This allows squeezing out the unused space in full-page writes. And more
importantly, it can be a useful debugging aid.

In hindsight we should've done this back when GIN was added - we wouldn't
need the 'maxoff' field in the page opaque struct if we had used pd_lower
and pd_upper like on normal pages. But as long as there can be pages in the
index that have been binary-upgraded from pre-9.4 versions, we can't rely
on that, and have to continue using 'maxoff'.

Most of the code churn comes from renaming some macros, now that they're
used on internal pages, too.

This change is completely backwards-compatible, no effect on pg_upgrade.

Maybe we'll settle on another way of solving this problem, but for
now this is the recommended procedure.

Per discussion with Michael Paquier.

Etsuro Fujita

Make sure we throw an error instead of silently doing the wrong thing when
fed a strategy number we don't recognize.  Also, in the places that did
already throw an error, spell the error message in a way more consistent
with our message style guidelines.

Per report from Paul Jones.  Although this is a bug, it won't occur unless
a superuser tries to do something he shouldn't, so it doesn't seem worth
back-patching.

Apparently, the old text was written at a time when the only use of
constraint_name here was for a constraint to be dropped, but that's
no longer true.

Etsuro Fujita

Etsuro Fujita

Ian Barwick

In some places, the function assumes the left page is valid, and in others,
it checks if it is valid. Remove all the checks.

The entry B-tree pages all follow the standard page layout. The 9.3 code has
this right. I inadvertently changed this at some point during the big
refactorings in git master.

Repositioning the tuplestore seek pointer in window_gettupleslot() turns
out to be a very significant expense when the window frame is sizable and
the frame end can move.  To fix, introduce a tuplestore function for
skipping an arbitrary number of tuples in one call, parallel to the one we
introduced for tuplesort objects in commit 8d65da1f.  This reduces the cost
of window_gettupleslot() to O(1) if the tuplestore has not spilled to disk.
As in the previous commit, I didn't try to do any real optimization of
tuplestore_skiptuples for the case where the tuplestore has spilled to
disk.  There is probably no practical way to get the cost to less than O(N)
anyway, but perhaps someone can think of something later.

Also fix PersistHoldablePortal() to make use of this API now that we have
it.

Based on a suggestion by Dean Rasheed, though this turns out not to look
much like his patch.

MSVC doesn't seem to like it when a constant initializer loses
precision upon being assigned.

David Rowley

Given that ALTER TABLESPACE has moved on from just existing for
general purpose rename/owner changes, it deserves its own top-level
production in the grammar.  This also cleans up the RenameStmt to
only ever be used for actual RENAMEs again- it really wasn't
appropriate to hide non-RENAME productions under there.

Noted by Alvaro.

Looks like we can end up with different plans happening on the
buildfarm, which breaks the regression tests when we include
EXPLAIN output (which is done in the regression tests for
updatable security views, to ensure that the user-defined
function isn't pushed down to a level where it could view the
rows before the security quals are applied).

This adds in ANALYZE to hopefully make the plans consistent.
The ANALYZE ends up changing the original plan too, so the
update looks bigger than it really is.  The new plan looks
perfectly valid, of course.

David Rowley and Florian Pflug, reviewed by Dean Rasheed

Views which are marked as security_barrier must have their quals
applied before any user-defined quals are called, to prevent
user-defined functions from being able to see rows which the
security barrier view is intended to prevent them from seeing.

Remove the restriction on security barrier views being automatically
updatable by adding a new securityQuals list to the RTE structure
which keeps track of the quals from security barrier views at each
level, independently of the user-supplied quals.  When RTEs are
later discovered which have securityQuals populated, they are turned
into subquery RTEs which are marked as security_barrier to prevent
any user-supplied quals being pushed down (modulo LEAKPROOF quals).

Dean Rasheed, reviewed by Craig Ringer, Simon Riggs, KaiGai Kohei

First installment of the promised moving-aggregate support in built-in
aggregates: count(), sum(), avg(), stddev() and variance() for
assorted datatypes, though not for float4/float8.

In passing, remove a 2001-vintage kluge in interval_accum(): interval
array elements have been properly aligned since around 2003, but
nobody remembered to take out this workaround.  Also, fix a thinko
in the opr_sanity tests for moving-aggregate catalog entries.

David Rowley and Florian Pflug, reviewed by Dean Rasheed

Until now, when executing an aggregate function as a window function
within a window with moving frame start (that is, any frame start mode
except UNBOUNDED PRECEDING), we had to recalculate the aggregate from
scratch each time the frame head moved.  This patch allows an aggregate
definition to include an alternate "moving aggregate" implementation
that includes an inverse transition function for removing rows from
the aggregate's running state.  As long as this can be done successfully,
runtime is proportional to the total number of input rows, rather than
to the number of input rows times the average frame length.

This commit includes the core infrastructure, documentation, and regression
tests using user-defined aggregates.  Follow-on commits will update some
of the built-in aggregates to use this feature.

David Rowley and Florian Pflug, reviewed by Dean Rasheed; additional
hacking by me

C-style block comments are passed to the server.

There were a couple of bugs here. First, if the fuzzy limit was exceeded,
the loop in entryGetItem might drop out too soon if a whole block needs to
be skipped because it's < advancePast ("continue" in a while-loop checks the
loop condition too). Secondly, the loop checked when stepping to a new page
that there is at least one offset on the page < advancePast, but we cannot
rely on that on subsequent calls of entryGetItem, because advancePast might
change in between. That caused the skipping loop to read bogus items in the
TbmIterateResult's offset array.

First item and fix by Alexander Korotkov, second bug pointed out by Fabrízio
de Royes Mello, by a small variation of Alexander's test query.

Hopefully this will fix the buildfarm failures on Windows.

And explain why.

Per report from Pavel Stehule

Tomonari Katsumata

This references the meaning of the fast/spread checkpoint option.

Per private IM report

This is more cleanup from commit 11a65eed.

Amit Kapila

Patches by Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>

I'm not sure if this is what's causing the Windows buildfarm members
to get unhappy, but I don't think it can be helping anything...

This operator class can accelerate subnet/supernet tests as well as
btree-equivalent ordered comparisons.  It also handles a new network
operator inet && inet (overlaps, a/k/a "is supernet or subnet of"),
which is expected to be useful in exclusion constraints.

Ideally this opclass would be the default for GiST with inet/cidr data,
but we can't mark it that way until we figure out how to do a more or
less graceful transition from the current situation, in which the
really-completely-bogus inet/cidr opclasses in contrib/btree_gist are
marked as default.  Having the opclass in core and not default is better
than not having it at all, though.

While at it, add new documentation sections to allow us to officially
document GiST/GIN/SP-GiST opclasses, something there was never a clear
place to do before.  I filled these in with some simple tables listing
the existing opclasses and the operators they support, but there's
certainly scope to put more information there.

Emre Hasegeli, reviewed by Andreas Karlsson, further hacking by me

Ian Barwick

Instead of storing the ID of the dynamic shared memory control
segment in a file within the data directory, store it in the main
control segment.  This avoids a number of nasty corner cases,
most seriously that doing an online backup and then using it on
the same machine (e.g. to fire up a standby) would result in the
standby clobbering all of the master's dynamic shared memory
segments.

Per complaints from Heikki Linnakangas, Fujii Masao, and Tom
Lane.

These functions won't throw an error if the object doesn't exist,
or if (for functions and operators) there's more than one matching
object.

Yugo Nagata and Nozomi Anzai, reviewed by Amit Khandekar, Marti
Raudsepp, Amit Kapila, and me.

Don't reset the rightlink of a page when replaying a page update record.
This was a leftover from pre-hot standby days, when it was not possible to
have scans concurrent with WAL replay. Resetting the right-link was not
necessary back then either, but it was done for the sake of tidiness. But
with hot standby, it's wrong, because a concurrent scan might still need it.

Backpatch all versions with hot standby, 9.0 and above.

This isn't strictly necessary, but helps debugging.

I missed this in the previous commit; Tom Lane spotted my error.

The one existing assertion of this type has tripped a few times in the
buildfarm lately, but it's not clear whether the problem is really
originating there or whether it's leftovers from a trip through one
of the other two paths that lack a matching assertion.  So add one.

Since the same bug(s) most likely exist(s) in the back-branches also,
back-patch to 9.2, where the fast-path lock mechanism was added.

This doesn't seem to be useful any more, and it's not really worth the
effort to keep updating it every time relevant dependencies or calling
signatures in the shared memory or semaphore code change.

Forgot to set the incomplete-split flag on the left page half, in redo of a
page split.

Spotted this by comparing the page contents on master and standby, after
inserting/applying each WAL record.

Infrastructure to allow
 plpgsql.extra_warnings
 plpgsql.extra_errors

Initial extra checks only for shadowed_variables

Marko Tiikkaja and Petr Jelinek
Reviewed by Simon Riggs and Pavel Stěhule