Re: Graphing query results from within psql.

On Wed, Feb 13, 2013 at 5:17 PM, Aleksey Tsalolikhin
<atsaloli.tech@gmail.com> wrote:
> Below is an example of feeding query output to gnuplot without leaving psql.
> I'd like to call it as "select graph(select * from example)", just for fun.
> What do I need to learn to do that, please?  Can I create a function that
> uses "\o"?  I think not, because a function runs server-side and \o is a
> client side feature.

plpython/plperl/etc plus this way of calling

select just_for_fun_graph('select ... from ...', 'My Graph', 78, 24, ...)

will do the trick.


>
> This is not a production issue, just learning, for fun.
>
>   # psql -U postgres
>   psql (8.4.15)
>   Type "help" for help.
>
>   postgres=# \t
>   Showing only tuples.
>   postgres=# \a
>   Output format is unaligned.
>   postgres=# \f ' '
>   Field separator is " ".
>   postgres=# select * from example;
>   1 1
>   2 2
>   3 3
>   4 4
>   postgres=# \o | /usr/bin/gnuplot
>   postgres=# select 'set title "My Graph"; set terminal dumb 78 24; set key
> off; set ylabel "Time"; set xlabel "Servers";' || 'plot ''-'' with lines;' ;
> select * from example;
>   postgres=# \o
>
>                                     My Graph
>   Time
>       4
> ++----------+----------+-----------+----------+-----------+---------**
>         +           +          +           +          +            +
> **** +
>       |                                                           ****     |
>   3.5 ++                                                      ****        ++
>       |                                                   ****             |
>       |                                               ****                 |
>     3 ++                                           ***                    ++
>       |                                        ****                        |
>       |                                    ****                            |
>   2.5 ++                               ****                               ++
>       |                            ****                                    |
>       |                        ****                                        |
>     2 ++                    ***                                           ++
>       |                 ****                                               |
>       |             ****                                                   |
>   1.5 ++        ****                                                      ++
>       |     ****                                                           |
>       + ****      +          +           +          +           +          +
>     1 **----------+----------+-----------+----------+-----------+---------++
>       1          1.5         2          2.5         3          3.5         4
>                                      Servers
>
>   postgres=#
>
> Best,
> Aleksey
>
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