When starting either an old or new postmaster, force it to place its Unix
socket in the current directory. This makes it even harder for accidental
connections to occur during pg_upgrade, and also works around some
scenarios where the default socket location isn't usable. (For example,
if the default location is something other than "/tmp", it might not exist
during "make check".)
When checking an already-running old postmaster, find out its actual socket
directory location from postmaster.pid, if possible. This dodges problems
with an old postmaster having a configured location different from the
default built into pg_upgrade's libpq. We can't find that out if the old
postmaster is pre-9.1, so also document how to cope with such scenarios
manually.
In support of this, centralize handling of the connection-related command
line options passed to pg_upgrade's subsidiary programs, such as pg_dump.
This should make future changes easier.
Bruce Momjian and Tom Lane
Extend xfunc.sgml's discussion of set-returning functions to show an
example of using LATERAL, and recommend that over putting SRFs in the
targetlist.
In passing, reword func.sgml's section on set-returning functions so
that it doesn't claim that the functions listed therein are all the
built-in set-returning functions. That hasn't been true for a long
time, and trying to make it so doesn't seem like it would be an
improvement. (Perhaps we should rename that section?)
Both per suggestions from Merlin Moncure.
Only warn when connecting to a newer server, since connecting to older
servers works pretty well nowadays. Also update the documentation a
little about current psql/server compatibility expectations.
The existing documentation in Linux Memory Overcommit seemed to
assume that PostgreSQL itself could never be the problem, or at
least it didn't tell you what to do about it.
Per discussion with Craig Ringer and Kevin Grittner.
This is so that these sections will have stable HTML tags that one can
link to, rather than things like "AEN1902". Perhaps we should mount a
campaign to do this everywhere, but I've found myself pointing at
syntax.sgml subsections often enough to be sure it's useful here.
As of 9.2, constraint exclusion should work okay with prepared statements:
the planner will try custom plans with actual values of the parameters,
and observe that they are a lot cheaper than the generic plan, and thus
never fall back to using the generic plan. Noted by Tatsuhito Kasahara.
The docs claimed that this mode only waits for the standby to receive WAL
data, but actually it waits for the data to be written out to the standby's
OS; which is a pretty significant difference because it removes the risk of
crash of the walreceiver process.
