Horton

Re: New GUC to sample log queries

Adrien NAYRAT <adrien.nayrat@anayrat.info>

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From: Adrien Mobile <adrien.nayrat@anayrat.info>
To: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, Michael Paquier <michael@paquier.xyz>, "Dmitry Dolgov" <9erthalion6@gmail.com>
Cc: Vik Fearing <vik.fearing@2ndquadrant.com>, Robert Haas <robertmhaas@gmail.com>, <david.rowley@2ndquadrant.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2019-01-04T16:10:04Z
Lists: pgsql-hackers 
Le 4 janvier 2019 13:16:48 GMT+01:00, Peter Eisentraut <peter.eisentraut@2ndquadrant.com> a écrit :
>On 19/11/2018 14:40, Tomas Vondra wrote:
>> On 11/19/18 2:57 AM, Michael Paquier wrote:
>>> On Sun, Nov 18, 2018 at 12:18:33PM +0100, Dmitry Dolgov wrote:
>>>> Since it's hard to come up with a concise name that will mention
>sampling rate
>>>> in the context of min_duration_statement, I think it's fine to name
>this
>>>> configuration "log_sample_rate", as long as it's dependency from
>>>> log_min_duration_statements is clearly explained in the
>documentation.
>>>
>>> log_sample_rate looks fine to me as a name.
>> 
>> That seems far too short to me - the name should indicate it applies
>to 
>> statement logging. I'd say log_statement_sample_rate is better.
>
>It was committed with this name, but then one has to wonder why it
>doesn't also apply to log_statement.
>
>-- 
>Peter Eisentraut              http://www.2ndQuadrant.com/
>PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Yes, but maybe log_min_duration_statements_sample is too long? 
-- 
Sent from my Android phone with K-9 Mail. Please excuse my brevity.

Commits

  1. Use pg_strong_random() to select each server process's random seed.

  2. Use a separate random seed for SQL random()/setseed() functions.

  3. Marginal performance hacking in erand48.c.

  4. Fix latent problem with pg_jrand48().

  5. Silence compiler warning

  6. Add log_statement_sample_rate parameter