X$KCCCP

X$KCCCP——[K]ernel [C]ache [C]ontrolfile management [c]heckpoint [p]rogress

SQL> DESC X$KCCCP;
 名称                                                  是否为空? 类型
 ----------------------------------------------------- -------- --------------
 ADDR                                                           RAW(4)
 INDX                                                           NUMBER  -----通常只需要关心indx=0
 INST_ID                                                        NUMBER
 CPTNO                                                          NUMBER
 CPSTA                                                          NUMBER
 CPFLG                                                          NUMBER
 CPDRT                                                  NUMBER ----select count(*) from v$bh where dirty='Y';检查点队列中的脏块数
 CPRDB                                                          NUMBER      
 CPLRBA_SEQ                                              NUMBER  ----最后一次增量检查点中LOW RBA中的序列号
 CPLRBA_BNO                                            NUMBER  ----最后一次增量检查点在LOW RBA中的块数
 CPLRBA_BOF                                           NUMBER  ----最后一次增量检查点在LOW RBA中的偏移量
 CPODR_SEQ                                    NUMBER  ----已写入日志文件的最后一个RBA的序列号=current日志$log.sequence#
CPODR_BNO                                            NUMBER  ----已写入日志文件最后一个RBA的块数
 CPODR_BOF                                                      NUMBER  ----已写入日志文件最后一个RBA的偏移量
 CPODS                                                          VARCHAR2(16)  ---- on disk rba 的 scn
 CPODT                                                          VARCHAR2(20)  ---- on disk rba 的时间
 CPODT_I                                                        NUMBER
 CPHBT                                                          NUMBER             -----心跳，每三秒钟加一
 CPRLS                                                          VARCHAR2(16)
 CPRLC                                                          NUMBER
 CPMID                                                          NUMBER
 CPSDR_SEQ                                                      NUMBER  
 CPSDR_BNO                                                      NUMBER
 CPSDR_ADB                                                      NUMBE

检查点队列中的脏块数

SQL> select cpdrt dirty,cpods on_disk_scn,cpodt on_disk_time,cphbt from x$kcccp where indx=0;
 
     DIRTY ON_DISK_SCN      ON_DISK_TIME              CPHBT
---------- ---------------- -------------------- ----------
        38 2346941          12/27/2009 23:17:56   706789519
 
SQL> select count(*) from v$bh where dirty='Y';
 
  COUNT(*)
----------
        38

当前日志序列号

SQL> select cpodr_seq,cpodr_bno from x$kcccp where indx=0;
 
 CPODR_SEQ  CPODR_BNO
---------- ----------
        33      30160
SQL> select sequence# from v$log where status='CURRENT';
 
 SEQUENCE#
----------
        33

实例恢复的时候会从CPLRBA_SEQ到CPODR_SEQ，高于cpodr_seq的还在log buffer中，未写入redo file 所以不能用来恢复。X$表没有文档，只能先记录这么多了........