沈一枫 wrote:
> the basic structures to implement the index is :
>
> 1.B- tree or the alike.
>
> 2.hash structures
>
Not only. R-tree, SS-tree, kd-tree, RD-tree etc
> So the question is arise:In the tsearch2 model, I thought the general
> access method is GiST tree, a tree this like B- tree.
>
> But when I saw the crc32_sz() function to hash the tsvector type, the
> index implementation again turns to be a hash list,
>
>
> which is the right? hash structures or tree like B tree to implment the
> index?
None of them. Tsearch2 use signature tree, which is very close to RD-tree.
GiST (its realisation in pgsql) can store tree likes to R-tree or B-tree (with
some limitations, such as now pgsql's GiST doesn't support order).
--
Teodor Sigaev E-mail: teodor@sigaev.ru
WWW: http://www.sigaev.ru/