On 12/12/2013 02:51 AM, Tom Lane wrote:
> The thing that I'm wondering is why the database would be the right place
> to be measuring it at all. If you've got a network usage problem,
> aggregate usage across everything on the server is probably what you
> need to be worried about, and PG can't tell you that.
I suspect this feature would be useful for when you want to try to drill
down and figure out what's having network issues - specifically, to
associate network behaviour with individual queries, individual users,
application_name, etc.
One sometimes faces the same issue with I/O: I know PostgreSQL is doing
lots of I/O, but what exactly is causing the I/O? Especially if you
can't catch it at the time it happens, it can be quite tricky to go from
"there's lots of I/O" to "this query changed from using synchronized
seqscans to doing an index-only scan that's hammering the cache".
-- Craig Ringer http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training & Services