Siapkan fungsionalitas Oracle UTL_FILE pada Aurora PostgreSQL yang kompatibel

Rakesh Raghav dan anuradha chintha, Amazon Web Services

Ringkasan

Sebagai bagian dari perjalanan migrasi Anda dari Oracle ke Amazon Aurora PostgreSQL Compatible Edition di Amazon Web Services (AWS) Cloud, Anda mungkin menghadapi beberapa tantangan. Misalnya, memigrasikan kode yang bergantung pada UTL_FILE utilitas Oracle selalu menjadi tantangan. Di Oracle PL/SQL, UTL_FILE paket ini digunakan untuk operasi file, seperti baca dan tulis, bersama dengan sistem operasi yang mendasarinya. UTL_FILEUtilitas ini berfungsi untuk sistem server dan mesin klien. 

Amazon Aurora PostgreSQL kompatibel adalah penawaran database terkelola. Karena itu, tidak mungkin mengakses file di server database. Pola ini memandu Anda melalui integrasi Amazon Simple Storage Service (Amazon S3) dan Amazon Aurora PostgreSQL yang kompatibel untuk mencapai subset fungsionalitas. UTL_FILE Dengan menggunakan integrasi ini, kita dapat membuat dan menggunakan file tanpa menggunakan alat atau layanan ekstrak, transformasi, dan muat (ETL) pihak ketiga.

Secara opsional, Anda dapat mengatur CloudWatch pemantauan Amazon dan notifikasi Amazon SNS.

Kami merekomendasikan pengujian solusi ini secara menyeluruh sebelum menerapkannya di lingkungan produksi.

Prasyarat dan batasan

Prasyarat

Batasan

Pola ini tidak menyediakan fungsionalitas untuk bertindak sebagai pengganti UTL_FILE utilitas Oracle. Namun, langkah-langkah dan kode sampel dapat ditingkatkan lebih lanjut untuk mencapai tujuan modernisasi database Anda.

Versi produk

Arsitektur

Tumpukan teknologi target

Arsitektur target

Diagram berikut menunjukkan representasi tingkat tinggi dari solusi.

Alat

Kode

Untuk mencapai fungsionalitas yang diperlukan, pola membuat beberapa fungsi dengan penamaan yang mirip denganUTL_FILE. Bagian Informasi tambahan berisi basis kode untuk fungsi-fungsi ini.

Dalam kode, ganti testaurorabucket dengan nama bucket S3 pengujian Anda. Ganti us-east-1 dengan Wilayah AWS tempat bucket S3 pengujian Anda berada.

Epik

CREATE SCHEMA utl_file_utility;

CREATE TYPE utl_file_utility.file_type AS (
    p_path character varying(30),
    p_file_name character varying
);

Sumber daya terkait

Informasi tambahan

Menyiapkan kebijakan IAM

Buat kebijakan berikut.

{
    "Version": "2012-10-17",		 	 	 
    "Statement": [
        {
            "Sid": "S3integrationtest",
            "Effect": "Allow",
            "Action": [
                "s3:GetObject",
                "s3:ListBucket"
            ],
            "Resource": [
         "arn:aws:s3:::testaurorabucket/*",
         "arn:aws:s3:::testaurorabucket"
            ]
        }
    ]
}

{
    "Version": "2012-10-17",		 	 	 
    "Statement": [
        {
            "Sid": "S3integrationtest",
            "Effect": "Allow",
            "Action": [
                "s3:PutObject",                
                "s3:ListBucket"
            ],
            "Resource": [                "arn:aws:s3:::testaurorabucket/*",                "arn:aws:s3:::testaurorabucket"
            ]
        }
    ]
}

Buat fungsi init

Untuk menginisialisasi variabel umum, seperti bucket atauregion, buat init fungsi dengan menggunakan kode berikut.

CREATE OR REPLACE FUNCTION utl_file_utility.init(
    )
    RETURNS void
    LANGUAGE 'plpgsql'

    COST 100
    VOLATILE 
AS $BODY$
BEGIN
      perform set_config
      ( format( '%s.%s','UTL_FILE_UTILITY', 'region' )
      , 'us-east-1'::text
      , false );

      perform set_config
      ( format( '%s.%s','UTL_FILE_UTILITY', 's3bucket' )
      , 'testaurorabucket'::text
      , false );
END;
$BODY$;

Buat fungsi pembungkus

Buat fungsifopen,put_line, dan fclose pembungkus.

fopen

CREATE OR REPLACE FUNCTION utl_file_utility.fopen(
    p_file_name character varying,
    p_path character varying,
    p_mode character DEFAULT 'W'::bpchar,
    OUT p_file_type utl_file_utility.file_type)
    RETURNS utl_file_utility.file_type
    LANGUAGE 'plpgsql'

    COST 100
    VOLATILE 
AS $BODY$
declare
    v_sql character varying;
    v_cnt_stat integer;
    v_cnt integer;
    v_tabname character varying;
    v_filewithpath character varying;
    v_region character varying;
    v_bucket character varying;

BEGIN
    /*initialize common variable */
    PERFORM utl_file_utility.init();
    v_region := current_setting( format( '%s.%s', 'UTL_FILE_UTILITY', 'region' ) );
    v_bucket :=  current_setting( format( '%s.%s', 'UTL_FILE_UTILITY', 's3bucket' ) );
    
    /* set tabname*/
    v_tabname := substring(p_file_name,1,case when strpos(p_file_name,'.') = 0 then length(p_file_name) else strpos(p_file_name,'.') - 1 end );
    v_filewithpath := case when NULLif(p_path,'') is null then p_file_name else concat_ws('/',p_path,p_file_name) end ;
    raise notice 'v_bucket %, v_filewithpath % , v_region %', v_bucket,v_filewithpath, v_region;
    
    /* APPEND MODE HANDLING; RETURN EXISTING FILE DETAILS IF PRESENT ELSE CREATE AN EMPTY FILE */
    IF p_mode = 'A' THEN
        v_sql := concat_ws('','create temp table if not exists ', v_tabname,' (col1 text)');
        execute v_sql;

        begin
        PERFORM aws_s3.table_import_from_s3 
            ( v_tabname, 
            '',  
            'DELIMITER AS ''#''', 
            aws_commons.create_s3_uri 
            (     v_bucket, 
                v_filewithpath ,
                v_region)
            );
        exception
            when others then
             raise notice 'File load issue ,%',sqlerrm;
             raise;
        end;
        execute concat_ws('','select count(*) from ',v_tabname) into v_cnt;

        IF v_cnt > 0 
        then
            p_file_type.p_path := p_path;
            p_file_type.p_file_name := p_file_name;
        else         
            PERFORM aws_s3.query_export_to_s3('select ''''', 
                            aws_commons.create_s3_uri(v_bucket, v_filewithpath, v_region)            
                              );

            p_file_type.p_path := p_path;
            p_file_type.p_file_name := p_file_name;        
        end if;
        v_sql := concat_ws('','drop table ', v_tabname);        
        execute v_sql;            
    ELSEIF p_mode = 'W' THEN
            PERFORM aws_s3.query_export_to_s3('select ''''', 
                            aws_commons.create_s3_uri(v_bucket, v_filewithpath, v_region)            
                              );
            p_file_type.p_path := p_path;
            p_file_type.p_file_name := p_file_name;
    END IF;    
    
EXCEPTION
        when others then
            p_file_type.p_path := p_path;
            p_file_type.p_file_name := p_file_name;
            raise notice 'fopenerror,%',sqlerrm;
            raise;
END;
$BODY$;

put_line

CREATE OR REPLACE FUNCTION utl_file_utility.put_line(
    p_file_name character varying,
    p_path character varying,
    p_line text,
    p_flag character DEFAULT 'W'::bpchar)
    RETURNS boolean
    LANGUAGE 'plpgsql'

    COST 100
    VOLATILE 
AS $BODY$
/**************************************************************************
* Write line, p_line in windows format to file, p_fp - with carriage return
* added before new line.
**************************************************************************/
declare
    v_sql varchar;
    v_ins_sql varchar;
    v_cnt INTEGER;
    v_filewithpath character varying;
    v_tabname  character varying;
    v_bucket character varying;
    v_region character varying;    

BEGIN
 PERFORM utl_file_utility.init();

/* check if temp table already exist */

 v_tabname := substring(p_file_name,1,case when strpos(p_file_name,'.') = 0 then length(p_file_name) else strpos(p_file_name,'.') - 1 end );

 v_sql := concat_ws('','select count(1) FROM pg_catalog.pg_class c LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace where n.nspname like ''pg_temp_%''' 
                         ,' AND pg_catalog.pg_table_is_visible(c.oid) AND Upper(relname) = Upper( '''
                         ,  v_tabname ,''' ) ');
  
 execute v_sql into v_cnt;
  
  IF v_cnt = 0 THEN
         v_sql := concat_ws('','create temp table ',v_tabname,' (col text)');
        execute v_sql;
        /* CHECK IF APPEND MODE */
        IF upper(p_flag) = 'A' THEN
            PERFORM utl_file_utility.init();                        
            v_region := current_setting( format( '%s.%s', 'UTL_FILE_UTILITY', 'region' ) );
            v_bucket :=  current_setting( format( '%s.%s', 'UTL_FILE_UTILITY', 's3bucket' ) );
            
            /* set tabname*/            
            v_filewithpath := case when NULLif(p_path,'') is null then p_file_name else concat_ws('/',p_path,p_file_name) end ;            
            
            begin
               PERFORM aws_s3.table_import_from_s3 
                     ( v_tabname, 
                          '',  
                       'DELIMITER AS ''#''', 
                        aws_commons.create_s3_uri 
                           ( v_bucket, 
                               v_filewithpath, 
                               v_region    )
                    );
            exception
                when others then
                    raise notice  'Error Message : %',sqlerrm;
                    raise;
            end;    
        END IF;    
    END IF;
    /* INSERT INTO TEMP TABLE */              
    v_ins_sql := concat_ws('','insert into ',v_tabname,' values(''',p_line,''')');
    execute v_ins_sql;
    RETURN TRUE;
    exception
            when others then
                raise notice  'Error Message : %',sqlerrm;
                raise;
END;
$BODY$;

fclose

CREATE OR REPLACE FUNCTION utl_file_utility.fclose(
    p_file_name character varying,
    p_path character varying)
    RETURNS boolean
    LANGUAGE 'plpgsql'

    COST 100
    VOLATILE 
AS $BODY$
DECLARE
    v_filewithpath character varying;
    v_bucket character varying;
    v_region character varying;
    v_tabname character varying;
    v_sql character varying;
BEGIN
      PERFORM utl_file_utility.init();
  
    v_region := current_setting( format( '%s.%s', 'UTL_FILE_UTILITY', 'region' ) );
    v_bucket :=  current_setting( format( '%s.%s', 'UTL_FILE_UTILITY', 's3bucket' ) );

    v_tabname := substring(p_file_name,1,case when strpos(p_file_name,'.') = 0 then length(p_file_name) else strpos(p_file_name,'.') - 1 end );
    v_filewithpath := case when NULLif(p_path,'') is null then p_file_name else concat_ws('/',p_path,p_file_name) end ;

    raise notice 'v_bucket %, v_filewithpath % , v_region %', v_bucket,v_filewithpath, v_region ;
    
    /* exporting to s3 */
    perform aws_s3.query_export_to_s3
        (concat_ws('','select * from ',v_tabname,'  order by ctid asc'), 
            aws_commons.create_s3_uri(v_bucket, v_filewithpath, v_region)
        );
    v_sql := concat_ws('','drop table ', v_tabname);
    execute v_sql;    
    RETURN TRUE;
EXCEPTION 
       when others then
     raise notice 'error fclose %',sqlerrm;
     RAISE;
END;
$BODY$;

Uji fungsi pengaturan dan pembungkus Anda

Gunakan blok kode anonim berikut untuk menguji pengaturan Anda.

Uji mode tulis

Kode berikut menulis file bernama s3inttest dalam bucket S3.

do $$
declare
l_file_name varchar := 's3inttest' ;
l_path varchar := 'integration_test' ;
l_mode char(1) := 'W';
l_fs utl_file_utility.file_type ;
l_status boolean;

begin
select * from
utl_file_utility.fopen( l_file_name, l_path , l_mode ) into l_fs ;
raise notice 'fopen : l_fs : %', l_fs;

select * from
utl_file_utility.put_line( l_file_name, l_path ,'this is test file:in s3bucket: for test purpose', l_mode ) into l_status ;
raise notice 'put_line : l_status %', l_status;

select * from utl_file_utility.fclose( l_file_name , l_path ) into l_status ;
raise notice 'fclose : l_status %', l_status;

end;
$$

Uji mode append

Kode berikut menambahkan baris ke s3inttest file yang dibuat dalam tes sebelumnya.

do $$
declare
l_file_name varchar := 's3inttest' ;
l_path varchar := 'integration_test' ;
l_mode char(1) := 'A';
l_fs utl_file_utility.file_type ;
l_status boolean;

begin
select * from
utl_file_utility.fopen( l_file_name, l_path , l_mode ) into l_fs ;
raise notice 'fopen : l_fs : %', l_fs;


select * from
utl_file_utility.put_line( l_file_name, l_path ,'this is test file:in s3bucket: for test purpose : append 1', l_mode ) into l_status ;
raise notice 'put_line : l_status %', l_status;

select * from
utl_file_utility.put_line( l_file_name, l_path ,'this is test file:in s3bucket : for test purpose : append 2', l_mode ) into l_status ;
raise notice 'put_line : l_status %', l_status;

select * from utl_file_utility.fclose( l_file_name , l_path ) into l_status ;
raise notice 'fclose : l_status %', l_status;

end;
$$

Pemberitahuan Amazon SNS

Secara opsional, Anda dapat mengatur CloudWatch pemantauan Amazon dan notifikasi Amazon SNS di bucket S3. Untuk informasi selengkapnya, lihat Memantau Amazon S3 dan Menyiapkan Pemberitahuan Amazon SNS.