Since PostgreSQL 9.0, we've emitted a warning message when an operator
named => is created, because the SQL standard now reserves that token
for another use.  But we've also shipped such an operator with hstore.
Use of the function hstore(text, text) has been recommended in
preference to =>(text, text).  Per discussion, it's now time to take
the next step and stop shipping the operator.  This will allow us to
prohibit the use of => as an operator name in a future release if and
when we wish to support the SQL standard use of this token.

The release notes should mention this incompatibility.

Patch by me, reviewed by David Wheeler, Dimitri Fontaine and Tom Lane.

README.links to explain xref properly.

Block elements with verbatim formatting (literallayout, programlisting,
screen, synopsis) should be aligned at column 0 independent of the surrounding
SGML, because whitespace is significant, and indenting them creates erratic
whitespace in the output.  The CSS stylesheets already take care of indenting
the output.

Assorted markup improvements to go along with it.

David Wheeler, with one small correction by me.

In HEAD, emit a warning when an operator named => is defined.
In both HEAD and the backbranches (except in 8.2, where contrib
modules do not have documentation), document that hstore's text =>
text operator may be removed in a future release, and encourage the
use of the hstore(text, text) function instead.  This function only
exists in HEAD (previously, it was called tconvert), so backpatch
it back to 8.2, when hstore was added.  Per discussion.

This is not yet in any released version, so we still have the option to
change the name.  We may want to reserve the token => in a future release.

This is not yet in any released version, so we still have the option to
backtrack.  Instead, document hstore(text[], text[]).  Per discussion.

(hope I got 'em all).  Per discussion, this release will be 9.0 not 8.5.

David E. Wheeler

Update hstore docs, mostly word-smithing.

David E. Wheeler

Remove the 64K limit on the lengths of keys and values within an hstore.
(This changes the on-disk format, but the old format can still be read.)
Add support for btree/hash opclasses for hstore --- this is not so much
for actual indexing purposes as to allow use of GROUP BY, DISTINCT, etc.
Add various other new functions and operators.

Andrew Gierth

data structure, rather than silently truncating them.  Andrew Gierth

Fix lots of bad markup, bad English, bad explanations.

This commit covers only about half the contrib modules, but I grow weary...

or will never be converted.