Re: [HACKERS] Tsearch Index Size and GiST vs. GIN

On Mon, 2006-11-06 at 13:14 -0600, Richard Whidden wrote:
> Due to popular demand (1 person), I've compared sizes with 90 and 100
> fillfactors, along with using the new GIN index.
>
> Findings were not surprising, except for the GIN indexes, which doubled in
> size.
>

This is how I understand it after reading up on the subject:

GIN inserts many index entries for every record inserted in the table,
and each index entry points to many tuples.

GiST is a one-to-one relationship, one insert causes one index entry to
be inserted and that points to one record.

> After several ALTER/RE INDEXes, here they are:
>
> GiST
> ----
> 8.1 = 94990
> 8.2 FF90 = 106244 relpages (8k)
> 8.2 FF100 = 95049
>
> GIN
> ---
> FF100 = 197702
>
>

Regards,
Jeff Davis