If the initial snapshot had overflowed then we can start whenever
the latest snapshot is empty, not overflowed or as we did already,
start when the xmin on primary was higher than xmax of our starting
snapshot, which proves we have full snapshot data.
Bug report by Chris Redekop
If a tuple in a syscache contains an out-of-line toasted field, and we
try to fetch that field shortly after some other transaction has committed
an update or deletion of the tuple, there is a race condition: vacuum
could come along and remove the toast tuples before we can fetch them.
This leads to transient failures like "missing chunk number 0 for toast
value NNNNN in pg_toast_2619", as seen in recent reports from Andrew
Hammond and Tim Uckun.
The design idea of syscache is that access to stale syscache entries
should be prevented by relation-level locks, but that fails for at least
two cases where toasted fields are possible: ANALYZE updates pg_statistic
rows without locking out sessions that might want to plan queries on the
same table, and CREATE OR REPLACE FUNCTION updates pg_proc rows without
any meaningful lock at all.
The least risky fix seems to be an idea that Heikki suggested when we
were dealing with a related problem back in August: forcibly detoast any
out-of-line fields before putting a tuple into syscache in the first place.
This avoids the problem because at the time we fetch the parent tuple from
the catalog, we should be holding an MVCC snapshot that will prevent
removal of the toast tuples, even if the parent tuple is outdated
immediately after we fetch it. (Note: I'm not convinced that this
statement holds true at every instant where we could be fetching a syscache
entry at all, but it does appear to hold true at the times where we could
fetch an entry that could have a toasted field. We will need to be a bit
wary of adding toast tables to low-level catalogs that don't have them
already.) An additional benefit is that subsequent uses of the syscache
entry should be faster, since they won't have to detoast the field.
Back-patch to all supported versions. The problem is significantly harder
to reproduce in pre-9.0 releases, because of their willingness to flush
every entry in a syscache whenever the underlying catalog is vacuumed
(cf CatalogCacheFlushRelation); but there is still a window for trouble.
The existing scan-direction-sensitive tests were overly complex, and
failed to stop the scan in cases where it's perfectly legitimate to do so.
Per bug #6278 from Maksym Boguk.
Back-patch to 8.3, which is as far back as the patch applies easily.
Doesn't seem worth sweating over a relatively minor performance issue in
8.2 at this late date. (But note that this was a performance regression
from 8.1 and before, so 8.2 is being left as an outlier.)
cash_out failed to handle multiple-byte thousands separators, as per bug
#6277 from Alexander Law. In addition, cash_in didn't handle that either,
nor could it handle multiple-byte positive_sign. Both routines failed to
support multiple-byte mon_decimal_point, which I did not think was worth
changing, but at least now they check for the possibility and fall back to
using '.' rather than emitting invalid output. Also, make cash_in handle
trailing negative signs, which formerly it would reject. Since cash_out
generates trailing negative signs whenever the locale tells it to, this
last omission represents a fail-to-reload-dumped-data bug. IMO that
justifies patching this all the way back.
When a foreign-key constraint references another column of the same table,
row updates will queue both the PK's ON UPDATE action and the FK's CHECK
action in the same event. The ON UPDATE action must execute first, else
the CHECK will check a non-final state of the row and possibly throw an
inappropriate error, as seen in bug #6268 from Roman Lytovchenko.
Now, the firing order of multiple triggers for the same event is determined
by the sort order of their pg_trigger.tgnames, and the auto-generated names
we use for FK triggers are "RI_ConstraintTrigger_NNNN" where NNNN is the
trigger OID. So most of the time the firing order is the same as creation
order, and so rearranging the creation order fixes it.
This patch will fail to fix the problem if the OID counter wraps around or
adds a decimal digit (eg, from 99999 to 100000) while we are creating the
triggers for an FK constraint. Given the small odds of that, and the low
usage of self-referential FKs, we'll live with that solution in the back
branches. A better fix is to change the auto-generated names for FK
triggers, but it seems unwise to do that in stable branches because there
may be client code that depends on the naming convention. We'll fix it
that way in HEAD in a separate patch.
Back-patch to all supported branches, since this bug has existed for a long
time.
The uniqueness condition might fail to hold intra-transaction, and assuming
it does can give incorrect query results. Per report from Marti Raudsepp,
though this is not his proposed patch.
Back-patch to 9.0, where both these features were introduced. In the
released branches, add the new IndexOptInfo field to the end of the struct,
to try to minimize ABI breakage for third-party code that may be examining
that struct.
No need to do "errcode(errcode_for_file_access())", just
"errcode_for_file_access()" is enough. The extra errcode() call is useless
but harmless, so there's no user-visible bug here. Nevertheless, backpatch
to 9.1 where this code were added.
Turns out that use of ShareUpdateExclusiveLock or ShareRowExclusiveLock
to protect DDL changes had gotten copied into several places that were
not touched by either of Simon's original patches for the feature, and
thus neither he nor I thought to revert them. (Indeed, it appears that
two of these uses were committed *after* the reversion, which just goes
to show that git merging is no panacea.) Change these places to use
AccessExclusiveLock again. If we ever manage to resurrect that feature,
we're going to have to think a bit harder about how to keep lock level
usage in sync for DDL operations that aren't within the AlterTable
infrastructure.
Two of these bugs are only in HEAD, but one is in the 9.1 branch too.
Alvaro found one of them, I found the other two.
Essentially, the "IF EXISTS" portion was being ignored, and an error
thrown anyway if the opfamily did not exist.
I broke this in commit fd1843ff8979c0461fb3f1a9eab61140c977e32d; so
backpatch to 9.1.X.
Report and diagnosis by KaiGai Kohei.
There's no need to clamp the standby's xmin to be greater than
GetOldestXmin's result; if there were any such need this logic would be
hopelessly inadequate anyway, because it fails to account for
within-database versus cluster-wide values of GetOldestXmin. So get rid of
that, and just rely on sanity-checking that the xmin is not wrapped around
relative to the nextXid counter. Also, don't reset the walsender's xmin if
the current feedback xmin is indeed out of range; that just creates more
problems than we already had. Lastly, don't bother to take the
ProcArrayLock; there's no need to do that to set xmin.
Also improve the comments about this in GetOldestXmin itself.
The heuristic for when to dump a cast failed for a cast between table
rowtypes, as reported by Frédéric Rejol. Fix it by setting
the "dump" flag for such a type the same way as the flag is set for the
underlying table or base type. This won't result in the auto-generated
type appearing in the output, since setting its objType to DO_DUMMY_TYPE
unconditionally suppresses that. But it will result in dumpCast doing what
was intended.
Back-patch to 8.3. The 8.2 code is rather different in this area, and it
doesn't seem worth any risk to fix a corner case that nobody has stumbled
on before.
This view was being insufficiently careful about matching the FK constraint
to the depended-on primary or unique key constraint. That could result in
failure to show an FK constraint at all, or showing it multiple times, or
claiming that it depended on a different constraint than the one it really
does. Fix by joining via pg_depend to ensure that we find only the correct
dependency.
Back-patch, but don't bump catversion because we can't force initdb in back
branches. The next minor-version release notes should explain that if you
need to fix this in an existing installation, you can drop the
information_schema schema then re-create it by sourcing
$SHAREDIR/information_schema.sql in each database (as a superuser of
course).
This patch restores the pre-9.1 behavior that pl/perl functions returning
VOID ignore the result value of their last Perl statement. 9.1.0
unintentionally threw an error if the last statement returned a reference,
as reported by Amit Khandekar.
Also, make sure it works to return a string value for a composite type,
so long as the string meets the type's input format. We already allowed
the equivalent behavior for arrays, so it seems inconsistent to not allow
it for composites.
In addition, ensure we throw errors for attempts to return arrays or hashes
when the function's declared result type is not an array or composite type,
respectively. Pre-9.1 versions rather uselessly returned strings like
ARRAY(0x221a9a0) or HASH(0x221aa90), while 9.1.0 threw an error for the
hash case and returned a garbage value for the array case.
Also, clean up assorted grotty coding in Perl array conversion, including
use of a session-lifespan memory context to accumulate the array value
(resulting in session-lifespan memory leak on error), failure to apply the
declared typmod if any, and failure to detect some cases of non-rectangular
multi-dimensional arrays.
Alex Hunsaker and Tom Lane
Relation rowtypes and automatically-generated array types do not need to
have their own extension membership dependency entries. If we create such
then it becomes more difficult to remove items from an extension, and it's
also harder for an extension upgrade script to make sure it duplicates the
dependencies created by the extension's regular installation script.
I changed the code in such a way that this happened in commit
988cccc620, I think because of worries about
the shell-type-replacement case; but that cure was worse than the disease.
It would only matter if one extension created a shell type that was
replaced with an auto-generated type in another extension, which seems
pretty far-fetched. Better to make this work unsurprisingly in normal
cases.
Report and patch by Robert Haas, comment adjustments by me.
We have seen one too many reports of people trying to use 9.1 extension
files in the old-fashioned way of sourcing them in psql. Not only does
that usually not work (due to failure to substitute for MODULE_PATHNAME
and/or @extschema@), but if it did work they'd get a collection of loose
objects not an extension. To prevent this, insert an \echo ... \quit
line that prints a suitable error message into each extension script file,
and teach commands/extension.c to ignore lines starting with \echo.
That should not only prevent any adverse consequences of loading a script
file the wrong way, but make it crystal clear to users that they need to
do it differently now.
Tom Lane, following an idea of Andrew Dunstan's. Back-patch into 9.1
... there is not going to be much value in this if we wait till 9.2.
The documentation neglected to explain its behavior in a script file
(it only ends execution of the script, not psql as a whole), and failed
to mention the long form \quit either.
This was broken in commit 53dbc27c62, which
introduced unlogged tables. Fortunately, as debugging tools go, this one
is pretty cheap, which is probably why it took nine months for someone to
notice, but it's not intended to be enabled by default, so revert.
Noted by Fujii Masao.
transform_null_equals is only supposed to affect "foo = NULL" expressions
given directly by the user, not the internal "foo = NULL" expression
generated from CASE-WHEN.
This fixes bug #6242, reported by Sergey. Backpatch to all supported
branches.
In oder to exit on SIGTERM when in non-walsender code,
such as do_pg_stop_backup(), we need to set the interrupt
variables that are used there, and not just the walsender
local ones.
A similar problem for pgstattuple() was fixed in April of 2010 by commit
33065ef8bc, but pgstatindex() seems to have
been overlooked.
Back-patch all the way, as with that commit, though not to 7.4 through
8.1, since those are now EOL.
CREATE EXTENSION needs to transiently set search_path, as well as
client_min_messages and log_min_messages. We were doing this by the
expedient of saving the current string value of each variable, doing a
SET LOCAL, and then doing another SET LOCAL with the previous value at
the end of the command. This is a bit expensive though, and it also fails
badly if there is anything funny about the existing search_path value,
as seen in a recent report from Roger Niederland. Fortunately, there's a
much better way, which is to piggyback on the GUC infrastructure previously
developed for functions with SET options. We just open a new GUC nesting
level, do our assignments with GUC_ACTION_SAVE, and then close the nesting
level when done. This automatically restores the prior settings without a
re-parsing pass, so (in principle anyway) there can't be an error. And
guc.c still takes care of cleanup in event of an error abort.
The CREATE EXTENSION code for this was modeled on some much older code in
ri_triggers.c, which I also changed to use the better method, even though
there wasn't really much risk of failure there. Also improve the comments
in guc.c to reflect this additional usage.
This oversight meant that on Windows, the pg_settings view would not
display source file or line number information for values coming from
postgresql.conf, unless the backend had received a SIGHUP since starting.
In passing, also make the error detection in read_nondefault_variables a
tad more thorough, and fix it to not lose precision on float GUCs (these
changes are already in HEAD as of my previous commit).
Thus, an object referenced in a default expression could be dropped while
the function remained present. This was unaccountably missed in the
original patch to add default parameters for functions. Reported by
Pavel Stehule.
If an indexable operator for a non-collatable indexed datatype has a
collatable right-hand input type, any OpExpr for it will be marked with a
nonzero inputcollid (since having one collatable input is sufficient to
make that happen). However, an index on a non-collatable column certainly
doesn't have any collation. This caused us to fail to match such operators
to their indexes, because indxpath.c required an exact match of index
collation and clause collation. It seems correct to allow a match when the
index is collation-less regardless of the clause's inputcollid: an operator
with both noncollatable and collatable inputs could perhaps depend on the
collation of the collatable input, but it could hardly expect the index for
the noncollatable input to have that same collation.
Per bug #6232 from Pierre Ducroquet. His example is specifically about
"hstore ? text" but the problem seems quite generic.
In commit c1d9579dd8, I changed things so
that the output of the Agg node that feeds the window functions would not
list any ungrouped Vars directly. Formerly, for example, the Agg tlist
might have included both "x" and "sum(x)", which is not really valid if
"x" isn't a grouping column. If we then had a window function ordering on
something like "sum(x) + 1", prepare_sort_from_pathkeys would find no exact
match for this in the Agg tlist, and would conclude that it must recompute
the expression. But it would break the expression down to just the Var
"x", which it would find in the tlist, and then rebuild the ORDER BY
expression using a reference to the subplan's "x" output. Now, after the
above-referenced changes, "x" isn't in the Agg tlist if it's not a grouping
column, so that prepare_sort_from_pathkeys fails with "could not find
pathkey item to sort", as reported by Bricklen Anderson.
The fix is to not break down Aggrefs into their component parts, but just
treat them as irreducible expressions to be sought in the subplan tlist.
This is definitely OK for the use with respect to window functions in
grouping_planner, since it just built the tlist being used on the same
basis. AFAICT it is safe for other uses too; most of the other call sites
couldn't encounter Aggrefs anyway.
pg_dump has historically understood -Z with no -F switch to mean that
it should emit a gzip-compressed version of its plain text output.
This got broken through a misunderstanding in the 9.1 patch that added
directory output format. Restore the former behavior.
Per complaint from Roger Niederland and diagnosis by Adrian Klaver.
This mode still exists for backwards compatibility, making
sslmode=require the same as sslmode=verify-ca when the file is present,
but not causing an error when it isn't.
Per bug 6189, reported by Srinivas Aji
