Thread: Re: Increasing the length of
How difficult would it be to make the combination log_statement = all log_duration = true just put the duration on the same line as the statement? Then log_min_duration_statement could be used to do the desired log-at-threshold behavior, which certainly seems valuable. You'd need a way to visually/scriptually (?) distinguish those log records, though, I guess. Note that my original post on this was more of a question than an objection - it's entirely possible to sed around having duration and statement on separate lines - I just wanted clarification. Having them on the same line IS handy, however.... - DAP >-----Original Message----- >From: Bruce Momjian [mailto:pgman@candle.pha.pa.us] >Sent: Wednesday, December 01, 2004 11:18 AM >To: Simon Riggs >Cc: David Parker; pgsql-hackers@postgresql.org >Subject: Re: [HACKERS] Increasing the length of > >Simon Riggs wrote: >> 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 have it so you can look in the log to see currently running >queries rather than just completed queries. > >> 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 > >I think our setup is confusing enough. Adding "automatic" >additions seems even more confusing than what we have now. We >could throw a log warning message somehow though. > >-- > Bruce Momjian | http://candle.pha.pa.us > pgman@candle.pha.pa.us | (610) 359-1001 > + If your life is a hard drive, | 13 Roberts Road > + Christ can be your backup. | Newtown Square, >Pennsylvania 19073 >
David Parker wrote: > How difficult would it be to make the combination > > log_statement = all > log_duration = true > > just put the duration on the same line as the statement? Then > log_min_duration_statement could be used to > do the desired log-at-threshold behavior, which certainly seems > valuable. You'd need a way to visually/scriptually (?) distinguish those > log records, though, I guess. > > Note that my original post on this was more of a question than an > objection - it's entirely possible to sed around having duration and > statement on separate lines - I just wanted clarification. Having them > on the same line IS handy, however.... Many people want the statement printed when it starts (for real-time server monitoring), not when it finishes, meaning we don't know the duration at start time. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
On Wed, 2004-12-01 at 11:47, Bruce Momjian wrote:
> David Parker wrote:
> > How difficult would it be to make the combination
> >
> > log_statement = all
> > log_duration = true
> >
> > just put the duration on the same line as the statement? Then
> > log_min_duration_statement could be used to
> > do the desired log-at-threshold behavior, which certainly seems
> > valuable. You'd need a way to visually/scriptually (?) distinguish those
> > log records, though, I guess.
> >
> > Note that my original post on this was more of a question than an
> > objection - it's entirely possible to sed around having duration and
> > statement on separate lines - I just wanted clarification. Having them
> > on the same line IS handy, however....
>
> Many people want the statement printed when it starts (for real-time
> server monitoring), not when it finishes, meaning we don't know the
> duration at start time.
>
I think what David is asking for is log_statement and log_duration to
print on the same line at query completion time. We could then change
log_min_duration_statement to print DurationExceeded <duration> rather
than just Duration <time> like it does now, also on the same line, but
with a way to differentiate the two.
Robert Treat
--
Build A Brighter Lamp :: Linux Apache {middleware} PostgreSQL
Robert Treat wrote: > On Wed, 2004-12-01 at 11:47, Bruce Momjian wrote: > > David Parker wrote: > > > How difficult would it be to make the combination > > > > > > log_statement = all > > > log_duration = true > > > > > > just put the duration on the same line as the statement? Then > > > log_min_duration_statement could be used to > > > do the desired log-at-threshold behavior, which certainly seems > > > valuable. You'd need a way to visually/scriptually (?) distinguish those > > > log records, though, I guess. > > > > > > Note that my original post on this was more of a question than an > > > objection - it's entirely possible to sed around having duration and > > > statement on separate lines - I just wanted clarification. Having them > > > on the same line IS handy, however.... > > > > Many people want the statement printed when it starts (for real-time > > server monitoring), not when it finishes, meaning we don't know the > > duration at start time. > > > > I think what David is asking for is log_statement and log_duration to > print on the same line at query completion time. We could then change > log_min_duration_statement to print DurationExceeded <duration> rather > than just Duration <time> like it does now, also on the same line, but > with a way to differentiate the two. I see. That just seems too confusing to me. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073