On Tue, Aug 9, 2016 at 5:37 AM, Bruce Momjian <br...@momjian.us> wrote:
> On Tue, Aug 9, 2016 at 02:06:40AM +0000, Tsunakawa, Takayuki wrote: > > I hope wait event monitoring will be on by default even if the overhead > is not > > almost zero, because the data needs to be readily available for faster > > troubleshooting. IMO, the benefit would be worth even 10% overhead. If > you > > disable it by default because of overhead, how can we convince users to > enable > > it in production systems to solve some performance problem? I’m afraid > severe > > users would say “we can’t change any setting that might cause more > trouble, so > > investigate the cause with existing information.” > > If you want to know why people are against enabling this monitoring by > default, above is the reason. What percentage of people do you think > would be willing to take a 10% performance penalty for monitoring like > this? I would bet very few, but the argument above doesn't seem to > address the fact it is a small percentage. > Just two notes from me: 1) 10% overhead from monitoring wait events is just an idea without any proof so soon. 2) We already have functionality which trades insight into database with way more huge overhead. auto_explain.log_analyze = true can slowdown queries *in times*. Do you think we should remove it? ------ Alexander Korotkov Postgres Professional: http://www.postgrespro.com The Russian Postgres Company
