如何使用events DUMP buffer cache中指定的数据块

介绍了DUMP  buffer cache中全部数据块及指定RDBA的数据块方法。

1.DUMP  buffer cache中全部数据块

ALTER SESSION SET EVENTS ‘immediate trace name buffers level n’;

1 buffer header

2 level 1 + block header

3 level 2 + block contents

4 level 1 + hash chain

5 level 2 + hash chain

6 level 3 + hash chain

8 level 4 + users/waiters

9 level 5 + users/waiters

10 level 6 + users/waiters

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2.DUMP  buffer cache中指定RDBA的数据块方法

BYS@ bys3>select dbms_rowid.rowid_relative_fno(rowid) fileid,dbms_rowid.rowid_object(rowid) obj#,dbms_rowid.rowid_block_number(rowid) block#,deptno from dept;

   FILEID       OBJ#    BLOCK#     DEPTNO

---------- ---------- ---------- ----------

       4     22327        251         10

        4      22327        251         20

        4      22327        251         40

        4      22327        251         99

BYS@ bys3>select dbms_utility.make_data_block_address(4,251) from dual;    --使用此函数算出rdba--就是rowid中的rfile#+block#

DBMS_UTILITY.MAKE_DATA_BLOCK_ADDRESS(4,251)

-------------------------------------------

                                  16777467

BYS@ bys3>alter session set events 'immediate trace name set_tsn_p1 level 5';    --这里的5是表空间号加1得到的。也就是TS#+1。select ts#,name from v$tablespace;

Session altered.

BYS@ bys3>alter session set events 'immediate trace name buffer level16777467';

Session altered.

BYS@ bys3>select value from v$diag_info where name like 'De%';

VALUE

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/u01/diag/rdbms/bys3/bys3/trace/bys3_ora_21011.trc

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