This patch restores the pre-9.1 behavior that pl/perl functions returning
VOID ignore the result value of their last Perl statement.  9.1.0
unintentionally threw an error if the last statement returned a reference,
as reported by Amit Khandekar.

Also, make sure it works to return a string value for a composite type,
so long as the string meets the type's input format.  We already allowed
the equivalent behavior for arrays, so it seems inconsistent to not allow
it for composites.

In addition, ensure we throw errors for attempts to return arrays or hashes
when the function's declared result type is not an array or composite type,
respectively.  Pre-9.1 versions rather uselessly returned strings like
ARRAY(0x221a9a0) or HASH(0x221aa90), while 9.1.0 threw an error for the
hash case and returned a garbage value for the array case.

Also, clean up assorted grotty coding in Perl array conversion, including
use of a session-lifespan memory context to accumulate the array value
(resulting in session-lifespan memory leak on error), failure to apply the
declared typmod if any, and failure to detect some cases of non-rectangular
multi-dimensional arrays.

Alex Hunsaker and Tom Lane

match the Linux Standard Base Core Specification 3.1.

Aaron W. Swenson

dummy_label -> dummy_seclabel

Thom Brown

Relation rowtypes and automatically-generated array types do not need to
have their own extension membership dependency entries.  If we create such
then it becomes more difficult to remove items from an extension, and it's
also harder for an extension upgrade script to make sure it duplicates the
dependencies created by the extension's regular installation script.

I changed the code in such a way that this happened in commit
988cccc6, I think because of worries about
the shell-type-replacement case; but that cure was worse than the disease.
It would only matter if one extension created a shell type that was
replaced with an auto-generated type in another extension, which seems
pretty far-fetched.  Better to make this work unsurprisingly in normal
cases.

Report and patch by Robert Haas, comment adjustments by me.

not matching the primary key.

Report from Marek.Balgar@seznam.cz

struct, to help pgindent.

include the ability to supply a typedef file, rather than list them on
the command line.  Also improve the README.

We have seen one too many reports of people trying to use 9.1 extension
files in the old-fashioned way of sourcing them in psql.  Not only does
that usually not work (due to failure to substitute for MODULE_PATHNAME
and/or @extschema@), but if it did work they'd get a collection of loose
objects not an extension.  To prevent this, insert an \echo ... \quit
line that prints a suitable error message into each extension script file,
and teach commands/extension.c to ignore lines starting with \echo.
That should not only prevent any adverse consequences of loading a script
file the wrong way, but make it crystal clear to users that they need to
do it differently now.

Tom Lane, following an idea of Andrew Dunstan's.  Back-patch into 9.1
... there is not going to be much value in this if we wait till 9.2.

The documentation neglected to explain its behavior in a script file
(it only ends execution of the script, not psql as a whole), and failed
to mention the long form \quit either.

Backpatch to 9.0.X and 9.1.X.

It's been bothering me for several days that pretending that the cstring
data stored in a btree name_ops column is really a "name" Datum could lead
to reading past the end of memory.  However, given the current memory
layout used for index-only scans in the btree code, a crash is in fact not
possible.  Document that so we don't break it.  I have not thought of any
other solutions that aren't fairly ugly too, and most of them lose the
functionality of index-only scans on name columns altogether, so this seems
like the way to go.

Dept. of second thoughts: as long as we've got that tlist hanging around
anyway, we can apply ExecTypeFromTL to it to get a suitable descriptor for
the ScanTupleSlot.  This is a nicer solution than the previous one because
it eliminates some hard-wired knowledge about btree name_ops, and because
it avoids the somewhat shaky assumption that we needn't set up the scan
tuple descriptor in EXPLAIN_ONLY mode.  It doesn't change what actually
happens at run-time though, and I'm still a bit nervous about that.

Andrew Dunstan

help prevent pg_ctl from getting confused.

Backpatch to 9.1.

By popular demand.

This commit changes index-only scans so that data is read directly from the
index tuple without first generating a faux heap tuple.  The only immediate
benefit is that indexes on system columns (such as OID) can be used in
index-only scans, but this is necessary infrastructure if we are ever to
support index-only scans on expression indexes.  The executor is now ready
for that, though the planner still needs substantial work to recognize
the possibility.

To do this, Vars in index-only plan nodes have to refer to index columns
not heap columns.  I introduced a new special varno, INDEX_VAR, to mark
such Vars to avoid confusion.  (In passing, this commit renames the two
existing special varnos to OUTER_VAR and INNER_VAR.)  This allows
ruleutils.c to handle them with logic similar to what we use for subplan
reference Vars.

Since index-only scans are now fundamentally different from regular
indexscans so far as their expression subtrees are concerned, I also chose
to change them to have their own plan node type (and hence, their own
executor source file).

There's no particular advantage to this change on its face; indeed,
it's possible that this might be slightly slower than the old way.
But it makes this information more easily accessible to other
functions, and therefore paves the way for future code consolidation.
Performance isn't critical here, so there's no need to be smart about
how we do the search.

This is a heavily cut-down version of a patch from KaiGai Kohei,
with several fixes by me.  Additional review from Dimitri Fontaine.

I broke this in commit 84e37126.  Report and
fix by Fujii Masao.

This might help to avoid confusion between the CREATE USER command,
and the deprecated CREATEUSER option to CREATE ROLE, as per a recent
complaint from Ron Adams.  At any rate, having a cross-link here
seems like a good idea; two commands that are so similar should
reference each other.

Per suggestions from Achilleas Mantzios and Greg Smith.

Shigehiro Honda

Fujii Masao

Marti Raudsepp

Per report from Thom Brown.

than '(none)'.

This appears to be another case where the relative sort order of letters
vs. numbers can throw things off.

Pavel Stehule

document its use for config-only directory installs.

When I consolidated two copies of the HOT-chain search logic in commit
4da99ea4, I introduced a behavior
change: the old code wouldn't necessarily traverse the entire chain,
if the most recently returned tuple were updated while the HOT chain
traversal is in progress.  The new behavior seems more correct, but
unfortunately, the code here relies on a scan with SnapshotNow failing
to see its own updates.  That seems pretty shaky even with the old HOT
chain traversal behavior, since there's no guarantee that these
updates will always be HOT, but it's trivial to broke a failure with
the new HOT search logic.  Fix by updating just the first matching
pg_constraint tuple, rather than all of them, since there should be
only one anyway.  But since nobody has reproduced this failure on older
versions, no back-patch for now.

Report and test case by Alex Hunsaker; tablecmds.c changes by me.

This was broken in commit 53dbc27c, which
introduced unlogged tables.  Fortunately, as debugging tools go, this one
is pretty cheap, which is probably why it took nine months for someone to
notice, but it's not intended to be enabled by default, so revert.

Noted by Fujii Masao.

The original idea of this patch was to make box picksplit run faster, by
eliminating unnecessary palloc() overhead, but that was obsoleted by the new
double-sorting split algorithm that doesn't call these functions so heavily
anymore. Nevertheless, the code looks better this way.

Original patch by me, reviewed and tidied up after the double-sorting patch
by Kevin Grittner.

We copy all the matched tuples off the page during _bt_readpage, instead of
expensively re-locking the page during each subsequent tuple fetch.  This
costs a bit more local storage, but not more than 2*BLCKSZ worth, and the
reduction in LWLock traffic is certainly worth that.  What's more, this
lets us get rid of the API wart in the original patch that said an index AM
could randomly decline to supply an index tuple despite having asserted
pg_am.amcanreturn.  That will be important for future improvements in the
index-only-scan feature, since the executor will now be able to rely on
having the index data available.

This bollixes the test because it's expecting to see the idx_tup_fetch
counter increase, which won't happen if heap fetches were avoided by use
of an index-only scan.  Per buildfarm results.

While at it, let's just make sure that enable_seqscan and enable_indexscan
are ON for this test ...

An index-only scan that avoids heap fetches will increment idx_tup_read
but not idx_tup_fetch.

visibility_fraction should not be applied to regular indexscans.
Noted by Cédric Villemain.

transform_null_equals is only supposed to affect "foo = NULL" expressions
given directly by the user, not the internal "foo = NULL" expression
generated from CASE-WHEN.

This fixes bug #6242, reported by Sergey. Backpatch to all supported
branches.