Remember the last page of an index insert if it's the rightmost leaf
page. If the next entry belongs on and can fit in the remembered page,
insert the new entry there as long as we can get a lock on the page.
Otherwise, fall back on the more expensive method of searching for
the right place to insert the entry.

This provides a performance improvement for the common case where an
index entry is for monotonically increasing or nearly monotonically
increasing value such as an identity field or a current timestamp.

Pavan Deolasee
Reviewed by Claudio Freire, Simon Riggs and Peter Geoghegan

Discussion: https://postgr.es/m/CABOikdM9DrupjyKZZFM5k8-0RCDs1wk6JzEkg7UgSW6QzOwMZw@mail.gmail.com

Section 10.5 didn't say explicitly that multiple UNIONs are resolved
pairwise.  Since the resolution algorithm is described as taking any
number of inputs, readers might well think that a query like
"select x union select y union select z" would be resolved by
considering x, y, and z in one resolution step.  But that's not what
happens (and I think that behavior is per SQL spec).  Add an example
clarifying this point.

Per bug #15129 from Philippe Beaudoin.

Discussion: https://postgr.es/m/152196085023.32649.9916472370480121694@wrigleys.postgresql.org

Commit 8694cc96 did this randomly differently from other callers of
parse_filename_for_nontemp_relation().  Perhaps unsurprisingly,
the randomly different way is wrong; it fails to ensure the
extracted string is null-terminated.  Per buildfarm member skink.

Discussion: https://postgr.es/m/14453.1522001792@sss.pgh.pa.us

This adds a new option --wal-segsize (analogous to initdb) that changes
the WAL segment size in pg_control.

Author: Nathan Bossart <bossartn@amazon.com>

Extend documentation.  Improve option parsing in case no argument was
specified.

Coverity complained that this check is pointless, and it's right.
There is no case where we'd call ExecutorStart with a null plannedstmt,
and if we did, it'd have crashed before here.  Thinko in commit cc415a56.

Noted by Scott Ure.  Back-patch to all supported branches.

Discussion: https://postgr.es/m/152199346794.4544.1888397173908716912@wrigleys.postgresql.org

introduced in f1a074b1

Leaving out getopt_long.h works on some platforms, but not all.
Per buildfarm.

Discussion: https://postgr.es/m/20180325030552.f462zqmohs6cqekg@alap3.anarazel.de

If random() returns a result sufficiently close to zero, float8out
switches to scientific notation, breaking this test case's expectation
that the output should look like '0.xxxxxxxxx'.  Casting to numeric
should fix that.  Per buildfarm member pogona.

Discussion: https://postgr.es/m/20180324212502.wt4serghfidge2on@alap3.anarazel.de

Missed these occurrences of some of the adjusted error messages.
Per buildfarm member pademelon.

We were running out of good single-letter options for some upcoming
pg_resetwal functionality, so add long options to create more
possibilities.  Add to pg_controldata as well for symmetry.

based on patch by Bossart, Nathan <bossartn@amazon.com>

Give separate error messages for when the argument is not a number and
when it is not the right kind of number.

Fix wording in the help message.

Clarify that the -l option takes a file name, not an "address", and that
that might be different from the LSN if nondefault WAL segment sizes are
used.

Extension scripts begin execution with pg_catalog at the front of the
search path, so type names reliably refer to pg_catalog.  Remove these
superfluous qualifications.  Earlier <programlisting> of this <sect1>
already omitted them.  Back-patch to 9.3 (all supported versions).

Put the "atomic" argument of ExecuteDoStmt() and ExecuteCallStmt() into
a variable instead of repeating the formula.

In the case that PostgreSQL uses stdbool.h but Perl doesn't, we need to
prevent Perl from defining bool, to prevent compiler warnings about
redefinition.

For years, our makefiles have correctly observed that "there is no correct
way to write a rule that generates two files".  However, what we did is to
provide empty rules that "generate" the secondary output files from the
primary one, and that's not right either.  Depending on the details of
the creating process, the primary file might end up timestamped later than
one or more secondary files, causing subsequent make runs to consider the
secondary file(s) out of date.  That's harmless in a plain build, since
make will just re-execute the empty rule and nothing happens.  But it's
fatal in a VPATH build, since make will expect the secondary file to be
rebuilt in the build directory.  This would manifest as "file not found"
failures during VPATH builds from tarballs, if we were ever unlucky enough
to ship a tarball with apparently out-of-date secondary files.  (It's not
clear whether that has ever actually happened, but it definitely could.)

To ensure that secondary output files have timestamps >= their primary's,
change our makefile convention to be that we provide a "touch $@" action
not an empty rule.  Also, make sure that this rule actually gets invoked
during a distprep run, else the hazard remains.

It's been like this a long time, so back-patch to all supported branches.

In HEAD, I skipped the changes in src/backend/catalog/Makefile, because
those rules are due to get replaced soon in the bootstrap data format
patch, and there seems no need to create a merge issue for that patch.
If for some reason we fail to land that patch in v11, we'll need to
back-fill the changes in that one makefile from v10.

Discussion: https://postgr.es/m/18556.1521668179@sss.pgh.pa.us

Exclude unlogged tables from base backup entirely except init fork which marks
created unlogged table. The next question is do not backup temp table but
it's a story for separate patch.

Author: David Steele
Review by: Adam Brightwell, Masahiko Sawada
Discussion: https://www.postgresql.org/message-id/flat/04791bab-cb04-ba43-e9c0-664a4c1ffb2c@pgmasters.net

Revert the PL/Perl-specific change in
9a95a77d.  We must not prevent Perl from
using stdbool.h when it has been built to do so, even if it uses an
incompatible size.  Otherwise, we would be imposing our bool on Perl,
which will lead to crashes because of the size mismatch.

Instead, we undef bool after including the Perl headers, as we did
previously, but now only if we are not using stdbool.h ourselves.
Record that choice in c.h as USE_STDBOOL.  This will also make it easier
to apply that coding pattern elsewhere if necessary.

Handle the case where the pg_control file specifies a WAL segment size
of 0 bytes.  This would previously have led to a division by zero error.
Change this to assume the whole file is corrupt and go to guess
everything.

Discussion: https://www.postgresql.org/message-id/a6163ad7-cc99-fdd1-dfad-25df73032ab8%402ndquadrant.com

Previously, FOR EACH ROW triggers were not allowed in partitioned
tables.  Now we allow AFTER triggers on them, and on trigger creation we
cascade to create an identical trigger in each partition.  We also clone
the triggers to each partition that is created or attached later.

This means that deferred unique keys are allowed on partitioned tables,
too.

Author: Álvaro Herrera
Reviewed-by: Peter Eisentraut, Simon Riggs, Amit Langote, Robert Haas,
	Thomas Munro
Discussion: https://postgr.es/m/20171229225319.ajltgss2ojkfd3kp@alvherre.pgsql

Some subsequent patches will add to this, but to avoid conflicts, set up
the basics separately.

The LLVM JIT provider uses clang to synchronize types between normal C
code and runtime generated code. Clang represents stdbool.h style
booleans in return values & parameters differently from booleans
stored in variables.

Thus the expression compilation code from 2a0faed9 needs to be
adapted to 9a95a77d. Instead of hardcoding i8 as the type for
booleans (which already was wrong on some edge case platforms!), use
postgres' notion of a boolean as used for storage and for parameters.

Per buildfarm animal xenodermus.

Author: Andres Freund

Since we now use stdbool.h in c.h, this workaround breaks the build and
is no longer necessary, so remove it.  (Technically, there could be
platforms with a 4-byte bool in stdbool.h, in which case we would not
include stdbool.h in c.h, and so the old problem that caused this
workaround would reappear.  But this combination is not known to happen
on the range of platforms where sepgsql can be built.)

Using the standard bool type provided by C allows some recent compilers
and debuggers to give better diagnostics.  Also, some extension code and
third-party headers are increasingly pulling in stdbool.h, so it's
probably saner if everyone uses the same definition.

But PostgreSQL code is not prepared to handle bool of a size other than
1, so we keep our own old definition if we encounter a stdbool.h with a
bool of a different size.  (Among current build farm members, this only
applies to old macOS versions on PowerPC.)

To check that the used bool is of the right size, add a static
assertions about size of GinTernaryValue vs bool.  This is currently the
only place that assumes that bool and char are of the same size.

Discussion: https://www.postgresql.org/message-id/flat/3a0fe7e1-5ed1-414b-9230-53bbc0ed1f49@2ndquadrant.com

In addition to the interpretation of expressions (which back
evaluation of WHERE clauses, target list projection, aggregates
transition values etc) support compiling expressions to native code,
using the infrastructure added in earlier commits.

To avoid duplicating a lot of code, only support emitting code for
cases that are likely to be performance critical. For expression steps
that aren't deemed that, use the existing interpreter.

The generated code isn't great - some architectural changes are
required to address that. But this already yields a significant
speedup for some analytics queries, particularly with WHERE clauses
filtering a lot, or computing multiple aggregates.

Author: Andres Freund
Tested-By: Thomas Munro
Discussion: https://postgr.es/m/20170901064131.tazjxwus3k2w3ybh@alap3.anarazel.de

Disable JITing for VALUES() nodes.

VALUES() nodes are only ever executed once. This is primarily helpful
for debugging, when forcing JITing even for cheap queries.

Author: Andres Freund
Discussion: https://postgr.es/m/20170901064131.tazjxwus3k2w3ybh@alap3.anarazel.de

For any interesting JIT target, fields inside structs need to be
accessed. b96d550e contains infrastructure for syncing the definition
of types between postgres C code and runtime code generation with
LLVM. But that doesn't sync the number or names of fields inside
structs, just the types (including padding etc).

One option would be to hardcode the offset numbers in the JIT code,
but that'd be hard to keep in sync. Instead add macros indicating the
field offset to the fields that need to be accessed. Not pretty, but
manageable.

Author: Andres Freund
Discussion: https://postgr.es/m/20170901064131.tazjxwus3k2w3ybh@alap3.anarazel.de

Author: Andres Freund
Discussion: https://postgr.es/m/20170901064131.tazjxwus3k2w3ybh@alap3.anarazel.de

Per the project style guide, details and hints should have leading
capitalization and end with a period.  On the other hand, errcontext should
not be capitalized and should not end with a period.  To support well
formatted error contexts in dblink, extend dblink_res_error() to take a
format+arguments rather than a hardcoded string.

Daniel Gustafsson

Discussion: https://postgr.es/m/B3C002C8-21A0-4F53-A06E-8CAB29FCF295@yesql.se

Without this patch, we can implement a UNION or UNION ALL as an
Append where Gather appears beneath one or more of the Append
branches, but this lets us put the Gather node on top, with
a partial path for each relation underneath.

There is considerably more work that could be done to improve
planning in this area, but that will probably need to wait
for a future release.

Patch by me, reviewed and tested by Ashutosh Bapat and Rajkumar
Raghuwanshi.

Discussion: http://postgr.es/m/CA+TgmoaLRAOqHmMZx=ESM3VDEPceg+-XXZsRXQ8GtFJO_zbMSw@mail.gmail.com

VACUUM thought that reltuples represents the total number of tuples in
the relation, while ANALYZE counted only live tuples.  This can cause
"flapping" in the value when background vacuums and analyzes happen
separately.  The planner's use of reltuples essentially assumes that
it's the count of live (visible) tuples, so let's standardize on having
it mean live tuples.

Another issue is that the definition of "live tuple" isn't totally clear;
what should be done with INSERT_IN_PROGRESS or DELETE_IN_PROGRESS tuples?
ANALYZE's choices in this regard are made on the assumption that if the
originating transaction commits at all, it will happen after ANALYZE
finishes, so we should ignore the effects of the in-progress transaction
--- unless it is our own transaction, and then we should count it.
Let's propagate this definition into VACUUM, too.

Likewise propagate this definition into CREATE INDEX, and into
contrib/pgstattuple's pgstattuple_approx() function.

Tomas Vondra, reviewed by Haribabu Kommi, some corrections by me

Discussion: https://postgr.es/m/16db4468-edfa-830a-f921-39a50498e77e@2ndquadrant.com

This adds simple cost based plan time decision about whether JIT
should be performed. jit_above_cost, jit_optimize_above_cost are
compared with the total cost of a plan, and if the cost is above them
JIT is performed / optimization is performed respectively.

For that PlannedStmt and EState have a jitFlags (es_jit_flags) field
that stores information about what JIT operations should be performed.

EState now also has a new es_jit field, which can store a
JitContext. When there are no errors the context is released in
standard_ExecutorEnd().

It is likely that the default values for jit_[optimize_]above_cost
will need to be adapted further, but in my test these values seem to
work reasonably.

Author: Andres Freund, with feedback by Peter Eisentraut
Discussion: https://postgr.es/m/20170901064131.tazjxwus3k2w3ybh@alap3.anarazel.de

These basically just help to make code a bit more concise and pgindent
proof.

Author: Andres Freund
Discussion: https://postgr.es/m/20170901064131.tazjxwus3k2w3ybh@alap3.anarazel.de

This currently requires patches to the LLVM codebase to be
effective (submitted upstream), the GUCs are available without those
patches however.

Author: Andres Freund
Discussion: https://postgr.es/m/20170901064131.tazjxwus3k2w3ybh@alap3.anarazel.de

This commit introduces the ability to actually generate code using
LLVM. In particular, this adds:

- Ability to emit code both in heavily optimized and largely
  unoptimized fashion
- Batching facility to allow functions to be defined in small
  increments, but optimized and emitted in executable form in larger
  batches (for performance and memory efficiency)
- Type and function declaration synchronization between runtime
  generated code and normal postgres code. This is critical to be able
  to access struct fields etc.
- Developer oriented jit_dump_bitcode GUC, for inspecting / debugging
  the generated code.
- per JitContext statistics of number of functions, time spent
  generating code, optimizing, and emitting it.  This will later be
  employed for EXPLAIN support.

This commit doesn't yet contain any code actually generating
functions. That'll follow in later commits.

Documentation for GUCs added, and for JIT in general, will be added in
later commits.

Author: Andres Freund, with contributions by Pierre Ducroquet
Testing-By: Thomas Munro, Peter Eisentraut
Discussion: https://postgr.es/m/20170901064131.tazjxwus3k2w3ybh@alap3.anarazel.de

It's useless.

Amit Langote

Discussion: http://postgr.es/m/b4c9dee6-d134-49b8-79c4-07fbd7c3b898@lab.ntt.co.jp

Michael Paquier

Discussion: http://postgr.es/m/20180205071404.GB17337@paquier.xyz

Thomas Munro

Discussion: http://postgr.es/m/CAEepm=3XdL=+bn3=WQVCCT5wwfAEv-4onKpk+XQZdwDXv6etzA@mail.gmail.com