This is a query that gathers 12 pieces of information from an XML column by using the xpath function. It performs very poorly, and causes PG's memory use to balloon, risking the availability of what is a production DB. (PG 9.1) How can this be rewritten to be more RAM-efficient, and possibly return results more quickly?

xpath-heavy.sql

drop table if exists temp_foo1;
select 
    foorr.id as foo_raw_responses_id
  , foorr.created_at as foo_created_at
  , foorr.customer_id
  , (xpath( '////foo:response/foo:RecordCount/text()',
            xmlconcat( foorr.value::xml ),
            ARRAY[ ARRAY[ 'soap', 'http://schemas.xmlsoap.org/soap/envelope/' ],
                   ARRAY[ 'foo', 'http://example.com/ExampleService' ] ] ))[1]::varchar::numeric 
    as foo_RecordCount
  , unnest(xpath( '////foo:response/foo:Records/foo:Record/foo:ObjectInfo/foo:ObjectID/text()',
            xmlconcat( foorr.value::xml ),
            ARRAY[ ARRAY[ 'soap', 'http://schemas.xmlsoap.org/soap/envelope/' ],
                   ARRAY[ 'foo', 'http://example.com/ExampleService' ] ] ) )::varchar 
    as foo_ObjectID

  , unnest(xpath( '////foo:response/foo:Records/foo:Record/foo:Registrants/foo:Registrant/foo:HistoryDescription/text()',
            xmlconcat( foorr.value::xml ),
            ARRAY[ ARRAY[ 'soap', 'http://schemas.xmlsoap.org/soap/envelope/' ],
                   ARRAY[ 'foo', 'http://example.com/ExampleService' ] ] ) )::varchar 
    as foo_HistoryDescription
  , unnest(xpath( '////foo:response/foo:Records/foo:Record/foo:Registrants/foo:Registrant/foo:RegistrationInfo/foo:LatestEffectiveDate/foo:Year/text()',
            xmlconcat( foorr.value::xml ),
            ARRAY[ ARRAY[ 'soap', 'http://schemas.xmlsoap.org/soap/envelope/' ],
                   ARRAY[ 'foo', 'http://example.com/ExampleService' ] ] ) )::varchar::numeric 
    as foo_LatestExpirationDate_year

  , unnest(xpath( '////foo:response/foo:Records/foo:Record/foo:Registrants/foo:Registrant/foo:RegistrantInfo/foo:Name/foo:First/text()',
            xmlconcat( foorr.value::xml ),
            ARRAY[ ARRAY[ 'soap', 'http://schemas.xmlsoap.org/soap/envelope/' ],
                   ARRAY[ 'foo', 'http://example.com/ExampleService' ] ] ) )::varchar 
    as foo_FirstName
  , unnest(xpath( '////foo:response/foo:Records/foo:Record/foo:Registrants/foo:Registrant/foo:RegistrantInfo/foo:Name/foo:Last/text()',
            xmlconcat( foorr.value::xml ),
            ARRAY[ ARRAY[ 'soap', 'http://schemas.xmlsoap.org/soap/envelope/' ],
                   ARRAY[ 'foo', 'http://example.com/ExampleService' ] ] ) )::varchar 
    as foo_LastName
  , unnest(xpath( '////foo:response/foo:Records/foo:Record/foo:Registrants/foo:Registrant/foo:RegistrantInfo/foo:Address/foo:StreetNumber/text()',
            xmlconcat( foorr.value::xml ),
            ARRAY[ ARRAY[ 'soap', 'http://schemas.xmlsoap.org/soap/envelope/' ],
                   ARRAY[ 'foo', 'http://example.com/ExampleService' ] ] ) )::varchar 
    as foo_StreetNumber
  , unnest(xpath( '////foo:response/foo:Records/foo:Record/foo:Registrants/foo:Registrant/foo:RegistrantInfo/foo:Address/foo:StreetName/text()',
            xmlconcat( foorr.value::xml ),
            ARRAY[ ARRAY[ 'soap', 'http://schemas.xmlsoap.org/soap/envelope/' ],
                   ARRAY[ 'foo', 'http://example.com/ExampleService' ] ] ) )::varchar 
    as foo_StreetName
  , unnest(xpath( '////foo:response/foo:Records/foo:Record/foo:Registrants/foo:Registrant/foo:RegistrantInfo/foo:Address/foo:StreetSuffix/text()',
            xmlconcat( foorr.value::xml ),
            ARRAY[ ARRAY[ 'soap', 'http://schemas.xmlsoap.org/soap/envelope/' ],
                   ARRAY[ 'foo', 'http://example.com/ExampleService' ] ] ) )::varchar 
    as foo_StreetSuffix
  , unnest(xpath( '////foo:response/foo:Records/foo:Record/foo:Registrants/foo:Registrant/foo:RegistrantInfo/foo:Address/foo:City/text()',
            xmlconcat( foorr.value::xml ),
            ARRAY[ ARRAY[ 'soap', 'http://schemas.xmlsoap.org/soap/envelope/' ],
                   ARRAY[ 'foo', 'http://example.com/ExampleService' ] ] ) )::varchar 
    as foo_City
  , unnest(xpath( '////foo:response/foo:Records/foo:Record/foo:Registrants/foo:Registrant/foo:RegistrantInfo/foo:Address/foo:State/text()',
            xmlconcat( foorr.value::xml ),
            ARRAY[ ARRAY[ 'soap', 'http://schemas.xmlsoap.org/soap/envelope/' ],
                   ARRAY[ 'foo', 'http://example.com/ExampleService' ] ] ) )::varchar 
    as foo_State
  , unnest(xpath( '////foo:response/foo:Records/foo:Record/foo:Registrants/foo:Registrant/foo:RegistrantInfo/foo:Address/foo:Zip5/text()',
            xmlconcat( foorr.value::xml ),
            ARRAY[ ARRAY[ 'soap', 'http://schemas.xmlsoap.org/soap/envelope/' ],
                   ARRAY[ 'foo', 'http://example.com/ExampleService' ] ] ) )::varchar 
    as foo_Zip5 
into temp temp_foo1

from foo_raw_responses foorr
limit 50
;