There are assorted situations wherein PQconnectPoll() will abandon a
connection attempt and try again with different parameters (eg, SSL versus
not SSL).  However, the code forgot to discard any pending data in libpq's
I/O buffers when doing this.  In at least one case (server returns E
message during SSL negotiation), there is unread input data which bollixes
the next connection attempt.  I have not checked to see whether this is
possible in the other cases where we close the socket and retry, but it
seems like a matter of good defensive programming to add explicit
buffer-flushing code to all of them.

This is one of several issues exposed by Daniel Farina's report of
misbehavior after a server-side fork failure.

This has been wrong since forever, so back-patch to all supported branches.

include dependencies.

Modify pgcompinclude to skip a common fcinfo error.

In PostgreSQL, this is included in the SELECT privilege, so show YES
or NO depending on whether SELECT is granted.

remove from local *.h files.

Per suggestion from Alvaro.

.h include files before .c files.

Mark some includes as needed to be ignored by pgrminclude.

tsvector_concat() allocated its result workspace using the "conservative"
estimate of the sum of the two input tsvectors' sizes.  Unfortunately that
wasn't so conservative as all that, because it supposed that the number of
pad bytes required could not grow.  Which it can, as per test case from
Jesper Krogh, if there's a mix of lexemes with positions and lexemes
without them in the input data.  The fix is to assume that we might add
a not-previously-present pad byte for each and every lexeme in the two
inputs; which really is conservative, but it doesn't seem worthwhile to
try to be more precise.

This is an aboriginal bug in tsvector_concat, so back-patch to all
versions containing it.

These changes allow backtick command evaluation and psql variable
interpolation to happen on substrings of a single meta-command argument.
Formerly, no such evaluations happened at all if the backtick or colon
wasn't the first character of the argument, and we considered an argument
completed as soon as we'd processed one backtick, variable reference, or
quoted substring.  A string like 'FOO'BAR was thus taken as two arguments
not one, not exactly what one would expect.  In the new coding, an argument
is considered terminated only by unquoted whitespace or backslash.

Also, clean up a bunch of omissions, infelicities and outright errors in
the psql documentation of variables and metacommand argument syntax.

As in the backend, the implementation actually accepts any non-ASCII
character, but we only document that you can use letters.

flex puts lex.backup in the current working directory regardless
of where the input and output are.

#if/#ifdefs.

introduced recently when trying to filter out temp tables.

Backpatch to 9.0 and 9.1.

This was deemed unnecessary initially but in later discussion it was
agreed otherwise.

Original file from Kevin Grittner, allegedly from Dan Ports.
I had to clean up whitespace a bit per changes from Heikki.

Per discussion, we should enforce the policy of "no backtracking" in these
performance-sensitive scanners.

Per previous experimentation, backtracking slows down lexing performance
significantly (by about a third).  It's usually pretty easy to avoid, just
need to have rules that accept an incomplete construct and do whatever the
lexer would have done otherwise.

The backtracking was introduced by the patch that added quoted variable
substitution.  Back-patch to 9.0 where that was added.

This is recommended in the flex manual, and there seems no good reason
not to use it everywhere.

Rather than dumping out the raw array as PostgreSQL represents it
internally, we now print it out in a format similar to the one in
which the user input it, which seems a lot more user friendly.

Shigeru Hanada

Shigeru Hanada

This makes it slightly more clear that '*' is not part of the default
value, in case that wasn't obvious.

As requested by Dougal Sutherland.

Noted by Hitoshi Harada.

This is mainly to prove that the NaN fix actually works cross-platform.

For an empty index, the pgstatindex() function would compute 0.0/0.0 for
its avg_leaf_density and leaf_fragmentation outputs.  On machines that
follow the IEEE float arithmetic standard with any care, that results in
a NaN.  However, per report from Rushabh Lathia, Microsoft couldn't
manage to get this right, so you'd get a bizarre error on Windows.

Fix by forcing the results to be NaN explicitly, rather than relying on
the division operator to give that or the snprintf function to print it
correctly.  I have some doubts that this is really the most useful
definition, but it seems better to remain backward-compatible with
those platforms for which the behavior wasn't completely broken.

Back-patch to 8.2, since the code is like that in all current releases.

With these changes, the isolation tests pass again on isolation levels
serializable and repeatable read.

Author: Kevin Grittner

The previous coding resulted in contrib modules unintentionally overriding
the use of CONTRIB_TESTDB.  There seems no particularly good reason to
allow that (after all, the makefile can set CONTRIB_TESTDB if that's really
what it intends).

In passing, document REGRESS_OPTS where the other pgxs.mk options are
documented.

Back-patch to 9.1 --- in prior versions, there were no cases of contrib
modules setting REGRESS_OPTS without including the --dbname switch, so
while the coding was fragile there was no actual bug.