OracleSu ort全球解答的最hot的21个问题(english)

文章作者 100test 发表时间 2007:10:24 13:30:10
来源 100Test.Com百考试题网

Oracle Worldwide Technical Support answers approximately 6000 questionsa week. In the RDBMS support group we find there is often a common theme tothe questions. Following are some of the most commonly asked questions andproblems encountered in the RDBMS technical support group. These questionsare based on problems encountered by relatively new DBAs. Also included　are answers and/or tools to help further identify the problem.

1. Q. What should I do about this warning: "Warning in SQLPLUS "product
information table not loaded"?
A. Run $ORACLE_HOME/sqlplus/admin/pupbld.sql as system (see appendix of
sqlplus reference guide for details).

2. Q. How can users be restricted from issuing DML from SQLPLUS (when within
forms they are restricted but in SQLPLUS they arent)
A. Use the Product User Profile table in SQLPLUS (created by pupbld.sql.)

3. Q. Trying to restore from a full export and getting "duplicate key in
index". Why is this occurring?
A. The DB was not reinitialized before import
recreate DB, run catalog.sql and expvew.sql.

4. Q. Why is performance slow on an particular application?
A. Run EXPLAIN PLAN and Tkprof to gather info about execution plan and
some statistics (this doesnt necessarily solve the problem but will
help to identify it).

5. Q. Why is a tablespace that has been 0dropped still in the Data
Dictionary?
A. It is probably in the DD as invalid...it will remain there unless
the DB is reinitialized.

6. Q. I cant create objects in new tablespaces. Whats wrong?
A. Look in DBA_ROLLBACK_SEGS to be sure there are 2 rollback segments. If
there isnt create another (restart DB with it added to init.ora if
it is private) before creating objects.

7. Q. Why is the private rollback segment that was just created not being
used?
A. If it is private it must be added to init.ora and the DB restarted
before it will be acquired.

8. Q. What do I do when an application is hanging?
A. Use SQLDBA Monitor Locks (also tables and processes) to determine if
the table (or row) is locked and review tracefiles and alert.log for
errors (this doesnt necessarily solve the problem but will help to
identify it).

9. Q. How can you shrink a Rollback Segment?? (Or the variation: arent
Rollback Segments deallocated?)
A. In V6 rollback segments arent deallocated and you must 0drop and
recreate to "shrink" them...in V7 you can specify an "OPTIMAL SIZE"
that the rollback segment will shrink to.

10. Q. How do you move data from one tablespace to another?
A. See page 3-3 of the V6 Utilities Guide (you need to revoke, grant,
alter user,imp)

11. Q. Why is a created Public Rollback Segment not used by the application?
A. If transactions/transactions_per_rollback_segment is less than one
than only one rollback_segment will be acquired and it will be system.
Make the ration of the two be equal to the number of Rollback Segments.