Re: How to inspect blocked queries

"Randall F. Kern" <randy@spoke.net> writes:
> I have an web application that sometimes hangs.  When I run ps I see a
> postgresql thread that says "INSERT waiting" (I don't have the exact
> text in front of me, but it's similar to that).  When this happens my
> only recourse is to restart my webserver or database.

> Now most likely I have another transaction that hasn't been committed or
> locks tables in a different order, but I don't see it in the output from
> ps.  Is there anyway for me to inspect the pending queries in postgesql
> so I can track this down?

Sorry, no good way to do that at the moment.  I'd suggest turning on
query logging (-d2 to the postmaster, and make sure the stderr output
is going somewhere and is not being suppressed by -S).  When the hang
occurs, you can look back in the log to see what other transactions
are in progress.

            regards, tom lane