This is for tools such as Coverity that don't know that the grammar
enforces that the case of not having a relation (but instead a query)
cannot happen in the FROM case.
Although we often don't care about freeing all memory in pg_dump,
these functions already freed the same memory in other code paths, so
we might as well do it consistently.
found by Coverity
Dave Malcolm of Red Hat is working on a static code analysis tool for
Python-related C code. It reported a number of problems in plpython,
most of which were failures to check for NULL results from object-creation
functions, so would only be an issue in very-low-memory situations.
Patch in HEAD and 9.1. We could go further back but it's not clear that
these issues are important enough to justify the work.
Jan Urbański
This replaces the former global variable PLy_curr_procedure, and provides
a place to stash per-call-level information. In particular we create a
per-call-level scratch memory context.
For the moment, the scratch context is just used to avoid leaking memory
from datatype output function calls in PLyDict_FromTuple. There probably
will be more use-cases in future.
Although this is a fix for a pre-existing memory leakage bug, it seems
sufficiently invasive to not want to back-patch; it feels better as part
of the major rearrangement of plpython code that we've already done as
part of 9.2.
Jan Urbański
Extracted from a larger patch by Jaime Casanova, reviewed by Noah Misch.
I think this error message could use some more extensive revision, but
this at least makes the handling of spgist consistent with what we do for
other types of indexes that this code doesn't know how to handle.
add ability to control permissions of created files
have psql echo its queries for easier debugging
output four separate log files, and delete them on success
add -r/--retain option to keep log files after success
make logs file append-only
remove -g/-G/-l logging options
sugggest tailing appropriate log file on failure
enhance -v/--verbose behavior
A leaf tuple that we need to delete could get moved as a consequence of an
insertion happening concurrently with the VACUUM scan. If it moves from a
page past the current scan point to a page before, we'll miss it, which is
not acceptable. Hence, when we see a leaf-page REDIRECT that could have
been made since our scan started, chase down the redirection pointer much
as if we were doing a normal index search, and be sure to vacuum every page
it leads to. This fixes the issue because, if the tuple was on page N at
the instant we start our scan, we will surely find it as a consequence of
chasing the redirect from page N, no matter how much it moves around in
between. Problem noted by Takashi Yamamoto.
We have always created a whole-table dependency for the target relation,
but that's not really good enough, as it doesn't prevent scenarios such
as dropping an individual target column or altering its type. So we
have to create an individual dependency for each target column, as well.
Per report from Bill MacArthur of a rule containing UPDATE breaking
after such an alteration. Note that this patch doesn't try to make
such cases work, only to ensure that the attempted ALTER TABLE throws
an error telling you it can't cope with adjusting the rule.
This is a long-standing bug, but given the lack of prior reports
I'm not going to risk back-patching it. A back-patch wouldn't do
anything to fix existing rules' dependency lists, anyway.
This patch fixes the other major compatibility-breaking limitation of
SPGiST, that it didn't store anything for null values of the indexed
column, and so could not support whole-index scans or "x IS NULL"
tests. The approach is to create a wholly separate search tree for
the null entries, and use fixed "allTheSame" insertion and search
rules when processing this tree, instead of calling the index opclass
methods. This way the opclass methods do not need to worry about
dealing with nulls.
Catversion bump is for pg_am updates as well as the change in on-disk
format of SPGiST indexes; there are some tweaks in SPGiST WAL records
as well.
Heavily rewritten version of a patch by Oleg Bartunov and Teodor Sigaev.
(The original also stored nulls separately, but it reused GIN code to do
so; which required undesirable compromises in the on-disk format, and
would likely lead to bugs due to the GIN code being required to work in
two very different contexts.)
It now prints the argument that was at fault.
Also fix a small misbehavior where the error message issued by
getopt() would complain about a program named "--single", because
that's what argv[0] is in the server process.
The original API definition was incapable of supporting whole-index scans
because there was no way to invoke leaf-value reconstruction without
checking any qual conditions. Also, it was inefficient for
multiple-qual-condition scans because value reconstruction got done over
again for each qual condition, and because other internal work in the
consistent functions likewise had to be done for each qual. To fix these
issues, pass the whole scankey array to the opclass consistent functions,
instead of only letting them see one item at a time. (Essentially, the
loop over scankey entries is now inside the consistent functions not
outside them. This makes the consistent functions a bit more complicated,
but not unreasonably so.)
In itself this commit does nothing except save a few cycles in
multiple-qual-condition index scans, since we can't support whole-index
scans on SPGiST indexes until nulls are included in the index. However,
I consider this a must-fix for 9.2 because once we release it will get
very much harder to change the opclass API definition.
This allows loadable modules to get control at drop time, perhaps for the
purpose of performing additional security checks or to log the event.
The initial purpose of this code is to support sepgsql, but other
applications should be possible as well.
KaiGai Kohei, reviewed by me.
Further reflection shows that a single callback isn't very workable if we
desire to let FDWs generate multiple Paths, because that forces the FDW to
do all work necessary to generate a valid Plan node for each Path. Instead
split the former PlanForeignScan API into three steps: GetForeignRelSize,
GetForeignPaths, GetForeignPlan. We had already bit the bullet of breaking
the 9.1 FDW API for 9.2, so this shouldn't cause very much additional pain,
and it's substantially more flexible for complex FDWs.
Add an fdw_private field to RelOptInfo so that the new functions can save
state there rather than possibly having to recalculate information two or
three times.
In addition, we'd not thought through what would be needed to allow an FDW
to set up subexpressions of its choice for runtime execution. We could
treat ForeignScan.fdw_private as an executable expression but that seems
likely to break existing FDWs unnecessarily (in particular, it would
restrict the set of node types allowable in fdw_private to those supported
by expression_tree_walker). Instead, invent a separate field fdw_exprs
which will receive the postprocessing appropriate for expression trees.
(One field is enough since it can be a list of expressions; also, we assume
the corresponding expression state tree(s) will be held within fdw_state,
so we don't need to add anything to ForeignScanState.)
Per review of Hanada Shigeru's pgsql_fdw patch. We may need to tweak this
further as we continue to work on that patch, but to me it feels a lot
closer to being right now.
Phil Sorber reported that a rewriting ALTER TABLE within an extension
update script failed, because it creates and then drops a placeholder
table; the drop was being disallowed because the table was marked as an
extension member. We could hack that specific case but it seems likely
that there might be related cases now or in the future, so the most
practical solution seems to be to create an exception to the general rule
that extension member objects can only be dropped by dropping the owning
extension. To wit: if the DROP is issued within the extension's own
creation or update scripts, we'll allow it, implicitly performing an
"ALTER EXTENSION DROP object" first. This will simplify cases such as
extension downgrade scripts anyway.
No docs change since we don't seem to have documented the idea that you
would need ALTER EXTENSION DROP for such an action to begin with.
Also, arrange for explicitly temporary tables to not get linked as
extension members in the first place, and the same for the magic
pg_temp_nnn schemas that are created to hold them. This prevents assorted
unpleasant results if an extension script creates a temp table: the forced
drop at session end would either fail or remove the entire extension, and
neither of those outcomes is desirable. Note that this doesn't fix the
ALTER TABLE scenario, since the placeholder table is not temp (unless the
table being rewritten is).
Back-patch to 9.1.
In constructs such as "x IN (1,2,3,4)" and "x <> ALL(ARRAY[1,2,3,4])",
we formerly always used a general-purpose assumption that the probability
of success is independent for each comparison of "x" to an array element.
But in real-world usage of these constructs, that's a pretty poor
assumption; it's much saner to assume that the array elements are distinct
and so the match probabilities are disjoint. Apply that assumption if the
operator appears to behave as equality (for ANY) or inequality (for ALL).
But fall back to the normal independent-probabilities calculation if this
yields an impossible result, ie probability > 1 or < 0. We could protect
ourselves against bad estimates even more by explicitly checking for equal
array elements, but that is expensive and doesn't seem worthwhile: doing
it would amount to optimizing for poorly-written queries at the expense
of well-written ones.
Daniele Varrazzo and Tom Lane, after a suggestion by Ants Aasma
Multi-line "Inherits:" and "Child tables:" footers were misindented when
those strings' translations involved multibyte characters, because we were
using strlen() instead of an appropriate display width measurement.
In passing, avoid doing gettext() more than once per loop in these places.
While at it, fix pg_wcswidth(), which has been entirely broken since about
8.2, but fortunately has been unused for the same length of time.
Report and patch by Sergey Burladyan (bug #6480)
GetForeignColumnOptions provides some abstraction for accessing
column-specific FDW options, on a par with the access functions that were
already provided here for other FDW-related information.
Adjust file_fdw.c to use GetForeignColumnOptions instead of equivalent
hand-rolled code.
In addition, add some SGML documentation for the functions exported by
foreign.c that are meant for use by FDW authors.
(This is the fdw_helper portion of the proposed pgsql_fdw patch.)
Hanada Shigeru, reviewed by KaiGai Kohei
Due to an apparent thinko, when printing a table in expanded mode
(\x), space would be allocated for 1 slot plus 1 byte per line,
instead of 1 slot per line plus 1 slot for the NULL terminator. When
the line count is small, reading or writing the terminator would
therefore access memory beyond what was allocated.
Now that cache invalidation callbacks get only a hash value, and not a
tuple TID (per commits 632ae6829f and
b5282aa893), the only way they can restrict
what they invalidate is to know what the hash values mean. setrefs.c was
doing this via a hard-wired assumption but that seems pretty grotty, and
it'll only get worse as more cases come up. So let's expose a calculation
function that takes the same parameters as SearchSysCache. Per complaint
from Marko Kreen.
Use-cases for this include custom log filtering rules and custom log
message transmission mechanisms (for instance, lossy log message
collection, which has been discussed several times recently).
As is our common practice for hooks, there's no regression test nor
user-facing documentation for this, though the author did exhibit a
sample module using the hook.
Martin Pihlak, reviewed by Marti Raudsepp
This simplifies the code a little bit. The new rule is that to update
XLogCtl->LogwrtResult, you must hold both WALWriteLock and info_lck, whereas
before we had two copies, one that was protected by WALWriteLock and another
protected by info_lck. The code that updates them was already holding both
locks, so merging the two is trivial.
The third copy, XLogCtl->Insert.LogwrtResult, was not totally redundant, it
was used in AdvanceXLInsertBuffer to update the backend-local copy, before
acquiring the info_lck to read the up-to-date value. But the value of that
seems dubious; at best it's saving one spinlock acquisition per completed
WAL page, which is not significant compared to all the other work involved.
And in practice, it's probably not saving even that much.
It's harmless to do full page writes even when not strictly necessary, so
when turning full_page_writes on, we can set the global flag first, and then
call XLogInsert. Likewise, when turning it off, we can write the WAL record
first, and then clear the flag. This way XLogInsert doesn't need any special
handling of the XLOG_FPW_CHANGE record type. XLogInsert is complicated
enough already, so anything we can keep away from there is a good thing.
Actually I don't think the atomicity of the shared memory flag matters,
anyway, because we only write the XLOG_FPW_CHANGE at the end of recovery,
when there are no concurrent WAL insertions going on. But might as well make
it safe, in case we allow changing full_page_writes on the fly in the
future.
The original API specification only allowed an FDW to create a single
access path, which doesn't seem like a terribly good idea in hindsight.
Instead, move the responsibility for building the Path node and calling
add_path() into the FDW's PlanForeignScan function. Now, it can do that
more than once if appropriate. There is no longer any need for the
transient FdwPlan struct, so get rid of that.
Etsuro Fujita, Shigeru Hanada, Tom Lane
