[pgpool-hackers: 263] Re: Patch for new parameter for searching primary node timeout

Tatsuo Ishii ishii at postgresql.org
Tue May 28 23:34:43 JST 2013


Hi Usama,

Thanks for the patch. I did a simple test and it worked great. I have
committed your patch along with Japanese doc (and slight editing of
English doc).
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp

> Hi Tatsuo
> 
> Please find the updated patch which takes care of the comments and
> suggestions on the previous version.
> Appart from documentation additions, the attached patch sets the default
> search_primary_node_timeout value to 10 and setting the same to 0 will make
> the pgpool-II to keep searching the primary node forever.
> 
> Thanks
> Muhammad Usama
> 
> 
> 
> On Mon, May 27, 2013 at 7:32 PM, Tatsuo Ishii <ishii at postgresql.org> wrote:
> 
>> > Hi Tatsuo
>> >
>> > Thanks for the comments and review. I will submit the updated patch after
>> > taking care of the comments.
>> > Please just clarify on one of the points, what should be the correct
>> > behaviour of setting the search_primary_node_timeout = 0
>> >
>> > Retrying forever OR  Try just one time.?
>> >
>> > Thanks
>> > Usama
>>
>> I vote for "retrying forever".
>> --
>> Tatsuo Ishii
>> SRA OSS, Inc. Japan
>> English: http://www.sraoss.co.jp/index_en.php
>> Japanese: http://www.sraoss.co.jp
>>
>> > On Mon, May 27, 2013 at 7:07 PM, Tatsuo Ishii <ishii at postgresql.org>
>> wrote:
>> >
>> >> Hi Usama,
>> >>
>> >> Welcome to pgpool developer's community!
>> >>
>> >> > I have been working on pgpool-II TODO item to add a new configuration
>> >> > parameter for searching the primary node timeout after failover.
>> >> Currently
>> >> > pgpool-II uses "recovery_timeout" config parameter as a timeout for
>> >> > searching the primary node after failover which is not originally
>> meant
>> >> for
>> >> > the purpose.
>> >> > The attached small patch is my first pgpool-II patch which adds the
>> new
>> >> > configuration parameter "search_primary_node_timeout", which can be
>> used
>> >> > for setting the timeout for searching the primary node after failover.
>> >>
>> >> I have looked into the patch. Here's my comment.  First, you need
>> >> patch for doc/pgpool-en.html.
>> >>
>> >> Second,
>> >>
>> >> +search_primary_node_timeout = 90
>> >> +                                   # Timeout in seconds to search for
>> the
>> >> +                                   # primary node at failover
>> >> +                                   # 0 means no wait
>> >>
>> >> I am not sure what you suppose when search_primary_node_timeout = 0.
>> >> If you mean retrying forever, the code below does not do that. Rather,
>> >> find_primary_node() is never called, thus
>> >> find_primary_node_repeatedly() always returns -1.
>> >>
>> >> +       for (sec = 0; sec < pool_config->search_primary_node_timeout;
>> >> sec++)
>> >>         {
>> >>                 node_id = find_primary_node();
>> >>
>> >> Third, the default timeout 90 seconds seems too long. Promoting to
>> >> primary should take less than 10 seconds unless there's huge back log
>> >> of WAL. What about set the default to 10?
>> >> --
>> >> Tatsuo Ishii
>> >> SRA OSS, Inc. Japan
>> >> English: http://www.sraoss.co.jp/index_en.php
>> >> Japanese: http://www.sraoss.co.jp
>> >>
>>


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