[pgpool-hackers: 1618] Re: Redirecting queries to standby as much as possible

[Tatsuo Ishii]

> On Fri, 10 Jun 2016 15:13:19 +0900 (JST)
> Tatsuo Ishii <ishii at postgresql.org> wrote:
> 
>> Submitter of bug 195 (http://www.pgpool.net/mantisbt/view.php?id=195)
>> wants to redirect queries to standby as much as possible if the
>> transaction is read only. This brings up interesting conflicts to
>> current behavior of pgpool-II:
>> 
>> - the weight parameters of backend info needs to be ignored if the
>>   transaction is read only
>> 
>> - black and white function list need to be ignored if the transaction
>>   is read only
>> 
>> - database_redirect_preference_list needs to be ignored if the
>>   transaction is read only
>> 
>> - app_name_redirect_preference_list needs to be ignored if the
>>   transaction is read only
>> 
>> After all, if we don't want to confuse existing users in the use cases
>> above, we need to invent a new switch to change the redirecting
>> behavior depending on whether the transaction is read only or not.
> 
> I agree that to add new switch is good because it is simple and preserves
> compatibility.

Question is, whether it's worth the trouble. Is there any people other
than the bug submitter who wants the feature?

> However, even in the current version, the priority of the above rules is
> confusing. I think the priority rule should be summarized in the document
> explicitly.

Welcome volunteering the work:-)

Best regards,
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese:http://www.sraoss.co.jp