Primarily, explain where to find the system-wide psqlrc file, per recent
gripe from John Sutton. Do some general wordsmithing and improve the
markup, too.
Also adjust psqlrc.sample so its comments about file location are somewhat
trustworthy. (Not sure why we bother with this file when it's empty,
but whatever.)
Back-patch to 9.2 where the startup file naming scheme was last changed.
These things didn't work because the planner omitted to do the necessary
preprocessing of a WindowFunc's argument list. Add the few dozen lines
of code needed to handle that.
Although this sounds like a feature addition, it's really a bug fix because
the default-argument case was likely to crash previously, due to lack of
checking of the number of supplied arguments in the built-in window
functions. It's not a security issue because there's no way for a
non-superuser to create a window function definition with defaults that
refers to a built-in C function, but nonetheless people might be annoyed
that it crashes rather than producing a useful error message. So
back-patch as far as the patch applies easily, which turns out to be 9.2.
I'll put a band-aid in earlier versions as a separate patch.
(Note that these features still don't work for aggregates, and fixing that
case will be harder since we represent aggregate arg lists as target lists
not bare expression lists. There's no crash risk though because CREATE
AGGREGATE doesn't accept defaults, and we reject named-argument notation
when parsing an aggregate call.)
For rather inscrutable reasons, SQL:2008 disallows copying-and-modifying a
window definition that has any explicit framing clause. The error message
we gave for this only made sense if the referencing window definition
itself contains an explicit framing clause, which it might well not.
Moreover, in the context of an OVER clause it's not exactly obvious that
"OVER (windowname)" implies copy-and-modify while "OVER windowname" does
not. This has led to multiple complaints, eg bug #5199 from Iliya
Krapchatov. Change to a hopefully more intelligible error message, and
in the case where we have just "OVER (windowname)", add a HINT suggesting
that omitting the parentheses will fix it. Also improve the related
documentation. Back-patch to all supported branches.
SGML documentation, as well as code comments, failed to note that an FDW's
validator will be applied to foreign-table options for foreign tables using
the FDW.
Etsuro Fujita
The previous coding attempted to activate all the GUC settings specified
in SET clauses, so that the function validator could operate in the GUC
environment expected by the function body. However, this is problematic
when restoring a dump, since the SET clauses might refer to database
objects that don't exist yet. We already have the parameter
check_function_bodies that's meant to prevent forward references in
function definitions from breaking dumps, so let's change CREATE FUNCTION
to not install the SET values if check_function_bodies is off.
Authors of function validators were already advised not to make any
"context sensitive" checks when check_function_bodies is off, if indeed
they're checking anything at all in that mode. But extend the
documentation to point out the GUC issue in particular.
(Note that we still check the SET clauses to some extent; the behavior
with !check_function_bodies is now approximately equivalent to what ALTER
DATABASE/ROLE have been doing for awhile with context-dependent GUCs.)
This problem can be demonstrated in all active branches, so back-patch
all the way.
It seems like a good idea to update these examples since some fairly
basic planner behaviors have changed in 9.3; notably that the startup cost
for an indexscan plan node is no longer invariably estimated at 0.00.
Currently we don't need to update the pg_tablespace catalog
after redefining the symbolic links to the tablespaces
because pg_tablespace.spclocation column was removed in
PostgreSQL 9.2.
Back patch to 9.2 where pg_tablespace.spclocation was removed.
Ian Barwick, with minor change by me.
plpgsql often just remembers SPI-result tuple tables in local variables,
and has no mechanism for freeing them if an ereport(ERROR) causes an escape
out of the execution function whose local variable it is. In the original
coding, that wasn't a problem because the tuple table would be cleaned up
when the function's SPI context went away during transaction abort.
However, once plpgsql grew the ability to trap exceptions, repeated
trapping of errors within a function could result in significant
intra-function-call memory leakage, as illustrated in bug #8279 from
Chad Wagner.
We could fix this locally in plpgsql with a bunch of PG_TRY/PG_CATCH
coding, but that would be tedious, probably slow, and prone to bugs of
omission; moreover it would do nothing for similar risks elsewhere.
What seems like a better plan is to make SPI itself responsible for
freeing tuple tables at subtransaction abort. This patch attacks the
problem that way, keeping a list of live tuple tables within each SPI
function context. Currently, such freeing is automatic for tuple tables
made within the failed subtransaction. We might later add a SPI call to
mark a tuple table as not to be freed this way, allowing callers to opt
out; but until someone exhibits a clear use-case for such behavior, it
doesn't seem worth bothering.
A very useful side-effect of this change is that SPI_freetuptable() can
now defend itself against bad calls, such as duplicate free requests;
this should make things more robust in many places. (In particular,
this reduces the risks involved if a third-party extension contains
now-redundant SPI_freetuptable() calls in error cleanup code.)
Even though the leakage problem is of long standing, it seems imprudent
to back-patch this into stable branches, since it does represent an API
semantics change for SPI users. We'll patch this in 9.3, but live with
the leakage in older branches.
Commit 7f7485a0cd made these changes
in master; per discussion, backport the API changes (but not the
functional changes), so that people don't get used to the 9.3 API
only to see it get broken in the next release. There are already
some people coding to the original 9.3 API, and this will cause
minor breakage, but there will be even more if we wait until next
year to roll out these changes.
Per discussion on pgsql-hackers, these aren't really needed. Interim
versions of the background worker patch had the worker starting with
signals already unblocked, which would have made this necessary.
But the final version does not, so we don't really need it; and it
doesn't work well with the new facility for starting dynamic background
workers, so just rip it out.
Also per discussion on pgsql-hackers, back-patch this change to 9.3.
It's best to get the API break out of the way before we do an
official release of this facility, to avoid more pain for extension
authors later.
