Re: Review: DTrace probes (merged version) - Mailing list pgsql-hackers

From Alvaro Herrera
Subject Re: Review: DTrace probes (merged version)
Date
Msg-id 20080704173305.GD3893@alvh.no-ip.org
Whole thread Raw
In response to Re: Review: DTrace probes (merged version)  (Zdenek Kotala <Zdenek.Kotala@Sun.COM>)
Responses Re: Review: DTrace probes (merged version)  (Zdenek Kotala <Zdenek.Kotala@Sun.COM>)
List pgsql-hackers
Zdenek Kotala wrote:
> Tom Lane napsal(a):

>> I see no value in cluttering the system with useless probes.  The worker
>> start/stop are the only ones here with any conceivable application IMHO.
>
> As I answered to Alvaro. I needed to catch start of backend several times 
> to track call flow or attach debugger. It is possible to use some other 
> dtrace magic for that, but it is not easy and there is not way how to 
> determine what kind of process it is.  For example how to measure how 
> many writes performs bgwriter?

If you need to attach a debugger to a backend, you can use the -W switch
(even on PGOPTIONS if you need it for a particular backend, AFAIR).  If
you want to "truss" it I guess you can use -W too.

Does it have any usefulness beyond that?

-- 
Alvaro Herrera                                http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.


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