Re: Performance monitoring - Mailing list pgsql-hackers

From Joshua D. Drake
Subject Re: Performance monitoring
Date
Msg-id 464630EA.5000701@commandprompt.com
Whole thread Raw
In response to Performance monitoring (was: [PATCHES] Logging checkpoints and other slowdown causes)  ("Jim C. Nasby" <decibel@decibel.org>)
Responses Re: Performance monitoring
Re: Performance monitoring
List pgsql-hackers
> Not to beat a dead horse, but do we really want to force folks to be
> parsing logs for performance monitoring? Especially if that log parsing
> is just going to result in data being inserted into a table anyway?
> 
> I know there's concern about performance of the stats system and maybe
> that needs to be addressed, but pushing users to log parsing is a lot of
> extra effort, non-standard, likely to be overlooked, and doesn't play
> well with other tools. It also conflicts with all the existing
> statistics framework.


One thing that doesn't seemed to be being looked at it is the cost of 
logging. Logging is very expensive. I don't know if it is more expensive 
than the stats system, but you can cut your tps in half by having any 
level of verbose logging on.

Yes that can be offset by pushing the logging to another spindle, and 
being careful about what you are logging but still.

Either way, we are taking the hit, it is just a matter of where. IMO it 
would be better to have the information in the database where it makes 
sense, than pushing out to a log that:

A. Will likely be forgotten
B. Is only accessible if you have shell access to the machine (not as 
common as all of us would like to think)

Sincerely,

Joshua D. Drake


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