Now that we have LATERAL, it's fairly painless to allow this case, which
was left as a TODO in the original multi-row VALUES implementation.

It said "XXX: The following could be improved if we had LATERAL" ...
so let's do that.

No catversion bump since either version of the view works fine.

Formerly, subquery pullup had no need to examine other entries in the range
table, since they could not contain any references to the subquery being
pulled up.  That's no longer true with LATERAL, so now we need to be able
to visit rangetable subexpressions to replace Vars referencing the
pulled-up subquery.  Also, this means that extract_lateral_references must
be unsurprised at encountering lateral PlaceHolderVars, since such might be
created when pulling up a subquery that's underneath an outer join with
respect to the lateral reference.

Fix grammar, put back some removed information, rearrange for clarity.

We had put a test for libxml2's xmlStructuredErrorContext variable in
configure, but of course that doesn't work on Windows builds.  The next
best alternative seems to be to test the LIBXML_VERSION symbol provided
by xmlversion.h.

Per report from Talha Bin Rizwan, though this fixes it in a different way
than his proposed patch.

from Dmitriy Igrishin

In the initial cut at the "parameterized paths" feature, I'd simplified
create_index_paths() to the point where it would only generate a single
parameterized bitmap path per relation.  Experimentation with an example
supplied by Josh Berkus convinces me that that's not good enough: we really
need to consider a bitmap path for each possible outer relation.  Otherwise
we have regressions relative to pre-9.2 versions, in which the planner
picks a plain indexscan where it should have used a bitmap scan in queries
involving three or more tables.  Indeed, after fixing this, several queries
in the regression tests show improved plans as a result of using bitmap not
plain indexscans.

the partition.

"unimportant".

Per request from Heikki

keywords and concepts, based on suggestions by Florian Pflug.

The implementation is a quad-tree, largely copied from the quad-tree
implementation for points. The lower and upper bound of ranges are the 2d
coordinates, with some extra code to handle empty ranges.

I left out the support for adjacent operator, -|-, from the original patch.
Not because there was necessarily anything wrong with it, but it was more
complicated than the other operators, and I only have limited time for
reviewing. That will follow as a separate patch.

Alexander Korotkov, reviewed by Jeff Davis and me.

We use a hash table to track the parents of inner pages, but when inserting
to a leaf page, the caller of gistbufferinginserttuples() must pass a
correct block number of the leaf's parent page. Before gistProcessItup()
descends to a child page, it checks if the downlink needs to be adjusted to
accommodate the new tuple, and updates the downlink if necessary. However,
updating the downlink might require splitting the page, which might move the
downlink to a page to the right. gistProcessItup() doesn't realize that, so
when it descends to the leaf page, it might pass an out-of-date parent block
number as a result. Fix that by returning the block a tuple was inserted to
from gistbufferinginserttuples().

This fixes the bug reported by Zdeněk Jílovec.

than the actual data storage directory.

Per suggestion from Thom Brown

startup.

Per report from Thom Brown

Per suggestion from Ray Stell

NULL), and OLD is unassigned for INSERT, and NEW/OLD are unassigned (not
NULL) for statement-level triggers.

Per report from Pavel Stehule

level, per report from Tom.

require all parameters for \c, rather than using the defaults, which
might be wrong.

The previous coding essentially assumed that nodes would be rescanned in
the same order they were initialized in; or at least that the "leader" of
a group of CTEscans would be rescanned before any others were required to
execute.  Unfortunately, that isn't even a little bit true.  It's possible
to devise queries in which the leader isn't rescanned until other CTEscans
on the same CTE have run to completion, or even in which the leader never
gets a rescan call at all.

The fix makes the leader specially responsible only for initial creation
and final destruction of the tuplestore; rescan resets are now a
symmetrically shared responsibility.  This means that we might reset the
tuplestore multiple times when restarting a plan subtree containing
multiple CTEscans; but resetting an already-empty tuplestore is cheap
enough that that doesn't seem like a problem.

Per report from Adam Mackler; the new regression test cases are based on
his example query.

Back-patch to 8.4 where CTE scans were introduced.

not supported in the error message, rather than the docs.

certain foreign data wrappers.

This situation creates a dependency loop that confuses pg_dump and probably
other things.  Moreover, since the mental model is that the extension
"contains" schemas it owns, but "is contained in" its extschema (even
though neither is strictly true), having both true at once is confusing for
people too.  So prevent the situation from being set up.

Reported and patched by Thom Brown.  Back-patch to 9.1 where extensions
were added.

supported.  Also add assert to catch future breakage.

Also, improve documentation that "double"-quotes must be used in
pg_hba.conf (not single quotes).

This essentially reverts commit e54b10a6,
in which I'd decided that the "last ditch" join logic was useless.  The
folly of that is now exposed by a report from Pavel Stehule: although the
function should always find at least one join in a self-contained join
problem, it can still fail to do so in a sub-problem created by artificial
from_collapse_limit or join_collapse_limit constraints.  Adjust the
comments to describe this, and simplify the code a bit to match the new
coding of the earlier loop in the function.

I'm not terribly happy about this: I still subscribe to the opinion stated
in the previous commit message that the "last ditch" code can obscure logic
bugs elsewhere.  But the alternative seems to be to complicate the earlier
tests for does-this-relation-have-a-join-clause to the point where they can
tell whether the join clauses link outside the current join sub-problem.
And that looks messy, slow, and possibly a source of bugs in itself.
In any case, now is not the time to be inserting experimental code into
9.2, so let's just go back to the time-tested solution.

updates of the column of interest.

libxslt offers the ability to read and write both files and URLs through
stylesheet commands, thus allowing unprivileged database users to both read
and write data with the privileges of the database server.  Disable that
through proper use of libxslt's security options.

Also, remove xslt_process()'s ability to fetch documents and stylesheets
from external files/URLs.  While this was a documented "feature", it was
long regarded as a terrible idea.  The fix for CVE-2012-3489 broke that
capability, and rather than expend effort on trying to fix it, we're just
going to summarily remove it.

While the ability to write as well as read makes this security hole
considerably worse than CVE-2012-3489, the problem is mitigated by the fact
that xslt_process() is not available unless contrib/xml2 is installed,
and the longstanding warnings about security risks from that should have
discouraged prudent DBAs from installing it in security-exposed databases.

Reported and fixed by Peter Eisentraut.

Security: CVE-2012-3488

xml_parse() would attempt to fetch external files or URLs as needed to
resolve DTD and entity references in an XML value, thus allowing
unprivileged database users to attempt to fetch data with the privileges
of the database server.  While the external data wouldn't get returned
directly to the user, portions of it could be exposed in error messages
if the data didn't parse as valid XML; and in any case the mere ability
to check existence of a file might be useful to an attacker.

The ideal solution to this would still allow fetching of references that
are listed in the host system's XML catalogs, so that documents can be
validated according to installed DTDs.  However, doing that with the
available libxml2 APIs appears complex and error-prone, so we're not going
to risk it in a security patch that necessarily hasn't gotten wide review.
So this patch merely shuts off all access, causing any external fetch to
silently expand to an empty string.  A future patch may improve this.

In HEAD and 9.2, also suppress warnings about undefined entities, which
would otherwise occur as a result of not loading referenced DTDs.  Previous
branches don't show such warnings anyway, due to different error handling
arrangements.

Credit to Noah Misch for first reporting the problem, and for much work
towards a solution, though this simplistic approach was not his preference.
Also thanks to Daniel Veillard for consultation.

Security: CVE-2012-3489