functionality, but I still need to make another pass looking at places
that incidentally use arrays (such as ACL manipulation) to make sure they
are null-safe. Contrib needs work too.
I have not changed the behaviors that are still under discussion about
array comparison and what to do with lower bounds.
1 Comparison operation for tsquery
2 Btree index on tsquery
3 numnode(tsquery) - returns 'length' of tsquery
4 tsquery @ tsquery, tsquery ~ tsquery - contains, contained for tsquery.
Note: They don't gurantee exact result, only MAY BE, so it
useful only for speed up rewrite functions
5 GiST index support for @,~
6 rewrite():
select rewrite(orig, what, to);
select rewrite(ARRAY[orig, what, to]) from tsquery_table;
select rewrite(orig, 'select what, to from tsquery_table;');
7 significantly improve cover algorithm