where
another backend could finish the transaction before it was in fact fully
prepared.

To fix, rewrite the locking mechanism of global transaction entries. Instead
of an XID, just have simple locked-or-not flag in each entry (we store the
locking backend's backend id rather than a simple boolean, but that's just
for debugging purposes). The backend is responsible for explicitly unlocking
the entry, and to make sure that that happens, install a callback to unlock
it on abort or process exit.

Backpatch to all supported versions.
2014-05-15 16:58:14 +03:00
Tom Lane
25c933c5c9 Get rid of bogus dependency on typcategory in to_json() and friends.
These functions were relying on typcategory to identify arrays and
composites, which is not reliable and not the normal way to do it.
Using typcategory to identify boolean, numeric types, and json itself is
also pretty questionable, though the code in those cases didn't seem to be
at risk of anything worse than wrong output.  Instead, use the standard
lsyscache functions to identify arrays and composites, and rely on a direct
check of the type OID for the other cases.

In HEAD, also be sure to look through domains so that a domain is treated
the same as its base type for conversions to JSON.  However, this is a
small behavioral change; given the lack of field complaints, we won't
back-patch it.

In passing, refactor so that there's only one copy of the code that decides
which conversion strategy to apply, not multiple copies that could (and
have) gotten out of sync.
2014-05-09 12:55:06 -04:00
Heikki Linnakangas
31633f9925 Protect against torn pages when deleting GIN list pages.
To-be-deleted list pages contain no useful information, as they are being
deleted, but we must still protect the writes from being torn by a crash
after a partial write. To do that, re-initialize the pages on WAL replay.

Jeff Janes caught this with a test program to test partial writes.
Backpatch to all supported versions.
2014-05-08 14:43:39 +03:00
Tom Lane
022b5f2b22 Fix failure to set ActiveSnapshot while rewinding a cursor.
ActiveSnapshot needs to be set when we call ExecutorRewind because some
plan node types may execute user-defined functions during their ReScan
calls (nodeLimit.c does so, at least).  The wisdom of that is somewhat
debatable, perhaps, but for now the simplest fix is to make sure the
required context is valid.  Failure to do this typically led to a
null-pointer-dereference core dump, though it's possible that in more
complex cases a function could be executed with the wrong snapshot
leading to very subtle misbehavior.

Per report from Leif Jensen.  It's been broken for a long time, so
back-patch to all active branches.
2014-05-07 14:25:17 -04:00
Bruce Momjian
0b44914c21 Remove tabs after spaces in C comments
This was not changed in HEAD, but will be done later as part of a
pgindent run.  Future pgindent runs will also do this.

Report by Tom Lane

Backpatch through all supported branches, but not HEAD
2014-05-06 11:26:27 -04:00
Heikki Linnakangas
17b04a1580 Fix use of free in walsender error handling after a sysid mismatch.
Found via valgrind. The bug exists since the introduction of the walsender,
so backpatch to 9.0.

Andres Freund
2014-05-06 15:17:00 +03:00
Tom Lane
c8fbeeb45e Fix possible cache invalidation failure in ReceiveSharedInvalidMessages.
Commit fad153ec45299bd4d4f29dec8d9e04e2f1c08148 modified sinval.c to reduce
the number of calls into sinvaladt.c (which require taking a shared lock)
by keeping a local buffer of collected-but-not-yet-processed messages.
However, if processing of the last message in a batch resulted in a
recursive call to ReceiveSharedInvalidMessages, we could overwrite that
message with a new one while the outer invalidation function was still
working on it.  This would be likely to lead to invalidation of the wrong
cache entry, allowing subsequent processing to use stale cache data.
The fix is just to make a local copy of each message while we're processing
it.

Spotted by Andres Freund.  Back-patch to 8.4 where the bug was introduced.
2014-05-05 14:43:46 -04:00
Tom Lane
8c43980a18 Fix failure to detoast fields in composite elements of structured types.
If we have an array of records stored on disk, the individual record fields
cannot contain out-of-line TOAST pointers: the tuptoaster.c mechanisms are
only prepared to deal with TOAST pointers appearing in top-level fields of
a stored row.  The same applies for ranges over composite types, nested
composites, etc.  However, the existing code only took care of expanding
sub-field TOAST pointers for the case of nested composites, not for other
structured types containing composites.  For example, given a command such
as

UPDATE tab SET arraycol = ARRAY[(ROW(x,42)::mycompositetype] ...

where x is a direct reference to a field of an on-disk tuple, if that field
is long enough to be toasted out-of-line then the TOAST pointer would be
inserted as-is into the array column.  If the source record for x is later
deleted, the array field value would become a dangling pointer, leading
to errors along the line of "missing chunk number 0 for toast value ..."
when the value is referenced.  A reproducible test case for this was
provided by Jan Pecek, but it seems likely that some of the "missing chunk
number" reports we've heard in the past were caused by similar issues.

Code-wise, the problem is that PG_DETOAST_DATUM() is not adequate to
produce a self-contained Datum value if the Datum is of composite type.
Seen in this light, the problem is not just confined to arrays and ranges,
but could also affect some other places where detoasting is done in that
way, for example form_index_tuple().

I tried teaching the array code to apply toast_flatten_tuple_attribute()
along with PG_DETOAST_DATUM() when the array element type is composite,
but this was messy and imposed extra cache lookup costs whether or not any
TOAST pointers were present, indeed sometimes when the array element type
isn't even composite (since sometimes it takes a typcache lookup to find
that out).  The idea of extending that approach to all the places that
currently use PG_DETOAST_DATUM() wasn't attractive at all.

This patch instead solves the problem by decreeing that composite Datum
values must not contain any out-of-line TOAST pointers in the first place;
that is, we expand out-of-line fields at the point of constructing a
composite Datum, not at the point where we're about to insert it into a
larger tuple.  This rule is applied only to true composite Datums, not
to tuples that are being passed around the system as tuples, so it's not
as invasive as it might sound at first.  With this approach, the amount
of code that has to be touched for a full solution is greatly reduced,
and added cache lookup costs are avoided except when there actually is
a TOAST pointer that needs to be inlined.

The main drawback of this approach is that we might sometimes dereference
a TOAST pointer that will never actually be used by the query, imposing a
rather large cost that wasn't there before.  On the other side of the coin,
if the field value is used multiple times then we'll come out ahead by
avoiding repeat detoastings.  Experimentation suggests that common SQL
coding patterns are unaffected either way, though.  Applications that are
very negatively affected could be advised to modify their code to not fetch
columns they won't be using.

In future, we might consider reverting this solution in favor of detoasting
only at the point where data is about to be stored to disk, using some
method that can drill down into multiple levels of nested structured types.
That will require defining new APIs for structured types, though, so it
doesn't seem feasible as a back-patchable fix.

Note that this patch changes HeapTupleGetDatum() from a macro to a function
call; this means that any third-party code using that macro will not get
protection against creating TOAST-pointer-containing Datums until it's
recompiled.  The same applies to any uses of PG_RETURN_HEAPTUPLEHEADER().
It seems likely that this is not a big problem in practice: most of the
tuple-returning functions in core and contrib produce outputs that could
not possibly be toasted anyway, and the same probably holds for third-party
extensions.

This bug has existed since TOAST was invented, so back-patch to all
supported branches.
2014-05-01 15:19:14 -04:00
Tom Lane
920fbc1b43 Check for interrupts and stack overflow during rule/view dumps.
Since ruleutils.c recurses, it could be driven to stack overflow by
deeply nested constructs.  Very large queries might also take long
enough to deparse that a check for interrupts seems like a good idea.
Stick appropriate tests into a couple of key places.

Noted by Greg Stark.  Back-patch to all supported branches.
2014-04-30 13:46:19 -04:00
Tom Lane
0901dbab33 Improve planner to drop constant-NULL inputs of AND/OR where it's legal.
In general we can't discard constant-NULL inputs, since they could change
the result of the AND/OR to be NULL.  But at top level of WHERE, we do not
need to distinguish a NULL result from a FALSE result, so it's okay to
treat NULL as FALSE and then simplify AND/OR accordingly.

This is a very ancient oversight, but in 9.2 and later it can lead to
failure to optimize queries that previous releases did optimize, as a
result of more aggressive parameter substitution rules making it possible
to reduce more subexpressions to NULL constants.  This is the root cause of
bug #10171 from Arnold Scheffler.  We could alternatively have fixed that
by teaching orclauses.c to ignore constant-NULL OR arms, but it seems
better to get rid of them globally.

I resisted the temptation to back-patch this change into all active
branches, but it seems appropriate to back-patch as far as 9.2 so that
there will not be performance regressions of the kind shown in this bug.
2014-04-29 13:12:33 -04:00
Heikki Linnakangas
1e96eff43a Fix two bugs in WAL-logging of GIN pending-list pages.
In writeListPage, never take a full-page image of the page, because we
have all the information required to re-initialize in the WAL record
anyway. Before this fix, a full-page image was always generated, unless
full_page_writes=off, because when the page is initialized its LSN is
always 0. In stable-branches, keep the code to restore the backup blocks
if they exist, in case that the WAL is generated with an older minor
version, but in master Assert that there are no full-page images.

In the redo routine, add missing "off++". Otherwise the tuples are added
to the page in reverse order. That happens to be harmless because we
always scan and remove all the tuples together, but it was clearly wrong.
Also, it was masked by the first bug unless full_page_writes=off, because
the page was always restored from a full-page image.

Backpatch to all supported versions.
2014-04-28 17:31:07 +03:00
Tom Lane
ea9ac77419 Reset pg_stat_activity.xact_start during PREPARE TRANSACTION.
Once we've completed a PREPARE, our session is not running a transaction,
so its entry in pg_stat_activity should show xact_start as null, rather
than leaving the value as the start time of the now-prepared transaction.

I think possibly this oversight was triggered by faulty extrapolation
from the adjacent comment that says PrepareTransaction should not call
AtEOXact_PgStat, so tweak the wording of that comment.

Noted by Andres Freund while considering bug #10123 from Maxim Boguk,
although this error doesn't seem to explain that report.

Back-patch to all active branches.
2014-04-24 13:30:00 -04:00
Heikki Linnakangas
6c5cba8e0b Fix typos in comment. 2014-04-23 12:58:18 +03:00
Tom Lane
bac05d622d Use AF_UNSPEC not PF_UNSPEC in getaddrinfo calls.
According to the Single Unix Spec and assorted man pages, you're supposed
to use the constants named AF_xxx when setting ai_family for a getaddrinfo
call.  In a few places we were using PF_xxx instead.  Use of PF_xxx
appears to be an ancient BSD convention that was not adopted by later
standardization.  On BSD and most later Unixen, it doesn't matter much
because those constants have equivalent values anyway; but nonetheless
this code is not per spec.

In the same vein, replace PF_INET by AF_INET in one socket() call, which
wasn't even consistent with the other socket() call in the same function
let alone the remainder of our code.

Per investigation of a Cygwin trouble report from Marco Atzeri.  It's
probably a long shot that this will fix his issue, but it's wrong in
any case.
2014-04-16 13:21:31 -04:00
Bruce Momjian
966f015b60 check socket creation errors against PGINVALID_SOCKET
Previously, in some places, socket creation errors were checked for
negative values, which is not true for Windows because sockets are
unsigned.  This masked socket creation errors on Windows.

Backpatch through 9.0.  8.4 doesn't have the infrastructure to fix this.
2014-04-16 10:45:48 -04:00
Heikki Linnakangas
a4c4e0bf60 Use correctly-sized buffer when zero-filling a WAL file.
I mixed up BLCKSZ and XLOG_BLCKSZ when I changed the way the buffer is
allocated a couple of weeks ago. With the default settings, they are both
8k, but they can be changed at compile-time.
2014-04-16 10:26:54 +03:00
Heikki Linnakangas
02b9fd73ee Fix hot standby bug with GiST scans.
Don't reset the rightlink of a page when replaying a page update record.
This was a leftover from pre-hot standby days, when it was not possible to
have scans concurrent with WAL replay. Resetting the right-link was not
necessary back then either, but it was done for the sake of tidiness. But
with hot standby, it's wrong, because a concurrent scan might still need it.

Backpatch all versions with hot standby, 9.0 and above.
2014-04-08 14:51:56 +03:00
Robert Haas
74cf802841 Assert that strong-lock count is >0 everywhere it's decremented.
The one existing assertion of this type has tripped a few times in the
buildfarm lately, but it's not clear whether the problem is really
originating there or whether it's leftovers from a trip through one
of the other two paths that lack a matching assertion.  So add one.

Since the same bug(s) most likely exist(s) in the back-branches also,
back-patch to 9.2, where the fast-path lock mechanism was added.
2014-04-07 11:15:13 -04:00
Tom Lane
53463e2479 Block signals earlier during postmaster startup.
Formerly, we set up the postmaster's signal handling only when we were
about to start launching subprocesses.  This is a bad idea though, as
it means that for example a SIGINT arriving before that will kill the
postmaster instantly, perhaps leaving lockfiles, socket files, shared
memory, etc laying about.  We'd rather that such a signal caused orderly
postmaster termination including releasing of those resources.  A simple
fix is to move the PostmasterMain stanza that initializes signal handling
to an earlier point, before we've created any such resources.  Then, an
early-arriving signal will be blocked until we're ready to deal with it
in the usual way.  (The only part that really needs to be moved up is
blocking of signals, but it seems best to keep the signal handler
installation calls together with that; for one thing this ensures the
kernel won't drop any signals we wished to get.  The handlers won't get
invoked in any case until we unblock signals in ServerLoop.)

Per a report from MauMau.  He proposed changing the way "pg_ctl stop"
works to deal with this, but that'd just be masking one symptom not
fixing the core issue.

It's been like this since forever, so back-patch to all supported branches.
2014-04-05 18:16:14 -04:00
Tom Lane
bdc3e95c2a Fix processing of PGC_BACKEND GUC parameters on Windows.
EXEC_BACKEND builds (i.e., Windows) failed to absorb values of PGC_BACKEND
parameters if they'd been changed post-startup via the config file.  This
for example prevented log_connections from working if it were turned on
post-startup.  The mechanism for handling this case has always been a bit
of a kluge, and it wasn't revisited when we implemented EXEC_BACKEND.
While in a normal forking environment new backends will inherit the
postmaster's value of such settings, EXEC_BACKEND backends have to read
the settings from the CONFIG_EXEC_PARAMS file, and they were mistakenly
rejecting them.  So this case has always been broken in the Windows port;
so back-patch to all supported branches.

Amit Kapila
2014-04-05 12:41:31 -04:00
Tom Lane
1a496a12b3 Fix tablespace creation WAL replay to work on Windows.
The code segment that removes the old symlink (if present) wasn't clued
into the fact that on Windows, symlinks are junction points which have
to be removed with rmdir().

Backpatch to 9.0, where the failing code was introduced.

MauMau, reviewed by Muhammad Asif Naeem and Amit Kapila
2014-04-04 23:09:41 -04:00