0xe3.e8e5.0] LSCN: [0x0.3a9dcd] HSCN: [0x0.3a9dcd] HSUB: [65535]
LSCN: [0x0.3a9dcd] HSCN: [0x0.3a9dcd] 修改时的SCN--如记录有修改时的SCN，可以转换此十六进制为SCN进行对比
LRBA: [0xe3.e8e5.0] 应该是最低REDO BYTE ADDRES，[0xe3.e8e5.0]对应日志号，块号，第几字节起。也可能会有HRBA ,recovery rba 。
use: [NULL] wait: [NULL] 对应BH中的 users list ; waiters list
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附：
flag中，每位代表如下含义： bit bit
0 buffer_dirty 14 stale
1 notify_after_change 15 deferred_ping
2 mod_started 16 direct_access
3 block_has_been_logged 17 hash_chain_dump
4 temp_data 18 ignore_redo
5 being_written 19 only_sequential_access
6 waiting_for_write 20 prefetched_block
7 multiple_waiters 21 block_written_once
8 recovery_reading 22 logically_flushed
9 unlink_from_lock 23 resilvered_already
10 down_grade_lock 25 redo_since_read
11 clone_being_written 29 plugged_from_foreign_db
12 reading_as_CR 30 flush_after_writing
13 gotten_in_current_mode
class:表示buffer header对应block的类型:
1=data block, 9=2nd level bmb,
2=sort block, 10=3rd level bmb,
3=save undo block, 11=bitmap block,
4=segment header, 12=bitmap index block,
5=save undo header, 13=unused,
6=free list, 14=undo header,
7=extent map, 15=undo block
state:
0, FREE, no valid block image
1, XCUR, a current mode block, exclusive to this instance 正在被当前的instance独占。
2, SCUR, a current mode block, shared with other instances正在被当前的instance共享
3, CR, a consistent read (stale) block image 一致读
4, READ, buffer is reserved for a block being read from disk 正在从磁盘上读取块
5, MREC, a block in media recovery mode 处于介质恢复模式
6, IREC, a block in instance (crash) recovery mode处于实例恢复模式
0,'free',1,'xcur',2,'scur',
3,'cr', 4,'read',5,'mrec',
6,'irec',7,'write',8,'pi', 9,'memory'
10,'mwrite',11,'donated', 12,'protected',
13,'securefile', 14,'siop',15,'recckpt',
16, 'flashfree', 17, 'flashcur', 18, 'flashna'
lru_flag
SYS@ bys3>select distinct(lru_flag) from x$bh;
LRU_FLAG
----------
6
4
8
0
select lru_flag,tch,BA,decode(state,0,'free',1,'xcur',2,'scur',3,'cr', 4,'read',5,'mrec',6,'irec',7,'write',8,'pi', 9,'memory',10,'mwrite',11,'donated', 12,'protected', 13,'securefile', 14,'siop',15,'recckpt', 16, 'flashfree', 17, 'flashcur', 18, 'flashna') status from x$bh where FILE#=4 and DBABLK=251;
select file#,block#,status from v$bh where objd=(select data_object_id from dba_objects where owner='bys' and object_name='TEST') and block#=341892 order by block#;
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