On Fri, Dec 5, 2014 at 5:14 PM, István <leccine@xxxxxxxxx> wrote: > I am wondering why the root cause might be here. My guess would be that an important text-based sort operation began to go to disk. The external sort code (tapesort) is known to do far more comparisons than quicksort. With text sorts, you tend to see tapesort very CPU bound, where that might not be the case with integer sorts. I'm currently trying to fix this across the board [1], but my first suggestion is to try enabling log_temp_files to see if external sorts can be correlated with these stalls. [1] https://commitfest.postgresql.org/action/patch_view?id=1462 -- Regards, Peter Geoghegan -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general