[pgpool-hackers: 3763] Re: Using volatile property instead of black_function_list

[Tatsuo Ishii]

>> Thanks for your explanation, I understand the point.
>> You are right, this patch is actually better.
> 
> Thank you for your understanding.
> 
>> For the relation cache, May be we can add a todo? 
> 
> Yeah, that's a good idea. I have added it to the TODO list.
> 
> https://pgpool.net/mediawiki/index.php/TODO#Use_a_hash_table_for_the_relation_cache

I have committed/pushed the patches. Unlike the initial proposal:

> 1. If black_function_list is empty, check volatile property of a
> function. If it is volatile, we regard the function will do writes.
> If black_function_list is not empty, keep the current behavior.
>
> 2. Then check white_function_list. If the function is listed in the
> list, we do not regard the function do writes. This will be useful if
> we want to load balance random() or timeofday().

The new feature is only available when both black_function_list and
white_function_list are empty. If one of them is not empty, keep on
existing behavior. I think this is more useful so that keeping on
backward compatibility. The price is, we cannot load balance a few
functions like random() or timeofday() when the new feature is
enabled. I don't think this is important though.

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