The motivation for a crash and restart cycle when a backend dies is
that it might have corrupted shared memory on the way down; and we
can't recover reliably except by reinitializing everything. But that
doesn't apply to processes that don't touch shared memory. Currently,
there's nothing to prevent a background worker that doesn't request
shared memory access from touching shared memory anyway, but that's a
separate bug.
Previous to this commit, the coding in postmaster.c was inconsistent:
an exit status other than 0 or 1 didn't provoke a crash-and-restart,
but failure to release the postmaster child slot did. This change
makes those cases consistent.
Commit 4318daecc9 introduced a test that
couldn't be made consistent between integer and floating-point
timestamps.
It was designed to test the longest possible interval output length,
so removing four zeros from the number of hours, as this patch does,
is not ideal. But the test still has some utility for its original
purpose, and there aren't a lot of other good options.
Noah Misch suggested a different approach where we test that the
output either matches what we expect from integer timestamps or what
we expect from floating-point timestamps. That seemed to obscure an
otherwise simple test, however.
Reviewed by Tom Lane and Noah Misch.
The coding in JsonbHashScalarValue might have accidentally failed to fail
given current representational choices, but the key word there would be
"accidental". Insert the appropriate datatype conversion macro. And
use the right conversion macro for hash_numeric's result, too.
In passing make the code a bit cleaner and less repetitive by factoring
out the xor step from the switch.
Index-only scans avoid taking a lock on the VM buffer, which would
cause a lot of contention. To be correct, that requires some intricate
assumptions that weren't completely documented in the previous
comment.
Reviewed by Robert Haas.
The main problem is that DocBook SGML allows indexterm elements just
about everywhere, but DocBook XML is stricter. For example, this common
pattern
<varlistentry>
<indexterm>...</indexterm>
<term>...</term>
...
</varlistentry>
needs to be changed to something like
<varlistentry>
<term>...<indexterm>...</indexterm></term>
...
</varlistentry>
See also bb4eefe7bf.
There is currently nothing in the build system that enforces that things
stay valid, because that requires additional tools and will receive
separate consideration.
The previous coding would potentially cause attaching to segment A to
fail if segment B was at the same time in the process of going away.
Andres Freund, with a comment tweak by me
Commit d298b50a3b by Heikki Linnakangas
requested that the version check message be updated at next release, suggesting
that the appropriate text would be “9.3 or later”. The logic used for the check
indicates that the correct text for 9.4 is “9.3 or 9.4”, since the logic would
cause this to fail for later releases.
When array of char * was used as target for a FETCH statement returning more
than one row, it tried to store all the result in the first element. Instead it
should dump array of char pointers with right offset, use the address instead
of the value of the C variable while reading the array and treat such variable
as char **, instead of char * for pointer arithmetic.
Patch by Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>
Commit fad153ec45 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.
Commit 261c7d4b65 removed the "m" field
from struct LINE, but neglected to make pg_type.h's idea of the type's
size match. This resulted in reading past the end of palloc'd LINE
values when inserting them into tuples etc. In principle that could
cause a SIGSEGV, though the odds of detectable problems seem low.
Bump catversion since this makes an incompatible on-disk format change.
Note that if the line type had been in use in the field, this would
break pg_upgrade'ability of databases containing line values; but
it seems unlikely that there are any (they'd have had to be compiled
with -DENABLE_LINE_TYPE).
Spotted by Andres Freund.
This was accidentally broken in commits cfa1b4a711/5e8e794e3b.
It saves a line or so to call ftello unconditionally in _CloseArchive,
but we have to expect that it might fail if we're not in hasSeek mode.
Per report from Bernd Helmle.
In passing, improve _getFilePos to print an appropriate message if
ftello fails unexpectedly, rather than just a vague complaint about
"ftell mismatch".
If they were not 'oldtup.t_data' would be dereferenced while set to NULL
in case of a full page image for block 0.
Do so primarily to silence coverity; but also to make sure this prerequisite
isn't changed without adapting the replay routine as that would appear to
work in many cases.
Andres Freund
It's easy to forget using SYSTEMQUOTEs when constructing command strings
for system() or popen(). Even if we fix all the places missing it now, it is
bound to be forgotten again in the future. Introduce wrapper functions that
do the the extra quoting for you, and get rid of SYSTEMQUOTEs in all the
callers.
We previosly used SYSTEMQUOTEs in all the hard-coded command strings, and
this doesn't change the behavior of those. But user-supplied commands, like
archive_command, restore_command, COPY TO/FROM PROGRAM calls, as well as
pgbench's \shell, will now gain an extra pair of quotes. That is desirable,
but if you have existing scripts or config files that include an extra
pair of quotes, those might need to be adjusted.
Reviewed by Amit Kapila and Tom Lane
ruleutils.c tries to cope with additions/deletions/renamings of columns in
tables referenced by views, by means of adding machine-generated aliases to
the printed form of a view when needed to preserve the original semantics.
A recent blog post by Marko Tiikkaja pointed out a case I'd missed though:
if one input of a join with USING is itself a join, there is nothing to
stop the user from adding a column of the same name as the USING column to
whichever side of the sub-join didn't provide the USING column. And then
there'll be an error when the view is re-parsed, since now the sub-join
exposes two columns matching the USING specification. We were catching a
lot of related cases, but not this one, so add some logic to cope with it.
Back-patch to 9.3, which is the first release that makes any serious
attempt to cope with such cases (cf commit 2ffa740be and follow-ons).
This test used to just define an unused static inline function and check
whether that causes a warning. But newer clang versions warn about
unused static inline functions when defined inside a .c file, but not
when defined in an included header, which is the case we care about.
Change the test to cope.
Andres Freund
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.
Be more clear about failure cases in relfilenode->relation lookup,
and fix some other places that were inconsistent or not per our
message style guidelines.
Andres Freund and Tom Lane
This was intended to work always, but the previous code only allowed
it if at least one message was successfully read by the receiver
before the sender detached the queue.
Report by Petr Jelinek. Patch by me.
Commit a730183926 created rather a mess by
putting dependencies on backend-only include files into include/common.
We really shouldn't do that. To clean it up:
* Move TABLESPACE_VERSION_DIRECTORY back to its longtime home in
catalog/catalog.h. We won't consider this symbol part of the FE/BE API.
* Push enum ForkNumber from relfilenode.h into relpath.h. We'll consider
relpath.h as the source of truth for fork numbers, since relpath.c was
already partially serving that function, and anyway relfilenode.h was
kind of a random place for that enum.
* So, relfilenode.h now includes relpath.h rather than vice-versa. This
direction of dependency is fine. (That allows most, but not quite all,
of the existing explicit #includes of relpath.h to go away again.)
* Push forkname_to_number from catalog.c to relpath.c, just to centralize
fork number stuff a bit better.
* Push GetDatabasePath from catalog.c to relpath.c; it was rather odd
that the previous commit didn't keep this together with relpath().
* To avoid needing relfilenode.h in common/, redefine the underlying
function (now called GetRelationPath) as taking separate OID arguments,
and make the APIs using RelFileNode or RelFileNodeBackend into macro
wrappers. (The macros have a potential multiple-eval risk, but none of
the existing call sites have an issue with that; one of them had such a
risk already anyway.)
* Fix failure to follow the directions when "init" fork type was added;
specifically, the errhint in forkname_to_number wasn't updated, and neither
was the SGML documentation for pg_relation_size().
* Fix tablespace-path-too-long check in CreateTableSpace() to account for
fork-name component of maximum-length pathnames. This requires putting
FORKNAMECHARS into a header file, but it was rather useless (and
actually unreferenced) where it was.
The last couple of items are potentially back-patchable bug fixes,
if anyone is sufficiently excited about them; but personally I'm not.
Per a gripe from Christoph Berg about how include/common wasn't
self-contained.
Robert Haas
Tom Lane
Jeff Davis
Peter Eisentraut
Bruce Momjian
Simon Riggs
Heikki Linnakangas
Michael Meskes