原文地址：https://oracle-base.com/articles/21c/data-pump-enhancements-21c 原文作者：Tim Hall
目录
- 环境准备
- JSON 数据类型支持
- CHECKSUM、CHECKSUM_ALGORITHM、VERIFY_ONLY 和 VERIFY_CHECKSUM 参数
- 同时支持INCLUDE和EXCLUDE
- 索引压缩
- 可传输表空间增强
- 从 Oracle 自治数据库导出
- 从云对象存储导出和导入
本文主要概述了 Oracle Database 21c 中的数据泵增强功能。
环境准备
在可插拔数据库中创建一个 testuser1 用户：
代码语言：javascript复制conn sys/SysPassword1@//localhost:1521/pdb1 as sysdba
--drop user testuser1 cascade;
create user testuser1 identified by testuser1 quota unlimited on users;
grant connect, resource to testuser1;
grant select_catalog_role to testuser1;创建一个新的目录并授予测试用户访问权限：
代码语言：javascript复制create or replace directory tmp_dir as '/tmp/';
grant read, write on directory tmp_dir to testuser1;在测试用户下创建以下表并插入数据：
代码语言：javascript复制conn testuser1/testuser1@//localhost:1521/pdb1
-- drop table t1 purge;
create table t1 (
id number generated always as identity,
json_data json,
constraint ta_pk primary key (id)
);
insert into t1 (json_data) values (json('{"fruit":"apple","quantity":10}'));
insert into t1 (json_data) values (json('{"fruit":"orange","quantity":20}'));
commit;JSON 数据类型支持
Oracle 21C 的导出和导入实用程序已包括对新 JSON 数据类型的支持。
以下示例，通过 expdp 实用程序导出 T1 表，需要注意的是，T1 表需要包含使用新 JSON 数据类型定义的列。
代码语言：javascript复制$ expdp testuser1/testuser1@//localhost:1521/pdb1
tables=t1
directory=tmp_dir
dumpfile=t1.dmp
logfile=expdp_t1.log
exclude=statistics
Export: Release 21.0.0.0.0 - Production on Sun Sep 5 08:41:15 2021
Version 21.3.0.0.0
Copyright (c) 1982, 2021, Oracle and/or its affiliates. All rights reserved.
Connected to: Oracle Database 21c Enterprise Edition Release 21.0.0.0.0 - Production
Starting "TESTUSER1"."SYS_EXPORT_TABLE_01": testuser1/********@//localhost:1521/pdb1
tables=t1 directory=tmp_dir dumpfile=t1.dmp logfile=expdp_t1.log exclude=statistics
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
Processing object type TABLE_EXPORT/TABLE/TABLE
Processing object type TABLE_EXPORT/TABLE/IDENTITY_COLUMN
Processing object type TABLE_EXPORT/TABLE/CONSTRAINT/CONSTRAINT
. . exported "TESTUSER1"."T1" 6.070 KB 2 rows
Master table "TESTUSER1"."SYS_EXPORT_TABLE_01" successfully loaded/unloaded
******************************************************************************
Dump file set for TESTUSER1.SYS_EXPORT_TABLE_01 is:
/tmp/t1.dmp
Job "TESTUSER1"."SYS_EXPORT_TABLE_01" successfully completed at Sun Sep 5 08:41:45 2021 elapsed 0 00:00:28
$我们导入 DUMP 文件，将表名重新映射为 T1_COPY：
代码语言：javascript复制$ impdp testuser1/testuser1@//localhost:1521/pdb1
tables=t1
directory=tmp_dir
dumpfile=t1.dmp
logfile=impdp_t1.log
remap_table=testuser1.t1:t1_copy
Import: Release 21.0.0.0.0 - Production on Sun Sep 5 08:46:32 2021
Version 21.3.0.0.0
Copyright (c) 1982, 2021, Oracle and/or its affiliates. All rights reserved.
Connected to: Oracle Database 21c Enterprise Edition Release 21.0.0.0.0 - Production
Master table "TESTUSER1"."SYS_IMPORT_TABLE_01" successfully loaded/unloaded
Starting "TESTUSER1"."SYS_IMPORT_TABLE_01": testuser1/********@//localhost:1521/pdb1
tables=t1 directory=tmp_dir dumpfile=t1.dmp logfile=impdp_t1.log remap_table=testuser1.t1:t1_copy
Processing object type TABLE_EXPORT/TABLE/TABLE
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
. . imported "TESTUSER1"."T1_COPY" 6.070 KB 2 rows
Processing object type TABLE_EXPORT/TABLE/IDENTITY_COLUMN
Processing object type TABLE_EXPORT/TABLE/CONSTRAINT/CONSTRAINT
ORA-31684: Object type CONSTRAINT:"TESTUSER1"."TA_PK" already exists
Job "TESTUSER1"."SYS_IMPORT_TABLE_01" completed with 1 error(s) at Sun Sep 5 08:46:39 2021 elapsed 0 00:00:05
$CHECKSUM、CHECKSUM_ALGORITHM、VERIFY_ONLY 和 VERIFY_CHECKSUM 参数
计算校验需要花费时间，DUMP 文件越大，计算校验所需的工作量就越大。
Oracle 21C 数据库泵已添加 CHECKSUM 和 CHECKSUM_ALGORITHM 参数，以防止 DUMP 文件的数据被篡改。如果我们设置 CHECKSUM_ALGORITHM 参数，那么 CHECKSUM 参数默认为 yes。如果两者都没有设置，则CHECKSUM 参数默认为 no。CHECKSUM_ALGORITHM 参数可以设置为 CRC32、SHA256、SHA384 或 SHA512，默认为 SHA256。
在下面的示例中，我们启用 CHECKSUM, 并将 显式设置 CHECKSUM_ALGORITHM 为模式导出的默认值：
代码语言：javascript复制$ expdp testuser1/testuser1@//localhost:1521/pdb1
schemas=testuser1
directory=tmp_dir
dumpfile=testuser1.dmp
logfile=expdp_testuser1.log
exclude=statistics
checksum=yes
checksum_algorithm=SHA256
Export: Release 21.0.0.0.0 - Production on Sun Sep 5 08:58:55 2021
Version 21.3.0.0.0
Copyright (c) 1982, 2021, Oracle and/or its affiliates. All rights reserved.
Connected to: Oracle Database 21c Enterprise Edition Release 21.0.0.0.0 - Production
Starting "TESTUSER1"."SYS_EXPORT_SCHEMA_01": testuser1/********@//localhost:1521/pdb1
schemas=testuser1 directory=tmp_dir dumpfile=testuser1.dmp logfile=expdp_testuser1.log exclude=statistics checksum=yes checksum_algorithm=SHA256
Processing object type SCHEMA_EXPORT/TABLE/TABLE_DATA
Processing object type SCHEMA_EXPORT/PRE_SCHEMA/PROCACT_SCHEMA
Processing object type SCHEMA_EXPORT/TABLE/TABLE
Processing object type SCHEMA_EXPORT/TABLE/COMMENT
Processing object type SCHEMA_EXPORT/TABLE/IDENTITY_COLUMN
Processing object type SCHEMA_EXPORT/TABLE/INDEX/INDEX
Processing object type SCHEMA_EXPORT/TABLE/CONSTRAINT/CONSTRAINT
. . exported "TESTUSER1"."T1" 6.070 KB 2 rows
. . exported "TESTUSER1"."T1_COPY" 6.078 KB 2 rows
Master table "TESTUSER1"."SYS_EXPORT_SCHEMA_01" successfully loaded/unloaded
Generating checksums for dump file set
******************************************************************************
Dump file set for TESTUSER1.SYS_EXPORT_SCHEMA_01 is:
/tmp/testuser1.dmp
Job "TESTUSER1"."SYS_EXPORT_SCHEMA_01" successfully completed at Sun Sep 5 08:59:38 2021 elapsed 0 00:00:41
$我们可以使用 VERIFY_ONLY 参数验证转储文件的校验：
代码语言：javascript复制$ impdp testuser1/testuser1@//localhost:1521/pdb1
directory=tmp_dir
dumpfile=testuser1.dmp
verify_only=yes
Import: Release 21.0.0.0.0 - Production on Sun Sep 5 09:10:55 2021
Version 21.3.0.0.0
Copyright (c) 1982, 2021, Oracle and/or its affiliates. All rights reserved.
Connected to: Oracle Database 21c Enterprise Edition Release 21.0.0.0.0 - Production
Verifying dump file checksums
Master table "TESTUSER1"."SYS_IMPORT_FULL_01" successfully loaded/unloaded
dump file set is complete
verified checksum for dump file "/tmp/testuser1.dmp"
dump file set is consistent
Job "TESTUSER1"."SYS_IMPORT_FULL_01" successfully completed at Sun Sep 5 09:10:57 2021 elapsed 0 00:00:01
$在导入过程中，我们可以使用 VERIFY_CHECKSUM 参数来验证校验。如果验证失败，则不会进行导入。如果不使用 VERIFY_CHECKSUM 参数，即使校验不正确，导入也会继续。
代码语言：javascript复制$ impdp testuser1/testuser1@//localhost:1521/pdb1
tables=t1
directory=tmp_dir
dumpfile=testuser1.dmp
logfile=impdp_t1_copy_again.log
remap_table=testuser1.t1:t1_copy_again
verify_checksum=yes
Import: Release 21.0.0.0.0 - Production on Sun Sep 5 09:16:24 2021
Version 21.3.0.0.0
Copyright (c) 1982, 2021, Oracle and/or its affiliates. All rights reserved.
Connected to: Oracle Database 21c Enterprise Edition Release 21.0.0.0.0 - Production
Verifying dump file checksums
Master table "TESTUSER1"."SYS_IMPORT_TABLE_01" successfully loaded/unloaded
Starting "TESTUSER1"."SYS_IMPORT_TABLE_01": testuser1/********@//localhost:1521/pdb1
tables=t1 directory=tmp_dir dumpfile=testuser1.dmp logfile=impdp_t1_copy_again.log
remap_table=testuser1.t1:t1_copy_again verify_checksum=yes
Processing object type SCHEMA_EXPORT/TABLE/TABLE
Processing object type SCHEMA_EXPORT/TABLE/TABLE_DATA
. . imported "TESTUSER1"."T1_COPY_AGAIN" 6.070 KB 2 rows
Processing object type SCHEMA_EXPORT/TABLE/IDENTITY_COLUMN
Processing object type SCHEMA_EXPORT/TABLE/CONSTRAINT/CONSTRAINT
ORA-31684: Object type CONSTRAINT:"TESTUSER1"."TA_PK" already exists
Job "TESTUSER1"."SYS_IMPORT_TABLE_01" completed with 1 error(s) at Sun Sep 5 09:16:30 2021 elapsed 0 00:00:04
$同时支持INCLUDE和EXCLUDE
在 Oracle 21C 中，INCLUDE 和 EXCLUDE 参数可以同时是一条命令的一部分。在以前的版本中 INCLUDE，EXCLUDE 参数是互斥的，只能存在一个。
以下示例在单个命令中同时使用 INCLUDE 和 EXCLUDE 参数：
代码语言：javascript复制$ expdp testuser1/testuser1@//localhost:1521/pdb1
schemas=testuser1
directory=tmp_dir
dumpfile=testuser1.dmp
logfile=expdp_testuser1.log
include="table:"in ('T1')""
exclude="table:"in ('T1_COPY','T1_COPY_AGAIN')""
exclude=statistics
Export: Release 21.0.0.0.0 - Production on Sun Sep 5 10:54:03 2021
Version 21.3.0.0.0
Copyright (c) 1982, 2021, Oracle and/or its affiliates. All rights reserved.
Connected to: Oracle Database 21c Enterprise Edition Release 21.0.0.0.0 - Production
Starting "TESTUSER1"."SYS_EXPORT_SCHEMA_01": testuser1/********@//localhost:1521/pdb1
schemas=testuser1 directory=tmp_dir dumpfile=testuser1.dmp logfile=expdp_testuser1.log
include=table:"in ('T1')" exclude=table:"in ('T1_COPY','T1_COPY_AGAIN')" exclude=statistics
Processing object type SCHEMA_EXPORT/TABLE/TABLE_DATA
Processing object type SCHEMA_EXPORT/TABLE/TABLE
Processing object type SCHEMA_EXPORT/TABLE/IDENTITY_COLUMN
Processing object type SCHEMA_EXPORT/TABLE/CONSTRAINT/CONSTRAINT
. . exported "TESTUSER1"."T1" 6.070 KB 2 rows
Master table "TESTUSER1"."SYS_EXPORT_SCHEMA_01" successfully loaded/unloaded
******************************************************************************
Dump file set for TESTUSER1.SYS_EXPORT_SCHEMA_01 is:
/tmp/testuser1.dmp
Job "TESTUSER1"."SYS_EXPORT_SCHEMA_01" successfully completed at Sun Sep 5 10:54:31 2021 elapsed 0 00:00:27
$索引压缩
在 Oracle 21C 中，我们可以选择使用 TRANSFORM 参数和 INDEX_COMPRESSION_CLAUSE 来进行索引压缩。
首先，创建一个带有一些索引的测试表：
代码语言：javascript复制conn testuser1/testuser1@//localhost:1521/pdb1
-- drop table t2 purge;
create table t2 as
select level as id,
'Description for ' || level as col1,
case mod(level, 2)
when 0 then 'one'
else 'two'
end as col2,
trunc(dbms_random.value(0,10)) as col3,
trunc(dbms_random.value(0,20)) as col4
from dual
connect by level <= 10000;
alter table t2 add constraint t2_pk primary key (id);
create index t2_col1_idx on t2(col1);
create index t2_col2_idx on t2(col2);
create index t2_col3_idx on t2(col3);
create index t2_col4_idx on t2(col4);检查表和索引是否开启压缩：
代码语言：javascript复制select compression
from user_tables
where table_name = 'T2';
COMPRESS
--------
DISABLED
SQL>
column index_name format a12
select index_name,
compression
from user_indexes
where table_name = 'T2'
order by 1;
INDEX_NAME COMPRESSION
------------ -------------
T2_COL1_IDX DISABLED
T2_COL2_IDX DISABLED
T2_COL3_IDX DISABLED
T2_COL4_IDX DISABLED
T2_PK DISABLED
SQL>导出表：
代码语言：javascript复制$ expdp testuser1/testuser1@//localhost:1521/pdb1
tables=t2
directory=tmp_dir
dumpfile=t2.dmp
logfile=expdp_t2.log
exclude=statistics
Export: Release 21.0.0.0.0 - Production on Sun Sep 5 11:57:18 2021
Version 21.3.0.0.0
Copyright (c) 1982, 2021, Oracle and/or its affiliates. All rights reserved.
Connected to: Oracle Database 21c Enterprise Edition Release 21.0.0.0.0 - Production
Starting "TESTUSER1"."SYS_EXPORT_TABLE_01": testuser1/********@//localhost:1521/pdb1
tables=t2 directory=tmp_dir dumpfile=t2.dmp logfile=expdp_t2.log exclude=statistics
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
Processing object type TABLE_EXPORT/TABLE/TABLE
Processing object type TABLE_EXPORT/TABLE/INDEX/INDEX
Processing object type TABLE_EXPORT/TABLE/CONSTRAINT/CONSTRAINT
. . exported "TESTUSER1"."T2" 384.8 KB 10000 rows
Master table "TESTUSER1"."SYS_EXPORT_TABLE_01" successfully loaded/unloaded
******************************************************************************
Dump file set for TESTUSER1.SYS_EXPORT_TABLE_01 is:
/tmp/t2.dmp
Job "TESTUSER1"."SYS_EXPORT_TABLE_01" successfully completed at Sun Sep 5 11:57:35 2021 elapsed 0 00:00:14
$删除源表，以便我们重新导入它：
代码语言：javascript复制conn testuser1/testuser1@//localhost:1521/pdb1
drop table t2 purge;从 DUMP 文件导入表，通过 TRANSFORM 参数组合 TABLE_COMPRESSION_CLAUSE 来压缩使用表，INDEX_COMPRESSION_CLAUSE 来压缩索引：
代码语言：javascript复制$ impdp testuser1/testuser1@//localhost:1521/pdb1
tables=t2
directory=tmp_dir
dumpfile=t2.dmp
logfile=impdp_t2.log
transform=table_compression_clause:"compress basic"
transform=index_compression_clause:"compress advanced low"
Import: Release 21.0.0.0.0 - Production on Sun Sep 5 12:02:22 2021
Version 21.3.0.0.0
Copyright (c) 1982, 2021, Oracle and/or its affiliates. All rights reserved.
Connected to: Oracle Database 21c Enterprise Edition Release 21.0.0.0.0 - Production
Master table "TESTUSER1"."SYS_IMPORT_TABLE_01" successfully loaded/unloaded
Starting "TESTUSER1"."SYS_IMPORT_TABLE_01": testuser1/********@//localhost:1521/pdb1
tables=t2 directory=tmp_dir dumpfile=t2.dmp logfile=impdp_t2.log
transform=table_compression_clause:"compress basic" transform=index_compression_clause:"compress advanced low"
Processing object type TABLE_EXPORT/TABLE/TABLE
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
. . imported "TESTUSER1"."T2" 384.8 KB 10000 rows
Processing object type TABLE_EXPORT/TABLE/INDEX/INDEX
Processing object type TABLE_EXPORT/TABLE/CONSTRAINT/CONSTRAINT
Job "TESTUSER1"."SYS_IMPORT_TABLE_01" successfully completed at Sun Sep 5 12:02:29 2021 elapsed 0 00:00:05
$检查表和索引是否开启压缩：
代码语言：javascript复制conn testuser1/testuser1@//localhost:1521/pdb1
select compression
from user_tables
where table_name = 'T2';
COMPRESS
--------
ENABLED
SQL>
column index_name format a12
select index_name,
compression
from user_indexes
where table_name = 'T2'
order by 1;
INDEX_NAME COMPRESSION
------------ -------------
T2_COL1_IDX ADVANCED LOW
T2_COL2_IDX ADVANCED LOW
T2_COL3_IDX ADVANCED LOW
T2_COL4_IDX ADVANCED LOW
T2_PK DISABLED
SQL>我们可以看到表和索引现在都被压缩了。
可传输表空间增强
在 Oracle 21c 中，可传输表空间导出 (expdp) 和导入 (impdp) 可以使用 PARALLEL 参数来并行化操作。
在 Oracle 21c 中，数据泵可以在故障点或故障点附近恢复失败的可传输表空间作业。在以前的版本中，可传输表空间作业无法恢复。
从 Oracle 自治数据库导出
我们可以使用本地 Oracle 21.3 安装将数据从自治数据库导出到使用该expdp实用程序的对象存储。您可以在本文中阅读有关此功能的信息。
- Oracle 云：自治数据库（ADW 或 ATP）- 将数据导出到对象存储 (expdp)
从云对象存储导出和导入
Data Pump 支持将云对象存储作为转储文件位置，用于从 Oracle 21c 开始的本地安装。
- 数据泵导出 (expdp) 到 Oracle Database 21c 中的云对象存储和从云对象存储导入 (impdp)
