针对这种数据量不匹配的问题：在 DTS 迁移工具中指定源 oracle 数据库的驱动为自动义的且是与 oracle 版本适配的 jdk 版本，因为默认 dts 工具在选择源端驱动时时默认的一个驱动版本，不一定和真实的库完全匹配。
oracle数据库与JDK的版本选择参考如下：
21.1—— ojdbc11.jar with JDK11, JDK12, JDK13, JDK14 and JDK15；ojdbc8.jar with JDK8, JDK11, JDK12, JDK13, JDK14 and JDK15
19.x——ojdbc10.jar with JDK10, JDK11；ojdbc8.jar with JDK8, JDK9, JDK11
18.3——ojdbc8.jar with JDK8, JDK9, JDK10, JDK11
12.2 or 12cR2——ojdbc8.jar with JDK 8
12.1 or 12cR1——ojdbc7.jar with JDK 7 and JDK 8；ojdbc6.jar with JDK 6
11.2 or 11gR2——ojdbc6.jar with JDK 6, JDK 7, and JDK 8(Note: JDK7 and JDK8 are supported in 11.2.0.3 and 11.2.0.4 only)；ojdbc5.jar with JDK 5

可以使用以下sql查询源端和目的端的具体索引信息
SELECT OWNER,INDEX_NAME,TO_CHAR(DBMS_METADATA.GET_DDL('INDEX',INDEX_NAME,OWNER))
from SYS.DBA_INDEXES WHERE
owner NOT IN ('SYSDBA','SYSAUDITOR','SYSSSO','SYS','SYSJOB');
因为DM 默认的表是索引组织表，而Oracle 默认是堆表，迁移后到达梦每个表都会多INDEX开头的索引，用一下sql可以统计排除达梦自身创建的索引（后面用户名自定义更改）
SELECT
A.USERNAME "用户名",
(SELECT COUNT(1) FROM DBA_TABLES B WHERE B.OWNER = A.USERNAME) "表数量",
( SELECT COUNT(1) FROM DBA_VIEWS G WHERE G.OWNER = A.USERNAME ) "视图数量",
( SELECT COUNT(1) FROM DBA_TRIGGERS H WHERE H.OWNER = A.USERNAME ) "触发器数量",
( SELECT COUNT(DISTINCT I.NAME) FROM DBA_SOURCE I WHERE I.OWNER = A.USERNAME AND I.TYPE = 'FUNCTION' ) "函数数量",
( SELECT COUNT(1) FROM DBA_SEQUENCES J WHERE J.SEQUENCE_OWNER = A.USERNAME ) "序列数量",
( SELECT COUNT(DISTINCT L.NAME) FROM DBA_SOURCE L WHERE L.OWNER = A.USERNAME AND L.TYPE = 'PROCEDURE' ) "存储过程数量",
( SELECT COUNT(1) FROM DBA_DB_LINKS M WHERE M.OWNER = A.USERNAME ) "DBLINK数量",
( SELECT COUNT(1) FROM DBA_INDEXES I WHERE UNIQUENESS = 'UNIQUE' AND OWNER =A.USERNAME OR INDEX_NAME NOT LIKE 'INDEX335%' AND OWNER =A.USERNAME) "索引数量",
( SELECT COUNT(1) FROM DBA_OBJECTS WHERE OBJECT_TYPE='TYPE' AND OWNER =A.USERNAME OR OBJECT_TYPE='CLASS' AND OWNER =A.USERNAME ) "自定义类型",
( SELECT COUNT(1) FROM DBA_OBJECTS WHERE OBJECT_TYPE='PACKAGE' AND OWNER =A.USERNAME) "PKG数量"
FROM
DBA_USERS A WHERE A.USERNAME IN ('SYSDBA');