On Tue, 2004-11-30 at 19:32, Bruce Momjian wrote:
> David Parker wrote:
> > I've been using "log_min_duration_statement = 0" to get durations on all
> > SQL statements for the purposes of performance tuning, because this logs
> > the duration on the same line as the statement. My reading of this TODO
> > is that now log_min_duration_statement = 0 would give me the statements
> > but no total duration?
>
> Oh, sorry, you are right. I forgot about the duration part! I got so
> excited I forgot.
>
> TODO item removed.
David's objection was noted, and why I hadn't coded it (yet).
There are currently two ways of getting statement and duration output,
which is confusing....
You can either
1. Individual statements
- log_statement = all
- log_duration = true
- log_line_prefix includes processid
which produces 2 log lines like
statement: xxxxxxxxx
duration: yyyyyyyyyy
2. log_min_duration
log_min_duration_statement=0
which produces 1 log line like
duration: yyyyyyy statement: xxxxxxxxxx
These two things do exactly the same thing, apart from the way the
output is presented to the user in the log line.
I'd like to change log_min_duration_statement as suggested, but this
side-effect behaviour of being a better log_statement than log_statement
kindof gets in the way. It makes me wonder why we have log_statement at
all.
We all want to do performance tracing. I'd also like to be able to
dynamically monitor what is actually happening *now* on the system.
There is no way right now to monitor for rogue queries, other than to
cancel anything that runs more than statement_timeout. Thats not good
either, even if it does keep the current behaviour.
My preference would be to do the following:
- add a script to contrib to process the log file
- always add processid to log_statement_prefix when both log_statement
and log_duration are specified, so you can always tie up the data
Anybody?
--
Best Regards, Simon Riggs
