Re: rtree/gist index taking enormous amount of space in 8.2.3

[Craig James <craig_james(at)emolecules(dot)com>]

Dolafi, Tom wrote:
> min(fmin) |   max(fmin)    |    avg(fmin)      
>    1      |   55296469     |    11423945     
>
> min(fmax) |   max(fmax)    |    avg(fmax)
>   18      |   55553288     |    11424491
>
> There are 5,704,211 rows in the table.

When you're looking for weird index problems, it's more interesting to know if there are certain numbers that occur a LOT.  From your statistics above, each number occurs about 10 times in the table.  But do some particular numbers occur thousands, or even millions, of times?

Here is a query that will print a list of the highest-occuring values.  You might expect a few occurances of 20, and maybe 30, but if you have thousands or millions of occurances of certain numbers, then that can screw up an index.

  select fmax, c from
   (select fmax, count(fmax) as c from your_table group by fmax) as foo
  where c > 3 order by c desc;

Craig