dynamic pool of event handles, we can permanently assign one for each
shared latch. Thanks to that, we no longer need a separate shared memory
block for latches, and we don't need to know in advance how many shared
latches there is, so you no longer need to remember to update
NumSharedLatches when you introduce a new latch to the system.
In these cases a qual can get marked with the removable rel in its
required_relids, but this is just to schedule its evaluation correctly, not
because it really depends on the rel. We were assuming that, in effect,
we could throw away *all* quals so marked, which is nonsense. Tighten up
the logic to be a little more paranoid about which quals belong to the
outer join being considered for removal, and arrange for all quals that
don't belong to be updated so they will still get evaluated correctly.
Also fix another problem that happened to be exposed by this test case,
which was that make_join_rel() was failing to notice some cases where
a constant-false qual could be used to prove a join relation empty. If it's
a pushed-down constant false, then the relation is empty even if it's an
outer join, because the qual applies after the outer join expansion.
Per report from Nathan Grange. Back-patch into 9.0.
make sense for walsender, but for example application_name and client_encoding
do. We still don't apply per-role settings from pg_db_role_setting, because
that would require connecting to a database to read the table.
Fujii Masao
transaction snapshots, i.e. a snapshot registered at the beginning of
a transaction. Change variable naming and comments to reflect this reality
in preparation for a future, truly serializable mode, e.g.
Serializable Snapshot Isolation (SSI).
For the moment transaction snapshots are still used to implement
SERIALIZABLE, but hopefully not for too much longer. Patch by Kevin
Grittner and Dan Ports with review and some minor wording changes by me.
wait until it is set. Latches can be used to reliably wait until a signal
arrives, which is hard otherwise because signals don't interrupt select()
on some platforms, and even when they do, there's race conditions.
On Unix, latches use the so called self-pipe trick under the covers to
implement the sleep until the latch is set, without race conditions. On
Windows, Windows events are used.
Use the new latch abstraction to sleep in walsender, so that as soon as
a transaction finishes, walsender is woken up to immediately send the WAL
to the standby. This reduces the latency between master and standby, which
is good.
Preliminary work by Fujii Masao. The latch implementation is by me, with
helpful comments from many people.
Peter's original patch had this right, but I dropped the check while revising
the code to search pg_constraint instead of pg_index. Spotted by Dean Rasheed.
A long time ago, this didn't work nicely, but it seems to work on all recent
versions of OS X. The blank-pad method is less desirable since it results
in lots of extra space in ps' output. Per Alexey Klyukin.
Since the code underlying pg_get_expr() is not secure against malformed
input, and can't practically be made so, we need to prevent miscreants
from feeding arbitrary data to it. We can do this securely by declaring
pg_get_expr() to take a new datatype "pg_node_tree" and declaring the
system catalog columns that hold nodeToString output to be of that type.
There is no way at SQL level to create a non-null value of type pg_node_tree.
Since the backend-internal operations that fill those catalog columns
operate below the SQL level, they are oblivious to the datatype relabeling
and don't need any changes.
SI invalidation events, rather than indirectly through the relcache.
In the previous coding, we had to flush a composite-type typcache entry
whenever we discarded the corresponding relcache entry. This caused problems
at least when testing with RELCACHE_FORCE_RELEASE, as shown in recent report
from Jeff Davis, and might result in real-world problems given the kind of
unexpected relcache flush that that test mechanism is intended to model.
The new coding decouples relcache and typcache management, which is a good
thing anyway from a structural perspective. The cost is that we have to
search the typcache linearly to find entries that need to be flushed. There
are a couple of ways we could avoid that, but at the moment it's not clear
it's worth any extra trouble, because the typcache contains very few entries
in typical operation.
Back-patch to 8.2, the same as some other recent fixes in this general area.
The patch could be carried back to 8.0 with some additional work, but given
that it's only hypothetical whether we're fixing any problem observable in
the field, it doesn't seem worth the work now.
initialize the rd_backend field of a fake Relation entry correctly.
Fortunately, that is easy, since only non-temp relations should ever be
mentioned in the WAL stream.
This patch changes _bt_split() and _bt_pagedel() to throw a plain ERROR,
rather than PANIC, for several cases that are reported from the field
from time to time:
* right sibling's left-link doesn't match;
* PageAddItem failure during _bt_split();
* parent page's next child isn't right sibling during _bt_pagedel().
In addition the error messages for these cases have been made a bit
more verbose, with additional values included.
The original motivation for PANIC here was to capture core dumps for
subsequent analysis. But with so many users whose platforms don't capture
core dumps by default, or who are unprepared to analyze them anyway, it's hard
to justify a forced database restart when we can fairly easily detect the
problems before we've reached the critical sections where PANIC would be
necessary. It is not currently known whether the reports of these messages
indicate well-hidden bugs in Postgres, or are a result of storage-level
malfeasance; the latter possibility suggests that we ought to try to be more
robust even if there is a bug here that's ultimately found.
Backpatch to 8.2. The code before that is sufficiently different that
it doesn't seem worth the trouble to back-port further.
Peter Eisentraut reports that some bits of the "address" variable
in get_object_address() give "may be used uninitialized" warnings;
this likes the only excuse his compiler could have for thinking
that's possible.
which is perhaps not a terribly good spot for it but there doesn't seem to be
a better place. Also add a source-code comment pointing out a couple reasons
for having a separate lock file. Per suggestion from Greg Smith.
returning "record" actually do have the same rowtype. This is needed because
the parser can't realistically enforce that they will all have the same typmod,
as seen in a recent example from David Wheeler.
Back-patch to 8.0, which is as far back as we have the notion of RECORD
subtypes being distinguished by typmod. Wheeler's example depends on
8.4-and-up features, but I suspect there may be ways to provoke similar
failures before 8.4.
It turns out that some platforms return ENOMEM for a request that violates
SHMALL, whereas we were assuming that ENOSPC would always be used for that.
Apparently the latter is a Linuxism while ENOMEM is the BSD tradition.
Extend the ENOMEM hint to suggest that raising SHMALL might be needed.
Per gripe from A.M.
Backpatch to 9.0, but not further, because this doesn't seem important
enough to warrant creating extra translation work in the stable branches.
(If it were, we'd have figured this out years ago.)
There is no reason that proc.c should have to get involved in this dirty hack
for letting the postmaster know which children are walsenders. Revert that
file to the way it was, and confine the kluge to pmsignal.c and postmaster.c.
array_in discards unquoted leading and trailing whitespace in array values,
while array_out is careful to quote array elements that contain whitespace.
This is problematic when the definition of "whitespace" varies between
locales: array_in could drop characters that were meant to be part of the
value. To avoid that, lock down "whitespace" to mean only the traditional
six ASCII space characters.
This change also works around a bug in OS X and some older BSD systems, in
which isspace() could return true for character fragments in UTF8 locales.
(There may be other places in PG where that bug could cause problems, but
this is the only one complained of so far; see recent report from Steven
Schlansker.)
Back-patch to 9.0, but not further. Given the lack of previous reports
of trouble, changing this behavior in stable branches seems to offer
more risk of breaking applications than reward of avoiding problems.
Since an SMgrRelation now knows whether or not the underlying relation is
temporary, there's no point in also passing that information via an
additional argument.
Per gripe from Fujii Masao, though this is not exactly his proposed patch.
Categorize as DEVELOPER_OPTIONS and set context PGC_SIGHUP, as per Fujii,
but set the default to LOG because higher values aren't really sensible
(see the code for trace_recovery()). Fix the documentation to agree with
the code and to try to explain what the variable actually does. Get rid
of no-op calls trace_recovery(LOG), which accomplish nothing except to
demonstrate that this option confuses even its author.
pointed out, it would need a 2nd pass after the whole query is processed to
correctly check that an unknown Param is coerced to the same target type
everywhere. Adding the 2nd pass would add a lot more code, which doesn't
seem worth the risk given that there isn't much of a use case for passing
unknown Params in the first place. The code would work without that check,
but it might be confusing and the behavior would be different from the
varparams case.
Instead, just coerce all unknown params in a PL/pgSQL USING clause to text.
That's simple, and is usually what users expect.
Revert the patch in CVS HEAD and master, and backpatch the new solution to
8.4. Unlike the previous solution, this applies easily to 8.4 too.
into TopMemoryContext. This makes no functional difference, but makes it
easier to see what the space is being used for in MemoryContextStats dumps.
Per a recent example in which I was surprised by the size of TopMemoryContext.
afterTriggerInvokeEvents failed to adjust events->tailfree when truncating
the last chunk of an event list. This could result in the data being
"de-truncated" by afterTriggerRestoreEventList during a subsequent
subtransaction abort. Even that wouldn't kill us, because the re-added data
would just be events marked DONE --- unless the data had been partially
overwritten by new events. Then we might crash, or in any case misbehave
(perhaps fire triggers twice, or fire triggers with the wrong event data).
Per bug #5622 from Thue Janus Kristensen.
Back-patch to 8.4 where the current trigger list representation was introduced.
In the new API introduced by my patch to include the backend ID in
temprel filenames, the last argument to smrgextend() became skipFsync
rather than isTemp, but these calls didn't get the memo. It's not
really a problem to pass rel->rd_istemp rather than just plain false,
because smgrextend() now automatically skips the fsync for temprels
anyway, but this seems cleaner and saves some minute number of cycles.
ExecModifyTable(). This avoids memory leakage when trigger functions leave
junk behind in that context (as they more or less must). Problem and solution
identified by Dean Rasheed.
I'm a bit concerned about the longevity of this solution --- once a plan can
have multiple ModifyTable nodes, we are very possibly going to have to do
something different. But it should hold up for 9.0.
elsewhere.
Similarly rename the version in mbprint.c, not because this affects anything
but just to keep the two copies in exact sync. There was some discussion of
having only one copy in src/port/ instead, but this function is so small
and unlikely to change that that seems like overkill.
Slightly editorialized version of a patch by Joseph Adams. (The bug-fix
aspect of his patch was applied separately, and back-patched.)
The implicitly created sequence was created as owned by the current user,
who could be different from the table owner, eg if current user is a
superuser or some member of the table's owning role. This caused sanity
checks in the SEQUENCE OWNED BY code to spit up. Although possibly we
don't need those sanity checks, the safest fix seems to be to make sure
the implicit sequence is assigned the same owner role as the table has.
(We still do all permissions checks as the current user, however.)
Per report from Josh Berkus.
Back-patch to 9.0. The bug goes back to the invention of SEQUENCE OWNED BY
in 8.2, but the fix requires an API change for DefineRelation(), which seems
to have potential for breaking third-party code if done in a minor release.
Given the lack of prior complaints, it's probably not worth fixing in the
stable branches.
_outPlannedStmt is only debug support, so the omission there was not very
serious, but the omission in _copyPlannedStmt is a real bug. The consequence
would be that a copied plan tree would never be marked as a transient plan,
so that we would forget we ought to replan it after some not-yet-ready index
becomes ready for use. This might explain some past complaints about indexes
created with CREATE INDEX CONCURRENTLY not being used right away. Problem
spotted by Yeb Havinga.
Back-patch to 8.3, where the field was added.
parse_analyze() function. That case occurs e.g with PL/pgSQL
EXECUTE ... USING 'stringconstant'.
The coercion with a CoerceViaIO node. The result is similar to the coercion
via input function performed for unknown constants in coerce_type(),
except that this happens at runtime.
Backpatch to 9.0. The issue is present in 8.4 as well, but the coerce param
hook infrastructure this patch relies on was introduced in 9.0. Given the
lack of user reports and harmlessness of the bug, it's not worth attempting
a different fix just for 8.4.
socket lockfile) when writing them. The lack of an fsync here may well
explain two different reports we've seen of corrupted lockfile contents,
which doesn't particularly bother the running server but can prevent a
new server from starting if the old one crashes. Per suggestion from
Alvaro.
Back-patch to all supported versions.
This is appropriate for the same reasons we already do it in
LockSharedObject(): things might have changed while we were waiting
for the lock. There doesn't seem to be a live bug here at the moment,
but that's mostly because it isn't currently used for very much.
Heikki Linnakangas
Tom Lane
Joe Conway
Robert Haas
Simon Riggs
Peter Eisentraut
Alvaro Herrera
Itagaki Takahiro
Magnus Hagander