O_DIRECT behavior.

opposed to O_DSYNC.

complex quoting, e.g. -t and -n.

Including collation in the behavior of that function promotes a world view
we do not want.  Moreover, it was producing the wrong behavior for pg_dump
anyway: what we want is to dump a COLLATE clause on attributes whose
attcollation is different from the underlying type, and likewise for
domains, and the function cannot do that for us.  Doing it the hard way
in pg_dump is a bit more tedious but produces more correct output.

In passing, fix initdb so that the initial entry in pg_collation is
properly pinned.  It was droppable before :-(

It's not a good idea to kill the postmaster just because someone muffs
this, and it's not consistent with what we do for other, similar GUCs.

Fujii Masao, with a bit more hacking by me

Fujii Masao

SyncRepRequested() must check not only the value of the
synchronous_replication GUC but also whether max_wal_senders > 0.
Otherwise, we might end up waiting for sync rep even when there's no
possibility of a standby ever managing to connect.  There are some
existing cross-checks to prevent this, but they're not quite sufficient:
the user can start the server with max_wal_senders=0,
synchronous_standby_names='', and synchronous_replication=off and then
subsequent make synchronous_standby_names not empty using pg_ctl reload,
and then SET synchronous_standby=on, leading to an indefinite hang.

Along the way, rename the global variable for the synchronous_replication
GUC to match the name of the GUC itself, for clarity.

Report by Fujii Masao, though I didn't use his patch.

In earlier versions of the sync rep patch, waiters removed themselves from
the queue, but now walsender removes them before doing the wakeup.

Report by Fujii Masao.

Fujii Masao, with a bit of additional wordsmithing by me.

Fujii Masao

Fujii Masao

Fujii Masao

Tom Lane pointed out that it was giving a warning: "-s option given but
default rule can be matched". That was because there was no rule to handle
newline in a quoted string. I made that throw an error.

Also, line number tracking was broken, giving incorrect line number on
error. Fixed that too.

At least two recent commits have apparently imagined that a comment in
a Makefile stating that something would be included in the distribution
tarball was sufficient to make it so.  They hadn't bothered to hook
into the upper maintainer-clean targets either.  Per bug #5923 from
Charles Johnson, in which it emerged that the 9.1alpha4 tarballs are
short a few files that should be there.

The initial collations patch treated a COLLATE spec as part of a TypeName,
following what can only be described as brain fade on the part of the SQL
committee.  It's a lot more reasonable to treat COLLATE as a syntactically
separate object, so that it can be added in only the productions where it
actually belongs, rather than needing to reject it in a boatload of places
where it doesn't belong (something the original patch mostly failed to do).
In addition this change lets us meet the spec's requirement to allow
COLLATE anywhere in the clauses of a ColumnDef, and it avoids unfriendly
behavior for constructs such as "foo::type COLLATE collation".

To do this, pull collation information out of TypeName and put it in
ColumnDef instead, thus reverting most of the collation-related changes in
parse_type.c's API.  I made one additional structural change, which was to
use a ColumnDef as an intermediate node in AT_AlterColumnType AlterTableCmd
nodes.  This provides enough room to get rid of the "transform" wart in
AlterTableCmd too, since the ColumnDef can carry the USING expression
easily enough.

Also fix some other minor bugs that have crept in in the same areas,
like failure to copy recently-added fields of ColumnDef in copyfuncs.c.

While at it, document the formerly secret ability to specify a collation
in ALTER TABLE ALTER COLUMN TYPE, ALTER TYPE ADD ATTRIBUTE, and
ALTER TYPE ALTER ATTRIBUTE TYPE; and correct some misstatements about
what the default collation selection will be when COLLATE is omitted.

BTW, the three-parameter form of format_type() should go away too,
since it just contributes to the confusion in this area; but I'll do
that in a separate patch.

background processing.

Formerly, any member of a role could change the role's comment, as of
course could superusers; but holders of CREATEROLE privilege could not,
unless they were also members.  This led to the odd situation that a
CREATEROLE holder could create a role but then could not comment on it.
It also seems a bit dubious to let an unprivileged user change his own
comment, let alone those of group roles he belongs to.  So, change the
rule to be "you must be superuser to comment on a superuser role, or
hold CREATEROLE to comment on non-superuser roles".  This is the same
as the privilege check for creating/dropping roles, and thus fits much
better with the rule for other object types, namely that only the owner
of an object can comment on it.

In passing, clean up the documentation for COMMENT a little bit.

Per complaint from Owen Jacobson and subsequent discussion.

gabrielle <gorthx@gmail.com>

I made a pass over this to familiarize myself with the feature, and found
some things that could be improved.

In addition to the

all-foo-recurse: all-bar-recurse

dependencies that constraint the order of the rule execution, we need

install-foo-recurse: install-bar-recurse

dependencies in case one runs make install without a make all first,
as some people apparently do.

We really need an automated check for this ... and did VALIDATE really
need to become a keyword at all, rather than picking some other syntax
using existing keywords?

race condition where SummarizeOldestCommittedSxact() is called even though
another backend already cleared out all finished sxact entries. That's OK,
RegisterSerializableTransactionInt() can just retry getting a news xact
slot from the available-list when that happens.

Reported by YAMAMOTO Takashi, bug #5918.

contains newly-inserted tuples that according to our OldestXmin are not
yet visible to everyone. The value returned by GetOldestXmin() is conservative,
and it can move backwards on repeated calls, so if we see that contradiction
between the PD_ALL_VISIBLE flag and status of tuples on the page, we have to
assume it's because an earlier vacuum calculated a higher OldestXmin value,
and all the tuples really are visible to everyone.

We have received several reports of this bug, with the "PD_ALL_VISIBLE flag
was incorrectly set in relation ..." warning appearing in logs. We were
finally able to hunt it down with David Gould's help to run extra diagnostics
in an environment where this happened frequently.

Also reword the warning, per Robert Haas' suggestion, to not imply that the
PD_ALL_VISIBLE flag is necessarily at fault, as it might also be a symptom
of corruption on a tuple header.

Backpatch to 8.4, where the PD_ALL_VISIBLE flag was introduced.