On Wed, Jan 16, 2019 at 2:03 AM Adrien NAYRAT <adrien.nay...@anayrat.info> wrote: > > On 1/15/19 11:42 AM, Masahiko Sawada wrote: > >> When you troubleshoot applicative issues with multi-statements > >> transaction, you may have to log all queries to find all statements of one > >> transaction. With high throughput, it could be hard to log all queries > >> without causing troubles. > > Hm, can we use log_min_duration_statement to find slow queries of a > > transaction instead? Could you please elaborate on the use-case? > > Hello, > > The goal is not to find slow queries in a transaction, but troubleshoot > applicative issue when you have short queries. > > Sometimes you want to understand what happens in a transaction, either > you perfectly know your application, either you have to log all queries > and find ones with the same transaction ID (%x). It could be problematic > if you have a huge traffic with fast queries. >
Thank you for the explain! I understood the use case of this patch. This feature would be helpful for troubleshooting. Since we set xact_is_sampled only when transaction starts and see it during transaction we cannot disable logging during transaction and vice versa. I can imagine the use case where user wants to disable logging during transaction. So it might be better to also check if log_xact_sample_rate > 0 in check_log_duration(). Regards, -- Masahiko Sawada NIPPON TELEGRAPH AND TELEPHONE CORPORATION NTT Open Source Software Center
