Re: Use case for enabling log_duration other than benchmarking

[Alicja Kucharczyk <zaledwie10minut@xxxxxxxxx>]

wt., 10 sty 2023 o 14:57 Ron <ronljohnsonjr@xxxxxxxxx> napisał(a):

On 1/10/23 07:14, Alicja Kucharczyk wrote:

Do you know any use case for enabling log_duration? Like 3rd party tools for instance.

I find this parameter pretty much useless (in opposite to log_min_duration_statement) as it does not show the query text, so besides having just the timing logged it is of no use in troubleshooting and often causes huge overhead. Am I missing something?

https://www.postgresql.org/docs/current/runtime-config-logging.html

Note

The difference between enabling log_duration and setting log_min_duration_statement to zero is that exceeding log_min_duration_statement forces the text of the query to be logged, but this option doesn't. Thus, if log_duration is on and log_min_duration_statement has a positive value, all durations are logged but the query text is included only for statements exceeding the threshold. This behavior can be useful for gathering statistics in high-load installations.

thank you Ron.

My question is a bit more practical - Does anyone really find it useful? 

What value brings the info that 20% of my query are under 1ms and 10% over 1 minute - If just checked once and then turned off - I can understand to have more visibility into the overall characteristics. But let say someone have it enabled on a production system all the time - what could be the reason for that?