At one time it wasn't terribly important what column names were associated
with the fields of a composite Datum, but since the introduction of
operations like row_to_json(), it's important that looking up the rowtype
ID embedded in the Datum returns the column names that users would expect.
That did not work terribly well before this patch: you could get the column
names of the underlying table, or column aliases from any level of the
query, depending on minor details of the plan tree.  You could even get
totally empty field names, which is disastrous for cases like row_to_json().

To fix this for whole-row Vars, look to the RTE referenced by the Var, and
make sure its column aliases are applied to the rowtype associated with
the result Datums.  This is a tad scary because we might have to return
a transient RECORD type even though the Var is declared as having some
named rowtype.  In principle it should be all right because the record
type will still be physically compatible with the named rowtype; but
I had to weaken one Assert in ExecEvalConvertRowtype, and there might be
third-party code containing similar assumptions.

Similarly, RowExprs have to be willing to override the column names coming
from a named composite result type and produce a RECORD when the column
aliases visible at the site of the RowExpr differ from the underlying
table's column names.

In passing, revert the decision made in commit 398f70ec to add
an alias-list argument to ExecTypeFromExprList: better to provide that
functionality in a separate function.  This also reverts most of the code
changes in d6858148, which we don't need because we're no longer
depending on the tupdesc found in the child plan node's result slot to be
blessed.

Back-patch to 9.4, but not earlier, since this solution changes the results
in some cases that users might not have realized were buggy.  We'll apply a
more restricted form of this patch in older branches.

Besides a couple of typo fixes, per David Rowley, Thom Brown, and Amit
Langote, and mentions of BRIN in the general CREATE INDEX page again per
David, this includes silencing MSVC compiler warnings (thanks Microsoft)
and an additional variable initialization per Coverity scanner.

Reported by Peter Geoghegan
David Rowley

Ian Barwick

It is invalid because the Gregorian calendar is used for all years.

Reported by David Rowley: variadic macros are a problem.  Get rid of
them using a trick suggested by Tom Lane: add extra parentheses where
needed.  In the future we might decide we don't need the calls at all
and remove them, but it seems appropriate to keep them while this code
is still new.

Also from David Rowley: brininsert() was trying to use a variable before
initializing it.  Fix by moving the brin_form_tuple call (which
initializes the variable) to within the locked section.

Reported by Peter Eisentraut: can't use "new" as a struct member name,
because C++ compilers will choke on it, as reported by cpluspluscheck.

Work around accidental test failures because the working directory path
is too long by creating a temporary directory in the (hopefully shorter)
system location, symlinking that to the working directory, and creating
the tablespaces using the shorter path.

The old note about how to use pg_receivexlog as an alternative to
archive_command was obsoleted by replication slots.

This allows extension modules to define their own methods for
scanning a relation, and get the core code to use them.  It's
unclear as yet how much use this capability will find, but we
won't find out if we never commit it.

KaiGai Kohei, reviewed at various times and in various levels
of detail by Shigeru Hanada, Tom Lane, Andres Freund, Álvaro
Herrera, and myself.

Now that the backup blocks are appended to the WAL record in xloginsert.c,
XLogInsert doesn't see them anymore and cannot remove them from the version
reconstructed for xlog_outdesc. This makes running with wal_debug=on more
expensive, as we now make (unnecessary) temporary copies of the backup
blocks, but it doesn't seem worth convoluting the code to keep that
optimization.

Reported by Alvaro Herrera.

This removes some fmgr overhead from cases such as btree index builds.

Peter Geoghegan, reviewed by Andreas Karlsson and me.

Test misc depends on brin, but it was earlier in the serial schedule
file.  I didn't notice this because I only run the parallel schedule,
but the buildfarm exposed my folly ...

BRIN is a new index access method intended to accelerate scans of very
large tables, without the maintenance overhead of btrees or other
traditional indexes.  They work by maintaining "summary" data about
block ranges.  Bitmap index scans work by reading each summary tuple and
comparing them with the query quals; all pages in the range are returned
in a lossy TID bitmap if the quals are consistent with the values in the
summary tuple, otherwise not.  Normal index scans are not supported
because these indexes do not store TIDs.

As new tuples are added into the index, the summary information is
updated (if the block range in which the tuple is added is already
summarized) or not; in the latter case, a subsequent pass of VACUUM or
the brin_summarize_new_values() function will create the summary
information.

For data types with natural 1-D sort orders, the summary info consists
of the maximum and the minimum values of each indexed column within each
page range.  This type of operator class we call "Minmax", and we
supply a bunch of them for most data types with B-tree opclasses.
Since the BRIN code is generalized, other approaches are possible for
things such as arrays, geometric types, ranges, etc; even for things
such as enum types we could do something different than minmax with
better results.  In this commit I only include minmax.

Catalog version bumped due to new builtin catalog entries.

There's more that could be done here, but this is a good step forwards.

Loosely based on ideas from Simon Riggs; code mostly by Álvaro Herrera,
with contribution by Heikki Linnakangas.

Patch reviewed by: Amit Kapila, Heikki Linnakangas, Robert Haas.
Testing help from Jeff Janes, Erik Rijkers, Emanuel Calvo.

PS:
  The research leading to these results has received funding from the
  European Union's Seventh Framework Programme (FP7/2007-2013) under
  grant agreement n° 318633.

I broke these in 8776faa8. Backpatch to
9.4, where that was done.

The code that generated a record to clear the F_TUPLES_DELETED flag hasn't
existed since we got rid of old-style VACUUM FULL. I kept the code that sets
the flag, although it's not used for anything anymore, because it might
still be interesting information for debugging purposes that some tuples
have been deleted from a page.

Likewise, the code to turn the root page from non-leaf to leaf page was
removed when we got rid of old-style VACUUM FULL. Remove the code to replay
that action, too.

dict_thesaurus stored phrase IDs in uint16 fields, so it would get confused
and even crash if there were more than 64K entries in the configuration
file.  It turns out to be basically free to widen the phrase IDs to uint32,
so let's just do so.

This was complained of some time ago by David Boutin (in bug #7793);
he later submitted an informal patch but it was never acted on.
We now have another complaint (bug #11901 from Luc Ouellette) so it's
time to make something happen.

This is basically Boutin's patch, but for future-proofing I also added a
defense against too many words per phrase.  Note that we don't need any
explicit defense against overflow of the uint32 counters, since before that
happens we'd hit array allocation sizes that repalloc rejects.

Back-patch to all supported branches because of the crash risk.

The default JSONB GIN opclass (jsonb_ops) converts numeric data values
to strings for storage in the index.  It must ensure that numeric values
that would compare equal (such as 12 and 12.00) produce identical strings,
else index searches would have behavior different from regular JSONB
comparisons.  Unfortunately the function charged with doing this was
completely wrong: it could reduce distinct numeric values to the same
string, or reduce equivalent numeric values to different strings.  The
former type of error would only lead to search inefficiency, but the
latter type of error would cause index entries that should be found by
a search to not be found.

Repairing this bug therefore means that it will be necessary for 9.4 beta
testers to reindex GIN jsonb_ops indexes, if they care about getting
correct results from index searches involving numeric data values within
the comparison JSONB object.

Per report from Thomas Fanghaenel.

Previously .ready file was created for the timeline history file at the end
of an archive recovery even when WAL archiving was not enabled.
This creation is unnecessary and causes .ready file to remain infinitely.

This commit changes an archive recovery so that it creates .ready file for
the timeline history file only when WAL archiving is enabled.

Backpatch to all supported versions.

xlog.c is huge, this makes it a little bit smaller, which is nice. Functions
related to putting together the WAL record are in xloginsert.c, and the
lower level stuff for managing WAL buffers and such are in xlog.c.

Also move the definition of XLogRecord to a separate header file. This
causes churn in the #includes of all the files that write WAL records, and
redo routines, but it avoids pulling in xlog.h into most places.

Reviewed by Michael Paquier, Alvaro Herrera, Andres Freund and Amit Kapila.

Etsuro Fujita

Fabrízio de Royes Mello, reviewed by Marti Raudsepp, Adam Brightwell and me.

Long ago we briefly had an "autocommit" GUC that turned server-side
autocommit on and off.  That behavior was removed in 7.4 after concluding
that it broke far too much client-side logic, and making clients cope with
both behaviors was impractical.  But the GUC variable was left behind, so
as not to break any client code that might be trying to read its value.
Enough time has now passed that we should remove the GUC completely.
Whatever vestigial backwards-compatibility benefit it had is outweighed by
the risk of confusion for newbies who assume it ought to do something,
as per a recent complaint from Wolfgang Wilhelm.

In passing, adjust what seemed to me a rather confusing documentation
reference to libpq's autocommit behavior.  libpq as such knows nothing
about autocommit, so psql is probably what was meant.

Obviously, every translation unit should not be declaring this
separately.  It needs to be PGDLLIMPORT as well, to avoid breaking
third-party code that uses any of the functions that the commit
mentioned above changed to macros.

This is a followup to commit 43ac12c6,
which added regression tests checking that I/O functions of built-in
types are not marked volatile.  Complaining in CREATE TYPE should push
developers of add-on types to fix any misdeclared functions in their
types.  It's just a warning not an error, to avoid creating upgrade
problems for what might be just cosmetic mis-markings.

Aside from adding the warning code, fix a number of types that were
sloppily created in the regression tests.

In general, datatype I/O functions are supposed to be immutable or at
worst stable.  Some contrib I/O functions were, through oversight, not
marked with any volatility property at all, which made them VOLATILE.
Since (most of) these functions actually behave immutably, the erroneous
marking isn't terribly harmful; but it can be user-visible in certain
circumstances, as per a recent bug report from Joe Van Dyk in which a
cast to text was disallowed in an expression index definition.

To fix, just adjust the declarations in the extension SQL scripts.  If we
were being very fussy about this, we'd bump the extension version numbers,
but that seems like more trouble (for both developers and users) than the
problem is worth.

A fly in the ointment is that chkpass_in actually is volatile, because
of its use of random() to generate a fresh salt when presented with a
not-yet-encrypted password.  This is bad because of the general assumption
that I/O functions aren't volatile: the consequence is that records or
arrays containing chkpass elements may have input behavior a bit different
from a bare chkpass column.  But there seems no way to fix this without
breaking existing usage patterns for chkpass, and the consequences of the
inconsistency don't seem bad enough to justify that.  So for the moment,
just document it in a comment.

Since we're not bumping version numbers, there seems no harm in
back-patching these fixes; at least future installations will get the
functions marked correctly.

The previous coding assumed that we could just let buffers for the
database's old tablespace age out of the buffer arena naturally.
The folly of that is exposed by bug #11867 from Marc Munro: the user could
later move the database back to its original tablespace, after which any
still-surviving buffers would match lookups again and appear to contain
valid data.  But they'd be missing any changes applied while the database
was in the new tablespace.

This has been broken since ALTER SET TABLESPACE was introduced, so
back-patch to all supported branches.

The old algorithm was found to not be the usual CRC-32 algorithm, used by
Ethernet et al. We were using a non-reflected lookup table with code meant
for a reflected lookup table. That's a strange combination that AFAICS does
not correspond to any bit-wise CRC calculation, which makes it difficult to
reason about its properties. Although it has worked well in practice, seems
safer to use a well-known algorithm.

Since we're changing the algorithm anyway, we might as well choose a
different polynomial. The Castagnoli polynomial has better error-correcting
properties than the traditional CRC-32 polynomial, even if we had
implemented it correctly. Another reason for picking that is that some new
CPUs have hardware support for calculating CRC-32C, but not CRC-32, let
alone our strange variant of it. This patch doesn't add any support for such
hardware, but a future patch could now do that.

The old algorithm is kept around for tsquery and pg_trgm, which use the
values in indexes that need to remain compatible so that pg_upgrade works.
While we're at it, share the old lookup table for CRC-32 calculation
between hstore, ltree and core. They all use the same table, so might as
well.

It hasn't been used for anything for a long time.

Reported by Peter Eisentraut.

pgp_sym_encrypt's option is spelled "sess-key", not "enable-session-key".
Spotted by Jeff Janes.

In passing, improve a comment in pgp-pgsql.c to make it clearer that
the debugging options are intentionally undocumented.

Marko Tiikkaja

The reasons behind commit 0d147e43 still
stand, so this reverts the non-cosmetic portion of commit
a7983e98.  Back-patch to 9.4, where the
latter commit first appeared.

Cygwin builds require this of dependencies pertaining to pattern rules.
On Cygwin, stat("foo") in the absence of a file with that exact name can
locate foo.exe.  While GNU make uses stat() for dependencies of ordinary
rules, it uses readdir() to assess dependencies of pattern rules.
Therefore, a pattern rule dependency should match any underlying file
name exactly.  Back-patch to 9.4, where the dependency was introduced.

Back-patch to 9.2, like commit db29620d.

Don't skip the TAP tests anymore when IPC::Run is not found.  This will
fail normally now.