Message-ID: <b22cd3c0-d76b-0379-5971-8637b65b8e87@oss.nttdata.com>
Date: Thu, 3 Feb 2022 14:33:12 +0900
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Subject: Re: maximum number of backtrace frames logged by backtrace_functions
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To: Peter Eisentraut <peter.eisentraut@enterprisedb.com>,
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 <4e16a3e9-e717-05e1-d905-6c21beba80f8@enterprisedb.com>
From: Fujii Masao <masao.fujii@oss.nttdata.com>
In-Reply-To: <4e16a3e9-e717-05e1-d905-6c21beba80f8@enterprisedb.com>
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On 2022/02/02 16:20, Peter Eisentraut wrote:
> On 01.02.22 18:04, Fujii Masao wrote:
>> The maximum number of backtrace frames logged by backtrace_functions is 100. Isn't it better to document this information so that users can understand not all backtrace always can be logged? Patch attached.
> 
> The 100 was chosen as more than you'll ever need.  If you are encountering cases with more than that, let's increase the limit.

I encountered the "more than 100 backtrace frames" case when investigating the bug of pg_log_query_plan() patch [1]. Since the function that the patch added can be called repeatedly during call to that function, the backtrace became larger than 100. I think this is not general case, so basically 100 sounds enough limit size to me.

OTOH I think it's helpful if the limit is documented when I occasionally encounter the case and want to understand why all backtrace frames are not logged.

[1]
https://commitfest.postgresql.org/37/3142/

Regards,

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