to be just a minor extension of the previous patch that made "x IS NULL"
indexable, because we can treat the IS NOT NULL condition as if it were
"x < NULL" or "x > NULL" (depending on the index's NULLS FIRST/LAST option),
just like IS NULL is treated like "x = NULL".  Aside from any possible
usefulness in its own right, this is an important improvement for
index-optimized MAX/MIN aggregates: it is now reliably possible to get
a column's min or max value cheaply, even when there are a lot of nulls
cluttering the interesting end of the index.

This is more in keeping with modern practice, and is a first step towards
porting to Win64 (which has sizeof(pointer) > sizeof(long)).

Tsutomu Yamada, Magnus Hagander, Tom Lane

This reflects the recently added support for triggers on columns.

pgstats message.  This might need to be done differently later, but
with the current logic that's what should happen.

decisions about when to auto-analyze.

The previous code depended on n_live_tuples + n_dead_tuples - last_anl_tuples,
where all three of these numbers could be bad estimates from ANALYZE itself.
Even worse, in the presence of a steady flow of HOT updates and matching
HOT-tuple reclamations, auto-analyze might never trigger at all, even if all
three numbers are exactly right, because n_dead_tuples could hold steady.

To fix, replace last_anl_tuples with an accurately tracked count of the total
number of committed tuple inserts + updates + deletes since the last ANALYZE
on the table.  This can still be compared to the same threshold as before, but
it's much more trustworthy than the old computation.  Tracking this requires
one more intra-transaction counter per modified table within backends, but no
additional memory space in the stats collector.  There probably isn't any
measurable speed difference; if anything it might be a bit faster than before,
since I was able to eliminate some per-tuple arithmetic operations in favor of
adding sums once per (sub)transaction.

Also, simplify the logic around pgstat vacuum and analyze reporting messages
by not trying to fold VACUUM ANALYZE into a single pgstat message.

The original thought behind this patch was to allow scheduling of analyzes
on parent tables by artificially inflating their changes_since_analyze count.
I've left that for a separate patch since this change seems to stand on its
own merit.

it in the control file at crash recovery following an archive recovery.

Per Fujii Masao and subsequent discussion.

at least in some Windows versions, these functions are capable of returning
a failure indication without setting errno.  That puts us into an infinite
loop if the previous value happened to be EINTR.  Per report from Brendan
Hill.

Back-patch to 8.2.  We could take it further back, but since this is only
known to be an issue on Windows and we don't support Windows before 8.2,
it does not seem worth the trouble.

Since the int2vector type is intended only for internal use, this patch doesn't
worry about prettifying the error messages, which has the fringe benefit of
avoiding creating additional translatable strings.  For a type intended to be
used by end-users, we would want to do better, but the approach taken here
seems like the correct trade-off for this case.

Caleb Welton

find_inheritance_children().  This is a complete no-op in databases without
any inheritance.  In databases where there are just a few entries in
pg_inherits, it could conceivably be a small loss.  However, in databases with
many inheritance parents, it can be a big win.

and teach ANALYZE to compute such stats for tables that have subclasses.
Per my proposal of yesterday.

autovacuum still needs to be taught about running ANALYZE on parent tables
when their subclasses change, but the feature is useful even without that.

PL/pgSQL function within an exception handler. Make sure we use the right
resource owner when we create the tuplestore to hold returned tuples.

Simplify tuplestore API so that the caller doesn't need to be in the right
memory context when calling tuplestore_put* functions. tuplestore.c
automatically switches to the memory context used when the tuplestore was
created. Tuplesort was already modified like this earlier. This patch also
removes the now useless MemoryContextSwitch calls from callers.

Report by Aleksei on pgsql-bugs on Dec 22 2009. Backpatch to 8.1, like
the previous patch that broke this.

libraries can access them.

The temporary hash tables made by pgstat_collect_oids should be allocated
in a short-term memory context, which is not the default behavior of
hash_create.  Noted while looking through hash_create calls in connection
with Robert Haas' recent complaint.

This is a pre-existing bug, but it doesn't seem important enough to
back-patch.  The hash table is not so large that it would matter unless this
happened many times within a session, which seems quite unlikely.

probably got there via blind copy-and-paste from one of the legitimate
callers, so rearrange and comment that code a bit to make it clearer that
this isn't a necessary prerequisite to hash_create.  Per observation
from Robert Haas.

use in binary upgrades.

Bump catalog version for detection by pg_migrator of new backend API.

Allow enums to be created with zero labels, for use during binary upgrade.

restrict list is not just something to ignore, it's actually grounds to
abandon the optimization entirely.  Per bug #5255 from Matteo Beccati.

variable names.

Modify pg_dump --binary-upgrade and add backend support routines to
support the preservation of pg_type oids when doing a binary upgrade.
This allows user-defined composite types and arrays to be binary
upgraded.

index page split.  This would result in index corruption, or even more likely
an error during WAL replay, if we were unlucky enough to crash during
end-of-recovery cleanup after having completed an incomplete GIST insertion.

Yoichi Hirai

choose an index name the same as it would do for an unnamed index constraint.
(My recent changes to the index naming logic have helped to ensure that this
will be a reasonable choice.)  Per a suggestion from Peter.

A necessary side-effect is to promote CONCURRENTLY to type_func_name_keyword
status, ie, it can't be a table/column/index name anymore unless quoted.
This is not all bad, since we have heard more than once of people typing
CREATE INDEX CONCURRENTLY ON foo (...) and getting a normal index build of
an index named "concurrently", which was not what they wanted.  Now this
syntax will result in a concurrent build of an index with system-chosen
name; which they can rename afterwards if they want something else.

their underlying table columns.  That code was not bright enough to cope with
collision situations (ie, new name conflicts with some other column of the
index).  Since there is no functional reason to do this at all, trying to
upgrade the logic to be bulletproof doesn't seem worth the trouble.

This change means that both the index name and the column names of an index
are set when it's created, and won't be automatically changed when the
underlying table columns are renamed.  Neatnik DBAs are still free to rename
them manually, of course.

CREATE FOREIGN DATA WRAPPER. Arguably it wasn't a bug because the
documentation said that it's passed the catalog ID or zero, but surely
we should provide it when it's known. And there isn't currently any
scenario where it's not known, and I can't imagine having one in the
future either, so better remove the "or zero" escape hatch and always
pass a valid catalog ID. Backpatch to 8.4.

Martin Pihlak

Index expression columns are now named after the FigureColname result for
their expressions, rather than always being "pg_expression_N".  Digits are
appended to this name if needed to make the column name unique within the
index.  (That happens for regular columns too, thus fixing the old problem
that CREATE INDEX fooi ON foo (f1, f1) fails.  Before exclusion indexes
there was no real reason to do such a thing, but now maybe there is.)

Default names for indexes and associated constraints now include the column
names of all their columns, not only the first one as in previous practice.
(Of course, this will be truncated as needed to fit in NAMEDATALEN.  Also,
pkey indexes retain the historical behavior of not naming specific columns
at all.)

An example of the results:

regression=# create table foo (f1 int, f2 text,
regression(# exclude (f1 with =, lower(f2) with =));
NOTICE:  CREATE TABLE / EXCLUDE will create implicit index "foo_f1_lower_exclusion" for table "foo"
CREATE TABLE
regression=# \d foo_f1_lower_exclusion
Index "public.foo_f1_lower_exclusion"
 Column |  Type   | Definition
--------+---------+------------
 f1     | integer | f1
 lower  | text    | lower(f2)
btree, for table "public.foo"

and composite types, which are the only relkinds for which pg_dump support
exists for dumping column comments.  There is no obvious usefulness for
comments on columns of sequences or toast tables; and while comments on
index columns might have some value, it's not worth the risk of compatibility
problems due to possible changes in the algorithm for assigning names to
index columns.  Per discussion.

In consequence, remove now-dead code for copying such comments in CREATE TABLE
LIKE.

Rewrite or adjust various comments for clarity.  Remove one bogus comment that
doesn't reflect what the code actually does.  Improve the description of the
lo_compat_privileges option.

have hard-wired knowledge of the rules for naming index columns.  It can
just look at the actual names in the source index, instead.  Do some minor
formatting cleanup too.

Enabled by recovery_connections = on (default) and forcing archive recovery using a recovery.conf. Recovery processing now emulates the original transactions as they are replayed, providing full locking and MVCC behaviour for read only queries. Recovery must enter consistent state before connections are allowed, so there is a delay, typically short, before connections succeed. Replay of recovering transactions can conflict and in some cases deadlock with queries during recovery; these result in query cancellation after max_standby_delay seconds have expired. Infrastructure changes have minor effects on normal running, though introduce four new types of WAL record.

New test mode "make standbycheck" allows regression tests of static command behaviour on a standby server while in recovery. Typical and extreme dynamic behaviours have been checked via code inspection and manual testing. Few port specific behaviours have been utilised, though primary testing has been on Linux only so far.

This commit is the basic patch. Additional changes will follow in this release to enhance some aspects of behaviour, notably improved handling of conflicts, deadlock detection and query cancellation. Changes to VACUUM FULL are also required.

Simon Riggs, with significant and lengthy review by Heikki Linnakangas, including streamlined redesign of snapshot creation and two-phase commit.

Important contributions from Florian Pflug, Mark Kirkwood, Merlin Moncure, Greg Stark, Gianni Ciolli, Gabriele Bartolini, Hannu Krosing, Robert Haas, Tatsuo Ishii, Hiroyuki Yamada plus support and feedback from many other community members.

Add comments about places where system oids have to be preserved for
binary migration.