From: Rajesh Kumar Mallah <mallah@trade-india.com>
Organization: Infocom Network Limited
To: pgsql-sql@postgresql.org
Subject: apparent problem with a PL
Date: Sat, 19 Apr 2003 11:29:39 +0530
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Hi,

If I limit  a particular query to show 3 results which has a function call
how can the function get called 4 times ? its apparently happening to me.

tradein_clients=# SELECT company_id, utils.pgxml_xpath_pl('/Company@CompanyId' , xml) from 
companies where xml is not null limit 3;

INFO:  function pgxml_xpath_pl has been called
INFO:  function pgxml_xpath_pl has been called
INFO:  function pgxml_xpath_pl has been called
INFO:  function pgxml_xpath_pl has been called
+------------+----------------+
| company_id | pgxml_xpath_pl |
+------------+----------------+
|         65 | 65             |
|        187 | 187            |
|        382 | 382            |
+------------+----------------+
(3 rows)


but when i filter by a column the behaviour is rite:

tradein_clients=# SELECT company_id, utils.pgxml_xpath_pl('/Company@CompanyId' , xml) from 
companies where xml is not null and company_id=65;
INFO:  function pgxml_xpath_pl has been called
+------------+----------------+
| company_id | pgxml_xpath_pl |
+------------+----------------+
|         65 | 65             |
+------------+----------------+
(1 row)
tradein_clients=#


output of vacuum full verbose analyze  :
( but the faulty behaviour persists)

tradein_clients=# VACUUM FULL Verbose ANALYZE companies ;
INFO:  --Relation public.companies--
INFO:  Pages 385: Changed 0, reaped 377, Empty 0, New 0; Tup 713: Vac 713, Keep/VTL 0/0, UnUsed 2759, MinLen 244, MaxLen 2033; Re-using: Free/Avail. Space 2525848/2524400; EndEmpty/Avail. Pages 0/374.
        CPU 0.00s/0.00u sec elapsed 0.00 sec.
INFO:  Index companies_company_id_key: Pages 15; Tuples 713: Deleted 713.
        CPU 0.00s/0.00u sec elapsed 0.00 sec.
INFO:  Index companies_keywordidx: Pages 75; Tuples 555: Deleted 555.
        CPU 0.00s/0.00u sec elapsed 0.00 sec.
INFO:  Index companies_email: Pages 34; Tuples 713: Deleted 713.
        CPU 0.00s/0.00u sec elapsed 0.00 sec.
INFO:  Rel companies: Pages: 385 --> 77; Tuple(s) moved: 359.
        CPU 0.01s/0.05u sec elapsed 0.11 sec.
INFO:  Index companies_company_id_key: Pages 15; Tuples 713: Deleted 359.
        CPU 0.00s/0.00u sec elapsed 0.00 sec.
INFO:  Index companies_keywordidx: Pages 75; Tuples 555: Deleted 329.
        CPU 0.00s/0.00u sec elapsed 0.00 sec.
INFO:  Index companies_email: Pages 34; Tuples 713: Deleted 359.
        CPU 0.00s/0.00u sec elapsed 0.00 sec.
INFO:  --Relation pg_toast.pg_toast_14656776--
INFO:  Pages 300: Changed 300, reaped 0, Empty 0, New 0; Tup 1382: Vac 0, Keep/VTL 0/0, UnUsed 0, MinLen 37, MaxLen 2034; Re-using: Free/Avail. Space 285232/284268; EndEmpty/Avail. Pages 0/289.
        CPU 0.00s/0.00u sec elapsed 0.00 sec.
INFO:  Index pg_toast_14656776_index: Pages 16; Tuples 1382.
        CPU 0.00s/0.00u sec elapsed 0.01 sec.
INFO:  Rel pg_toast_14656776: Pages: 300 --> 300; Tuple(s) moved: 0.
        CPU 0.00s/0.00u sec elapsed 0.00 sec.
INFO:  Analyzing public.companies
VACUUM
tradein_clients=#


CREATE OR REPLACE FUNCTION utils.pgxml_xpath_pl (varchar,text) RETURNS text AS '
use XML::XPath::Simple;

my ($xpath , $xml ) = @_;
my $xp;

elog INFO , "function pgxml_xpath_pl has been called";

eval {
        $xp = new XML::XPath::Simple(xml => $xml ,context => "/");
};
if ($@)
{
        elog ERROR , "There was an error: $@ ";
}

my $content = $xp->valueof($xpath);

return $content;

' LANGUAGE 'plperlu';

Can anyone shed some light

Regds
Mallah.


-- 
Rajesh Kumar Mallah,
Project Manager (Development)
Infocom Network Limited, New Delhi
phone: +91(11)6152172 (221) (L) ,9811255597 (M)

Visit http://www.trade-india.com ,
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