This makes merging and diffing with upstream easier. There were so many
GPDB-added GUCs in guc.c that "git merge" didn't handle it very well, and
you easily got merge conflicts that were error-prone to fix manually.

I kept a few GUCs in guc.c that are not present in REL8_2_0, because they
were backported from later PostgreSQL versions, rather than being
completely GPDB-specific.

Clean up the diff between guc.c and upstream, by removing unnecessary
includes, reordering a few GUCs to match upstream better, and similar
cosmetic changes.

I had to move MAX_KILOBYTES from guc.c to guc_tables.h, because guc_gp.c
needs it too. I also had to export assign_msglvl() function from guc.c, so
that it can be called from other assign_* functions from guc_gp.c. And I
had to add the code to process the ConfigureNames*_gp arrays in addition
to the upstream ones. These things increase the diff against upstream, but
not by too much, IMHO. I also copy-pasted constants like MS_PER_S and
KB_PER_MB, which seems safe as those are natural constants, and should
never change.

Previously the  classpath was relative
to $GPHOME/lib/postgresql/java/

The implication of this is that in order to reference jars outside
of this directory the classpath will look like ../../../ etc.

This patch retains that behaviour but adds the ability to use absolute
paths.

For security purposes changing the classpath can only be done by a
super user or set in postgresql.conf

Also, rephrase the message you get from enable_xform() etc. functions, if
the server has been built without ORCA.

Add alternative expected output files to make the regression tests pass
without --enable-orca.

Exchanging a default partition is currently not allowed because there is
no validation on the data being exchanged. This commit add a GUC to
enable this if the user chooses to do so.

recent discussion in which majority opinion was that this is a more
widely useful setting than the previous default of PANIC.

in PITR scenarios.  We now WAL-log the replacement of old XIDs with
FrozenTransactionId, so that such replacement is guaranteed to propagate to
PITR slave databases.  Also, rather than relying on hint-bit updates to be
preserved, pg_clog is not truncated until all instances of an XID are known to
have been replaced by FrozenTransactionId.  Add new GUC variables and
pg_autovacuum columns to allow management of the freezing policy, so that
users can trade off the size of pg_clog against the amount of freezing work
done.  Revise the already-existing code that forces autovacuum of tables
approaching the wraparound point to make it more bulletproof; also, revise the
autovacuum logic so that anti-wraparound vacuuming is done per-table rather
than per-database.  initdb forced because of changes in pg_class, pg_database,
and pg_autovacuum catalogs.  Heikki Linnakangas, Simon Riggs, and Tom Lane.

from Magnus that MSVC complains about this.

max_stack_depth is not set to an unsafe value.

This commit also provides configure-time checking for <sys/resource.h>,
and cleans up some perhaps-unportable code associated with use of that
include file and getrlimit().

postgresql.conf.

- shared_buffers = 32000kB => 32MB
- temp_buffers = 8000kB => 8MB
- wal_buffers = 8 => 64kB

The code of initdb was a bit modified to write MB-unit values.
Values greater than 8000kB are rounded out to MB.

GUC_UNIT_XBLOCKS is added for wal_buffers. It is like GUC_UNIT_BLOCKS,
but uses XLOG_BLCKSZ instead of BLCKSZ.

Also, I cleaned up the test of GUC_UNIT_* flags in preparation to
add more unit flags in less bits.

ITAGAKI Takahiro

return true for exactly the characters treated as whitespace by their flex
scanners.  Per report from Victor Snezhko and subsequent investigation.

Also fix a passel of unsafe usages of <ctype.h> functions, that is, ye olde
char-vs-unsigned-char issue.  I won't miss <ctype.h> when we are finally
able to stop using it.

match what SHOW displays as default value, to make the user experience
uniform.

--- was part of autovacuum default 'on' patch that was reverted, but we
want this part.

Peter Eisentraut

possible autovacuum use.

overhead for every connection, per Tom.

"server_version" but uses the handy PG_VERSION_NUM which allows apps to
do things like if ($version >= 80200) without having to parse apart the
value of server_version themselves.

Greg Sabino Mullane greg@turnstep.com

Threshold and scale factor are cut in half for more aggressive behavior.

than N seconds apart.  This allows a simple, if not very high performance,
means of guaranteeing that a PITR archive is no more than N seconds behind
real time.  Also make pg_current_xlog_location return the WAL Write pointer,
add pg_current_xlog_insert_location to return the Insert pointer, and fix
pg_xlogfile_name_offset to return its results as a two-element record instead
of a smashed-together string, as per recent discussion.

Simon Riggs

such as debugging and performance measurement.  This consists of two features:
a table of "rendezvous variables" that allows separately-loaded shared
libraries to communicate, and a new GUC setting "local_preload_libraries"
that allows libraries to be loaded into specific sessions without explicit
cooperation from the client application.  To make local_preload_libraries
as flexible as possible, we do not restrict its use to superusers; instead,
it is restricted to load only libraries stored in $libdir/plugins/.  The
existing LOAD command has also been modified to allow non-superusers to
LOAD libraries stored in this directory.

This patch also renames the existing GUC variable preload_libraries to
shared_preload_libraries (after a suggestion by Simon Riggs) and does some
code refactoring in dfmgr.c to improve clarity.

Korry Douglas, with a little help from Tom Lane.

values, due to concern about the patch.

default values.

failures.

default values.  Was causing regression failures.

defaults.

Zdenek Kotala

The main reason for refactoring was that set_config_option() was too
overloaded function and its behavior did not consistent. Old version of
set_config_function hides some messages. For example if you type:

tcp_port = 5432.1

then old implementation ignore this error without any message to log
file in the signal context (configuration reload). Main problem was that
semantic analysis of postgresql.conf is not perform in the
ProcessConfigFile function, but in the set_config_options *after*
context check. This skipped check for variables with PG_POSTMASTER
context. There was request from Joachim Wieland to add more messages
about ignored changes in the config file as well.

Zdenek Kotala

it's handled just about like timezone; in particular, don't try
to read anything during InitializeGUCOptions.  Should solve current
startup failure on Windows, and avoid wasted cycles if a nondefault
setting is specified in postgresql.conf too.  Possibly we need to
think about a more general solution for handling 'expensive to set'
GUC options.

not "unset".  An "unset" state doesn't really exist; all variables behave
like an empty string value if the string being pointed to has not been
initialized.

upcoming units feature.

configuration files that can be altered by a DBA.  The australian_timezones
GUC setting disappears, replaced by a timezone_abbreviations setting (set this
to 'Australia' to get the effect of australian_timezones).  The list of zone
names defined by default has undergone a bit of cleanup, too.  Documentation
still needs some work --- in particular, should we fix Table B-4, or just get
rid of it?  Joachim Wieland, with some editorializing by moi.

Strip unused include files out unused include files, and add needed
includes to C files.

The next step is to remove unused include files in C files.