Postgresql函数创建外部表

Question

我在greenplum DB中有这个功能，由于某种原因它无法正常工作。 当我运行这个函数时，它应该创建一个外部表，但事实并非如此，这是我第一次在Greenplum中编写一个函数，所以请原谅我是否应该是一个愚蠢的错误。任何人都可以尝试帮助我。

-------------------------------------------------------------------------------
-- begin maintenance wrapper 
-- check and delete function with different return type
if (
    select 1 from pg_proc p
        inner join pg_namespace n on p.pronamespace = n.oid
        inner join pg_type t on p.prorettype = t.oid
    where n.nspname = 'staging'
        and p.proname = 'fn_file_data_create_external'
        and oidvectortypes(p.proargtypes) = 'text, text'
        and t.typname <> 'void'
)
    drop function if exists staging.fn_file_data_create_external(text, text);
-- second check
if (
    select 1 from pg_proc p
        inner join pg_namespace n on p.pronamespace = n.oid
        inner join pg_type t on p.prorettype = t.oid
    where n.nspname = 'staging'
        and p.proname = 'fn_file_data_create_external'
        and oidvectortypes(p.proargtypes) = 'text, text'
        and t.typname <> 'void'
)
begin
    print '<<< Cannot delete last version of staging.fn_file_data_create_external >>>';
end
else
begin
-- end maintenance wrapper
-------------------------------------------------------------------------------
/******************************************************************************
author name         :   XXXXXXXXXXX
svn location        :   
table name          :   staging.fn_file_data_create_external
description         :   create file_data external table

revision history    :
version date        modified by     issue no    description
------- ----------  ----------------    --------    ---------------
1.0 12-26-2013  XXXXXXXXXXXX        initial version
******************************************************************************/
CREATE OR REPLACE FUNCTION staging.fn_file_data_create_external( gpfdist_server_ text, file_name_ text)
  RETURNS void AS
$BODY$
declare
    schema_ constant text := 'staging';
    owner_ constant text := 'dev_staging_develop';
    table_ text := 'file_data';
    source_ text := schema_ ||'.'||'ext_'||table_||'_'||file_name_;
begin

    -----------------------------------------------------------------------
    raise notice 'Prepare external table';
    -----------------------------------------------------------------------
    execute 'drop external table if exists '||source_;
    execute 'create external table '||source_||' (data_line text)
        location('||quote_literal(
            'gpfdist://'
            ||gpfdist_server_
            ||'/'
            ||file_name_
            ||'.dat')
        ||') format ''TEXT'' encoding ''LATIN1''';
    execute 'ALTER EXTERNAL TABLE '||source_||' OWNER TO '||owner_;
end 
$BODY$
  LANGUAGE plpgsql VOLATILE;
ALTER FUNCTION staging.fn_file_data_create_external(text, text)
  OWNER TO dev_staging_develop;
-------------------------------------------------------------------------------
-- begin maintenance wrapper 
if (
    select 1 from pg_proc p
        inner join pg_namespace n on p.pronamespace = n.oid
    where n.nspname = 'staging'
        and p.proname = 'fn_file_data_create_external'
        and oidvectortypes(p.proargtypes) = 'text, text'
)
    print '<<< Function staging.fn_file_data_create_external exists, check errors in output >>>';
else
    print '<<< Error creation function staging.fn_file_data_create_external exists >>>';
end
-- end maintenance wrapper
-------------------------------------------------------------------------------