Re: Gist indexing performance with cidr types

On Wed, 26 Aug 2015, Jeff Janes wrote:

> Any chance you can share the actual underlying data?

Sure. I added a snapshot to the repo:
https://github.com/job/irrexplorer/blob/master/data/irrexplorer_dump.sql.gz?raw=true

> I noticed it wasn't on github, but is that because it is proprietary, or
> just because you don't think it is interesting?

I hoped it wouldn't be this complicated :-).

BGP and IRR data is (mostly) public, but it changes constantly, so there
is little sense in putting in the repo, as it is not the authorative
source (we have a script to boostrap with instead).

> If you loop over the 732 rows yourself, issuing the simple query against each retrieved constant value:
>
> explain (analyze,buffers) select routes.route from routes where route && $1
>
> Does each one take about the same amount of time, or are there some outlier values which take much more time than the others?

I wrote a small script to try this out. It queries for each route 20 times
to try and suppress the worst noise. I've sorted the results by time and
put it here: https://gist.github.com/htj/1817883f92a9cb17a4f8
(ignore the ntp timing issue causing a negative value)

Some observations:

- v6 is faster than v4 which is expected.

- The slowest prefixes by all seem to start bits '11'.
However it is only by a factor of 1.5x which is not really significant

Best regards, Henrik

Henrik Thostrup Jensen <htj at nordu.net>
Software Developer, NORDUnet