Also look at GIN. Although the documentation claims it is typically larger than GIST, in certain cases (a small lexeme set, which is not true in the general ca

Also look at GIN. Although the documentation claims it is typically larger than GIST, in certain cases (a small lexeme set, which is not true in the general case full-text) it can seem to be smaller and faster. Mostly this can be true over constrained symbolic domains (which is a lot of computing also). We've recently replaced a GIST index with a GIN one and got a lot more than the 'rule of thumb' speedup. More like an order of magnitude. Or two. So much, that Tom Lane suggested we might have stumbled onto a bug in GIST, so we'll see.