pgsql: Create a type-specific typanalyze routine for tsvector, which

Log Message:
-----------
Create a type-specific typanalyze routine for tsvector, which collects stats
on the most common individual lexemes in place of the mostly-useless default
behavior of counting duplicate tsvectors. Future work: create selectivity
estimation functions that actually do something with these stats.

(Some other things we ought to look at doing: using the Lossy Counting
algorithm in compute_minimal_stats, and using the element-counting idea for
stats on regular arrays.)

Jan Urbanski

Modified Files:
--------------
pgsql/doc/src/sgml:
catalogs.sgml (r2.167 -> r2.168)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/catalogs.sgml?r1=2.167&r2=2.168)
pgsql/src/backend/catalog:
system_views.sql (r1.52 -> r1.53)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/catalog/system_views.sql?r1=1.52&r2=1.53)
pgsql/src/backend/tsearch:
Makefile (r1.6 -> r1.7)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/tsearch/Makefile?r1=1.6&r2=1.7)
pgsql/src/include/catalog:
catversion.h (r1.466 -> r1.467)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/catversion.h?r1=1.466&r2=1.467)
pg_operator.h (r1.160 -> r1.161)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_operator.h?r1=1.160&r2=1.161)
pg_proc.h (r1.504 -> r1.505)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_proc.h?r1=1.504&r2=1.505)
pg_statistic.h (r1.35 -> r1.36)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_statistic.h?r1=1.35&r2=1.36)
pg_type.h (r1.196 -> r1.197)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_type.h?r1=1.196&r2=1.197)
pgsql/src/include/tsearch:
ts_type.h (r1.12 -> r1.13)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/tsearch/ts_type.h?r1=1.12&r2=1.13)
pgsql/src/test/regress/expected:
rules.out (r1.139 -> r1.140)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/rules.out?r1=1.139&r2=1.140)

Added Files:
-----------
pgsql/src/backend/tsearch:
ts_typanalyze.c (r1.1)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/tsearch/ts_typanalyze.c?rev=1.1&content-type=text/x-cvsweb-markup)