Recent commits have removed the various uses it was supporting.  It was a
performance bottleneck, according to bug report #4919 by Lauris Ulmanis; seems
it slowed down user creation after a billion users.

to fix the problem that SetClientEncoding needs to be done before
InitializeClientEncoding, as reported by Zdenek Kotala.  We get at least
the small consolation of being able to remove the bizarre API detail that
had InitPostgres returning whether user is a superuser.

via the "flat files" facility.  This requires making it enough like a backend
to be able to run transactions; it's no longer an "auxiliary process" but
more like the autovacuum worker processes.  Also, its signal handling has
to be brought into line with backends/workers.  In particular, since it
now has to handle procsignal.c processing, the special autovac-launcher-only
signal conditions are moved to SIGUSR2.

Alvaro, with some cleanup from Tom

XID) in checkpoint records.  This eliminates the need to recompute the value
from scratch during database startup, which is one of the two remaining
reasons for the flatfile code to exist.  It should also simplify life for
hot-standby operation.

To avoid bloating the checkpoint records unreasonably, I switched from
tracking the oldest database by name to tracking it by OID.  This turns
out to save cycles in general (everywhere but the warning-generating
paths, which we hardly care about) and also helps us deal with the case
that the oldest database got dropped instead of being vacuumed.  The prior
coding might go for a long time without updating the wrap limit in that case,
which is bad because it might result in a lot of useless autovacuum activity.

from clang static checker, and makes the code more readable anyway IMO.

One of these represents a nontrivial bug (a promptly-leaked palloc), so
backpatch.

Greg Stark

(That flat file is now completely useless, but removal will come later.)

To do this, postpone client authentication into the startup transaction
that's run by InitPostgres.  We still collect the startup packet and do
SSL initialization (if needed) at the same time we did before.  The
AuthenticationTimeout is applied separately to startup packet collection
and the actual authentication cycle.  (This is a bit annoying, since it
means a couple extra syscalls; but the signal handling requirements inside
and outside a transaction are sufficiently different that it seems best
to treat the timeouts as completely independent.)

A small security disadvantage is that if the given database name is invalid,
this will be reported to the client before any authentication happens.
We could work around that by connecting to database "postgres" instead,
but consensus seems to be that it's not worth introducing such surprising
behavior.

Processing of all command-line switches and GUC options received from the
client is now postponed until after authentication.  This means that
PostAuthDelay is much less useful than it used to be --- if you need to
investigate problems during InitPostgres you'll have to set PreAuthDelay
instead.  However, allowing an unauthenticated user to set any GUC options
whatever seems a bit too risky, so we'll live with that.

now.

source directory even for out-of-tree builds.  They are now alsl built in
the build tree.  This should be more convenient for certain developers'
workflows, and shouldn't really break anything else.

PostgresMain switch.  In point of fact, FrontendProtocol is already set
in a backend process, since ProcessStartupPacket() is executed inside
the backend --- it hasn't been run by the postmaster for many years.
And if it were, we'd still certainly want FrontendProtocol to be set before
we get as far as PostgresMain, so that startup errors get reported in the
right protocol.

-v might have some future use in standalone backends, so I didn't go so
far as to remove the switch outright.

Also, initialize FrontendProtocol to 0 not PG_PROTOCOL_LATEST.  The only
likely result of presetting it like that is to mask failure-to-set-it
mistakes.

change ... it's got to return true.

so that their elements are always taken as simple expressions over the
query's input columns.  It originally seemed like a good idea to make them
act exactly like GROUP BY and ORDER BY, right down to the SQL92-era behavior
of accepting output column names or numbers.  However, that was not such a
great idea, for two reasons:

1. It permits circular references, as exhibited in bug #5018: the output
column could be the one containing the window function itself.  (We actually
had a regression test case illustrating this, but nobody thought twice about
how confusing that would be.)

2. It doesn't seem like a good idea for, eg, "lead(foo) OVER (ORDER BY foo)"
to potentially use two completely different meanings for "foo".

Accordingly, narrow down the behavior of window clauses to use only the
SQL99-compliant interpretation that the expressions are simple expressions.

Jan Urbański

Per bug #5016, although I think the MSVC build scripts may need a similar fix.

In the original coding, setting a single reloption would cause default
values to be used for all the other reloptions.  This is a problem
particularly for autovacuum reloptions.

Itagaki Takahiro

script.

To do this, have pg_ctl pass down its parent shell's PID in an environment
variable PG_GRANDPARENT_PID, and teach CreateLockFile() to disregard that PID
as a false match if it finds it in postmaster.pid.  This allows us to cope
with one level of postgres-owned shell process even with pg_ctl in the way,
so it's just as safe as starting the postmaster directly.  You still have to
be careful about how you write the initscript though.

Adjust the comments in contrib/start-scripts/ to not deprecate use of
pg_ctl.  Also, fix the ROTATELOGS option in the OSX script, which was
indulging in exactly the sort of unsafe coding that renders this fix
pointless :-(.  A pipe inside the "sudo" will probably result in more
than one postgres-owned process hanging around.

with the sed rules.

static checker.  Paul Matthews

was incorrectly initialized with timeline ID 0. That rendered the WAL page
unrecoverable, making a subsequent archive recovery stop at that point.
ThisTimeLineID needs to be initialized before calling AdvanceXLInsertBuffer().

This fixes bug #5011 reported by James Bardin. Backpatch to 8.4, as the bug
was introduced by the changes to use of bgwriter for writing the
end-of-archive-recovery checkpoint. Patch by Tom Lane.

Update install-sh to that from Autoconf 2.63, plus our Darwin-specific
changes (which I simplified a bit).  install-sh is now able to install
multiple files in one run, so we could simplify our makefiles sometime.

install-sh also now has a -d option to create directories, so we don't need
mkinstalldirs anymore.

Use AC_PROG_MKDIR_P in configure.in, so we can use mkdir -p when available
instead of install-sh -d.  For consistency with the rest of the world,
the corresponding make variable has been renamed from $(mkinstalldirs) to
$(MKDIR_P).

Extract the "while creating return value" and "while modifying trigger
row" parts of some error messages into another layer of error context.
This will simplify the upcoming patch to improve data type support, but
it can stand on its own.

Switch the implementation of the plan and result types to generic attribute
management, as described at <http://docs.python.org/extending/newtypes.html>.
This modernizes and simplifies the code a bit and prepares for Python 3.1,
where the old way doesn't work anymore.

This changes a bunch of incidentially used constructs in the PL/Python
regression tests to equivalent constructs in cases where Python 3 no longer
supports the old syntax.  Support for older Python versions is unchanged.

Instead of sending stdout/stderr to /dev/null after forking away from the
terminal, send them to postmaster.log within the data directory.  Since
this opens the door to indefinite logfile bloat, recommend even more
strongly that log output be redirected when using silent_mode.

Move the postmaster's initial calls of load_hba() and load_ident() down
to after we have started the log collector, if we are going to.  This
is so that errors reported by them will appear in the "usual" place.

Reclassify silent_mode as a LOGGING_WHERE, not LOGGING_WHEN, parameter,
since it's got absolutely nothing to do with the latter category.

In passing, fix some obsolete references to -S ... this option hasn't
had that switch letter for a long time.

Back-patch to 8.4, since as of 8.4 load_hba() and load_ident() are more
picky (and thus more likely to fail) than they used to be.  This entire
change was driven by a complaint about those errors disappearing into
the bit bucket.

for a dead_end child, because we didn't AssignPostmasterChildSlot.

This causes problems when the system load is high, per report from Zdenek
Kotala in <1250860954.1239.114.camel@localhost>; instead of calling kill
directly, have the signal handler set a flag which is checked in ServerLoop.
This way, the handler can return before being called again by a subsequent
signal sent from the autovacuum launcher.  Also, increase the sleep in the
launcher in this failure path to 1 second.

Backpatch to 8.3, which is when the signalling between autovacuum
launcher/postmaster was introduced.

Also, add a couple of ReleasePostmasterChildSlot calls in error paths; this
part backpatched to 8.4 which is when the child slot stuff was introduced.

#include the version of history.h that is in the same directory as the
readline.h we are using.  This avoids problems in some scenarios where both
readline and editline are installed.  Report and patch by Zdenek Kotala.

Per Grzegorz Jaskiewicz report from LLVM static checker

renders useless one of the few test methodologies we have for WAL replay,
which is to intentionally crash the system just after completing the
regression tests and see if it recovers to the expected database state.
The reason is that DROP TABLESPACE forces a checkpoint, so there's essentially
no WAL available for replay after the tests complete.

"all tuples visible" flag in heap page headers.  The flag update *must*
be applied before calling XLogInsert, but heap_update and the tuple
moving routines in VACUUM FULL were ignoring this rule.  A crash and
replay could therefore leave the flag incorrectly set, causing rows
to appear visible in seqscans when they should not be.  This might explain
recent reports of data corruption from Jeff Ross and others.

In passing, do a bit of editorialization on comments in visibilitymap.c.

or previously truncated in the current (sub)transaction.  This is safe since
if the (sub)transaction later rolls back, we'd just discard the rel's current
physical file anyway.  This avoids unreasonable growth in the number of
transient files when a relation is repeatedly truncated.  Per a performance
gripe a couple weeks ago from Todd Cook.

values before they get passed to the index access method.  This avoids
repeated detoastings that will otherwise ensue as the comparison value
is examined by various index support functions.  We have seen a couple of
reports of cases where repeated detoastings result in an order-of-magnitude
slowdown, so it seems worth adding a bit of extra logic to prevent this.

I had previously proposed trying to avoid duplicate detoastings in general,
but this fix takes care of what seems the most important case in practice
with very little effort or risk.

Back-patch to 8.4 so that the PostGIS folk won't have to wait a year to
have this fix in a production release.  (The issue exists further back,
of course, but the code's diverged enough to make backpatching further a
higher-risk action.  Also it appears that the possible gains may be limited
in prior releases because of different handling of lossy operators.)

Peter did that without fixing this ...

per Pavel Stehule