Re: track_planning causing performance regression

On 2021/06/30 0:12, Julien Rouhaud wrote:
>> Enabling this parameter may incur a noticeable performance penalty,
>> - especially when a fewer kinds of queries are executed on many
>> - concurrent connections.
>> + especially when queries with identical structure are executed by many
>> + concurrent connections which compete to update a small number of
>> + pg_stat_statements entries.
>>
>> It could say "identical structure" or "the same queryid" or "identical queryid".
>
> I think we should try to reuse the previous formulation. How about
> "statements with identical query structure"?

I'm fine with this. So what about the following diff? I added <structname> tag.

<varname>pg_stat_statements.track_planning</varname> controls whether
planning operations and duration are tracked by the module.
Enabling this parameter may incur a noticeable performance penalty,
- especially when a fewer kinds of queries are executed on many
- concurrent connections.
+ especially when statements with identical query structure are executed
+ by many concurrent connections which compete to update a small number of
+ <structname>pg_stat_statements</structname> entries.
The default value is <literal>off</literal>.
Only superusers can change this setting.

Regards,

--
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION