Re: Queryplan within FTS/GIN index -search.

"Kevin Grittner" <Kevin.Grittner@wicourts.gov> writes:
> Perhaps I'm missing something.  My point was that there are words
> which are too common to be useful for index searches, yet uncommon
> enough to usefully limit the results.  These words could typically
> benefit from tsearch2 style parsing and dictionaries; so declaring
> them as stop words would be bad from a functional perspective, yet
> searching an index for them would be bad from a performance
> perspective.

Right, but the original complaint in this thread was that a GIN index is
slow about searching for very common terms.  The answer to that clearly
is to not index common terms, rather than worry about making the case
a bit faster.

It may well be that Jesper's identified a place where the GIN code could
be improved --- it seems like having the top-level search logic be more
aware of the AND/OR structure of queries would be useful.  But the
particular example shown here doesn't make a very good case for that,
because it's hard to tell how much of a penalty would be taken in more
realistic examples.

            regards, tom lane