From: | Adrien Nayrat <adrien(dot)nayrat(at)anayrat(dot)info> |
---|---|
To: | Vik Fearing <vik(dot)fearing(at)2ndquadrant(dot)com>, Michael Paquier <michael(at)paquier(dot)xyz> |
Cc: | David Rowley <david(dot)rowley(at)2ndquadrant(dot)com>, PostgreSQL mailing lists <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: New GUC to sample log queries |
Date: | 2018-07-10 18:34:15 |
Message-ID: | 9e94de9f-4c44-3abd-6160-ac5e543f9a74@anayrat.info |
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Lists: | pgsql-hackers |
On 06/27/2018 11:13 PM, Adrien Nayrat wrote:
>> 3) Is it intentional to only sample with log_min_duration_statement and
>> not also with log_duration? It seems like it should affect both. In
>> both cases, the name is too generic. Something called "log_sample_rate"
>> should sample **everything**.
> I do not think it could be useful to sample other case such as log_duration.
>
> But yes, the GUC is confusing and I am not comfortable to introduce a new GUC in
> my initial patch.
>
> Maybe we should adapt current GUC with something like :
>
> log_min_duration_statement = <time>,<sample rate>>
> This give :
>
> log_min_duration_statement = 0,0.1
>
> Equivalent to :
> log_min_duration_statement = 0
> log_sample_rate = 0.1
>
> Thought?
>
After reflection it seems a bad idea :
* it breaks compatibility with external tools
* it introduce a kind of "composite" GUC which may add complexity to use. For
example in pg_settings view.
What do you think of : log_min_duration_statement_sample ? Is it too long?
I saw a few days ago this error on http://commitfest.cputube.org
postgres.sgml:5202: element xref: validity error : IDREF attribute linkend
references an unknown ID "log_min_duration_statement"
Patch attached with fix on linkend marker
Regards,
--
Adrien
Attachment | Content-Type | Size |
---|---|---|
sample_rate-4.patch | text/x-patch | 4.4 KB |
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