Обсуждение: [HACKERS] [PATCH] Warn users about duplicate configuration parameters

Hi.

Recently I've discovered that if there are multiple values of the same
parameter in postgresql.conf PostgreSQL will silently use the last one.
It looks like not the best approach to me. For instance, user can find
the first value in the config file and expect that it will be used, etc.

I suggest to warn users about duplicated parameters. Here is a
corresponding patch.

Thoughts?

--
Best regards,
Aleksander Alekseev

On 2017-04-07 18:14:27 +0300, Aleksander Alekseev wrote:
> Hi.
> 
> Recently I've discovered that if there are multiple values of the same
> parameter in postgresql.conf PostgreSQL will silently use the last one.
> It looks like not the best approach to me. For instance, user can find
> the first value in the config file and expect that it will be used, etc.
> 
> I suggest to warn users about duplicated parameters. Here is a
> corresponding patch.
> 
> Thoughts?

-1 - I frequently just override earlier parameters by adding an include
at the end of the file.  Also, with postgresql.auto.conf it's even more
common to override parameters.


Greetings,

Andres Freund

>> Recently I've discovered that if there are multiple values of the same
>> parameter in postgresql.conf PostgreSQL will silently use the last one.
>> It looks like not the best approach to me. For instance, user can find
>> the first value in the config file and expect that it will be used, etc.
>> 
>> I suggest to warn users about duplicated parameters. Here is a
>> corresponding patch.
>> 
>> Thoughts?
> 
> -1 - I frequently just override earlier parameters by adding an include
> at the end of the file.  Also, with postgresql.auto.conf it's even more
> common to override parameters.

-1 from me too by the same reason Andres said.
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese:http://www.sraoss.co.jp

Andres, Tatsuo,

Thank you for sharing your thoughts.

> -1 - I frequently just override earlier parameters by adding an
> include at the end of the file.  Also, with postgresql.auto.conf it's
> even more common to override parameters.

> -1 from me too by the same reason Andres said.

I see no problem here. After all, it's just warnings. We can even add
a GUC that disables them specially for experienced users who knows what
she or he is doing. And/or add special case for postgresql.auto.conf.

--
Best regards,
Aleksander Alekseev

On 2017-04-07 18:29:40 +0300, Aleksander Alekseev wrote:
> Andres, Tatsuo,
> 
> Thank you for sharing your thoughts.
> 
> > -1 - I frequently just override earlier parameters by adding an
> > include at the end of the file.  Also, with postgresql.auto.conf it's
> > even more common to override parameters.
> 
> > -1 from me too by the same reason Andres said.
> 
> I see no problem here. After all, it's just warnings. We can even add
> a GUC that disables them specially for experienced users who knows what
> she or he is doing. And/or add special case for postgresql.auto.conf.

More useless warnings make actual warnings less useful.

Greetings,

Andres Freund

On 4/7/17 11:22 AM, Tatsuo Ishii wrote:
>>> Recently I've discovered that if there are multiple values of the same
>>> parameter in postgresql.conf PostgreSQL will silently use the last one.
>>> It looks like not the best approach to me. For instance, user can find
>>> the first value in the config file and expect that it will be used, etc.
>>>
>>> I suggest to warn users about duplicated parameters. Here is a
>>> corresponding patch.
>>>
>>> Thoughts?
>>
>> -1 - I frequently just override earlier parameters by adding an include
>> at the end of the file.  Also, with postgresql.auto.conf it's even more
>> common to override parameters.
> 
> -1 from me too by the same reason Andres said.

-1 from me for the same reason.

-- 
-David
david@pgmasters.net