EXECUTE DBMS_STATS.GATHER_SCHEMA_STATS(OWNNAME=>'USERNAME')，收集用户下所有表，索引的统计信息。
SYS@J>EXECUTE DBMS_STATS.GATHER_SCHEMA_STATS(OWNNAME=>'EDMADMIN')

PL/SQL procedure successfully completed.

SYS@J>conn edmadmin/J*****
Connected.
EDMADMIN@JLEDM01>SELECT sum(num_rows) FROM user_tables;

SUM(NUM_ROWS)
-------------
598951038

DMADMIN@J>select sum(num_rows) from user_indexes;

SUM(NUM_ROWS)
-------------
771129407

统计用户下所有表、索引记录数