Re: [PERFORM] PG Logging is Slow
Title: RE: [PERFORM] PG Logging is Slow Thankyou Alexander, That has worked and appears to have fixed the issue with syslog. Theo -Original Message- From: Alexander Borkowski [mailto:[EMAIL PROTECTED]] Sent: Tuesday, 21 December 2004 10:09 AM To: Theo Galanakis Cc: '[EMAIL PROTECTED]' Subject: Re: [PERFORM] PG Logging is Slow Theo, > I tried the -/var/log/postgresql.log option however I noticed no > performance improvement. May be the fact that we use redhad linux and > syslog, I'm no sys-admin, so I'm not sure if there is a difference between > syslogd and syslog. Did you restart syslogd (that's the server process implementing the syslog (= system log) service) after you changed its configuration? In order to do so, try running /etc/init.d/syslog restart as root from a commandline. HTH Alex __ This email, including attachments, is intended only for the addressee and may be confidential, privileged and subject to copyright. If you have received this email in error, please advise the sender and delete it. If you are not the intended recipient of this email, you must not use, copy or disclose its content to anyone. You must not copy or communicate to others content that is confidential or subject to copyright, unless you have the consent of the content owner.
Re: [PERFORM] PG Logging is Slow
Theo, > I tried the -/var/log/postgresql.log option however I noticed no > performance improvement. May be the fact that we use redhad linux and > syslog, I'm no sys-admin, so I'm not sure if there is a difference between > syslogd and syslog. Did you restart syslogd (that's the server process implementing the syslog (= system log) service) after you changed its configuration? In order to do so, try running /etc/init.d/syslog restart as root from a commandline. HTH Alex ---(end of broadcast)--- TIP 4: Don't 'kill -9' the postmaster
Re: [PERFORM] PG Logging is Slow
Title: RE: [PERFORM] PG Logging is Slow Thank-you Grega, I ended up using the pg_ctl -l parameter to write the output to a specified file. Much quicker to do so. I tried the -/var/log/postgresql.log option however I noticed no performance improvement. May be the fact that we use redhad linux and syslog, I'm no sys-admin, so I'm not sure if there is a difference between syslogd and syslog. Theo -Original Message- From: Grega Bremec [mailto:[EMAIL PROTECTED]] Sent: Monday, 20 December 2004 3:49 PM To: Theo Galanakis Cc: [EMAIL PROTECTED] Subject: Re: [PERFORM] PG Logging is Slow ...and on Mon, Dec 20, 2004 at 03:17:11PM +1100, Theo Galanakis used the keyboard: > Under postgres 7.3 logging is incredibly slow! > > I have applied the following settings: > > syslog = 2 > syslog_facility = 'LOCAL0' > syslog_ident = 'postgres' > > log_connections = true > log_duration = true > log_pid = true > log_statement = true > log_timestamp = true > > This severely impacted the performance of our production system, a > search page which took 1-3 seconds now takes over 30, is this normal? > > I need to get some performance indicators from our production db, > however I cant turn on logging with such performance degradation. > Hi Theo, One thing you should be sure about is that whichever logfile you have configured for the local0 facility is being written to asynchronously. Synchronous logging is REALLY expensive. If you're using the standard syslogd, you can achieve that by prefixing the filename in syslogd.conf with a dash. For example, local0.* /var/log/postgresql.log would become local0.* -/var/log/postgresql.log One other option would be to turn off syslog logging completely and let postmaster take care of the log on its own, which may or may not be possible for you, depending on the policy in effect (remote logging, etc.). Hope this helped, -- Grega Bremec gregab at p0f dot net __ This email, including attachments, is intended only for the addressee and may be confidential, privileged and subject to copyright. If you have received this email in error, please advise the sender and delete it. If you are not the intended recipient of this email, you must not use, copy or disclose its content to anyone. You must not copy or communicate to others content that is confidential or subject to copyright, unless you have the consent of the content owner.
Re: [PERFORM] PG Logging is Slow
On Mon, Dec 20, 2004 at 03:17:11PM +1100, Theo Galanakis wrote: > Under postgres 7.3 logging is incredibly slow! > > I have applied the following settings: > > syslog = 2 > syslog_facility = 'LOCAL0' > syslog_ident = 'postgres' > > log_connections = true > log_duration = true > log_pid = true > log_statement = true > log_timestamp = true > > This severely impacted the performance of our production system, a search > page which took 1-3 seconds now takes over 30, is this normal? > > I need to get some performance indicators from our production db, however I > cant turn on logging with such performance degradation. I've experienced this problem many times due to hanging dns lookups. /etc/resolv.conf may point to a nonexistent nameserver. Comment it out and restart syslogd. Or use a syslog implementation that allows you to disable dns lookups. Or just give the nameserver a kick. -Mike Adler ---(end of broadcast)--- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
Re: [PERFORM] PG Logging is Slow
...and on Mon, Dec 20, 2004 at 03:17:11PM +1100, Theo Galanakis used the keyboard: > Under postgres 7.3 logging is incredibly slow! > > I have applied the following settings: > > syslog = 2 > syslog_facility = 'LOCAL0' > syslog_ident = 'postgres' > > log_connections = true > log_duration = true > log_pid = true > log_statement = true > log_timestamp = true > > This severely impacted the performance of our production system, a search > page which took 1-3 seconds now takes over 30, is this normal? > > I need to get some performance indicators from our production db, however I > cant turn on logging with such performance degradation. > Hi Theo, One thing you should be sure about is that whichever logfile you have configured for the local0 facility is being written to asynchronously. Synchronous logging is REALLY expensive. If you're using the standard syslogd, you can achieve that by prefixing the filename in syslogd.conf with a dash. For example, local0.*/var/log/postgresql.log would become local0.*-/var/log/postgresql.log One other option would be to turn off syslog logging completely and let postmaster take care of the log on its own, which may or may not be possible for you, depending on the policy in effect (remote logging, etc.). Hope this helped, -- Grega Bremec gregab at p0f dot net pgpjQ91yejeKo.pgp Description: PGP signature
Re: [PERFORM] PG Logging is Slow
Theo Galanakis wrote: > Under postgres 7.3 logging is incredibly slow! > > I have applied the following settings: > > syslog = 2 > syslog_facility = 'LOCAL0' > syslog_ident = 'postgres' > > log_connections = true > log_duration = true > log_pid = true > log_statement = true > log_timestamp = true > > This severely impacted the performance of our production system, a search > page which took 1-3 seconds now takes over 30, is this normal? > > I need to get some performance indicators from our production db, however I > cant turn on logging with such performance degradation. Linux syslog has this bad behavior of fsync'ing all log writes. See the syslog manual page for a way to turn off the fsync. -- Bruce Momjian| http://candle.pha.pa.us [EMAIL PROTECTED] | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup.| Newtown Square, Pennsylvania 19073 ---(end of broadcast)--- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faqs/FAQ.html
[PERFORM] PG Logging is Slow
Title: Message Under postgres 7.3 logging is incredibly slow! I have applied the following settings: syslog = 2 syslog_facility = 'LOCAL0' syslog_ident = 'postgres' log_connections = true log_duration = true log_pid = true log_statement = true log_timestamp = true This severely impacted the performance of our production system, a search page which took 1-3 seconds now takes over 30, is this normal? I need to get some performance indicators from our production db, however I cant turn on logging with such performance degradation. Theo __This email, including attachments, is intended only for the addresseeand may be confidential, privileged and subject to copyright. If youhave received this email in error, please advise the sender and deleteit. If you are not the intended recipient of this email, you must notuse, copy or disclose its content to anyone. You must not copy or communicate to others content that is confidential or subject to copyright, unless you have the consent of the content owner.
