On Thu, Mar 10, 2016 at 10:07 PM, Petr Jelinek <p...@2ndquadrant.com> wrote:
> On 10/03/16 20:59, Julien Rouhaud wrote: > >> On 10/03/2016 04:37, Petr Jelinek wrote: >> >>> On 17/02/16 01:17, Julien Rouhaud wrote: >>> >>>> >>>> Agreed, it's too obscure. Attached v4 fixes as you said. >>>> >>>> >>> Seems to be simple enough patch and works. However I would like >>> documentation to say that the range is 0 to 1 and represents fraction of >>> the queries sampled, because right now both the GUC description and the >>> documentation say it's in percent but that's not really true as percent >>> is 0 to 100. >>> >>> >> Agreed. v5 attached fixes that. >> >> > Great, I will test it once more (just because when I don't bugs suddenly > appear out of nowhere) and mark it ready for committer. > > Coming back to the previous discussions about random() - AFAICT this patch will introduce the random() call always (in explain_ExecutorStart): + if (auto_explain_log_min_duration >= 0 && nesting_level == 0) + current_query_sampled = (random() < auto_explain_sample_ratio * + MAX_RANDOM_VALUE); Not sure what the overhead is, but wouldn't it be better to include a check for current_query_sampled>0 in the if part of that statement? Regardless of performance, that feels cleaner to me. Or am I missing something? -- Magnus Hagander Me: http://www.hagander.net/ Work: http://www.redpill-linpro.com/