如何从BasicFile迁移到SecureFile存储（一）

2024-04-02 19:55

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Oracle 11g新的SecureFile存储特性扩展了大对象(LOB)的灵活性和容量，本文研究如何有效地从BasicFile迁移到SecureFile存储，如何测量SecureFile vs BasicFile LOB的效率，以及如何为SecureFile LOB使用不同的压缩和重复数据删除选项。

　　我创建了一个新表TRBTKT.SECURE_TICKETS重新定义了原始表TRBTKT.TICKETS的结构，将原始的BasicFile LOB映射到对应的SecureFile LOB，然后执行了一条INSERT INTO … SELECT FROM DML语句将原始表中的内容传输到新表中。

　　在一个相对简单的应用程序环境中，这种载入方式足以应付，但目前在数据仓库和商业智能应用程序中广泛地使用了LOB，特别是存储那些包含了复杂商务交易的XML文档和医院信息系统捕获到的医疗影像数据。

　　为了便于说明，我使用清单1中的代码重新创建了这两个表，我使用了列表分区对这两个表进行了分区，在清单2中，我使用更大的数据重新载入TRBTKT.TICKETS表。

　　清单1 使用列表分区重新创建这两个表以模拟数据仓库环境

-- 重新创建表TRBTKT.TICKETS，这次包括了一个STATUS列
CREATE TABLE trbtkt.tickets (
     tkt_id         NUMBER
    ,description    VARCHAR2(30)
    ,submit_dtm     TIMESTAMP
    ,status         VARCHAR2(8)
    ,document       BLOB
    ,scrnimg        BLOB
)
    LOB(document)
        STORE AS BASICFILE (TABLESPACE basicfiles)
   ,LOB(scrnimg)
        STORE AS BASICFILE (TABLESPACE basicfiles)
    PARTITION BY LIST (status) (
        PARTITION sts_open
            VALUES ('OPEN')
       ,PARTITION sts_pending
            VALUES ('PENDING')
       ,PARTITION sts_closed
            VALUES ('CLOSED')
       ,PARTITION sts_other
            VALUES (DEFAULT)
    )
;

--注释
COMMENT ON TABLE trbtkt.tickets
    IS 'Contains Trouble Ticket transaction data';
COMMENT ON COLUMN trbtkt.tickets.tkt_id
    IS 'Unique identifier for a Trouble Ticket';
COMMENT ON COLUMN trbtkt.tickets.description
    IS 'Trouble Ticket Description';
COMMENT ON COLUMN trbtkt.tickets.submit_dtm
    IS 'Trouble Ticket Submission Time Stamp';
COMMENT ON COLUMN trbtkt.tickets.status
    IS 'Trouble Ticket Status';
COMMENT ON COLUMN trbtkt.tickets.document
    IS 'Large Object (LOB) that contains a Microsoft Word document that provides detailed information about a Trouble Ticket';
COMMENT ON COLUMN trbtkt.tickets.scrnimg
    IS 'Large Object (LOB) that contains a screen print or other p_w_picpath that helps a problem solver identify how to act on a Trouble Ticket';

-- 创建索引和约束
CREATE UNIQUE INDEX trbtkt.tickets_pk_idx
    ON trbtkt.tickets(tkt_id)
    TABLESPACE users;

ALTER TABLE trbtkt.tickets
    ADD CONSTRAINT tickets_pk
    PRIMARY KEY (tkt_id);

-----
-- 创建表TRBTKT.SECURE_TICKETS的一个改良版本，使用分区划分SecureFile LOB的存储，基于STATUS 的值设置合适的保留周期
DROP TABLE trbtkt.secure_tickets PURGE;
CREATE TABLE trbtkt.secure_tickets (
     tkt_id         NUMBER
    ,description    VARCHAR2(30)
    ,submit_dtm     TIMESTAMP
    ,status         VARCHAR2(8)
    ,document       BLOB
    ,scrnimg        BLOB
)
    LOB(document)
        STORE AS SECUREFILE (
            TABLESPACE securefiles
            DISABLE STORAGE IN ROW
            CACHE
        )
   ,LOB(scrnimg)
        STORE AS SECUREFILE (
            TABLESPACE securefiles
            DISABLE STORAGE IN ROW
            CACHE READS
        )
    PARTITION BY LIST (status) (
        PARTITION sts_open
            VALUES ('OPEN')
                LOB (document) STORE AS SECUREFILE (KEEP_DUPLICATES NOCOMPRESS)
               ,LOB (scrnimg)  STORE AS SECUREFILE (KEEP_DUPLICATES COMPRESS)
       ,PARTITION sts_pending
            VALUES ('PENDING')
                LOB (document) STORE AS SECUREFILE (KEEP_DUPLICATES NOCOMPRESS)
               ,LOB (scrnimg)  STORE AS SECUREFILE (DEDUPLICATE COMPRESS)
       ,PARTITION sts_closed
            VALUES ('CLOSED')
                LOB (document) STORE AS SECUREFILE (DEDUPLICATE COMPRESS)
               ,LOB (scrnimg)  STORE AS SECUREFILE (DEDUPLICATE COMPRESS HIGH)
       ,PARTITION sts_other
            VALUES (DEFAULT)
                LOB (document) STORE AS SECUREFILE (DEDUPLICATE COMPRESS HIGH)
               ,LOB (scrnimg)  STORE AS SECUREFILE (DEDUPLICATE COMPRESS HIGH)
    )
;

--注释
COMMENT ON TABLE trbtkt.secure_tickets
    IS 'Contains Trouble Ticket transaction data';
COMMENT ON COLUMN trbtkt.secure_tickets.tkt_id
    IS 'Unique identifier for a Trouble Ticket';
COMMENT ON COLUMN trbtkt.secure_tickets.description
    IS 'Trouble Ticket Description';
COMMENT ON COLUMN trbtkt.secure_tickets.submit_dtm
    IS 'Trouble Ticket Submission Time Stamp';
COMMENT ON COLUMN trbtkt.secure_tickets.status
    IS 'Trouble Ticket Status';
COMMENT ON COLUMN trbtkt.secure_tickets.document
    IS 'Large Object (LOB) that contains a Microsoft Word document that provides detailed information about a Trouble Ticket';
COMMENT ON COLUMN trbtkt.secure_tickets.scrnimg
    IS 'Large Object (LOB) that contains a screen print or other p_w_picpath that helps a problem solver identify how to act on a Trouble Ticket';

　　　清单2 使用附加数据重新载入表TRBTKT.TICKETS

SET SERVEROUTPUT ON
TRUNCATE TABLE trbtkt.tickets;

BEGIN

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 101
        ,description => 'Trouble Ticket 101'
        ,submit_dts => '2008-12-31 23:45:00'
        ,status => 'OPEN'
        ,docFileName => 'New_101.doc'
        ,imgFileName => 'DBRIssues.jpg'
    );

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 102
        ,description => 'Trouble Ticket 102'
        ,submit_dts => '2009-01-04 00:00:00'
        ,status => 'OPEN'
        ,docFileName => 'New_102.doc'
        ,imgFileName => 'Unresolved.jpg'
    );

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 103
        ,description => 'Trouble Ticket 103'
        ,submit_dts => '2009-01-02 00:00:00'
        ,status => 'OPEN'
        ,docFileName => 'New_103.doc'
        ,imgFileName => 'Unresolved.jpg'
     );

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 104
        ,description => 'Trouble Ticket 104'
        ,submit_dts => '2009-01-14 12:30:00'
        ,status => 'OPEN'
        ,docFileName => 'New_104.doc'
        ,imgFileName => 'DBRIssues.jpg'
   );

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 105
        ,description => 'Trouble Ticket 105'
        ,submit_dts => '2009-01-09 00:00:00'
        ,status => 'OPEN'
        ,docFileName => 'New_105.doc'
        ,imgFileName => 'Unresolved.jpg'
    );

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 106
        ,description => 'Trouble Ticket 106'
        ,submit_dts => '2009-01-11 00:00:00'
        ,status => 'OPEN'
        ,docFileName => 'New_106.doc'
        ,imgFileName => 'Unresolved.jpg'
    );

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 107
        ,description => 'Trouble Ticket 107'
        ,submit_dts => '2009-01-16 00:00:00'
        ,status => 'OPEN'
        ,docFileName => 'New_107.doc'
        ,imgFileName => 'DBRIssues.jpg'
    );

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 108
        ,description => 'Trouble Ticket 108'
        ,submit_dts => '2009-01-12 00:00:00'
        ,status => 'OPEN'
        ,docFileName => 'New_108.doc'
        ,imgFileName => 'Unresolved.jpg'
    );

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 109
        ,description => 'Trouble Ticket 109'
        ,submit_dts => '2009-01-02 00:00:00'
        ,status => 'OPEN'
        ,docFileName => 'New_109.doc'
        ,imgFileName => 'Unresolved.jpg'
     );

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 110
        ,description => 'Trouble Ticket 110'
        ,submit_dts => '2009-01-14 12:45:00'
        ,status => 'OPEN'
        ,docFileName => 'New_110.doc'
        ,imgFileName => 'DBRIssues.jpg'
   );

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 201
        ,description => 'Trouble Ticket 201'
        ,submit_dts => '2008-12-31 23:45:00'
        ,status => 'PENDING'
        ,docFileName => 'New_101.doc'
        ,imgFileName => 'DBRIssues.jpg'
    );

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 202
        ,description => 'Trouble Ticket 202'
        ,submit_dts => '2009-01-04 00:00:00'
        ,status => 'OPEN'
        ,docFileName => 'New_102.doc'
        ,imgFileName => 'Unresolved.jpg'
    );

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 203
        ,description => 'Trouble Ticket 203'
        ,submit_dts => '2009-01-02 00:00:00'
        ,status => 'CLOSED'
        ,docFileName => 'New_103.doc'
        ,imgFileName => 'Unresolved.jpg'
     );

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 204
        ,description => 'Trouble Ticket 204'
        ,submit_dts => '2009-01-14 12:30:00'
        ,status => 'OPEN'
        ,docFileName => 'New_104.doc'
        ,imgFileName => 'DBRIssues.jpg'
   );

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 205
        ,description => 'Trouble Ticket 205'
        ,submit_dts => '2009-01-09 00:00:00'
        ,status => 'OPEN'
        ,docFileName => 'New_105.doc'
        ,imgFileName => 'Unresolved.jpg'
    );

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 206
        ,description => 'Trouble Ticket 206'
        ,submit_dts => '2009-01-11 00:00:00'
        ,status => 'PENDING'
        ,docFileName => 'New_106.doc'
        ,imgFileName => 'Unresolved.jpg'
    );

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 207
        ,description => 'Trouble Ticket 207'
        ,submit_dts => '2009-01-16 00:00:00'
        ,status => 'OPEN'
        ,docFileName => 'New_107.doc'
        ,imgFileName => 'DBRIssues.jpg'
    );

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 208
        ,description => 'Trouble Ticket 208'
        ,submit_dts => '2009-01-12 00:00:00'
        ,status => 'OPEN'
        ,docFileName => 'New_108.doc'
        ,imgFileName => 'Unresolved.jpg'
    );

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 209
        ,description => 'Trouble Ticket 209'
        ,submit_dts => '2009-01-02 00:00:00'
        ,status => 'PENDING'
        ,docFileName => 'New_109.doc'
        ,imgFileName => 'Unresolved.jpg'
     );

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 210
        ,description => 'Trouble Ticket 210'
        ,submit_dts => '2009-01-14 12:45:00'
        ,status => 'OPEN'
        ,docFileName => 'New_110.doc'
        ,imgFileName => 'DBRIssues.jpg'
   );

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 301
        ,description => 'Trouble Ticket 301'
        ,submit_dts => '2008-12-31 23:45:00'
        ,status => 'CLOSED'
        ,docFileName => 'New_101.doc'
        ,imgFileName => 'DBRIssues.jpg'
    );

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 302
        ,description => 'Trouble Ticket 302'
        ,submit_dts => '2009-01-04 00:00:00'
        ,status => 'OPEN'
        ,docFileName => 'New_102.doc'
        ,imgFileName => 'Unresolved.jpg'
    );

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 303
        ,description => 'Trouble Ticket 303'
        ,submit_dts => '2009-01-02 00:00:00'
        ,status => 'OPEN'
        ,docFileName => 'New_103.doc'
        ,imgFileName => 'Unresolved.jpg'
     );

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 304
        ,description => 'Trouble Ticket 304'
        ,submit_dts => '2009-01-14 12:30:00'
        ,status => 'CLOSED'
        ,docFileName => 'New_104.doc'
        ,imgFileName => 'DBRIssues.jpg'
   );

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 305
        ,description => 'Trouble Ticket 305'
        ,submit_dts => '2009-01-09 00:00:00'
        ,status => 'PENDING'
        ,docFileName => 'New_105.doc'
        ,imgFileName => 'Unresolved.jpg'
    );

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 306
        ,description => 'Trouble Ticket 306'
        ,submit_dts => '2009-01-11 00:00:00'
        ,status => 'CLOSED'
        ,docFileName => 'New_106.doc'
        ,imgFileName => 'Unresolved.jpg'
    );

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 307
        ,description => 'Trouble Ticket 307'
        ,submit_dts => '2009-01-16 00:00:00'
        ,status => 'OPEN'
        ,docFileName => 'New_107.doc'
        ,imgFileName => 'DBRIssues.jpg'
    );

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 308
        ,description => 'Trouble Ticket 308'
        ,submit_dts => '2009-01-12 00:00:00'
        ,status => 'OPEN'
        ,docFileName => 'New_108.doc'
        ,imgFileName => 'Unresolved.jpg'
    );

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 309
        ,description => 'Trouble Ticket 309'
        ,submit_dts => '2009-01-02 00:00:00'
        ,status => 'CLOSED'
        ,docFileName => 'New_109.doc'
        ,imgFileName => 'Unresolved.jpg'
     );

    trbtkt.pkg_securefiles.AddTroubleTicket (
         tkt_id => 310
        ,description => 'Trouble Ticket 310'
        ,submit_dts => '2009-01-14 12:45:00'
        ,status => 'CLOSED'
        ,docFileName => 'New_110.doc'
        ,imgFileName => 'DBRIssues.jpg'
   );

    COMMIT;

END;
/
-- 收集优化器统计信息
BEGIN
    DBMS_STATS.GATHER_SCHEMA_STATS(ownname => 'TRBTKT', CASCADE => TRUE);
END;
/

　　有效地从BasicFile移植到SecureFile

　　现在已经将这些表进行了分区，以便在数据仓库环境更有效地使用，我也已经考虑过如何将LOB从BasicFile格式快速有效地转换成对应的SecureFile格式，幸运的是，Oracle 11g提供了两个方法：分区交换和在线重定义。

　　1、分区交换

　　分区交换载入(Partition Exchange Load，即PDL)有时也叫做分区转动，包含创建一个非分区表，它的格式和内容完全匹配目标分区表想要的分区，一旦原始表创建好了，就可以开始可已经分区的表的目标分区进行交换了，这个方法确实提供了许多好处，换句话说，原始表的本地索引在交换期间得到维护，它可以并行执行，这个方法可以重复多次以填充每个分区，它的主要缺点是接收数据的分区在进行交换时必须离线。

　　2、在线重定义

　　Oracle推荐使用DBMS_REDEFINITION包对源表和目标表执行在线重定义，因为它实现了分区交换方法相同的目标。但它不需要在重定义过程中将目标离线。在线重定义可以在表级也可以在分区级执行，它也可以同时并行为多个分区执行，我喜欢在线重定义的特性是在这个过程成功执行完毕后，源和目标对象将对真正地在数据库数据目录中转换定义，这意味着任何引用了新对象名的PL/SQL对象都不需要进行任何修改。清单3显示了如何使用TRBTKT.TICKETS表作为源对象，使用TRBTKT.SECURE_TICKETS表作为目标对象进行在线重定义的。从BasicFile LOB转换到SecureFile LOB最后一个注意事项是：一旦转换完成，LOB就不能再降级回到BasicFile LOB了。

　　管理SecureFile元数据

　　这些新的SecureFile特性无疑扩展了LOB的能力，对于DBA而言，也需要注意几个在传统的BasicFile LOB上增加的额外属性，幸运的是，Oracle 11g提供了多个方法跟踪BasicFile和SecureFile LOB的元数据。

　　1、数据字典视图

　　Oracle 11g也更新了多个关于SecureFile信息的数据字典视图，下面列出这些做了变动的视图。

如何从BasicFile迁移到SecureFile存储（一）

　　清单4显示了多条SQL*Plus查询，它们使用了这些数据字典视图返回关于SecureFile元数据的信息，报告1显示了从这些查询返回的结果。

　　清单4 查询BasicFile和SecureFile LOB的元数据

SET PAGESIZE 1000
SET LINESIZE 140
-- 视图: DBA_SEGMENTS
--显示关于BasicFile 和SecureFile 段的元数据
TTITLE 'LOB Segment Information|(from DBA_SEGMENTS)'
COL segment_name        FORMAT A30      HEADING 'Segment Name'
COL segment_type        FORMAT A20      HEADING 'Segment|Type'
COL segment_subtype     FORMAT A20      HEADING 'Segment|SubType'
COL partition_name      FORMAT A12      HEADING 'Partition|Name'
COL tablespace_name     FORMAT A12      HEADING 'Tablespace'
SELECT
    segment_name
   ,segment_type
   ,segment_subtype
   ,partition_name
   ,tablespace_name
  FROM dba_segments
WHERE owner = 'TRBTKT'
ORDER BY segment_name
;
TTITLE OFF
-- 视图: DBA_LOBS
--显示关于BasicFile和SecureFile LOB的元数据
TTITLE 'BasicFile and SecureFile LOBs Metadata|(from DBA_LOBS)'
COL table_name      FORMAT A14      HEADING 'Table'
COL segment_name    FORMAT A26      HEADING 'Segment'
COL column_name     FORMAT A10      HEADING 'Column'
COL tablespace_name FORMAT A12      HEADING 'Tablespace'
COL logging         FORMAT A08      HEADING 'Logging'
COL cache           FORMAT A10      HEADING 'Cacheing'
COL in_row          FORMAT A07      HEADING 'Stored|In Row'
COL encrypt         FORMAT A07      HEADING 'Encryp-|tion'
COL compression     FORMAT A07      HEADING 'Compre-|ssion'
COL deduplication   FORMAT A08      HEADING 'DeDupli-|cation'
COL securefile      FORMAT A07      HEADING 'Secure|File?'
COL partitioned     FORMAT A07      HEADING 'Parti-|tioned'
SELECT
    table_name
   ,column_name
   ,segment_name
   ,tablespace_name
   ,logging
   ,cache
   ,in_row
   ,encrypt
   ,compression
   ,deduplication
   ,securefile
   ,partitioned
  FROM dba_lobs
WHERE owner = 'TRBTKT'
ORDER BY table_name, column_name
;
TTITLE OFF
--视图: DBA_PART_LOBS
--显示BasicFile和SecureFile LOB的默认值
TTITLE 'BasicFile and SecureFile Partitioned LOB Default Settings|(from DBA_PART_LOBS)'
COL table_name          FORMAT A20      HEADING 'Table'
COL column_name         FORMAT A12      HEADING 'Column'
COL def_cache           FORMAT A12      HEADING 'Cached'
COL def_tablespace_name FORMAT A12      HEADING 'Tablespace'
COL def_securefile      FORMAT A12      HEADING 'SecureFile'
COL def_encrypt         FORMAT A12      HEADING 'Encrypted'
COL def_compress        FORMAT A12      HEADING 'Compressed'
COL def_deduplicate     FORMAT A12      HEADING 'DeDuplicated'
SELECT
    table_name
   ,column_name
   ,def_cache
   ,def_tablespace_name
   ,def_securefile
   ,def_compress
   ,def_deduplicate
   ,def_encrypt
  FROM dba_part_lobs
WHERE table_owner = 'TRBTKT'
ORDER BY table_name, column_name
;
TTITLE OFF
--视图: DBA_LOB_PARTITIONS
--在独立的LOB级描述BasicFile和SecureFile设置
TTITLE 'BasicFile and SecureFile LOB Partitions|(from DBA_LOB_PARTITIONS)'
COL table_name      FORMAT A16      HEADING 'Table'
COL column_name     FORMAT A12      HEADING 'Column'
COL partition_name  FORMAT A12      HEADING 'Stored in|Partition'
COL cache           FORMAT A10      HEADING 'Cacheing'
COL in_row          FORMAT A10      HEADING 'Stored|In Row'
COL encrypt         FORMAT A10      HEADING 'Encrypted'
COL compression     FORMAT A10      HEADING 'Compressed'
COL deduplication   FORMAT A10      HEADING 'DeDupli-|cated'
COL securefile      FORMAT A10      HEADING 'SecureFile?'
SELECT
    table_name
   ,column_name
   ,partition_name
   ,cache
   ,in_row
   ,encrypt
   ,compression
   ,deduplication
   ,securefile
  FROM dba_lob_partitions
WHERE table_owner = 'TRBTKT'
ORDER BY table_name, column_name
;
TTITLE OFF