Re: New function pg_stat_statements_reset_query() to reset statistics of a specific query

On Fri, Sep 28, 2018 at 7:45 AM Haribabu Kommi <kommi(dot)haribabu(at)gmail(dot)com> wrote:
>
> On Tue, Sep 25, 2018 at 3:09 PM Michael Paquier <michael(at)paquier(dot)xyz> wrote:
>>
>> On Tue, Sep 25, 2018 at 01:49:09PM +1000, Haribabu Kommi wrote:
>> Hmm. I see a problem with the tests and the stability of what
>> pg_stat_statements_reset() can return. Normally installcheck is
>> disabled in contrib/pg_stat_statements/Makefile but if you remove this
>> barrier and run the tests with a server loading the module in
>> shared_preload_libraries then things are not stable. We don't have this
>> kind of instability on HEAD. Some call to pg_stat_statements_reset()
>> system-wide is visibly missing.
>
>
> The difference in results of the output of the pg_stat_statements_reset()
> function is based on the earlier statements that are stored in the pg_stat_statements
> table, this varies based on the environment. So I created a wrapper function
> that masks the return value of the first reset and then the test is stable.
>
> check whether is it fine or any better approach to handle it?
>

Before trying out any solution or deciding which is better, I think we
want to understand why the variability in results occurred only after
your patch? Without the patch, it works just fine.

--
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com