[pgpool-hackers: 3636] Re: add the command of pcp_reload_config

Fri May 22 01:48:03 JST 2020

On Tue, May 12, 2020 at 2:51 PM 周建身 <zhoujianshen at highgo.com> wrote:

> Hi Muhammad Usama:
>
>     Thanks for the suggestions you giving and the help you provided
> during my development. I have rebased my patch with the current head of the
> master branch.
>
> And,in this patch,I used  (--scope=cluster) to implement the cluster mode.
>
>
> How to use the patch to test pcp_reload_config command
> 1、do patch under the directory of pgpool
> patch -p1 < pcp_reload_config.patch
> 2、you should need automake and autoconf
>
> for example:
>  $ autoheader
>  $ aclocal
>  $ automake -a -c
>  $ autoconf
>
> 3、then to do make and make install
>
> 4、under the directory of bin，you can find the pcp_reload_config
>
> ./pcp_reload_config -s c or ./pcp_reload_config --scope=cluster
> this can reload the config file of all pgpool nodes
>
> ./pcp_reload_config or ./pcp_reload_config -s l or ./pcp_reload_config
> --scope=local
> this can only reload the config file of local pgpool node
>
>
> Thanks
> Best regards
> Zhou Jianshen
>
> zhoujianshen at highgo.com
> ------------------------------
> *发件人:* Muhammad Usama <m.usama at gmail.com>
> *发送时间:* 2020年5月4日 21:43
> *收件人:* 周建身
> *抄送:* pgpool-hackers; Muhammad
> *主题:* Re: [pgpool-hackers: 3606] add the command of pcp_reload_config
>
> Hi Zhou Jianshen,
>
> Welcome to the Pgpool-II community and thanks for the patch.
>
> I just committed a reorganization patch and now this patch does not apply
> anymore
> so can you please rebase it with the current head of the master branch.
>
> Secondly, you need to implement the cluster mode (--scope=cluster) for the
> PCP reload config utility as well.
>
> For the reference, you can see the implementation same ( scope=cluster)
> in the pcp_stop_pgpool utility.
>
>
> https://git.postgresql.org/gitweb/?p=pgpool2.git;a=commitdiff;h=87e6e11c1931555e90a1cc65cc3ee79759ebaaab
>
> You can find more info on steps for executing the command over watchdog
> network
> in the following email.
>
> https://www.pgpool.net/pipermail/pgpool-hackers/2020-May/003608.html
>
>
> Do let me know if you need further information or clarification
>
> Best Regards
>
>
> On Wed, Apr 29, 2020 at 12:10 PM 周建身 <zhoujianshen at highgo.com> wrote:
>
>> Hi Hackers,
>>
>>     As Usama Muhammad said in his email before,we should enhance/add the
>> PCP utilities more cluster-mode friendly.
>>
>> There are four commands which need to be added or enhanced.The first
>> command which should be added is pcp_reload_config.
>>
>>
>>
>>     1- pcp_reload_config
>> ==================
>> The utility to make the whole Pgpool-II cluster to reload the
>> configuration files at once.
>> I think this is required because currently if some installation has
>> let say 3 node Pgpool-II cluster
>> and we want to change one specific configuration parameter ( for
>> example: adding a new backend node)
>> we would require to go on and edit Pgpool configuration files on each
>> node separately and then
>> issue pgpool reload on each node one by one.
>>
>> In my opinion, we need multiple enhancement in this area.
>> We need some mechanisms to let pgpool-II cluster use the centralized
>> configuration
>> ( except watchdog config) or at least a mechanism to push the
>> configuration settings using some
>> new utility like "pcp_load_config" that could take a pgpool.conf file
>> and propagate it to all nodes
>> using watchdog.
>> The centralized configuration part of the problem is a big task and I
>> believe we could take it on after the
>> "simplifying watchdog config" feature that Peng is working on.
>> Meanwhile, I think we can work on pcp_reload_config utility in
>> parallel to make reloading part easier.
>>
>>
>>
>> I tried to solve this command.And I realized reloading the configuration
>> of an individual node.After Peng's working on
>>
>> watchdog config,we can eventually realize the reloading the
>> configurations of all nodes.
>>
>>
>> How to use the patch,
>>
>> 1、do patch under the directory of pgpool-II-4.1.1
>>
>> patch -p1 < pcp_reload_config.patch
>>
>> 2、you should need automake and autoconf
>>
>>
>> for example:
>>  $ autoheader
>>  $ aclocal
>>  $ automake -a -c
>>  $ autoconf
>>
>> 3、then to do make and make install
>>
>>
>> 4、under the directory of bin，you can find the pcp_reload_config ,try is
>> as  ./pcp_reload_config
>>
>>
>>
>>
>> Comments and suggestions are welcome.
>>
>>
>> Thanks
>> Best regards
>> Zhou Jianshen
>>
>> zhoujianshen at highgo.com
>>
>>
>> _______________________________________________
>> pgpool-hackers mailing list
>> pgpool-hackers at pgpool.net
>> http://www.pgpool.net/mailman/listinfo/pgpool-hackers
>>
>
>
> Hi Jianshen,

Thank you for the patch. Overall the patch looks and had few minor issues.

1- In process_reload_config() function the log message was mentioning
pcp_stop_pgpool instead of pgpool_reload_config

2- When you want to throw an error to client from PCP processor you can just
use 'ereport' instead of creating the error message by hand.

3- No need to use different PCP packet type (Z and z ) for cluster and
local modes.
instead, we can send the command scope in the packet load.
The reason we used the different packet types in the pcp_stop_pgpool was to
keep
the backward compatibility. And since this is a new utility so we can send
that
information in the packet data without worrying about compatibility.

4-  '-n' argument is not required in the pcp_reload_config
5-  The patch contains some whitespace warnings.

I have committed the patch after fixing the above-mentioned issues along
with
few code re-arrangements in the pcp_frontend_client.c

https://git.postgresql.org/gitweb/?p=pgpool2.git;a=commitdiff;h=987b69945dc914b88099d1d0420c4b49f1097f2f

Also, the documentation part for the pcp_reload_utility was not included in
the
patch. So can you please also submit the documentation updates for the
utility,
I have marked this as a remaining item in the commit message.

P.S updated patch that I committed is also attached

Thanks
Best Regards

> ...
> Muhammad Usama
> Highgo Software (Canada/China/Pakistan)
> URL : http://www.highgo.ca
> ADDR: 10318 WHALLEY BLVD, Surrey, BC
>

-- 
...
Muhammad Usama
Highgo Software (Canada/China/Pakistan)
URL : http://www.highgo.ca
ADDR: 10318 WHALLEY BLVD, Surrey, BC
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