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如何从BasicFile迁移到SecureFile存储（一）
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。
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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。
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
报告1 从BasicFIle和SecureFile LOB元数据报告返回的结果
当前题目：如何从BasicFile迁移到SecureFile存储（一）
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