On Thu, Oct 15, 2020 at 11:41:23AM +0800, Julien Rouhaud wrote: > On Wed, Oct 14, 2020 at 10:40 PM Bruce Momjian <br...@momjian.us> wrote: > > There is that, and log_line_prefix, which I can imaging being useful. > > My point is that if the queryid is visible, there should be a reason it > > defaults to show empty. > > I did some naive benchmarking. Using a custom pgbench script with this query: > > SELECT * > FROM pg_class c > JOIN pg_attribute a ON a.attrelid = c.oid > ORDER BY 1 DESC > LIMIT 1; > > I can see around 2% overhead (this query is reported with ~ 3ms > latency average). Adding a few joins, overhead goes down to 1%.
That number is too high to enable this by default. I suggest we either improve the performance of this, or clearly document that you have to enable the hash computation to see the pg_stat_activity and log_line_prefix fields. -- Bruce Momjian <br...@momjian.us> https://momjian.us EnterpriseDB https://enterprisedb.com The usefulness of a cup is in its emptiness, Bruce Lee
