Benedict Holland <benedict(dot)m(dot)holland(at)gmail(dot)com> wrote:
> I ran the scripts on the page and both returned empty (though I
> have queries running and currently nothing blocks). I don't know
> what they should have been.
It only shows information on blocking, so the list should be empty
when there is none. :-) If it works as intended, it would have
shown the chain of blocking, from the update to the alter to the
select.
> The output was from PgAdmin3 which is a UI for postgres. I assume
> that they get this queried information from something inside of
> postgres as I can't imagine the query tool doing something other
> than querying the database for specs.
They are probably doing something internally which is somewhat
similar to the recursive query on that page. It sounds like when
there is a chain or tree of blocking, they show the process at the
front of the parade, rather than the immediate blocker. I can't say
that's right or wrong, but it should be documented so that people
can understand what they're looking at. Even better would be to
make a nice graphical tree of the blocking, but that would be
getting pretty fancy. :-)
-Kevin