Tracks one counter for each database, which is reset whenever
the statistics for any individual object inside the database is
reset, and one counter for the background writer.

Tomas Vondra, reviewed by Greg Smith

Flattening of subquery range tables during setrefs.c could lead to the
rangetable indexes in PlanRowMark nodes not matching up with the column
names previously assigned to the corresponding resjunk ctid (resp. tableoid
or wholerow) columns.  Typical symptom would be either a "cannot extract
system attribute from virtual tuple" error or an Assert failure.  This
wasn't a problem before 9.0 because we didn't support FOR UPDATE below the
top query level, and so the final flattening could never renumber an RTE
that was relevant to FOR UPDATE.  Fix by using a plan-tree-wide unique
number for each PlanRowMark to label the associated resjunk columns, so
that the number need not change during flattening.

Per report from David Johnston (though I'm darned if I can see how this got
past initial testing of the relevant code).  Back-patch to 9.0.

This follows my proposal of yesterday, namely that we try to recreate the
previous state of the extension exactly, instead of allowing CREATE
EXTENSION to run a SQL script that might create some entirely-incompatible
on-disk state.  In --binary-upgrade mode, pg_dump won't issue CREATE
EXTENSION at all, but instead uses a kluge function provided by
pg_upgrade_support to recreate the pg_extension row (and extension-level
pg_depend entries) without creating any member objects.  The member objects
are then restored in the same way as if they weren't members, in particular
using pg_upgrade's normal hacks to preserve OIDs that need to be preserved.
Then, for each member object, ALTER EXTENSION ADD is issued to recreate the
pg_depend entry that marks it as an extension member.

In passing, fix breakage in pg_upgrade's enum-type support: somebody didn't
fix it when the noise word VALUE got added to ALTER TYPE ADD.  Also,
rationalize parsetree representation of COMMENT ON DOMAIN and fix
get_object_address() to allow OBJECT_DOMAIN.

Add the views character_sets, collations, and
collation_character_set_applicability.

This is an essential component of making the extension feature usable;
first because it's needed in the process of converting an existing
installation containing "loose" objects of an old contrib module into
the extension-based world, and second because we'll have to use it
in pg_dump --binary-upgrade, as per recent discussion.

Loosely based on part of Dimitri Fontaine's ALTER EXTENSION UPGRADE
patch.

Specifying this option makes the server not wait for the
xlog to be archived, or emit a warning that it can't,
instead leaving the responsibility with the client.

This is useful when the log is being streamed using
the streaming protocol in parallel with the backup,
without having log archiving enabled.

This patch adds the server infrastructure to support extensions.
There is still one significant loose end, namely how to make it play nice
with pg_upgrade, so I am not yet committing the changes that would make
all the contrib modules depend on this feature.

In passing, fix a disturbingly large amount of breakage in
AlterObjectNamespace() and callers.

Dimitri Fontaine, reviewed by Anssi Kääriäinen,
Itagaki Takahiro, Tom Lane, and numerous others

This adds collation support for columns and domains, a COLLATE clause
to override it per expression, and B-tree index support.

Peter Eisentraut
reviewed by Pavel Stehule, Itagaki Takahiro, Robert Haas, Noah Misch

new recovery.conf parameter recovery_target_name allows PITR to
specify named points as recovery targets.

Jaime Casanova, reviewed by Euler Taveira de Oliveira, plus minor edits

Status check functions only. Also, new recovery.conf parameter to
pause_at_recovery_target, default on.

Simon Riggs, reviewed by Fujii Masao

FK constraints that are marked NOT VALID may later be VALIDATED, which uses an
ShareUpdateExclusiveLock on constraint table and RowShareLock on referenced
table. Significantly reduces lock strength and duration when adding FKs.
New state visible from psql.

Simon Riggs, with reviews from Marko Tiikkaja and Robert Haas

Waiting for relation locks can lead to starvation - it pins down an
autovacuum worker for as long as the lock is held.  But if we're doing
an anti-wraparound vacuum, then we still wait; maintenance can no longer
be put off.

To assist with troubleshooting, if log_autovacuum_min_duration >= 0,
we log whenever an autovacuum or autoanalyze is skipped for this reason.

Per a gripe by Josh Berkus, and ensuing discussion.

I thought we didn't need that, but then I remembered that it added a new
SLRU subdirectory, pg_serial. While we're at it, document what pg_serial is.

Until now, our Serializable mode has in fact been what's called Snapshot
Isolation, which allows some anomalies that could not occur in any
serialized ordering of the transactions. This patch fixes that using a
method called Serializable Snapshot Isolation, based on research papers by
Michael J. Cahill (see README-SSI for full references). In Serializable
Snapshot Isolation, transactions run like they do in Snapshot Isolation,
but a predicate lock manager observes the reads and writes performed and
aborts transactions if it detects that an anomaly might occur. This method
produces some false positives, ie. it sometimes aborts transactions even
though there is no anomaly.

To track reads we implement predicate locking, see storage/lmgr/predicate.c.
Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared
memory is finite, so when a transaction takes many tuple-level locks on a
page, the locks are promoted to a single page-level lock, and further to a
single relation level lock if necessary. To lock key values with no matching
tuple, a sequential scan always takes a relation-level lock, and an index
scan acquires a page-level lock that covers the search key, whether or not
there are any matching keys at the moment.

A predicate lock doesn't conflict with any regular locks or with another
predicate locks in the normal sense. They're only used by the predicate lock
manager to detect the danger of anomalies. Only serializable transactions
participate in predicate locking, so there should be no extra overhead for
for other transactions.

Predicate locks can't be released at commit, but must be remembered until
all the transactions that overlapped with it have completed. That means that
we need to remember an unbounded amount of predicate locks, so we apply a
lossy but conservative method of tracking locks for committed transactions.
If we run short of shared memory, we overflow to a new "pg_serial" SLRU
pool.

We don't currently allow Serializable transactions in Hot Standby mode.
That would be hard, because even read-only transactions can cause anomalies
that wouldn't otherwise occur.

Serializable isolation mode now means the new fully serializable level.
Repeatable Read gives you the old Snapshot Isolation level that we have
always had.

Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and
Anssi Kääriäinen

If the foreign table's rowtype is being used as the type of a column in
another table, we can't just up and change its data type.  This was
already checked for composite types and ordinary tables, but we
previously failed to enforce it for foreign tables.

This fixes make distprep, and seems more robust in other ways as well.
Some special handling is required because errcodes.txt is needed by
some stuff in src/port, but just by src/backend as is the case for the
other generated headers.

While I'm at it, fix a few other things that were overlooked in the
original patch.

src/pl/plpgsql/src/plerrcodes.h, src/include/utils/errcodes.h, and a
big chunk of errcodes.sgml are now automatically generated from a single
file, src/backend/utils/errcodes.txt.

Jan Urbański, reviewed by Tom Lane.

'E:abc' Win32 path handling.

path variables, not directory paths.

Jan Urbański, reviewed by Hitoshi Harada

New versions of libintl redefine setlocale() to a macro
which causes problems when the backend and libintl are
linked against different versions of the runtime, which
is often the case in msvc builds.

Hiroshi Inoue, slightly updated comment by me

Previously reported as ERRCODE_ADMIN_SHUTDOWN, this case is now
reported as ERRCODE_T_R_DATABASE_DROPPED. No message text change.
Unlikely to happen on most servers, so low impact change to allow
session poolers to correctly handle this situation.

Tatsuo Ishii, edits by me, review by Robert Haas

With this patch, pg_basebackup doesn't write a backup_label file in the
data directory, so it doesn't interfere with a pg_start/stop_backup() based
backup anymore. backup_label is still included in the backup, but it is
injected directly into the tar stream.

Heikki Linnakangas, reviewed by Fujii Masao and Magnus Hagander.

This can be used to build 64 bit Windows binaries, not only on 64 bit
Windows but on supported cross-compiling hosts including 32 bit Windows,
Cygwin, Darwin and Linux.

When included, this makes the base backup a complete working
"clone" of the initial database, ready to have a postmaster
started against it without the need to set up any log archiving
or similar.

Magnus Hagander, reviewed by Fujii Masao and Heikki Linnakangas

Synchronize pg_config.h.in with configure.in (someone must have
forgotten to run autoheader or autoreconf), and clean up some spurious
change in configure introduced by the last commit there.

There isn't any need to track this state on a table-wide basis, and trying
to do so introduces undesirable semantic fuzziness.  Move the flag to
pg_index, where it clearly describes just a single index and can be
immutable after index creation.

This feature allows a unique or pkey constraint to be created using an
already-existing unique index.  While the constraint isn't very
functionally different from the bare index, it's nice to be able to do that
for documentation purposes.  The main advantage over just issuing a plain
ALTER TABLE ADD UNIQUE/PRIMARY KEY is that the index can be created with
CREATE INDEX CONCURRENTLY, so that there is not a long interval where the
table is locked against updates.

On the way, refactor some of the code in DefineIndex() and index_create()
so that we don't have to pass through those functions in order to create
the index constraint's catalog entries.  Also, in parse_utilcmd.c, pass
around the ParseState pointer in struct CreateStmtContext to save on
notation, and add error location pointers to some error reports that didn't
have one before.

Gurjeet Singh, reviewed by Steve Singer and Tom Lane

While doing this, also move base backup options into
a struct instead of increasing the number of parameters
to multiple functions for each new option.

This tool makes it possible to do the pg_start_backup/
copy files/pg_stop_backup step in a single command.

There are still some steps to be done before this is a
complete backup solution, such as the ability to stream
the required WAL logs, but it's still usable, and
could do with some buildfarm coverage.

In passing, make the checkpoint request optionally
fast instead of hardcoding it.

Magnus Hagander, reviewed by Fujii Masao and Dimitri Fontaine

As in commit fb4c5d27 on 2011-01-21,
this avoids spurious debug messages and allows idempotent changes at
any time.  Along the way, make assign_XactIsoLevel allow idempotent
changes even when not within a subtransaction, to be consistent with
the new coding of assign_transaction_read_only and because there's
no compelling reason to do otherwise.

Kevin Grittner, with some adjustments.

The new coding avoids a spurious debug message when a transaction
that has changed the isolation level has been rolled back.  It also
allows the property to be freely changed to the current value within
a subtransaction.

Kevin Grittner, with one small change by me.

Failure to do so can lead to constraint violations.  This was broken by
commit 1ddc2703 on 2010-02-07, so
back-patch to 9.0.

Noah Misch.  Regression test by me.

backend, as far as the postmaster shutdown logic is concerned. That means,
fast shutdown will wait for WAL sender processes to exit before signaling
bgwriter to finish. This avoids race conditions between a base backup stopping
or starting, and bgwriter writing the shutdown checkpoint WAL record. We don't
want e.g the end-of-backup WAL record to be written after the shutdown
checkpoint.

Makes it easier to parse mainly the BASE_BACKUP command
with it's options, and avoids having to manually deal
with quoted identifiers in the label (previously broken),
and makes it easier to add new commands and options in
the future.

In passing, refactor the case statement in the walsender
to put each command in it's own function.