databases, per gripe from hubert depesz lubaczewski.  Patch from
Simon Riggs.

< * Reduce XID consumption of read-only queries
<
<    http://archives.postgresql.org/pgsql-hackers/2007-08/msg00516.php
<
<
> * -Reduce XID consumption of read-only queries

rows will normally never obtain an XID at all.  We already did things this way
for subtransactions, but this patch extends the concept to top-level
transactions.  In applications where there are lots of short read-only
transactions, this should improve performance noticeably; not so much from
removal of the actual XID-assignments, as from reduction of overhead that's
driven by the rate of XID consumption.  We add a concept of a "virtual
transaction ID" so that active transactions can be uniquely identified even
if they don't have a regular XID.  This is a much lighter-weight concept:
uniqueness of VXIDs is only guaranteed over the short term, and no on-disk
record is made about them.

Florian Pflug, with some editorialization by Tom.

Random other wordsmithing.

(Actually, it works as a plain statement too, but I didn't document that
because it seems a bit useless.)  Unify VariableResetStmt with
VariableSetStmt, and clean up some ancient cruft in the representation of
same.

There are still some loose ends: I didn't do anything about the SET FROM
CURRENT idea yet, and it's not real clear whether we are happy with the
interaction of SET LOCAL with function-local settings.  The documentation
is a bit spartan, too.

Some alignment cleanups.

tool chains).

"index" entries for GIN/GiST.

entire section, per Peter.

entries in textsearch.sgml.

older SGML toolchains.

to be more logical.

the main documentation, out of its own text search chapter.

section makes a little more sense.

corrections.  Not sure why these were not in CVS.  Researching.

fixes.  Not sure how these weren't comitted before.

but just hardwire the specified timezone database path into the executable.
Per discussion, this avoids some packaging disadvantages of using a
symlink.

minor rewording, some markup fixups.  Lots left to do here ...

Transactional Information Systems by Gerhard Weikum, Kaufmann

This prevents needing to do complex and poorly-defined updates of the
mapping table if the new parser has different token types than the old.
Per discussion.

syncing the existing docs with the final syntax decisions.

init options of the template as top-level options in the syntax.  This also
makes ALTER a bit easier to use, since options can be replaced individually.
I also made these statements verify that the tmplinit method will accept
the new settings before they get stored; in the original coding you didn't
find out about mistakes until the dictionary got invoked.

Under the hood, init methods now get options as a List of DefElem instead
of a raw text string --- that lets tsearch use existing options-pushing code
instead of duplicating functionality.