[pgpool-hackers: 1559] Re: Syntax for pgpool SHOW and SET commands

[Muhammad Usama]

On Sat, May 7, 2016 at 12:10 PM, Tatsuo Ishii <ishii at postgresql.org> wrote:

> > On Fri, May 6, 2016 at 4:44 PM, Tatsuo Ishii <ishii at postgresql.org>
> wrote:
> >
> >> Usama,
> >>
> >> Why do we need "PGPOOL" keyword? It seems to be annoying.
> >>
> >
> > Basically, there are two reasons. First,is there are some configuration
> > parameter names that are same in PostgreSQL and pgpool-II like
> > "port", "log_min_messages"  and many others. So if we use the same syntax
> > without any difference, we would have no way of telling if the command is
> > referring to the pgpool-II or Backend.
> >
> > like
> > SHOW port;
> > This command would be valid for both pgpool-II and PostgreSQL parameter.
> >
> > Second, I think it's good to have distinction in commands for
> > setting/showing GUC and pgpool variables, otherwise it could cause the
> > confusions.
>
> Ok, fair enough. BTW, I thought very limited number of pgpool
> variables can be changed by the "PGPOOL SET" command. Do you have
> complete list of such variable names which can be changed using
> "PGPOOL SET"?
>

Thanks for looking into this. I have added the command with this syntax.

On the part of variables that can be changed for session only using the
PGPOOL SET command I was thinking to start a separate discussion thread
once the coding part is complete.

I have given a little thought on the parameters that we can allow to be
changed through SET command and currently, I can only think of parameter
related to life connection and child's lifetime that can be safely changed
through SET command. i.e.

--child_life_time
--client_idle_limit
--connection_life_time
--child_max_connections

But to finalize the list of parameters I think we should carefully consider
each and every pgpool-II config parameter and its effect if it is changed
for a particular session only.

And it would be great to get your and the community input on making that
list of parameters.


Kind regards
Muhammad Usama




> Best regards,
> --
> Tatsuo Ishii
> SRA OSS, Inc. Japan
> English: http://www.sraoss.co.jp/index_en.php
> Japanese:http://www.sraoss.co.jp
>
> >> > Hi
> >> >
> >> > I am currently working on adding the SHOW and SET commands for
> pgpool-II
> >> > configuration parameter, these commands will allow the user to alter
> the
> >> > specific pgpool-II configuration parameter values for a user session.
> >> More
> >> > or less, these commands will work in similar ways as PostgreSQL's SET
> and
> >> > SHOW commands for PostgreSQL's GUC variables. I have already checked
> in
> >> the
> >> > configuration parameter framework to the pgpool master branch and
> before
> >> I
> >> > push the SET and SHOW command functionality I want the opinion on the
> >> > syntax of these two commands.
> >> >
> >> > I am thinking of using the PG's syntax with an addition of PGPOOL
> keyword
> >> > at the start
> >> >
> >> > For example
> >> >
> >> > PostgreSQL uses the following syntax for SHOW and SET command
> >> >
> >> > SHOW variable_name;
> >> > SHOW all;
> >> > SET variable_name to value;
> >> > SET variable_name to DEFAULT;
> >> > ..
> >> >
> >> > And for pgpool variables we can use
> >> >
> >> > PGPOOL SHOW variable_name;
> >> > PGPOOL SHOW all;
> >> > PGPOOL SET variable_name to value;
> >> > PGPOOL SET variable_name to DEFAULT;
> >> > ..
> >> >
> >> > Suggestions and thoughts.
> >> >
> >> > Kind Regards
> >> > Muhammad Usmaa
> >>
>
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