We must not return any "okay to proceed" result code without having checked
for too many children, else we might fail later on when trying to add the
new child to one of the per-child state arrays.  It's not clear whether
this oversight explains Stefan Kaltenbrunner's recent report, but it could
certainly produce a similar symptom.

Back-patch to 8.4; the logic was not broken before that.

3.80 breaks if the expansion of $(eval) is long enough to require expansion
of its internal variable_buffer.  For the purposes of $(recurse) that means
it'll work so long as no single evaluation of _create_recursive_target
produces more than 195 bytes.  We can manage that by looping over
subdirectories outside the call instead of complicating the generated rule.
This coding is simpler and more readable anyway.

Or at least, this works for me.  We'll see if the buildfarm likes it.

This is needed to support debug_print_parse, per report from Jon Nelson.
Cursory testing via the regression tests suggests we aren't missing
anything else.

Having this in src/include/port.h makes no sense, now that copydir.c lives
in src/backend/strorage rather than src/port.  Along the way, remove an
obsolete comment from contrib/pg_upgrade that makes reference to the old
location.

Once we have found a non-null constant argument, there is no need to
examine additional arguments of the COALESCE.  The previous coding got it
right only if the constant was in the first argument position; otherwise
it tried to simplify following arguments too, leading to unexpected
behavior like this:

regression=# select coalesce(f1, 42, 1/0) from int4_tbl;
ERROR:  division by zero

It's a minor corner case, but a bug is a bug, so back-patch all the way.

Replace for loops in makefiles with proper dependencies.  Parallel
make can now span across directories.  Also, make -k and make -q work
properly.

GNU make 3.80 or newer is now required.

belonging to a user at DROP OWNED BY. Foreign data wrappers and servers
don't do anything useful yet, which is why no-one has noticed, but since we
have them, seems prudent to fix this. Per report from Chetan Suttraway.
Backpatch to 9.0, 8.4 has the same problem but this patch didn't apply
there so I'm not going to bother.

location read from backup label file can be found: wasShutdown was set
incorrectly when a backup label file was found.

Jeff Davis, with a little tweaking by me.

This code was just plain wrong: what you got was not a line through the
given point but a line almost indistinguishable from the Y-axis, although
not truly vertical.  The only caller that tries to use this function with
m == DBL_MAX is dist_ps_internal for the case where the lseg is horizontal;
it would end up producing the distance from the given point to the place
where the lseg's line crosses the Y-axis.  That function is used by other
operators too, so there are several operators that could compute wrong
distances from a line segment to something else.  Per bug #5745 from
jindiax.

Back-patch to all supported branches.

Fujii Masao, with a little wordsmithing by me.

by gcc version 4 on mingw and cygwin. We don't use dllexport here
because dllexport and dllwrap don't work well together.

Explicitly document that the -o options of pg_ctl init mode are meant
for initdb, not postgres (Euler Taveira de Oliveira).  Assorted other
copy-editing (Tom).

The general design of memory management in Postgres is that intermediate
results computed by an expression are not freed until the end of the tuple
cycle.  For expression indexes, ANALYZE has to re-evaluate each expression
for each of its sample rows, and it wasn't bothering to free intermediate
results until the end of processing of that index.  This could lead to very
substantial leakage if the intermediate results were large, as in a recent
example from Jakub Ouhrabka.  Fix by doing ResetExprContext for each sample
row.  This necessitates adding a datumCopy step to ensure that the final
expression value isn't recycled too.  Some quick testing suggests that this
change adds at worst about 10% to the time needed to analyze a table with
an expression index; which is annoying, but seems a tolerable price to pay
to avoid unexpected out-of-memory problems.

Back-patch to all supported branches.

length stored in the line pointer the same way it's calculated in the normal
heap_insert() codepath. As noted by Jeff Davis, the length stored by
raw_heap_insert() included padding but the one stored by the normal codepath
did not. While the mismatch seems to be harmless, inconsistency isn't good,
and the normal codepath has received a lot more testing over the years.

Backpatch to 8.3 where the heap rewrite code was introduced.

Author: Marti Raudsepp <marti@juffo.org>

The original coding in FileClose() reset the file-is-temp flag before
unlinking the file, so that if control came back through due to an error,
it wouldn't try to unlink the file twice.  This was correct when written,
but when the log_temp_files feature was added, the logging action was put
in between those two steps.  An error occurring during the logging action
--- such as a query cancel --- would result in the unlink not getting done
at all, as in recent report from Michael Glaesemann.

To fix this, make sure that we do both the stat and the unlink before doing
anything that could conceivably CHECK_FOR_INTERRUPTS.  There is a judgment
call here, which is which log message to emit first: if you can see only
one, which should it be?  I chose to log unlink failure at the risk of
losing the log_temp_files log message --- after all, if the unlink does
fail, the temp file is still there for you to see.

Back-patch to all versions that have log_temp_files.  The code was OK
before that.

get_database_list was uselessly allocating its output data, along some
created along the way, in a permanent memory context.  This didn't
matter when autovacuum was a single, short-lived process, but now that
the launcher is permanent, it shows up as a permanent leak.

To fix, make get_database list allocate its output data in the caller's
context, which is in charge of freeing it when appropriate; and the
memory leaked by heap_beginscan et al is allocated in a throwaway
transaction context.

Formerly, we could convert a UNION ALL structure inside a subquery-in-FROM
into an appendrel, as a side effect of pulling up the subquery into its
parent; but top-level UNION ALL always caused use of plan_set_operations().
That didn't matter too much because you got an Append-based plan either
way.  However, now that the appendrel code can do things with MergeAppend,
it's worthwhile to hack up the top-level case so it also uses appendrels.

This is a bit of a stopgap; but going much further than this will require
a major rewrite of the planner's set-operations support, which I'm not
prepared to undertake now.  For the moment let's grab the low-hanging fruit.

PG 8.4 added a built-in feature for casting pretty much any data type to
string types (text, varchar, etc).  We allowed this to work in any of the
historically-allowed syntaxes: CAST(x AS text), x::text, text(x), or
x.text.  However, multiple complaints have shown that it's too easy to
invoke such casts unintentionally in the latter two styles, particularly
field selection.  To cure the problem with the narrowest possible change
of behavior, disallow use of I/O conversion casts from composite types to
string types via functional/attribute syntax.  The new functionality is
still available via cast syntax.

In passing, document the equivalence of functional and attribute syntax
in a more visible place.

\dn without "S" now hides all pg_XXX schemas as well as information_schema.
Thus, in a bare database you'll only see "public".  ("public" is considered
a user schema, not a system schema, mainly because it's droppable.)
Per discussion back in late September.

Per recent investigation, the register stack can grow faster than the
regular stack depending on compiler and choice of options.  To avoid
crashes we must check both stacks in check_stack_depth().

Since this is poorly-tested code, committing only to HEAD for the
moment ... but we might want to consider back-patching later.

Rather than considering this result as meaning "unknown", report LONG_MAX.
This won't change what superusers can set max_stack_depth to, but it will
cause InitializeGUCOptions() to set the built-in default to 2MB not 100kB.
The latter seems like a fairly unreasonable interpretation of "infinity".
Per my investigation of odd buildfarm results as well as an old complaint
from Heikki.

Since this should persuade all the buildfarm animals to use a reasonable
stack depth setting during "make check", revert previous patch that dumbed
down a recursive regression test to only 5 levels.

I'm mainly interested in finding out what it is on buildfarm machines,
but including the active value in the message seems like good practice
in any case.  Add the info to the HINT, not the ERROR string, so as not
to change the regression tests' expected output.

Dirk Heinrichs

The nominally equivalent call appendStringInfo(buf, "%s", str) can be
significantly slower when str is large.  In particular, the former usage in
EVALUATE_MESSAGE led to O(N^2) behavior when collecting a large number of
context lines, as I found out while testing recursive functions.  The other
changes are just neatnik-ism and seem unlikely to save anything meaningful,
but a cycle shaved is a cycle earned.

Per my recent proposal, get rid of all the direct inspection of indexes
and manual generation of paths in planagg.c.  Instead, set up
EquivalenceClasses for the aggregate argument expressions, and let the
regular path generation logic deal with creating paths that can satisfy
those sort orders.  This makes planagg.c a bit more visible to the rest
of the planner than it was originally, but the approach is basically a lot
cleaner than before.  A major advantage of doing it this way is that we get
MIN/MAX optimization on inheritance trees (using MergeAppend of indexscans)
practically for free, whereas in the old way we'd have had to add a whole
lot more duplicative logic.

One small disadvantage of this approach is that MIN/MAX aggregates can no
longer exploit partial indexes having an "x IS NOT NULL" predicate, unless
that restriction or something that implies it is specified in the query.
The previous implementation was able to use the added "x IS NOT NULL"
condition as an extra predicate proof condition, but in this version we
rely entirely on indexes that are considered usable by the main planning
process.  That seems a fair tradeoff for the simplicity and functionality
gained.

Some buildfarm members fail the test with the original depth of 10 levels,
apparently because they are running at the minimum max_stack_depth setting
of 100kB and using ~ 10k per recursion level.  While it might be
interesting to try to figure out why they're eating so much stack, it isn't
likely that any fix for that would be back-patchable.  So just change the
test to recurse only 5 levels.  The extra levels don't prove anything
correctness-wise anyway.

Like plperl and unlike plpgsql, there isn't any cached state that could
depend on exactly which relation the trigger is being fired for.  So we
can use just one hash entry for all relations, which might save a little
something.

Alex Hunsaker

A proposed patch will require GNU make 3.80 or newer.  We will let this patch
run for a while to see how much damage that would do to the buildfarm.

It was reporting that these were fully indexed (hence cheap), when of
course they're the exact opposite of that.  I'm not certain if the case
would arise in practice, since a clauseless semijoin is hard to produce
in SQL, but if it did happen we'd make some dumb decisions.

Problem reported, and cause identified, by Hernan Gonzalez.

We failed to record any dependency on the underlying table for an index
declared like "create index i on t (foo(t.*))".  This would create trouble
if the table were dropped without previously dropping the index.  To fix,
simplify some overly-cute code in index_create(), accepting the possibility
that sometimes the whole-table dependency will be redundant.  Also document
this hazard in dependency.c.  Per report from Kevin Grittner.

In passing, prevent a core dump in pg_get_indexdef() if the index's table
can't be found.  I came across this while experimenting with Kevin's
example.  Not sure it's a real issue when the catalogs aren't corrupt, but
might as well be cautious.

Back-patch to all supported versions.

Use bool as type for booleans instead of int.
Do not implicitely cast size_t to int.
Make the compiler stop complaining about unused variables by adding an empty statement.

rather than 0/0, so that we can safely use 0/0 as an invalid value. This is a
more future-proof fix for the corner-case bug in streaming replication that
was fixed yesterday. We had a similar corner-case bug with log/seg 0/0 back in
February as well. Avoiding 0/0 as a valid value should prevent bugs like that
in the future. Per Tom Lane's idea.

Back-patch to 9.0. Since this only affects bootstrapping, it makes no
difference to existing installations. We don't need to worry about the
bug in existing installations, because if you've managed to get past the
initial base backup already, you won't hit the bug in the future either.

and related routines.

We already had a redundant FunctionCallInfoData struct in FuncExprState,
but were using that copy only in set-returning-function cases, to avoid
keeping function evaluation state in the expression tree for the benefit
of plpgsql's "simple expression" logic.  But of course that didn't work
anyway.  Given the recent fixes in plpgsql there is no need to have two
separate behaviors here.  Getting rid of the local FunctionCallInfoData
structs should make things a little faster (because we don't need to do
InitFunctionCallInfoData each time), and it also makes for a noticeable
reduction in stack space consumption during recursive calls.

streaming replication. We used log/seg 0/0 to indicate that no WAL segments
have been removed since startup, but 0/0 is a valid value for the very first
WAL segment after initdb. To make that disambiguous, store
(latest removed WAL segment + 1) in the global variable.

Per report from Matt Chesler, also reproduced by Greg Smith.