< * Allow buffered WAL writes and fsync

before reporting a transaction committed.  Data consistency is still
guaranteed (unlike setting fsync = off), but a crash may lose the effects
of the last few transactions.  Patch by Simon, some editorialization by Tom.

clauses in which one side or the other references both sides of the join
cannot be removed as redundant, because that expression won't have been
constrained below the join.  Per report from Sergey Burladyan.

CVS HEAD does not contain this bug due to EquivalenceClass rewrite, but it
seems wise to include the regression test for it anyway.

simplify a bit further.

never worked because fmgr_security_definer() neglected to pass the fn_expr
information through.  Per report from Viatcheslav Kalinin.

ExecRelationIsTargetRelation() to check if the relation is a target
rel, rather than scanning through the result relation array ourselves.

found by Michael Glaesemann

with the recent patch to log temp file sizes at removal time.  Doesn't seem
worth fixing since it's unused.
In passing, make a few elog messages conform to the message style guide.

named pg_toast_temp_nnn, alongside the pg_temp_nnn schemas used for the temp
tables themselves.  This allows low-level code such as the relcache to
recognize that these tables are indeed temporary, which enables various
optimizations such as not WAL-logging changes and using local rather than
shared buffers for access.  Aside from obvious performance benefits, this
provides a solution to bug #3483, in which other backends unexpectedly held
open file references to temporary tables.  The scheme preserves the property
that TOAST tables are not in any schema that's normally in the search path,
so they don't conflict with user table names.

initdb forced because of changes in system view definitions.

supposed to be included when using mkdir().

a few queries.  Should fix buildfarm failures arising from new,
more aggressive autovac settings.

third party includes (like tcl) that define DLLIMPORT.

Hiroshi Saito

warns about things that aren't wrong.

sugar for PL/PgSQL set-returning functions that want to return the result
of evaluating a query; it should also be more efficient than repeated
RETURN NEXT statements. Based on an earlier patch from Pavel Stehule.

checking whether an IS NULL/IS NOT NULL clause is implied or refuted by
a strict function.  Per example from Dawid Kuroczko.
Backpatch to 8.2 since this is arguably a performance bug.

by dynamically loading the function that's missing from the MingW
headers and library.

and fsync WAL at convenient intervals.  For the moment it just tries to
offload this work from backends, but soon it will be responsible for
guaranteeing a maximum delay before asynchronously-committed transactions
will be flushed to disk.

This is a portion of Simon Riggs' async-commit patch, committed to CVS
separately because a background WAL writer seems like it might be a good idea
independently of the async-commit feature.  I rebased walwriter.c on
bgwriter.c because it seemed like a more appropriate way of handling signals;
while the startup/shutdown logic in postmaster.c is more like autovac because
we want walwriter to quit before we start the shutdown checkpoint.

I/O utilization, per discussion.

While at it, lower the autovacuum vacuum and analyze threshold values to 50
tuples.  It is a bit higher (i.e. more conservative) than what I originally
proposed but much better than the old values for small tables.

whereas in the backend it's been 64 for some time.  Hasn't mattered
because no actual tags exceed 40 bytes, but for consistency they should
be alike.

In passing, change functions that passedin both PGconn and
parts of it to just pass in the PGconn.

Jim Nasby.

against a Unix server, and Windows-specific server-side authentication
using SSPI "negotiate" method (Kerberos or NTLM).

Only builds properly with MSVC for now.

log_min_error_statement is active and there is some problem in logging the
current query string; for example, that it's too long to include in the log
message without running out of memory.  This problem has existed since the
log_min_error_statement feature was introduced.  No doubt the reason it
wasn't detected long ago is that 8.2 is the first release that defaults
log_min_error_statement to less than PANIC level.
Per report from Bill Moran.

Per request from Luca Ferrari.

truncated relation was deleted later in the WAL sequence.  Since replay
normally auto-creates a relation upon its first reference by a WAL log entry,
failure is seen only if the truncate entry happens to be the first reference
after the checkpoint we're restarting from; which is a pretty unusual case but
of course not impossible.  Fix by making truncate entries auto-create like
the other ones do.  Per report and test case from Dharmendra Goyal.

lot more sensible if we check the chunk-output case first.  Not
back-patched since it's just a cosmetic improvement.

when handed an invalidly-encoded pattern.  The previous coding could get
into an infinite loop if pg_mb2wchar_with_len() returned a zero-length
string after we'd tested for nonempty pattern; which is exactly what it
will do if the string consists only of an incomplete multibyte character.
This led to either an out-of-memory error or a backend crash depending
on platform.  Per report from Wiktor Wodecki.

be catching stderr output, and we are not ourselves the
syslogger. Otherwise, go directly to stderr.
Bug noticed by Tom Lane.
Backpatch as far as 8.0.

Minor rearrangements to make a few tests in a more logical order.

a MIN or MAX aggregate call into an indexscan: the initplan is being made at
the current query nesting level and so we shouldn't increment query_level.
Though usually harmless, this mistake could lead to bogus "plan should not
reference subplan's variable" failures on complex queries.  Per bug report
from David Sanchez i Gregori.