[Dbix-class] Strange beaviour with bind_params for function call

[Ash Berlin]

Since someone on irc asked on why this was actually being called 28 times:

my $rs= $App->schema->resultset('PriceVersion')->search({});
print $rs->first->get_column('cnt'), "\n";

that first there doesn't limit the sql, it just gets the first row - the other 27 are there in the cursor. The SQL underneath is still:

SELECT ... FROM price_version;

It's not

SELECT ... FROM price_version LIMIT 1;

Think of the difference in these two statements:

SELECT 1 FROM table;
SELECT 1;

-ash

On 4 Oct 2010, at 13:25, Ash Berlin wrote:
> If you want the function to be called once and don't want to use ->dbh->do the other option is to create a resultset for this. See:
> 
>  http://search.cpan.org/~frew/DBIx-Class-0.08123/lib/DBIx/Class/Manual/Cookbook.pod#Arbitrary_SQL_through_a_custom_ResultSource
>  http://search.cpan.org/~frew/DBIx-Class-0.08123/lib/DBIx/Class/ResultSource/View.pm
> 
> -ash
> 
> On 4 Oct 2010, at 12:55, Rolf Schaufelberger wrote:
>> Hi, 
>> I want to call a stored function  in Postgresql with several bind_parameters:
>> 
>> The function definition looks like:
>> 
>> create or replace function system.test_prices ( commentval varchar(255), delta_eigen float, delta_material float, set_active integer, paper_ids integer[] ) returns integer AS
>> $BODY$
>> DECLARE
>> 
>> BEGIN
>> raise notice 'ARGS : Comment %, delta_e %, delta_m %, act %', commentval, delta_eigen, delta_material, set_active;
>> insert into xx (val) values (delta_eigen) ;
>> return 123;
>> END;
>> $BODY$
>> LANGUAGE plpgsql;
>> 
>> 
>> The functions loggs the args to console and inserts some debug value  in a table;
>> The special thing here is, that the last arg is an Array of Integer (which is why I have to call with bind params), yet I believe that is not the problem, since calling a function  with one arg of type integer  array works fine.
>> 
>> My code for calling the function is:
>> ...
>> my $ids = [6024];  #the integer array
>> my $rs= $App->schema->resultset('PriceVersion')->search({},
>>               { select => {'test_prices' => \[ "?, ?, ?, ?, ?::integer[]", 
>> 	                                                                       [comment=> 'MyComment'],
>>                                                                              [delta_eigen =>5.0], 
>>                                                                              [delta_material => 10.0],
>>                                                                               [active=>0],
>>                                                                               [paper =>$ids]]},
>>                 as     => 'cnt'});
>> print $rs->first->get_column('cnt'), "\n";
>> 
>> Now,  running it gives me :
>> 
>> ~/perl/xx.pl 
>> HINWEIS:  ARGS : Comment MyComment, delta_e 5, delta_m 10, act 0
>> HINWEIS:  ARGS : Comment MyComment, delta_e 5, delta_m 10, act 0
>> HINWEIS:  ARGS : Comment MyComment, delta_e 5, delta_m 10, act 0
>> HINWEIS:  ARGS : Comment MyComment, delta_e 5, delta_m 10, act 0
>> HINWEIS:  ARGS : Comment MyComment, delta_e 5, delta_m 10, act 0
>> HINWEIS:  ARGS : Comment MyComment, delta_e 5, delta_m 10, act 0
>> HINWEIS:  ARGS : Comment MyComment, delta_e 5, delta_m 10, act 0
>> HINWEIS:  ARGS : Comment MyComment, delta_e 5, delta_m 10, act 0
>> HINWEIS:  ARGS : Comment MyComment, delta_e 5, delta_m 10, act 0
>> HINWEIS:  ARGS : Comment MyComment, delta_e 5, delta_m 10, act 0
>> HINWEIS:  ARGS : Comment MyComment, delta_e 5, delta_m 10, act 0
>> HINWEIS:  ARGS : Comment MyComment, delta_e 5, delta_m 10, act 0
>> HINWEIS:  ARGS : Comment MyComment, delta_e 5, delta_m 10, act 0
>> HINWEIS:  ARGS : Comment MyComment, delta_e 5, delta_m 10, act 0
>> HINWEIS:  ARGS : Comment MyComment, delta_e 5, delta_m 10, act 0
>> HINWEIS:  ARGS : Comment MyComment, delta_e 5, delta_m 10, act 0
>> HINWEIS:  ARGS : Comment MyComment, delta_e 5, delta_m 10, act 0
>> HINWEIS:  ARGS : Comment MyComment, delta_e 5, delta_m 10, act 0
>> HINWEIS:  ARGS : Comment MyComment, delta_e 5, delta_m 10, act 0
>> HINWEIS:  ARGS : Comment MyComment, delta_e 5, delta_m 10, act 0
>> HINWEIS:  ARGS : Comment MyComment, delta_e 5, delta_m 10, act 0
>> HINWEIS:  ARGS : Comment MyComment, delta_e 5, delta_m 10, act 0
>> HINWEIS:  ARGS : Comment MyComment, delta_e 5, delta_m 10, act 0
>> HINWEIS:  ARGS : Comment MyComment, delta_e 5, delta_m 10, act 0
>> HINWEIS:  ARGS : Comment MyComment, delta_e 5, delta_m 10, act 0
>> HINWEIS:  ARGS : Comment MyComment, delta_e 5, delta_m 10, act 0
>> HINWEIS:  ARGS : Comment MyComment, delta_e 5, delta_m 10, act 0
>> HINWEIS:  ARGS : Comment MyComment, delta_e 5, delta_m 10, act 0
>> 123
>> 
>> The function is called 28 times !!
>> 
>> Changing the "raise notice" to "raise exception" gives :
>> 
>> rs at ubuntu:	~/perl/xx.pl DBIx::Class::ResultSet::first(): DBI Exception: DBD::Pg::st execute failed: FEHLER: ARGS : Comment MyComment, delta_e 5, delta_m 10, act 0 [for Statement "SELECT TEST_PRICES( ?, ?, ?, ?, ?::integer[] ) FROM price_version me" with ParamValues: 1='MyComment', 2='5', 3='10', 4='0', 5='{"6024"}'] at /home/rs/perl/xx.pl line 37 
>> rs at ubuntu:
>> 
>> That looks quite perfect, so the syntax for binding seems to be ok. But why is the function called 28 times ??
>> DBIx::Class is 0.08121
>> 
>> 
>> Rolf Schaufelberger